I DRIVE A 93 4.9 and when im doing alot of erreands around town somtimes my car won't start back up I have to let it sit for a bit, then it works again. Is it the Starte motor or is it some thing like a distributor problem?:hmm: :annoyed:

I DRIVE A 93 4.9 and when im doing alot of erreands around town somtimes my car won't start back up I have to let it sit for a bit, then it works again. Is it the Starte motor or is it some thing like a distributor problem?:hmm: :annoyed:
Mine does exactly the same... If it is above 190 and i do not restart it in a few minutes it will not start untill it cools down to some 170... I am planing to put an additional cable to the ground on the engine close to the starter. Perhaps old starter needs more power (current) when it is hot. Another possibility is the battery does not provide enough current when ot is hot. the battery is 5 years old and works well though.

It would be pretty easy to check starter current draw using a clip on inductive current probe. Chances are either the starter is toast or an injector weep is causing vapor lock. By now there would be plenty of techinical service bullitens (TSB's) on the subject. Any non-backyard service facility will need to have some connection with the real world as far as subscribing to online service data. Maybe find a fix-it shop and ask them to pull TSB's on your vehicle.

It would be pretty easy to check starter current draw using a clip on inductive current probe. Chances are either the starter is toast or an injector weep is causing vapor lock. By now there would be plenty of techinical service bullitens (TSB's) on the subject. Any non-backyard service facility will need to have some connection with the real world as far as subscribing to online service data. Maybe find a fix-it shop and ask them to pull TSB's on your vehicle.

What is "an injector weep is causing vapor lock"? and how to diagose that?

That sounds like the start motor commutator (the spinning thingy) is failing. The heat expands the brush contacts (not the brushes, where the brushes contact) and the commutator windings are open at that time. Then it cools and makes a connection again. If you can turn the starter a little, it will work fine.

I can get a replacement commutator at local start rebuild shop for $25. Then I keep my good starter and not get someone elses junk that a resale shop (like Autozone or NAPA) gets from a rebuild shop. They replace enough to get it out the door. Heck, some don't even replace the brushes!!!

I put up with it for about 6 months before it started to leave me stranded. Then I tore it down, resoldered the connection (which you CAN do), but within the next year, it failed the same joint again. It is a common problem the shop told me that the commutators on the 5MT/SD250 staters corrode and open up. Once it starts to spin, it will turn as long as it turns fast enough to pass the open wire. But with that much current you are getting lucky that it turns at all, it opens up almost immediately. Hence the slow starter speeds when hot out. As for parts, you need to find a shop that will sell you parts, no one on the mainstream parts houses do anymore around here.

How to troubleshoot?

Real World: Stick a long bar or shaft down to the starter. You can get to it through the exhaust manifold. Get on the starter, not the solenoid! Have someone turn key and hold, and whack that sucker hard with a hammer and it will kick over and start. Got me off the side of the road, but only a couple times, after that you need it up on ramps and fix it.

Technical Answer: Get out the ohmmeter and ohm from the big wire/bolt on the back of the starter that comes from the solenoid to the starter motor. This one is the one that handles the high current. It should have nearly 0 ohms from that to ground. If it isn't, the starter motor is open, only 3 things there, brushes, commutator and the field windings. Ohm them all if you tear it down. Look for corroision and broken things, make sure it is clean. Be careful when you pull the commutator out of the starter nose, there is a washer that will fall out, note the direction it is pointing. The books don't show it well. I am uncomfortable about greasing anything in there, so I would avoid it.

Basically you don't get a click when it fails bad is the starter windings are the shunt to ground to get the solenoid bendix to engage. So if the starter windings are open, no solenoid action. No starter "kick".

As for injector weep? Never heard of it called that, but my guess is it fills the cyl with fuel and causes a hydro lock. Doubt that is the case. But check for fuel in the oil, you WILL see it if that is the case. Not to mention fast drop of fuel pressure on the rails.

That sounds like the start motor commutator (the spinning thingy) is failing. The heat expands the brush contacts (not the brushes, where the brushes contact) and the commutator windings are open at that time. Then it cools and makes a connection again. If you can turn the starter a little, it will work fine.

I can get a replacement commutator at local start rebuild shop for $25. Then I keep my good starter and not get someone elses junk that a resale shop (like Autozone or NAPA) gets from a rebuild shop. They replace enough to get it out the door. Heck, some don't even replace the brushes!!!

I put up with it for about 6 months before it started to leave me stranded. Then I tore it down, resoldered the connection (which you CAN do), but within the next year, it failed the same joint again. It is a common problem the shop told me that the commutators on the 5MT/SD250 staters corrode and open up. Once it starts to spin, it will turn as long as it turns fast enough to pass the open wire. But with that much current you are getting lucky that it turns at all, it opens up almost immediately. Hence the slow starter speeds when hot out. As for parts, you need to find a shop that will sell you parts, no one on the mainstream parts houses do anymore around here.

How to troubleshoot?

Real World: Stick a long bar or shaft down to the starter. You can get to it through the exhaust manifold. Get on the starter, not the solenoid! Have someone turn key and hold, and whack that sucker hard with a hammer and it will kick over and start. Got me off the side of the road, but only a couple times, after that you need it up on ramps and fix it.

Technical Answer: Get out the ohmmeter and ohm from the big wire/bolt on the back of the starter that comes from the solenoid to the starter motor. This one is the one that handles the high current. It should have nearly 0 ohms from that to ground. If it isn't, the starter motor is open, only 3 things there, brushes, commutator and the field windings. Ohm them all if you tear it down.

Basically you don't get a click when it fails bad is the starter windings are the shunt to ground to get the solenoid bendix to engage. So if the starter windings are open, no solenoid action.

As for injector weep? Never heard of it called that, but my guess is it fills the cyl with fuel and causes a hydro lock. Doubt that is the case. But check for fuel in the oil, you WILL see it if that is the case. Not to mention fast drop of fuel pressure on the rails.

Thanks NODITH! Is there any way to remove the starter without removing the exhaust manifold?

Sure, unbolt it! At least on my 1991 Deville it was easy. I have no idea why the book says to remove the exhaust manifold!

On a Seville or Eldo I don't know, never been under the hood of one.

You will need a 10mm socket, deep 15mm socket, a shallow (regular, not deep) 15mm socket, 3 and a 6in extension, an universal joint. And a 11/32 nut driver or socket or open end wrench.

Disconnect battery, unbolt 3 10mm cover bolts and remove 2 piece cover on flywheel, unbolt rear bolt on starter (deep socket with ujoint) hidden behind crossmember, then front bolt 15mm std socket, (catch any shims if any, mine didn't), drop down starter out the front, don't let the hang on the wires! Disconnect small (11/32") and large (14 or 15mm, probably a 9/16") wires and you have it. Cold engine is helpful, as it gets hot there quick. And if you forget to disconnect battery you will be hot quick!

Another advantage of fixing vs replacing, GM didn't typically use shims (at least non of my cars had any), so measuring for shims is far easier with the original starter, as you don't have to!!! I can get a Deville starter out in about 10-15 min taking my time. They are quite easy, but still not my favorite job.

Thanks NODITH! I'll see if I can get a replacement commutator. Yesterday I had to wait for 45 minutes at a gas station before the starter cooled down enougth to start up....Needless to say it will fail when you need it most! LOL

What is "an injector weep is causing vapor lock"? and how to diagose that?

Er uh, when you shut the hot engine off and the pintle in the injector allows fuel to weep into the engine. The fuel vaporizes and gives the starter a hard time compressing it. Read "vapor lock".

How to diagnose that would be done by a trained person using a good quality oscilloscope set to look at injector waveform. Injectors that work properly produce a Voltage kickback when the injection pulse has ended. This is from mechanical movement of the internal parts. If things are gummed up then the waveform will appear different from the other injector(s).

Er uh, when you shut the hot engine off and the pintle in the injector allows fuel to weep into the engine. The fuel vaporizes and gives the starter a hard time compressing it. Read "vapor lock".
Well... this can explain why one can restart HOT engine in a minute or so after it was shut down but cannot do that if a few minutes passed. Perhaps it takes a few minutes for fuel to vaporize. And when the engine cools down the vapor condenses and allows the starter do the job. Sounds reasonable, but... would not the starter or at least the solenoid make some noise? It is completely silent.
I think NODIH scenario is more appropriate for the described case. what do you think?

On a Seville or Eldo I don't know, never been under the hood of one.


Also very easy to remove on a Seville/Eldorado/Allante. Allante's are the easiest since they've got gear reduction starters that are very small and light weight.

I went back and re-read your original post. I had Assumed that you had a starter which was spinning but slowly. Are you saying that the starter does nothing at all when hot?

Er uh, when you shut the hot engine off and the pintle in the injector allows fuel to weep into the engine. The fuel vaporizes and gives the starter a hard time compressing it. Read "vapor lock".
Cars that I have seen do this usually will crank normally and then drag when it comes to the cylinder with the gas in it. If the gas vaporizes then it should drag at all. Liquids dont compress, but vapor does. Unless all the cylinders are leaking which would be evident by the fuel getting into the oil.

Blaze

I went back and re-read your original post. I had Assumed that you had a starter which was spinning but slowly. Are you saying that the starter does nothing at all when hot?
Yep, starter does nothing when hot. I think it needs to be rebuilt or maybe cavles must be changed /enforced to provide more current to the old starter...

Yep, starter does nothing when hot. I think it needs to be rebuilt or maybe cavles must be changed /enforced to provide more current to the old starter...
When you pull into your house and it wont start back up, try running the garden hose on the starter and see if it starts after a few minutes of that. I have had them start after hosing them.

Blaze

Look in the phone book for starter shops, they are there, especially in bigger cites. I found the one I bought my part from in Pell Lake, WI. Small town, but hey, he was doing good business.

Talk to semi truck repair shops. You think they "buy a new one" when the starter fails? NOT! So they will know where the local rebuild shop is.

If you read the FSM's, they never mention replacement of the starter, only fixing it. That is the best way in my book. Starters, Alternators both are best to be rebuilt than buy rebuilt ones from a store.

The description I had is a common case, and the shop I got my part from said the 5MT/SD250 starter (on all HT4x00 engines and many many more, like Olds 307's, etc) were common to have this exact part fail. They can be repaired, but I don't know how much I trust the repair, unless you use silver solder or something like that. Or braze it. Low temp solder like electronic stuff will get you 6 months or so. So if you are hard up, by all means, you can keep it going on and on like that. Do a good solid job, and likely longer. The shop I was at said he used to repair them, but too many came back, so he went to replacing the commutator and that took care of it.

Thanks NODIH! I'll try to find commutator. Advance has starter repair kit for $12. I am not sure it includes the commutator. If I do not get the part I'll try to repair it with solid solder.

Starter repair kits don't normally. It is as long as the starter, (ok, minus a half inch or so) . I got brushes from NAPA for $1 each ($4 for a box, it takes 4). I recommend them, cheap. You can strip a starter down, rebuild it and back to test (always test!) in maybe 10 minutes. It is very easy. Just note where the bolts go, the washer on the end of the nose of the commutator direction, and make sure the gear is not chipped. The rebuild kit typically comes with brushes and the gear, maybe holders. If the brushes get too worn, they take out the holders. The FSM is great to troubleshoot. if somone has a scanner, have them post from any GM book on the 307 or 4.9L Cad starter. That is the 5MT/SD250 starter. The Chevy engines have a differnet style, but I don't know the breakdown on years. The older cars like the 425/472/500 likely have the old 10MT, the big one. Nothing interchagnes between a 10MT and a 5MT/SD250. I tried..... Now, on the 307, you can use a older Olds 10MT from a 330/350/400/400/403/425/455. But with the lower compression you are just adding weight.

Make sure you don't get a repaired commutator, only a new one. Repairs may or may not last, so I wouldn't risk it.

Starter repair kits don't normally. It is as long as the starter, (ok, minus a half inch or so) . I got brushes from NAPA for $1 each ($4 for a box, it takes 4). I recommend them, cheap. You can strip a starter down, rebuild it and back to test (always test!) in maybe 10 minutes. It is very easy. Just note where the bolts go, the washer on the end of the nose of the commutator direction, and make sure the gear is not chipped. The rebuild kit typically comes with brushes and the gear, maybe holders. If the brushes get too worn, they take out the holders. The FSM is great to troubleshoot. if somone has a scanner, have them post from any GM book on the 307 or 4.9L Cad starter. That is the 5MT/SD250 starter. The Chevy engines have a differnet style, but I don't know the breakdown on years. The older cars like the 425/472/500 likely have the old 10MT, the big one. Nothing interchagnes between a 10MT and a 5MT/SD250. I tried..... Now, on the 307, you can use a older Olds 10MT from a 330/350/400/400/403/425/455. But with the lower compression you are just adding weight. Make sure you don't get a repaired commutator, only a new one. Repairs may or may not last, so I wouldn't risk it.


Thanks NODIH! Still cannot find a commutator. Here is a PDF file from GM regarding SD250 testing.
http://www.v8mr2.com/reference/Starter.pdf

That is it, item 9 on figure 8. Some call it an Armature, which I did, but the starter guy corrected me and said it is a commutator. I don't remember the differences. Even the diagram is conflicting. Item 1 on Figure 8 is the commutator end....

Oh well....

You can get one at the shop by me, he keeps them in stock. $25 is what he charged me. Maybe he would ship it. I have a hard time getting there, as he isn't open when I am around, I am at work most of the time.

That is it, item 9 on figure 8. Some call it an Armature, which I did, but the starter guy corrected me and said it is a commutator. I don't remember the differences. Even the diagram is conflicting. Item 1 on Figure 8 is the commutator end....

Oh well....

You can get one at the shop by me, he keeps them in stock. $25 is what he charged me. Maybe he would ship it. I have a hard time getting there, as he isn't open when I am around, I am at work most of the time.
Yeh, they call it armature and commutator and... I would just call it rotor. I think i have found one for $30.

That spinning thingy works for me...

Make sure you do troubleshoot it before buying parts, in my case I tore it open, repaired it, and drive for 6 months before it finally failed again. But you do want to make sure it isn't a $4 set of brushes first. Or a broken holder., or a shorted field winding (which are often easily repairable ifyou can find them).

That spinning thingy works for me...

Make sure you do troubleshoot it before buying parts, in my case I tore it open, repaired it, and drive for 6 months before it finally failed again. But you do want to make sure it isn't a $4 set of brushes first. Or a broken holder., or a shorted field winding (which are often easily repairable ifyou can find them).
NODIH, looks like the whole piece is called "armature" and there is a commutator on it which consists of 27 bars.

I have found a new armature for SD250 ($30 Made in Mexico), but before buying and going through the installation would like to ask a couple of questions. Could a bad battery, cables, connections contribute to "no crank when hot"? The matter is that some 18 months ago the solenoid clicked but the starter would not turn. I put a jumper from the battery's positive terminal directly to the solenoid's positive assuming the solenoid did not get enough ampers. Never had a problem starting the car when COLD since. Nevertheless, a year ago HOT start cranking problem occurred. It is more pronounced after long drives (an hour or so). There is NO sound at all while turning the key. Looks like some devices got heated thoroughly during the long drive and when I shut the engine down and try to restart in a minute or so... no luck until it cools down. Last time it took 50 minutes to restart. The question is could a five-year-old battery (DieHard Gold) be a problem or a part of problem? It is much easier to replace the battery furthermore the current battery did not owe me a dime. The battery never let me down while starting cold engine. The only unusual sound accmpanying the starting is a clap I did not hear before.

As always any input is appreciated.

I have similar, but different starter problem in my 4.9L, 1995 DeVille. When the engine is hot, the starter rotates, but slowly until it goes over the first one cylinder. Once it starts rotating, it will go as usual and starts right up. I am not sure if this is the right description, but it appears like that to me.

The car always starts, but it really sounds like the starter will be stuck and the car won't start next time. The previous owner replaced the starter (I don't know if the new one was installed or rebuild one was installed...), so I thought this was caused by the bad connection somewhere. I meant I thought the starter itself was fine. As far as I can tell, all connections seem to be fine to me. Since it always starts, I kind of give up on that, but this thread makes me think one more time.

Anyway, what do you think? What would be the most possible cause? Brushes are worn? Or contacts on the rotor are going bad? By the way, when the engine is cold, I have no problem at all. The battery is only a couple of months old.

I have similar, but different starter problem in my 4.9L, 1995 DeVille. When the engine is hot, the starter rotates, but slowly until it goes over the first one cylinder. Once it starts rotating, it will go as usual and starts right up. I am not sure if this is the right description, but it appears like that to me.

The car always starts, but it really sounds like the starter will be stuck and the car won't start next time. The previous owner replaced the starter (I don't know if the new one was installed or rebuild one was installed...), so I thought this was caused by the bad connection somewhere. I meant I thought the starter itself was fine. As far as I can tell, all connections seem to be fine to me. Since it always starts, I kind of give up on that, but this thread makes me think one more time.

Anyway, what do you think? What would be the most possible cause? Brushes are worn? Or contacts on the rotor are going bad? By the way, when the engine is cold, I have no problem at all. The battery is only a couple of months old.

Your situation is different, but the cuase may be the same - things just deteriorate inside and outside of the starter. The electrical resistance of all cables, connections increases, and it naturally increases even more when they are hot. The starter can rotate only if it gets sirtain ampers. It just does not get enough any more when it is hot (and old). I am not sure thermal contraction and expansion has anything to do with the problem... If, say ends of the winding get unsoldered slight contact will melt/burn them completely and you will never get contact no matter hot or cold. Now, what people usually do they replace the starter/solenoid with a rebuilt unit. Replacing means reconnection of old connections which may make them better for a while, so people would think "aha! it was the starter(solenoid)) though actually little changed. What I would do before replacing starter I would reinforce the old cables with jumpers. First, I would put a nice jumper from battery negative post directly to the ground on the engine right by starter.
I believe it is 8x1.25 mm stud, i would just put new stud , star washers, nuts, clean the surrounding area. I have already installed a jumper from positive to the solenoid positive. Otherwise I would get only clic. The jumper bypasses starter enable relay and neutral safety one though. Disassembling the starter, replacing the rotor (aka "armature') brushes etc. is definitely helpful as NODIH noticed.

A few words about the "dynamics" of the hot starter problem... I hav enoticed the problem is the worst after long drives (more than say an hour). If you shut the engine and restart within a minute or so chances are you will do. But if you wait for a few minutes... forget it until it cools down (sometimes for 40-50 minutes!). The reason as I understand is that during long drives the engine and the starter gets a stable temperature and the starter is thoroughly heated up (including the internal parts). As soon as you stop the engine and the starter continue to heat up since there is no wind and coolant circulation and the heat from the internal parts of the engine moves to the external parts. It will take a minute (minutes) for the parts inside the starter to heat up. During that period you stall have a chance to start it up, but later the resistance will get the point the old cables, connections (usually battery too!) won't provide enouth ampers for hot starer. You have to wait until it cools down. Sorry for lengthy speculations, but it is the only support I can provide at this point since it takes a while (sometimes years) for me to address a specific problem unless the car just does not move. LOL

does anyone know if any of
the GM performance parts
for (usually chevy) starters will
work on these caddy starters???

does anyone know if any of
the GM performance parts
for (usually chevy) starters will
work on these caddy starters???
i do not know. The new starter at dealer costs a lot...

Thanks adalla.

Since everything is OK, I mean it always start even when hot, I have left this problem for long time... When I find some time (for some reason, it is harder to do so when the car runs, don't you think?), I will open up the starter and OH it.

:histeric: I think I may haave found the answer to my original question! It seems to have been the Rotor, ANd Distributor. Its only been 2 days but it seems to be running pretty good. My father says it sounds like its "missing" now ..what could that be?:confused:

Er uh, when you shut the hot engine off and the pintle in the injector allows fuel to weep into the engine. The fuel vaporizes and gives the starter a hard time compressing it. Read "vapor lock".



Hmmm. Vapor lock is usually reserved for describing a condition where the fuel in the fuel line, either before the fuel pump with a carb engine or in the fuel rail with a fuel injected engine, vaporizes due to the head and causes a vapor bubble in the line. This causes hard starting on hot restarts due to the fact that the injectors are not delivering liquid fuel. Fuel leaking from an injector will simply cause a rich conditon at startup not a no start for 45 minutes.

From the description I assume that the starter motor will not even turn the engine over when this happens. When it happens, turn on the headlights including high beams or other heavy electrical load. Watch the headlights or the electrical device when trying to crank. If the lights stay nice and bright then that indicates that there is no drag on the system voltage from the starter. If the lights dim severely it indicates that the starter is trying to turn the engine over and is being stalled for some reason.

I suspect that the starter "bendix" or solenoid is failed. That pulls the starter into contact with the flex plate engaging the starter drive and also "makes" the contact that draws the high current from the large battery cable to start the starter turning. If the solenoid windings have an open connection that opens up when hot then the starter will not engage and will not crank the engine.

It's entirely possible that the complete problem that you are having is the starter simply getting old and tired. A new set of brushes and new solenoid (the smaller can on the top of the starter) should put it back into operation. The other option is that the battery is failing. Try jump starting it when this happens and see if it is the battery.

It could also be the cables or ground connection failing due to corrosion or some such problem. It takes a lot of juice to crank a hot engine so if a ground wire is bad it will not carry the load when the engine is hot and the starter draws a lot of current. Try putting a jumper cable directly from the negative terminal of the battery to a ground point on the engine when it will not crank. This adds a redundant ground connection. If the engine will crank with the extra ground lead then the battery ground cable/connection is failing when hot. Check both ends of the ground wire not just the battery end.

Try putting a jumper cable directly from the negative terminal of the battery to a ground point on the engine when it will not crank. This adds a redundant ground connection. If the engine will crank with the extra ground lead then the battery ground cable/connection is failing when hot.

Geno Castellano,

This is exactly what I plan to do before replacing starter/solenoid or parts of them. There is a grounf stud on the engine block right by the starter. Thank you.

thanks

Today I finally had the time to replace the starter on my 4.9. It would not crank (no noise, nothing) when engine’s hot after driving for some 30 plus minutes…It let me down several times in two years… I put an ACDelco remanufactured starter for $120 plus core. Despite I bought an used armature for $30, I did not have the time to disassemble the old starter to see what was wrong with it. I rent a hoist.I will do that before handing it to the store for refund. NODIH, thank you very much for all the information on the subject! As you advised me, I did not remove exhaust manifold to remove the starter as the FSM recommends. Just disconnected all the wires, unbolted the fly wheel inspection cover, starter's shield, two mounting bolts, pushed the starter’s “nose” up and pulled the bottom down. That’s it!
Changes noticed:
1. Old one would just click without a jumper from the battery to solenoid’s positive. The new one has worked fine without any jumper.
2. After driving to home for an hour and trying to start the hot engine (210 F) in 10 minutes after the motor was shut off it would not start. The starter did make some noise but did not crank. Before it would not do any noise under similar conditions. Finally it started at the seventh attempt. UFFFF! At least it did start! LOL
Looks like the next suspect is the battery. It is a five- years-old DieHard Gold. I have never had any problem to start even very cold engine…The voltage is usually 11.7 -12.1.
Questions:
1.What if the battery just gets too hot during long drives and cannot provide enough ampers to the starter?
2. Cold starts are hard on batteries… How about hot starts? Same thing? What if I turn lights on for a couple of minutes before cranking when engine is hot (just like I do in very cold winter mornings) to “wake up” the battery.

Any battery experts able to shed some light?
Thanks in advance.

Today I finally had the time to replace the starter on my 4.9. It would not crank (no noise, nothing) when engine’s hot after driving for some 30 plus minutes…It let me down several times in two years… I put an ACDelco remanufactured starter for $120 plus core. Despite I bought an used armature for $30, I did not have the time to disassemble the old starter to see what was wrong with it. I rent a hoist.I will do that before handing it to the store for refund. NODIH, thank you very much for all the information on the subject! As you advised me, I did not remove exhaust manifold to remove the starter as the FSM recommends. Just disconnected all the wires, unbolted the fly wheel inspection cover, starter's shield, two mounting bolts, pushed the starter’s “nose” up and pulled the bottom down. That’s it!
Changes noticed:
1. Old one would just click without a jumper from the battery to solenoid’s positive. The new one has worked fine without any jumper.
2. After driving to home for an hour and trying to start the hot engine (210 F) in 10 minutes after the motor was shut off it would not start. The starter did make some noise but did not crank. Before it would not do any noise under similar conditions. Finally it started at the seventh attempt. UFFFF! At least it did start! LOL
Looks like the next suspect is the battery. It is a five- years-old DieHard Gold. I have never had any problem to start even very cold engine…The voltage is usually 11.7 -12.1.
Questions:
1.What if the battery just gets too hot during long drives and cannot provide enough ampers to the starter?
2. Cold starts are hard on batteries… How about hot starts? Same thing? What if I turn lights on for a couple of minutes before cranking when engine is hot (just like I do in very cold winter mornings) to “wake up” the battery.

Any battery experts able to shed some light?
Thanks in advance.
I would most definitely check the grounds at the engine block. There is even a service bulletin that tells the mechanic to move the ground from where it is to the starter bracket bolt. There is a little bracket that goes from the back of the starter to the block, use that bolt, clean the connections and put it there. I did that on mine and it fixed a whole host of driveability problems.

Blaze

Oh and check the purple wire goinf from the starter to the Park/Neutral switch, make sure the connections for the park/neatral switch are clean. The computer looks at a lot of stuff from that believe it or not.

Blaze

I would most definitely check the grounds at the engine block. There is even a service bulletin that tells the mechanic to move the ground from where it is to the starter bracket bolt. There is a little bracket that goes from the back of the starter to the block, use that bolt, clean the connections and put it there. I did that on mine and it fixed a whole host of driveability problems.

Blaze
Blaze,

I put a jumper from battery to that gorund stud yesterday while on it... AFTER I arrived home I thought I should have probably put it directly to the starter! LOL I am going to try that today if I convince my mechanic to lift the car one more time. He is a great man I believe I'll try it today. Thanks for heads up!

I would most definitely check the grounds at the engine block. There is even a service bulletin that tells the mechanic to move the ground from where it is to the starter bracket bolt. There is a little bracket that goes from the back of the starter to the block, use that bolt, clean the connections and put it there. I did that on mine and it fixed a whole host of driveability problems.

Blaze

Blaze,
I put a nice 4 guage jumper directly from the battery to one of two starter's mounting bolts. I drove the car for an hour, let it seat for 10 minutes (the worst case scenario to start a hot engine). It started right away! These grounds are indeed essential on 10-plus years old Cadillacs. So far so good. Thanks again!

Blaze,
I put a nice 4 guage jumper directly from the battery to one of two starter's mounting bolts. I drove the car for an hour, let it seat for 10 minutes (the worst case scenario to start a hot engine). It started right away! These grounds are indeed essential on 10-plus years old Cadillacs. So far so good. Thanks again!
I had some serious computer problems that seemed like a much needed tune-up. Then the o2 sensor just quit working. I was losing ground at the cable on the block. There was a service bulletin to relocate to the L-bracket thing on the back of the starter so I did that and it retified a bunch of problems. Although my latest problems was with injectors and now that is solved.

Blaze

There was a service bulletin to relocate to the L-bracket thing on the back of the starter so I did that and it retified a bunch of problems.

Is this SB for all 4.5/4.9's? I havn't heard of it, and mine didn't get it. SB Chevies often got this bracket, I wonder if is the same one.

I am wondering if we are seeing possibly corroision on aluminum mounting points of various electrical grounds and bolts that are transmitting the electricity from one part of the engine (through the aluminum via bolts and gaskets) to another might be starting to fail with age.

It covers 1990 4.5 PFI engines and 91-94 4.9's

Blaze