: Starting troubles



MauiV
02-04-11, 11:53 AM
Over the past few weeks on 3 different occasions my car has had trouble starting. Takes between 3-8 minutes before it will fire. All electronics are working. It has always been when the car is sitting off for a short period of time, pump gas, run into a store. This morning I started the car (didnt act exactly normal, I credited cold weather) in the garage, walk inside to grab a few things and when I come back out the infamous low oil pressure slot machine lights are blinging. I check out the car smell oil no where and figure the sensor (installed less htan 6 months ago) is bad again . On my 23 mile commute the oil pressure varied from 3psi to 15 most of the trip, then by the time I got to work it was up to 55.

I just went out to give it a try and its doing the same thing again, only this time the car has been sitting for 3.5 hours and the oil and water temp both show int he high 80's.

Only thing I could think of originally was if a temp sensor is bad and so Im not getting enough fuel to the engine to fire when cranked. The oil thing now has me wondering if the oil pump possibly going bad and contributing?

MauiV
02-04-11, 12:22 PM
P.S. oil pressure shows 28 with key in on position now.

darkman
02-04-11, 12:29 PM
The hard starting after a short shut down may be a leaky fuel injector (continues to flow after the ignition is turned-off).

MauiV
02-04-11, 02:48 PM
Crank position sensor? Fuel pump or filter clogged? Some at work mentionefd their Subaru required a security system reset to get a spark. Where is the fuel filter located? No fuel smell at all after multiple attempts to start.

darkman
02-04-11, 03:02 PM
See attached.

MauiV
02-04-11, 07:33 PM
Car started when I left work. Oil pressure fluctuated between 5 and 67 and seems to be higher at highway speed. Car still runs strong and no other problems so I guess its just another bad oil pressure sensor.

Is there an intake temperature sensor in the MAF or TB? Any possibility that if it isnt showing cool enough it wont allow the engine to fire? I am not getting any codes. Any thing other than the clogged filter that would keep the engine from either sparking or sending fuel?

darkman
02-04-11, 08:40 PM
See attached.

MauiV
02-04-11, 09:30 PM
Thanks. Now all I need is a scan tool!! LOL

darkman
02-04-11, 09:38 PM
Thanks. Now all I need is a scan tool!! LOL

Yeah, I know the stuff I found isn't all that useful. If you have not done so already, the next time it is not starting you might - (a) pull a plug wire and put in a spare plug to see if it is getting spark while it is being cranked; and then (b) pull one of the injectors and see if it squirts while being cranked. It would be nice to know if you are chasing a spark or fuel related problem. Intermittent symptoms are a pain.

MauiV
02-08-11, 06:01 PM
Fuel filter replaced. After a few cycles through trying to start it fired up a few times, then when we tried to to leave it running it died and wont restart. So its firing and getting gas.

MAF? Going to try to clean it before replacing with an $85 model available at Advance (ACDelco $210)

Checked all the fuses we could think of. Any other ideas? Any other sensors? My O2's are tuned off.

MauiV
02-08-11, 07:57 PM
MAF replaced, didnt change anything.

Fuel pump? Im guessing its in the tank so that will mean a trip to the shop to see if they can chase this thing down. Fuel vents off the fuel rails on the Maggie but I know they hold quite a bit anyway. Magnavolt burn up the oem pump? Would that make the problemintermitant at first? Air bubble in the fuel line between the new filter and the injectors reason for not firing now?

When it did fire coincidently the fuel pump fuse was pulled then reinstalled, couldnt reproduce it though.

Any chance its the starter? Reading a recent starter thread the symptoms sound very similiar.

I am running out of ideas.

TIA

CancerJCC
02-09-11, 12:54 AM
Is there an intake temperature sensor in the MAF or TB? Any possibility that if it isnt showing cool enough it wont allow the engine to fire? I am not getting any codes. Any thing other than the clogged filter that would keep the engine from either sparking or sending fuel?

Stock the IAT sensor is integrated into the MAF. After Maggie install it is broken out and installed at the passenger rear of the blower. There should be no reason that temperature is causing a no start. Although there are various tables that will add fuel in the event of high IATs or ECTs. I don't think you are on the right track with these items though.


Fuel filter replaced. After a few cycles through trying to start it fired up a few times, then when we tried to to leave it running it died and wont restart. So its firing and getting gas.

MAF? Going to try to clean it before replacing with an $85 model available at Advance (ACDelco $210)

Checked all the fuses we could think of. Any other ideas? Any other sensors? My O2's are tuned off.

Try disconnecting the fuel line at the quick disconnect on the Maggie end. You will need to extend the line but you can then run the pump by turning on the key to see if the fuel pump is your problem. Although (trying to get my head wrapped around all of the things you stated without being there) if it is running fine sometimes your fuel pump is fine.

You REAR o2 sensors are turned off as they are for emmisions only. Your front o2's are still on and help to control light throttle fueling. (Just FYI). Also if they died the car would still run but you would get a P code...


MAF replaced, didnt change anything.

Fuel pump? Im guessing its in the tank so that will mean a trip to the shop to see if they can chase this thing down. Fuel vents off the fuel rails on the Maggie but I know they hold quite a bit anyway. Magnavolt burn up the oem pump? Would that make the problemintermitant at first? Air bubble in the fuel line between the new filter and the injectors reason for not firing now?

When it did fire coincidently the fuel pump fuse was pulled then reinstalled, couldnt reproduce it though.

Any chance its the starter? Reading a recent starter thread the symptoms sound very similiar.

I am running out of ideas.

TIA

I don't think the MAF is your problem either (although you say you replaced it). There are a number of fail safes within the areas you are chasing that catch each other. For instance, MAF failure and your VE table takes over (still runs) plus you get a code. Or vice versa...

Keep feeding us information and hopefully we can come up with something! (Sorry I missed this thread but I'll check in more often now).

Good luck!

MauiV
02-09-11, 01:56 AM
I went out about 30 mins ago just to fire it up and of course it caught on the 2nd crank. Its still running to let it get up to operating temp and seems to be no problems. The oil pressure at start up was --- and right now its bouncing all over the place 13-23-32-15.

Like I said before this is at least the 2nd Oil Pressure sensor and the last time it failed I droe it for almost 2 years with no problems so I have been considering it a coincidence but does a 0 indication keep from igniting?

I have read the failed starter thread and it sounds like very similiar problems but mine doesnt just click it actually sounds like trying to start in really cold weather or with a dying battery. Not just the click-then nothing.

Its still running right now so obvioulsy its geting fuel, spark and oil. Im just wondering what its not getting the other 95% of the times I've try to crank it this past week.

Thanks guys

MauiV
02-09-11, 02:50 AM
Drove to the post office then around town a bit, brought it home, shut her down and restarts. Let her sit for 10-15 mins (the first 3 times it was short periods off) and she restarted. I am getting "Service Vehicle Soon" message on the Nav screen on start up and the scan tool I have isnt picking up anything but Im guessing its that the oil pressure is showing ---, I dont remember if it did that or not last time. If it seems to run normal tomorrow I will see if I can get it hooked up to a TechII.

I REALLY hope this gremlin has worked itself out. Is it possible there was a air bubble between the new fuel filter and the injectors after the install?

The randomness of this has me perplexed. I really want to lean to the starter but the fact it cranks instead of "clicks" has me still chasing sensors.

Stepside
02-09-11, 09:18 AM
??-:suspect:--flickering oil pressure, slow cranking, intermittent starting, and possibly cold weather affected . .

Sounds like a bad ground connection to me.

Clean all your ground connetions between the engine and body.

ewill3rd
02-09-11, 09:23 AM
You need to quit all this stuff and start over with the basics.

You need 3 things for an engine to start. Spark, Fuel, and compression.

Compression: Since the engine runs periodically (without issue from what I read) it is likely that you have good timing and nothing like broken valve springs or things of that nature so the compression issue is not necessarily a factor.

Spark: You need to test for spark when the no start condition occurs. For that you need a real spark tester. An ST-125 is the tester of choice for a GM car.
http://www.thetoolwarehouse.net/p-2460-k-d-tools-2756.aspx
It looks like that. You clip the clamp onto a good ground and I bet you know where the other end goes. If it has spark on this then you are good. If not then you do have lots of systems to check, cam and crank sensors, power systems, engine controls, etc. The key is to first identify which system is at fault and then to pinpoint tests to find the source. I can tell you I have been seeing issues where the cam gear bolts back out and that pushes the camshaft reluctor out of range of the sensor, you should see codes if this is happening but it could cause something similar to what you describe.

Fuel: The best test here is to install a fuel pressure gage. Key on the fuel pump should run for 2 seconds then stop. Pressure should hold and not fall off too quickly. You might lose a couple psi over a 10 minute period but anything more than that would indicate a fuel system leak. from there you'd have to pinpoint the source by removing the fuel rail or shutting off sections of the fuel system.

Once you establish the source of the problem we can all help you more.

MauiV
02-09-11, 02:20 PM
Running like a champ this morning. Stopped and talked to a guy at the local dealer that said fuel pump failure after topping off is a sign that the pump is about to fail. 2 of the times I had trouble starting were either immediatly after a fill up or the 1st start after since I filled with it running. The other times the car was on slight uphill grades. My garage is a slight up hill grade so I just pulled in the drive and shut it down, no start. Let it roll back to flat ground and it started. Car was backed in last night and started fine this morning (other than the "Service Vehicle Soon" message). Car has 118,XXX miles and about 65,XXX+ of that with the MagnaVolt attached. Fuel pump finally giving up?

Ill be surprised if I have hair left after this.Thanks for the input guys.

CancerJCC
02-09-11, 03:08 PM
??-:suspect:--flickering oil pressure, slow cranking, intermittent starting, and possibly cold weather affected . .

Sounds like a bad ground connection to me.

Clean all your ground connetions between the engine and body.


Running like a champ this morning. Stopped and talked to a guy at the local dealer that said fuel pump failure after topping off is a sign that the pump is about to fail. 2 of the times I had trouble starting were either immediatly after a fill up or the 1st start after since I filled with it running. The other times the car was on slight uphill grades. My garage is a slight up hill grade so I just pulled in the drive and shut it down, no start. Let it roll back to flat ground and it started. Car was backed in last night and started fine this morning (other than the "Service Vehicle Soon" message). Car has 118,XXX miles and about 65,XXX+ of that with the MagnaVolt attached. Fuel pump finally giving up?

Ill be surprised if I have hair left after this.Thanks for the input guys.

You can easily hear if your fuel pump is kicking on and off when you turn the key. When it no starts does it crank and not start or just nothing? (Can't remember)

+1 on the grounds. It might not cure your problem but grounding offsets can cause all sorts of crazy issues.

As to what Bill said I completely agree with him. Especially on the fuel pump, I believe you can rent fuel pressure gauges as well and the port on the maggie rail would make hook up a breeze.


Oh just had another thought. Connect the magnavolt splice back to factory (eliminating magnavolt completely) and see if any start issues are present. This way you eliminate the magnavolt as not completing your connection and thus being intermittently faulty. Just do this at idle though as the magnavolt doesn't come in until 3k RPM I believe and so you will be safe.

V-Guy
02-09-11, 09:01 PM
You can easily hear if your fuel pump is kicking on and off when you turn the key. When it no starts does it crank and not start or just nothing? (Can't remember)

+1 on the grounds. It might not cure your problem but grounding offsets can cause all sorts of crazy issues.

As to what Bill said I completely agree with him. Especially on the fuel pump, I believe you can rent fuel pressure gauges as well and the port on the maggie rail would make hook up a breeze.


Oh just had another thought. Connect the magnavolt splice back to factory (eliminating magnavolt completely) and see if any start issues are present. This way you eliminate the magnavolt as not completing your connection and thus being intermittently faulty. Just do this at idle though as the magnavolt doesn't come in until 3k RPM I believe and so you will be safe.

Man, bro. I wish I knew 10% of what you do about these cars. If I could do a Vulcan mind weld with you and Brian (PISNUOFF) and darkman, I'd be a lot better off. (And so would my car.)

MauiV
02-09-11, 09:09 PM
Of course its back to cranking, coughing but not running, like its starving for gas. I am going to try to find a fuel pressure gauge in the A.M. I presume it just screws into the port on the passenger side fuel rail?

I know the pump stops after 2 seconds but should I leave the key on for the 10 minute test or shut it back off?

What is the normal pressure it should read?

If it is the fuel pump I was just browsing prices online, new pumps run from about $260 to $550ish. I found a Racetronix system at Thunder Racing and wonder if I should just upgrade and I guess I could get rid of the MagnaVolt? r just replace with an OEM style and keep it as it is. My local garage charges $150 to drop the tank + pump cost so not too bad.

MauiV
02-10-11, 11:29 AM
N/M got it to fit

Chris0nllyn
02-10-11, 11:50 AM
Not sure about the oil pressure issues, but I had a truck that did the slow start issue...after throwing TONS of money at it, I replaced the injectors (I had put a new set in). Come to find out, the injectors I got were bad and stuck open.

I found out by removing the plugs and turning the motor over by hand....fuel squirted out of the plug hole all over the place...

CancerJCC
02-10-11, 06:25 PM
Man, bro. I wish I knew 10% of what you do about these cars. If I could do a Vulcan mind weld with you and Brian (PISNUOFF) and darkman, I'd be a lot better off. (And so would my car.)

All I know about the V specifically comes from reading, reading, and a bit of experience. Mechanical background comes from my father and his DIY ways. Saturday mornings I hated him when we had a "project" but now I really appreciate all the knowledge he passed on to me!


Of course its back to cranking, coughing but not running, like its starving for gas. I am going to try to find a fuel pressure gauge in the A.M. I presume it just screws into the port on the passenger side fuel rail?

I know the pump stops after 2 seconds but should I leave the key on for the 10 minute test or shut it back off?

What is the normal pressure it should read?

If it is the fuel pump I was just browsing prices online, new pumps run from about $260 to $550ish. I found a Racetronix system at Thunder Racing and wonder if I should just upgrade and I guess I could get rid of the MagnaVolt? r just replace with an OEM style and keep it as it is. My local garage charges $150 to drop the tank + pump cost so not too bad.

Fuel pressure should be at 58 psi on LS motors.

Upgrade for sure while you are in there! The magnavolt is a band aid by nature and if you can run with just a pump and injectors it is one less piece of the puzzle that can go bad. BTW did you rule out the magnavolt by bypassing it? Pretty hard to test things if you don't isolate them one by one. (ie. injectors, fuel pump, magnavolt).


Not sure about the oil pressure issues, but I had a truck that did the slow start issue...after throwing TONS of money at it, I replaced the injectors (I had put a new set in). Come to find out, the injectors I got were bad and stuck open.

I found out by removing the plugs and turning the motor over by hand....fuel squirted out of the plug hole all over the place...

Strange for MauiV though as he has had his for a while. Not that it couldn't be a sticky injector for sure. Its to bad he doesn't have HP Tuners and he could look at Inj. pulse width on each bank and see if there was any variance...

MauiV
02-11-11, 12:28 AM
Well it looks like the mystery may in fact be solved. Got my hands on a fuel pressure test kit this morning and bled the system, hooked it up and of course the car starts and shows 50psi, but not hte 55-61 a LS6 should have. Cant get the car to die before I leave for work (when I want it to not start I cant get it to die). Got home tonight, bled the system, no fuel at all out of the rail, hook the gauge up and crank, nothin. Set the key to on and check the gauge...... dead set on ZERO. Going to run by my garage in the morning and make sure they can install the Racetronix 255 set up with no problem (they are all gear heads with muscle cars so Im not expecting a problem) and they only charge $150 to drop the tak, so that + $159.99 for the pump + $59.99 for the harness + $15 I think I read for the Magnavolt to plug and play and this should be rather painless on the wallet.

Thanks for all the help and getting me refocused on the basics. Much appreciated.

P.S. The car had to have gas added after the Maggie rebuild and install after sitting for a month with very low gas and one other time it died while coasting into a gas station with our phenominal fuel gauge showing slightly less than an 1/8th of a tank. Apparently that combined with a Magnavolt and 118,XXX miles is enough to kill the pump.

ewill3rd
02-11-11, 08:29 AM
If it has a magnavolt, stop everything and look at the connector. Unplug it and look at the white wire.
If it is melted you can get a service connector and fix it.
(I think it is white, it may not be)
This would cause your problem if it were melted. Most of he newer installs don't have the magnavolt.

Fuel pumps don't customarily fail part time. When they go they go, but you could have a connection issue anywhere. Don't make the investment of a new pump and leave bad wiring.

MauiV
02-11-11, 10:38 AM
Is there a fuel pump relay? Cant that cause intermitent working? I am on my way out the door to work so I will check it out later. I didnt install my Maggie so Im no real sure how all of the Magnavolt is wired up but I think its on magnasons site.

Thanks

MauiV
02-11-11, 01:45 PM
Will strikes again! There's a reason we all wish Lindsay had a traveling service dept. Pulled the connector and sure enough the gray wire was brown around the "prong" (top right one). I guess this can be ordered from Magnason? Or should I replace the whole unit? When it was running the pressure was only 50.

ewill3rd
02-11-11, 11:41 PM
You can get a GM "pigtail connector".
Hang on, let me see if I can find it.

Gah, I am looking here, is that an 8 way connector?
http://www.acdelcotechconnect.com/pi/wiring-connectors/gm/pigtails/8-cavity/female/

Anyway, if you can find the pigtail part number here is what you do.
Open the taping on the wire bundle, then cut it back about 6 inches, just the gray wire.
Get the new pigtail and remove all the wires except the one that matches the location of the gray wire, cut it to length and splice it together.
Disassemble the old connector and transfer one wire at a time to the new connector body. This way you only have to cut the one wire that is melted and all the other stuff stays healthy.
You may research options to remove the magnavolt because it may do this to you again someday.
Only too glad to help, if you can't find the connector let me know and I will find one for you.
Luke may know if you PM him, if not he can bug me too.
It should be good if you replace this as I indicated and be sure the male terminals are clean in the magnavolt.

Twitch
02-12-11, 09:31 AM
Damn, sorry I didn't see this earlier. I had the same issue this past summer. Few times it didn't start, few times it just died on me when pulling away from a stop. It was also the connector on the Magnavolt. Top corner wire looked burnt (forget which side). When I took it apart, I noticed the connecting piece that should have been sprung like a V (sorry for the dopy way I described it) was flat. Obviously this caused a bad connection and a lot of heat. Fixed it, cleaned it real good to get a good metal to metal connection and she's been running great since. I did not replace anything.

Man, reading this whole thread was like watching a slasher movie knowing whats gonna happen next. "No, don't go through that door", "don't buy a new pump".

MauiV
02-12-11, 03:31 PM
PT1208 15306048 6th row, middle LOOKS pretty close but it isnt white Im gonna try Twitch's remedy here in about an hour.

CancerJCC
02-13-11, 05:41 PM
PT1208 15306048 6th row, middle LOOKS pretty close but it isnt white Im gonna try Twitch's remedy here in about an hour.

Magnavolt, not suprising. If you had isolated like I said I would have beat Bill to the punch though! :kick: J/k Can I have a consolation prize though?

MauiV
02-14-11, 11:00 PM
Much thanks for all the help to everyone. The funny thing is the Magnavolt wiring was one of the first things checked. The crimps, the fuse box connector, the red wire plug just not the plug into the actual Magnavolt itself.

CancerJCC
02-15-11, 12:01 PM
Much thanks for all the help to everyone. The funny thing is the Magnavolt wiring was one of the first things checked. The crimps, the fuse box connector, the red wire plug just not the plug into the actual Magnavolt itself.

N/P Just glad you got it all figured out! I like these sort of threads because then when mine starts acting up I have a few "easy" things to check...

Are you still going to drop your tank and upgrade the pump?