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5K views 38 replies 5 participants last post by  daedalus__ 
#1 ·
Hey guys. I bought a '93 Sedan Deville last week. It seems to run good. Shifting feels smooth, acceleration is quick, and gas mileage is great. However, it does have some issues that I am trying to figure out.

In the morning when I start her up, she usually idles smooth and is very responsive. As the car warms up and I start driving her that will change. When I stop at a light I'll get some shaking from the motor. It seems to be fine while it is driving though. It is particularly bad after my long drive home.

I went ahead and replaced the spark plugs, plug wires, rotor cap, and coil. The plugs were red when I pulled them out. The contact and the part that holds the electrode. The coil was toast also. It seems to run better and is more responsive but still shaking.

Sometimes when I get in the car, before I turn the radio on I can hear a whistle coming from the dash (almost sounds like it's through the vents). I tried to go listen for the whistle under the hood but I can't hear it or it isn't something on the engine. I almost want to say that perhaps is a vacuum leak but I can't find any lines or hoses that are obviously damaged. One thing that I know is wrong is that the back of the car is sinking and I can hear compressed air when the compressor is running.

This coming payday I am going to replace the O2 sensor ($20 :D) and buy a compression tester.

I've had a service engine light a couple of time so I keep pulling the codes the best I know how. So far I have seen:

E00
E39
E47
E52
E70

and something that looks really exactly like this (found this on another forum)

..F F47 .F.F F47 .7.0 .8.8.8

So I was reading around the forum and someone had a similar problem and said that they replaced their ECM. I was thinking that maybe I should do the same because the engine seems to run good it just likes to act up here and there. Is there a way I can check to see if my ECM is working properly?

I'm mechanically inclined but inexperienced so I appreciate any help or advice.

I was also wondering if there are any ways to increase my gas mileage. I swear there used to be a thread about it a long time ago but I couldn't find it.

Thanks!
 
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#3 ·
Your model the ECM is called a PCM (Powertrain Control Module) There is also, the BCM (Body Control Module). As you can see from the codes, the DATA line between them is a problem. It could all be intermittant wiring and dirt. Make sure all GND points are Clean and tight.

E00 = START OF CODE DISPLAY SEQUENCE
E39 = VCC engagement problem-
E47 = BCM-PCM Data Problem
E52 = PCM memory Reset
E70 = Intermittent TPS (Throttle Position Sensor)

..F F47 = HISTORY - LOW REFRIGERANT
.F.F F47 = CURRENT LOW REFRIGERANT
.7.0 .8.8.8 = end of codes

As you can see, A/C needs some FREON.
The rough ride may be due to faulty Throttle Position Sensor (TPS)
and then there is a possible problem with your Trans Clutch slipping. Lots of Diagnostics involved with that in the FSM.

Consider getting a FSM on Ebay if you want to start doing your own work, otherwise you will forever be in the dark, just guessing. Compression check is not going to solve the TCC/VCC problem. You will need to get a good VOM to help you check the wiring to and from the BCM-PCM as almost all diagnostic charts call for voltage and resistance readings at certain points in the connectors, etc.
I can help you some since I do have the FSM for your model but you will do better with your own copy. Start with the TPS, check the wiring to make sure it is plugged in properly and clean the throttle body with a toothbrush and some solvent for that purpose. Most of all, have fun.:highfive:
 
#8 ·
Yeah I think I have seen that ground before, very cute place to put it. I really liked the water pump on my 4.9 also.

Checking the grounds is a really good idea so I will do that. I've noticed that when I start the car most of the time the starter turns for a while before it will start unless I back off the key, then try starting again. On the second try it fires right up like the ignition system is brand new. I'm not really sure what that is about. I thought that replacing the cap and rotor and coil would fix that but it didn't.

Does anyone know what the whistle from the dash is about? I've noticed that it does it mostly when the car is in drive or reverse, and sometimes if I put it in neutral it stops. I really hope it isn't the transmission but I don't really know anything about transmissions.

Also, I always have fun when I work on my car :)

Unless I drop things in those rails under the motor :(
 
#12 ·
Yeah, I was thinking about it after work and I think you could be right because the parking brake does not disengage when I put it into gear, I have to pull the lever. I'm actually going to go look at it, the TPS, and the grounds literally right this second. Today on the way home, twice, I came to a stop from 50+MPH and when I went to step on the gas it was in neutral and popped into gear. =\
 
#16 ·
I hate to say this but if those tubes (EGR stack tubes) are that gunked up, chances are so is your EGR valve. So maybe while you are at it, that should be removed and it can be dry scoured (no liquids) and checked, too. Also, the FSM says to clean the stack tubes with a 11/32" drill bit if you just "happen" to have one lying around. It scrapes the sides a little better than a "coat hanger", but whatever works for you. Then there is the problem of loosening up all that gunk and then having it clog the EGR valve on it's way out. With the EGR removed however you can just blow the stuff out with an air hose to get rid of it before you start it up. Your car is going to love you for all this cleaning you are doing.
 
#17 ·
Okay I did and there was a horsepower and MPG gain. :) While I was cleaning it I noticed what the problem is. When I gave it just a little bit of gas the motor started breathing so there is a vacuum leak somewhere. I'm not good at finding those, I don't really know how. Is there a way I can track it down without having to replace all the hoses? I'm going to get a compression tester and hope it's not the head gasket. :)

Thanks for all the help so far!
 
#20 ·
The FSM also states "be careful not to drill through the intake manifold" I guess they intend for you to use the drill with it if you have the electricity handy, but I just used it manually to ream it.

ONE MORE, if you do end up taking off the EGR, you'll need a new gasket for it and like really clean the mating surface where it seats down to clean metal. In fact,if the current gasket is too worn out already, that could be where your vacuum leak is. Just a thought.
 
#19 ·
All the vacuum hose "circuit" should be on a label under your hood somewhere like near the radiator. it is possibly covered with dirt and if you start wiping away you'll find it. Just check all the vaccuum hoses visually to see if they are cracked and falling apart. Anything that is not a wire or clearly a water hose or A/C is probly a vacuum line. Also doesn't hurt to do the compression just for your peace of mind. FYI, I got a good deal on the screw type Gauge, with extra fittings, for $25 on sale, used it once for all cylinders and that was all. LOL! God was it a B--ch getting at those 4 cylinders next to the firewall. Houdini had nothing on me. But at least I was happy to know all cylinders had good compression.
 
#21 ·
yeah i did my spark plugs the other day let me tell you i was laying across the engine and shit. lol. i checked all the hoses and stuff today they all look kinda fresh, nothing torn or too dirty. the label is there and it's clean so i'll look around. i guess i just have to do the compression test and then start replacing hoses cause it's there but it's gotta be really small. i can't hear it over the engine and it doesn't breathe unless i press the throttle just right.

yeah you know you could be right because the EGR valve seems to be one of the older parts on the car. there is a lot of stuff that really needs to go on it but i'll get to it. i'm gonna look at it all more tomorrow cause i have a friend to help :)

so i guess if it is okay to run a drill through there that i could ream the stacks a little bit bigger. i wonder if that would make the car happier? i don't really understand every part of an engine yet.
 
#25 ·
the only thing i use the chiltons for is if i need to know what something looks like or i can't find it. lol. i learn the most when im trying to take something off and i have to go through the 50 parts in front of it. im going to get that FSM. but it's 3 days until payday and im completely out of gas and cash :(

so i noticed that when i am trying to start the car that if i give it a little gas it won't take 50 turns to start. what could that be about? should i check my fuel pressure? or could that be hinting at where my vacuum leak is? the fuel lines in the engine bay look okay but i don't think i found them all.

i also noticed that the charcoal can in the car is the stock one so i think i should change it? im not actually sure what it does but i know charcoal is used as a filter for some things
 
#27 ·
Your car should have 45-50 psi fuel pressure.
On your Fuel Pressure Regulator take the little vaccuum hose that goes to the throttle body off and inspect for gas leak. There should not be even a drop. If there is gasoline there you will need to change it out. That would explain the vacuum leak and the slow 50 crank start.. Lots of threads about that one. Common problem.
U could check fuel pressure also with a gauge but if it reads low, again either the FPR or fuel pump is a problem. My money is on the FPR if it is below 45-50 PSI

The charcoal canister is part of the EGR system, probably would love a new one but IDK, I'd think that is the least of your worries right now. Check for DTC again to see if the EGR is still throwing a code.
 
#28 ·
well now this is starting to make sense because the computer says i get 24-28 mpg highway but it seems like a lot less because it'll say i used 2.4 gallons but my tank meter will says i lost 4. its driving me crazy.

also i was thinking about the reaming the stacks thing. if i ream them too big will the engine have trouble pulling air and things through them?
 
#29 ·
you can ream them down to the brass metal but don't go farther than that. Lol! get ALL the crud off with that drill bit. but remember the EGR valve itself maybe so gunked up it is stuck. I had to remove mine while I had the fuel rail off. Otherwise, it's pita to get off. but whew! was it dirty. The pintle was clogged but once it was cleaned the pintle spring was all okay!
Hate to say this but you may also have some leaking FI's. if your fuel center is off from the actual mileage.
 
#32 ·
no they were dry. some had what looked like residual oil and all of them were rusty red. no gasoline smell or anything either. i had let it sit all night before i changed them though. i'll probably pull them out if i get home today if that's a fast way to find out. i'm really thinking and hoping that isn't the problem
 
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