[daedalus__]

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 ) 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!

 

[daedalus__]

oh and sometimes when i have been driving for a couple of hours and i let it idle it'll feel like the engine is breathing very slow and heavy, it's kind of faint too....?

 

[AMENCADDY]

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:

 

[HUF]

As Amencaddy said, start with TPS to solve your rough idle problem. You can live with VCC issue as many do. It will only affect a bit your fuel economy.

 

[steelybill]

When these cars get older, the grounds, and there are a bunch of them, can cause problems. The factory manuals usually show their locations. Some are not too easy to access, but worth inspecting if problems persist.

 

[HUF]

When these cars get older, the grounds, and there are a bunch of them, can cause problems. The factory manuals usually show their locations. Some are not too easy to access, but worth inspecting if problems persist.

Agree. One of the most important grounds is on the engine block by the starter.

 

[AMENCADDY]

Agree. One of the most important grounds is on the engine block by the starter.

And that one is the lallapalooza to make sure is "clean and tight". Dutiful to Murphy's Law, the hardest, and filthiest one to access, covered with engine grime oil and road dirt. Lovely!. Even damn near impossible to access with a wrench. What a genious the GM guy who put that into the design. :thepan:

 

[daedalus__]

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

 

[AMENCADDY]

The whistle may be from a climate control vacuum line disconnected or broken. that is where they run from behind the glove compartment. Something to do with that low refrigerant problem maybe.

 

[cadillac_al]

test

 

[cadillac_al]

The whistling sounds like the vacuum line to the park brake release,

 

[daedalus__]

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. =\

 

[daedalus__]

ONE MORE quick thing. I noticed this air intake is only an inch wide and behind the headlight ? that doesn't seem right. can i just take off that fitting or should i route a bigger tube towards the bottom of the engine bay?

 

[daedalus__]

lol ONE MORE

im cleaning the throttle body with a can of that spray so i open the butterflys and look in there with a flash light and there are these two pipes in there that are completely gunked up. no wonder it doesn't run great without gas!

 

[HUF]

lol ONE MORE

im cleaning the throttle body with a can of that spray so i open the butterflys and look in there with a flash light and there are these two pipes in there that are completely gunked up. no wonder it doesn't run great without gas!

Here you go! Clean them up with a piece of coat hanger really good.

 

[AMENCADDY]

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.

 

[daedalus__]

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!

 

[daedalus__]

yeah actually i have an 11/32" bit at work I just used it yesterday

would it be a bad idea to stick a reamer in there? i don't really know what will happen if i open the stacks up? i'll take the thing off and ream it to .345" lol

 

[AMENCADDY]

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.

 

[AMENCADDY]

yeah actually i have an 11/32" bit at work I just used it yesterday

would it be a bad idea to stick a reamer in there? i don't really know what will happen if i open the stacks up? i'll take the thing off and ream it to .345" lol

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.