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Discussion Starter #1 (Edited)
This is my first forum to ever get on so I'm sorry if I break any forum rules. I have 2 Cadillacs that both have crazy undefinable (so far) problems. The first is a 91 Sedan Deville with the 4.9 liter. The second is an 84 Eldorado with the H4100. I will place the problem with the Eldorado on the next slip.
My Deville is hesitating and sometimes backfiring. Somedays it does better than others and somedays it will or won't have the check engine light on. So far I have:

changed the fuel pump
changed the wires
checked the plugs (they look good but they r to hard to change just for a guess)
changed the fuel filter twice
only used premium gas even though it's $3.50gl here
cleaned the fuel injectors
filed down the leads on the rotor button and the distributor cap
:hmm:done a lot of head scratching
and changed the front motor mount that was completely broken and probably jarred something lose

None of this has changed anything except my motor isn't doing jumping jacks anymore (by the way, stay away from buying foreign parts that bolt holes have to line up on). I also had 2 diagnostic tests run on it. The first one said nothing but the second one said the torque convertor and the clutch were going out. It doesn't act at all like a transmission problem though that may be in the near future.

This is my daily driver and I don't have shop money to send it to them and tell them to fix it. Especially since I just lost my job. So any advice or thoughts would be very helpfull. Thx
 

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Discussion Starter #2 (Edited)
The second and less imporant problem as of right now because it's a project is my 84 Eldorado Biarritz. It was given to me by my best friend as a birthday present last year not running. I wanted one just like my 85 Biarritz that I had wrecked a year before into 2 cop cars (they were on the wrong side of the road around a blind corner and blamed it on me). We got it running but after it was running we found that the brakes didn't work. So far I have:

changed the back calipers
changed the brake booster twice
changed the master cylinder twice
changed the pads
checked the lines (as well as I could)
changed the thing that splits the lines after the master cylinder twice
hooked up the vacuum lines the right way
and each time I did every one of those things I bled the brakes and bled the master cylinder and sometimes even that splitter thing to

The brakes work barely but not enough to even think about going on a main road. No offense but I'm hoping that someone has had a similar experiance with either one of these crazy cadillac problems so I can (sorry) learn from others mistakes, or from their genius minds.
 

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With engine idling pull the vacuum hose off the fuel pressure regulator (mushhroom shaped device on the fuel rail near throttle body). If there is fuel leaking from the nipple - replace the FPR. Just an easy thing to check out....
 

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Discussion Starter #5 (Edited)
OK. I just checked the engine with that trick that DaveSmed put on there and it showed:
E39- VCC Engagement Problem
E52- PCM Memory Reset
F11- A/C High Side Temperature Siensor Circuit
and F12- A/C Low Side Temperature Sensor Circuit

Now I know I have my A/C disconnected but what in the world is the VCC and the PCM? What do I do to fix those?

Oh ya. I just remembered I also emptied out the Catalytic Converter. That was my first try at the problem.
 

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jonwayneanstey said:
OK. I just checked the engine with that trick that DaveSmed put on there and it showed:
E39- VCC Engagement Problem
E52- PCM Memory Reset
F11- A/C High Side Temperature Siensor Circuit
and F12- A/C Low Side Temperature Sensor Circuit

Now I know I have my A/C disconnected but what in the world is the VCC and the PCM? What do I do to fix those?

Oh ya. I just remembered I also emptied out the Catalytic Converter. That was my first try at the problem.
do not worry about 52 it shows up when you disconnect the battery. VCC is more serious issue. to check the proper operation of VCC (viscosuos clutch) drive maintaining constant speed some 50-55 mph and with your right foot on gas pedal SLIGHTLY touch the break pedal with left one just to engage the brake switch. If VCC works properly it willl result in its disengagement and RPM jump (some 150-200). you can watch the latter on DIC with Eng Data pressed several times until it shows RPM's . Good luck.
 

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Discussion Starter #7
I have no clue how to know what the rpm is except for by listening.

I did that trick to find the codes but is there a similar trick that'll show me different things such as how high the rpms are?
 

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jonwayneanstey said:
I have no clue how to know what the rpm is except for by listening.

I did that trick to find the codes but is there a similar trick that'll show me different things such as how high the rpms are?
My car Seville 1991 has a Driver Information Center (climate controls?) with several buttons including Eng Data. Pressing that button shows coolant temp, battery voltage, RPM etc. Is the same year Deville different?????
 

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Discussion Starter #9
Mine is different. It is a DeVille. I see where there would be space for it in the dash but its not there though. That would be awesome to have though. Does anyone know if you can put one in a car that didn't have it originally with just basic part changing knowledge?
 

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Discussion Starter #11 (Edited)
I just checked the fuel pressure regulator. At least I think thats what it was. It looked like a mushroom and had a small hose coming out the side of the top. There was no gas leaking out of it though while it was idleing though.
Another thought. Could lack of back pressure do something like this? I would think not because of all the people talking about straight piping it. But anyways, I have a gutted catalytic and an exhaust leak at the manifold and where my buddy welded the cat back. It sounds like complete crap. Especially with the hesitating because it's sputtering LOUDLY.

By the way, thank u very much, Adalla, for the help so far!
 

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I think that you're describing the EGR valve not a fuel press. regulator.
On a 84 HT4100 Eldo the regulator in inside of the throttle body. Not sure where it is on a 91 Caddy.

Peteski
 

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peteski said:
I think that you're describing the EGR valve not a fuel press. regulator.
On a 84 HT4100 Eldo the regulator in inside of the throttle body. Not sure where it is on a 91 Caddy.

Peteski
If it is like my '93 4.9, facing the engine bay with the air horn off, it is about 6" to the right of the throttle body and connected to the fuel rail. There is a vac hose going to it from the TB.
 

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DFBonnett said:
If it is like my '93 4.9, facing the engine bay with the air horn off, it is about 6" to the right of the throttle body and connected to the fuel rail. There is a vac hose going to it from the TB.
Correct. The EGR valve has nothing to do with fuel rail and it's behind the throttle body.

You are welcome, jonwayneanstey. Too bad we cannot figure out your problem....
 

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Discussion Starter #15
Your right. I was looking at the thing thats behind the TB. And the fuel rail is in front of the TB and has a place to hook up a fuel pressure gage right? If so if your facing the engine which side of the fuel rail would it be on?
 

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jonwayneanstey said:
Your right. I was looking at the thing thats behind the TB. And the fuel rail is in front of the TB and has a place to hook up a fuel pressure gage right? If so if your facing the engine which side of the fuel rail would it be on?
FPR is on the right side of the TB just some three inches off. if you have an email I can send a picture.
 

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Discussion Starter #17 (Edited)
I just checked my fuel pressure regulator and I'm positive it was it this time and it was'nt leaking any gas at an idle or when I pulled the wires to rev it either. I'm sorry I forgot to put n't after was when I first wrote this.
 

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Discussion Starter #18
Anybody have any other ideas what it could be? Sounds like megatron may be having the same problem. My car runs worse when it's low on gas also. Not as much since I changed the pump though.
 
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