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Discussion Starter #1
Hey guys,

I'm new to this forum and not sure how to navigate. I am having major issues with my 1991 cadilac deville and I am desperate for some opinions. I have been trying to get this car running right for a month. I have had lots of people say differnt things so if anyone could tell me where the help forums are for something like this it would be greatly appreciated.
 

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My car is a 1991 sedan deville. Car has 153,000 miles on it. Recently I had the brake lines replaced and two days after it started idling real high. I read through the forums on here and decided the air idle control motor was bad. I replaced it and no more high idle issues. I did the idle re-learn procedure after I put the part in. Car ran ok for two days but stemmed to have lack of power. After day 2 it was hard to start in the morning and when I drove it 2 miles up to the store it had no acceleration. There was no backfiring or anything. The car just kept falling flat on its face when I tried to accelerate. I changed the ignition coil and nothing changed. I changed the distributor cap and rotor button and no change. Now the car is getting worse. I tested the fpr gauge by taking the vacuum line off and watching to see if gas came out of the nipple. I watched for 15 minutes and nothing happened. I put a fuel pressure gauge on it and it read out 45psi with the key in the on position and 32psi while idling. The car is now idling rough at first start up and then mellows out with no odd engine noise. If I push the peddle ever so slightly it will gradually rev up to I'm guessing 3000-4000rpm. Anything past that is starts chugging if you will. I am lost as to what this could be. Any advice would be a life saver for me this is my only car.
 

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Discussion Starter #5
That is what I thought. In my owners manual it says 32 and that is what I was going by. What should it be?
 

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2001 Seville STS, 1990 Seville (RIP), 1972 Sedan Deville
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Owners manual? Shouldn't be any info in there about fuel pressure.

No idea on the exact spec, but about 45-50 would be about right.
 

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Discussion Starter #7
That's what I thought. I'm going to change the fuel filter in the morning I have one ready to go. Hopefully that fixes the problem. If not i will change the fuel pump next. Thank you for your advice
 

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2013 ATS Performance 2.0T M6, 2016 Mustang GT Performance Pack, M6
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Re: Need help with a 1991 cadilac sedan deville.

Moved to DeVille forum
 

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2011 Crown Vic LX, 2009 Chevy Malibu 2LT
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Re: Need help with a 1991 cadilac sedan deville.

There is nothing wrong with 32 PSI AT IDLE (engine running). REST pressure should be 40-50 pound range, and yours is at 45 pounds.

To truly test fuel delivery, put the gauge back on it, run the engine, and snap the throttle. Pressure should NOT drop under the load. If it does, you should be looking for a restriction or a weak pump. If not, your problem is elsewhere.
 

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2010 DTS
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Re: Need help with a 1991 deville

Tape the gauge to the windshield and see what it does when the car starts acting up.

If that's OK, then maybe a clogged CAT.

P.S.
Everyone who posts here needs help. I edited your title to be more descriptive AND merged duplicate threads.
 

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Discussion Starter #11
Thank you ranger. I am getting ready to put that gauge on it and do what you said. After that I will unbolt the converter then report back.
 

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Discussion Starter #12
I wanted to let you guys know, I am about ready to start doing what you advised to do. I started the car this morning an it drove with no issues for about 2 miles. From there the longer it runs the worse it gets. I have no idle issues when in park. I can not rev it past I would say 500-1000 Rpms when it is at it's worst. I reset the codes last night and the only code coming up at this time is e53. Is E53 distributor interrupt signal. Also a friend of mine reset the timing after we put the new cap on. We actually had to take the distributor and cut the bolts off to the cap to remove it. We also had to re-drill the holes and re-tap. I read in these forums somewhere that when setting the timing,you need to be in diagnostics mode and some other things to put the car in timing mode? Is this true?

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I have the gas pressure gauge on the car right now. It is at a steady 38 psi and drops down to 29-31psi when I press the gas down hard. The idle is steady right now and the engine revs fine with no missing and no popping. This was not the case yesterday after I drove to the parts store and back. It's about a 20 mile trip there and back. The car was almost to the point where I thought I would not make it home. I shut it off,checked under the hood and turned it back on. I got up to 55-60 by barley pressing the gas and made it home. After that I could not hold a steady rev over I'm guessing 2000 rpm. Anything over that and the car started missing and fluctuating with no consistency. I checked that cat converter last night to see if it was glowing red and it was not. I am going to drive the car down the road and see if I can get it to act up then look at the gauge and see what it says. After that I will unbolt the cat converter and see if that changes anything. I will check this post periodically to see if anyone can help with that e53 code
 

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2001 Seville STS, 1990 Seville (RIP), 1972 Sedan Deville
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E53 can be either a bad ICM, or the wiring/connectors to it inside the distributor. They tend to get brittle and disintegrate.
 

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Discussion Starter #14
I changed the icm prior to all of this. The car ran at a high idle when I started it and that problem has since been fixed with the new icm. Should I start focusing on the distributor connection or still go ahead and check the cat converter first?

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I just ran it down the road. The car has no acceleration and pops when I try to floor it. I can not tape this gauge to the window because it's not long enough. I opened the hood and floored it while in park. The psi dropped down to12-15psi. Would this be a weak fuel pump or a fuel restriction problem? I'm trying to talk myself out of that cat converter problem because it has no signs of being clogged. What would you do next?
 

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I opened the hood and floored it while in park. The psi dropped down to12-15psi. Would this be a weak fuel pump or a fuel restriction problem? What would you do next?
That's a problem (and why you never rely on static fuel pressure readings).

While you likely have a fuel pump replacement ahead of you, you should eliminate the possibility of a restricted fuel filter. You COULD test the system ahead of the filter, but it's so cheap and easy that if you have no idea if/when it was replaced, now would be a good time to just do it and cross your fingers...
 

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Discussion Starter #16
Ok I replaced the fuel filter and it was definitely restricted. The car gets up to speed much easier now but I still have no power. I did all the pressure gauge test and everything is pointing to a bad fuel pump. After I replace that I will report back. I did take the cat converter off and ran the car like that and nothing changed. I do not believe it's clogged.
 

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1992 DeVille, 2013 ATS 3.6
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Ok I replaced the fuel filter and it was definitely restricted. The car gets up to speed much easier now but I still have no power. I did all the pressure gauge test and everything is pointing to a bad fuel pump. After I replace that I will report back. I did take the cat converter off and ran the car like that and nothing changed. I do not believe it's clogged.
how did it sound with no cat when you fired it up? =)
 
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