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92 Deville intermittently dies


PAUL T

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My wifes 92 Deville with a 4.9 has been dying when you come to a stop while turning. I suspect the ISC motor because I have had it stick before. I am going to re-adjust it as soon as I can find time to do it. I checked the power steering pressure switch and its o.k.. I tried to get into the archives but they are not working for me today. I recently had the altenator out and it check o.k., so I replaced the battery. Walmart 36 month battery died in the 38th month, go figure. The air filter is clean and I had the fuel filter changed about a year ago. It idles fine, and accelerates o.k.. No related codes are showing. What do you think?

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There is a pressure switch on the rack that detects increased pressure when you turn the steering wheel. When a load is placed on the power steering, such as full lock, the switch opens. The PCM uses the switch status to extend the ISC control motor during high power steering pressure loads to help maintain a stable idle. Code E040 sets when vehicle speed is above 45 MPH and the switch is open.

Give this some thought, it still may be your ISC maladjusted but or slow as molassas, but think about the possibility that this switch is not operating properly, look for an E040, Mike

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Does this by chance only happen with less than 1/4 tank of fuel?

No it usually happens when the tank is almost full.

Scotty, I did the power steering pressure switch test but it came up o.k. I have been looking for the P040 code but it has not come up. Maybe I have not been doing 45 when it happens. I had it come up a long time ago when the FPR was bad but, not lately. I have also been having trouble with WOT with a full tank of gas. It will spit and sputter, but not cut out, it only does this intermittently. I thought I got a bad tank of gas. So I ran dry gas in the last 2 tanks, but it happened again today. Gradual acceleration is O.K., it only does it on WOT. I am hoping that the fuel pump is not going out.

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I might get lucky and have it cut out with the fuel guage attached in the drive way. That is a good idea Ranger. If not, it may reach the windshield so I can monitor it while driving. I will let you know what I find.

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Car has done fine until my wife takes it out and about 3 miles from home it starts missing bad. When I got in the car it was idling fine then when I went to take off it started sputtering and backfireing like crazy. Also the fuel lights and dash lights start flickering like it was possesed. Anyway I limped it down the road until it completely quit so I put it in neutral and it would not even crank plus dash was giving me a light show. Finally I put it in park turned it off, then restarted it and it drove fine the last mile home. Turned it off, hooked up the fuel pressure gage and it reads 35 lbs at key on engine off. I start it up and it flutters around 34-36 lbs, but I could not get it to stumble. Turned it off and it holds at 35. I am going to change the fuel filter tomorrow. I am leaning toward fuel pump or a bad ground somewhere. I am going to check the battery terminals in the morning, I just changed the battery. No codes come up. It is either not getting gas or not getting power. It always idles fine when it acts up though. FPR is fine. Remember it is a 4.9.

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This is sounding like a bad ground to me Paul. Do a search for MATT, he had similar problems with his 92 4.9, this is very very similar.

See this post by MATT

Dirty Fuel ? or Something Else ?, Engine has been perfect, but then----

and especially this one also by Matt

Rough idle,kick,buck,hesitate,load up,hissy fit, Then shut off and restart and ok again

and this one:

Engine ran rough just after starting, shut it off and restarted and it was ok

If nothing else, it will be good reading! If I recall it was a missing a ground to the starter and possibly a bad PCM

Mike

You probably have this in your manual but here are the grounds for the 92

post-3-1125618940_thumb.jpg

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Hi Paul, yup Scotty is correct. Read those posts by me. I started to shutter my self reading what you were describing. It brings back bad memmories.My car was doing things like yours. To tell ya the truth I learned so much fixing those problems my self with all the help the guys gave me that it was allmost worth it.( I said allmost ). I would head right for the ground wires that go from the battery to the front nose area of the frame. Take em off and re do them good. But ya know what did it for me as a great test? Wait for the car to go into its hissy fit and take a battery jumper cable then hook the ground end to the battery ground and take the other ground end and hook it to a bracket on the engine. That will give a good ground to the system and the PCM and see what happens. On my car it cleared up as soon as I clamped the cable on to the alternator bracket. On my 4.9 it was missing all the grounds from the engine to frame and from the frame to starter. You see I had just had a new 4.9 put it by a couple of maroons and they did not put back any of the grounds. I added 3 of those brades 1 1/2" wide ground straps and boy that fixed it all up good. I hope you find the problem fast Paul.

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Grounds not withstanding, 35 psi is well below specs. You really need to get a guage on it and see what happens when you are expiriencing the problem. My money is on the fuel pump.

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The only thing I see that reminds me of my problems is what he said about the dash. He said, "Also the fuel lights and dash lights start flickering like it was possesed. Anyway I limped it down the road until it completely quit so I put it in neutral and it would not even crank plus dash was giving me a light show". I Also duct taped the fuel pressure guage to my window, but I cant remember if I had 35 to 38 PSI or if it was 45 to 48 PSI. I wish I could remember.

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PFI chart A-5 states that fuel pressure should be 32 to 38 depending upon engine load, and altitude.

By disconnecting the vacuum hose at the FPR, engine load compensation is taken away from the fuel pressure regulator. Pressure should rise to approximately 45 PSI. If pressure is above 50 PSI, replace the regulator. If pressure is lower than 40 PSI check fuel pump operation filter and electrical circuits..

Source: 1991, 4.9 Service Manual

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Thanks guys, when the lights started flickering I was leaning toward a ground. I just had the altenator off and had it checked, I put that ground back where it was. In my earlier days (before my Caddy's) I would say it acted like a clogged fuel filter. I plan on working with it tonight, my work lately has had me swamped. I might add that my 94 Concours started giving my wife fits Tuesday, so both Caddy's are down. I am stuck driving my 96 F250 with the 460 at 10 MPG, I am not having fun.

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Paul, did you say this? "Turned it off, hooked up the fuel pressure gage and it reads 35 lbs at key on engine off. I start it up and it flutters around 34-36 lbs, but I could not get it to stumble"

According to my manual, the fuel pressure is right on... Let me repeat what I found in the 4.9 manual...

PFI chart A-5 states that fuel pressure should be 32 to 38 depending upon engine load, and altitude

According to the 4.9 manual, your fuel pump pressure seems right on, right on, right on...I wouldn't worry about fuel pressure at this point..UNLESS it drops off from the figures you reported...which you did not find yet...

Matt, you have a 92 Seville with a 4.9 don't you? You have 93 Seville on your profile, that is a 4.6... what am I missing

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Paul, did you say this? "Turned it off, hooked up the fuel pressure gage and it reads 35 lbs at key on engine off. I start it up and it flutters around 34-36 lbs, but I could not get it to stumble"

According to my manual, the fuel pressure is right on... Let me repeat what I found in the 4.9 manual...

PFI chart A-5 states that fuel pressure should be 32 to 38 depending upon engine load, and altitude

According to the 4.9 manual, your fuel pump pressure seems right on, right on, right on...I wouldn't worry about fuel pressure at this point..UNLESS it drops off from the figures you reported...which you did not find yet...

Matt, you have a 92 Seville with a 4.9 don't you? You have 93 Seville on your profile, that is a 4.6... what am I missing

Yea that is what I said. I am buffaloed though because I can not find a pattern of when it does it. My wife had driven over 100 miles before it acted up. Sometimes it acts up within a few miles. The only consistant thing is that when I shut it off and restart it is better. I thought it was only doing it on a full tank but there were 13 gallons left when it acted up last. I am sort of wondering if maybe the PCM is acting up. I may have to expose it and tap on it when it does it again. I am going to work on it tonight so wish me luck.

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The thing here that is similar to Matt's problem is that when he restarted it, it was better. Someone else had the same thing, when he restarted it it was better. His topic was FREE Seville.... I think he had a bad PCM... I will try to find the thread.. Mike

Here is it, Search for these threads on a 1992 ELdorado that had a similar problem as you. The members name was dkedrowitsch, this will be good reading for you, Mike

Got a free 92 Eldorado, need help!

and

My free Eldorado UPDATE!!

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Well to update, I have been driving the car for the last 3 days on trips from 20 to 50 miles,and I have not had any problems. I have not done anything to the car except check the fuel pressure. I have also gone through a tank of gas since it acted up last. My wife is going to take it to work in the morning so I will expect her to call me tomorrow and say it is not running again. It always seems to act up on her. I am really leaning on getting a new ECM though. I will keep you updated though.

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  • 2 weeks later...

Well the car finally acted up today. I would come to a stop and it would surge forward before stopping. I was glad I was not following anyone too close. Then it died at a stop light, I put it in neutral to restart and it was like a dead battery, dash lights lit up everywhere, not even a crank. I then put it in park and turned the key completely off and it restarted like nothing was wrong. It ran fine the rest of the day. I finally got a code E031-shorted map sensor circuit. I still think the computer is the culprit. I am going to get one soon if it gets more frequent. I will let you know.

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I would troubleshoot the MAP sensor circuit. A malfunctioning MAP system will cause severe driveability problems like you are experiencing.

The no-start symptom could be a bad neutral safety switch - since the car started up when you shifted into park.

Kevin
'93 Fleetwood Brougham
'05 Deville
'04 Deville
2013 Silverado Z71

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The biggest agrivation is that after starting it back up it may run fine for another week. It is like it resets itself when you shut it completely off and restart. No fuses look like they are blown. I can troubleshoot the MAP sensor circuit with the manual, but I am going to clear the codes and see if it reoccurs soon first. I will be driving it again today.

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