before getting into what and why, please provide details
on what it does or doesnt do when you turn the key.

also, what codes come up ?

do you have a owners manual?
a factory service manual?

 

We need to know whether the engine cranks over normally or does not crank. The system fault light will be on simply as a bulb illumination test prior to the engine starting.

 

I didn't realize until I was reading through the service manual that the light is always suppose to come on, I guess I hadn't noticed it before. The engine will turn over but not fire. There are no codes showing.

 

On the fuel rail to the injectors is a fuel pressure test port with a screw-on cap much like an air fill valve on an inner tube. With a shop rag over the top of it, depress that valve, ignition key off. Should see fuel be ejected if the fuel pump is working. Report back.

 

I had similar problem on my 89 it was a bad distributor

 

Cochise29
I had similar problem on my 89 it was a bad distributor

My 89 starts and runs great, but the engine control system fault light on the dash will come on and stay on, but if I turn off the engine and restart, then the light stays off. The DIC indicates that all monitored systems are fine. Did yours act like this at all, before leading up to your distributor problem?

 

No I had no warning, no messages or codes at all, i drove car to the store about 30 minutes of drive time, went inside for about 15-20 minutes, came out tried to start the car, and no start, ENGINE CONTROL SYSTEM FAULT was on solidly.Engine turned over but would not start. Prior to this the car was fine.

 

BGINGERI, did you verify fuel pressure at the test port. Or is it fixed and you haven't reported back?

 

I had the car looked at by a mechanic and was told it was the fuel pump. I replaced it and the car ran for a day, then the next morning it was back to cranking but not firing. Is there some sort of electrical component for the fuel pump I should be looking at, it seems like a bad connection somewhere?

 

ahhh .. the fuel pump ...

i had to pull down the gas tank three times in one year.
damn pumps keep failing. no rhyme or reason.

that was one time i wished i had paid a mechanic to do it
and use the guarantee over and over.

pulling the gas tank is at the very far end of my list of fun things to do.

however, carnut has asked the right question ..
have you checked the fuel pressure? we really need to know to
provide advice beyond the fuel system.

there are two ways i check fuel pumps (there may be others):

1. i turn on power - w/o starting the engine - and listen for the pump.
This tells me if the fuel pump is even running.
however, often you can also tell when a pump is going bad by its
sound. One still needs to CHECK PRESSURE - #2.
(after pulling the gas tank 3 times, i got into the habit of doing this
every day i use that vehicle - the last failure i could hear the bearings
failing)

2. fuel pressure gage at the fuel rail. no pressure or low pressure, change
FUEL FILTER, then check pressure again. filters are CHEAP and easier to
change than dropping fuel tanks. a whole lot easier

 

I checked the fuel pressure and it is fine. I decided to recheck the distributor and found I'm not getting a spark from the plug wires. I checked the ignition coil and found the ground wire had touched another wire and they had melted. I replaced the ignition coil and still no spark, what other components should I check to see if they were shorted out also?

 

1987 silver hardtop Allante has 128,000 miles. Began to run rough and to stall on occasion at redlights or as slowed or coasted when approaching a turn. Was told the vacuum was low and the idle seemed to be searching for the right idle speed. He also looked for a leak around the top of the engine and recommended a smoke test. He advanced the timing which seemed to end the stalling for awhile. It would run rough in the lower rpm but once I got the rpms up it would run fine, on the expressway for instance.. The ENGINE CONTROL SYSTEM FAULT light would come on even if it seemingly was running well. The message might stay on or go off during the trip.

Mechanic found codes 31, 46, 49.
Replaced tps pigtail, MAP sensor, temperature sensor (was reading minus 22 degrees). Then he replaced the ECM. He also replaced the oil sending unit wires (said they were melted). Said he has tested fuel pressure.

Said it may need O2 sensors because it wouldn't run smooth when cold, (however it sometimes starts, idles or runs well even when cold; and sometimes it stalls when fully warmed up, and it may run very rough or not restart even when warm.} He said I would have to warm it up for 3-4 minutes and then it would run fine. Test drove it for 4 miles and was really pleased with its improved performance.
Next morning it was 20 degrees out, it started up and idled perfectly for a minute or so. Then it ran rough 5- to 7,000 rpm and stalled. It continued to run rough and could not keep it going. Then, miraculously, it started and idled perfectly 8,000 rpm. I then drove it around for 3.5 miles . It was perfect . As I came to a redlight it began to falter. I made it to a parking lot. Tried to start it for 10 minutes, wouldn't keep going. Later, started on the 1st try, drove it 1/4 mile and it faltered again. Couldn't get it going . Later started right up , drove it 1/4 mile stallled.

Next morning ran perfectly, so drove it about 1 mile back to the shop. He ran it for 45 minutes and thought it was fixed but then it faltered again. Help!

Can the car diagnostics tell if it needs 02 sensor?

 

DO we assume they are all "E" codes?

Although E031 pointed to a connector problem in the MAP, nothing done so far is going to cure the stall.
My MAP connector disintegrated with the heat and age.


After all that trowing parts at it we need to see current status. Clear the codes, drive it to a stall.
then pull codes. FRESH ONES.

The E046 is most likely a fuel injector CONNECTOR.
The E049 not sure .. air pump?
The stalling is most likely
. a) coked throttle intake
. b) TPS out of adjsutment
. c) both

About the ECM .. did YOU verify the part number on the replacement ECM vs your old ECM ?
These cars dont take subs very well.



report back.









.

 

I agree with STEALTH. Remove the air intake from the air cleaner to the throttle body and with carb cleaner and a tooth brush, clean the intake all around the throttle plates. These really get coked up and my 88 needed cleaned about every 15 to 18 months. It will restart hard and run rough for a few seconds then smooth out. Do that and report back. Also put year and type of Cadillac in your profile and signature so you dont have to list it every time you post. And yes you can monitor an OXY sensor thru diagnostics. Do you have the factory manual?

 

Thanks for all the input. No, I don't have the factory manual.
Mechanic found codes 31, 46, 49. I took that to mean E codes
Replaced tps pigtail, MAP sensor, temperature sensor (was reading minus 22 degrees). Then he replaced the ECM. He also replaced the oil sending unit wires (said they were melted). Said he has tested fuel pressure.
He then said that it needed a distributor because the line on his diagnostic eqpmt was supposed to be flat, but when it began to act up the line would go crazy. He replaced the distributor, rotor and distributor cap and, oh yeah, the fuel filter. It now runs very well. It is very much improved but I CONTINUE to get an ENGINE CONTROL SYSTEM FAULT light and a SERVICE ENGINE SOON message. I returned to the shop to have him read the code and he said it was the idle speed control motor. He said there is a wormgear in there that is worn but that he would not worry about it. The car drives REALLY well but when idling it isn't 100% smooth, although it might be 97 %. I think he is saying it wouldn't be worth the $$$ to deal with it. 1987 Allante, 129,000 miles.
Should I worry about the message?

 

moneypits create frustration and disappointmnet on car, and often NOT the fault of the car,
but point to the one trowing parts at it, as well intentioned as that may be.

so ... ok .. lets try this again.

do it in this order ..

Clean the Throttle intake,
CLEAR THE CODES, CLEAR THE CODES, CLEAR THE CODES ...

run it a couple of days, until it acts up, stalls, whatever.

PULL NEW CODES ..
post results....


IT continues to sound like a breathing issue .. inhale, exhale.









.

 

I did tell him to look for the coke problem mentioned in the forum. And it no longer stalls, nor does it seem to want to.

 

I wondered if most of the problem could have been a fouled fuel filter in the first place?