I have a 1990 Cadillac Deville that is running ruff. At the same time in started running ruff, the car starting having problem starting up. In order to start I had to push on the gas. Also every other time I start the car the seatbelt light and indicator sound would stay on. The only way to stop this from happening is to turn the car off and start again. I do not know if this problem is related but could it be the ignition control module? There is no check engine light that comes up so I don't think a code will show up. I took it to my mechanic and he replaced the spark plugs and fuel filter. He said that cylinder #3 is not working. I asked him if it may be the fuel injector and he said that for my car all 8 cylinders go through the same fuel injector and that the injector is good. He said that Cylinder #3 has spark, and passed a compression test and the injector is fine. He thinks there may be a crack in the motor. Please e-mail me at [email protected]
Cars & Trucks - Cadillac - DeVille - 1990 Cadillac Deville
Answers & Comments
There can be a misfire too from the cylinders.
An engine that hesitates, stumbles or misfires when accelerating or when it is under load is an engine that is either sucking too much air, not getting enough fuel or misfiring. If the Check Engine
Light comes on, you may find any of the following codes:
• P0171, P0174 Lean fuel condition codes
• P0120 to P0124 Throttle position sensor codes
• P0222 to P0229 Throttle position sensor codes
• P0400 to P0409 EGR related codes
If there are no misfire codes, a common cause of acceleration stumble is a bad throttle position sensor (TPS). The TPS tells the computer how far the throttle is open. The computer uses this information to determine how much fuel is needed to maintain the correct air/fuel mixture and when extra fuel is needed if the throttle suddenly opens wide.
Another common cause is dirty fuel injectors. If varnish deposits have built up in the tips of the injectors, they won’t spray as much fuel as they normally do, or will “dribble” fuel instead of
spraying a fine mist. This creates a lean fuel mixture and conditions that are ripe for stumble and hesitation (also misfire). Look at short term fuel trim (STFT) and long term fuel trim (LTFT) with your
scantool. If the numbers are high, it tells you the engine is running lean and the injectors need cleaning. Treat mild cases with a high quality fuel-injector cleaner additive. Severe cases require professional cleaning equipment.
Good luck and rate this.
1st u are wrong about the fact that an code is not in memory, these older OBD1 electronic system stored codes and many times never turn the CE light on, so that is where u start. There are 8 fuel injectors in the engine one for each of the 8 cylinders so think you had better go get your car and take it to a GM dealer where they know what they are doing, u need a really good GM trained technician to diagnose this problem, it will not get fixed over this key board, to many weird electrical and engine symptom's, I speak form 35 years as a automotive electronics factory trained Master tech.
failure rate of the ECM (Electronic Control Module) which controls the fuel injection and emission systems is around 5%, but with the age of the car it is possible, also the PROM inside the computer may be defective. You could have a defective ignition module or a Crankshaft position sensor problem as well, u may also have coolant leaking into the cylinders which is really common on the all Aluminum engine, that can be checked with a gas analyzer buy probing the coolant recover tank when the engine is cold at idle, they would check for the presence of combustion gases in the coolant.
It is typical at my dealer to charge 1.5 hours to diagnose this type of problem problem, a typical shop rate outside of the east coast and Calif (about $125) is about $85 per hour. Remember the dealer has the proper test gear and the techs the training to find out what is wrong more quickly, based on what you have been told by the shop your car is at now you are wasting your hard earned money on them, them seem to not know what they are doing, of course maybe u didn't understand what they told you and this would change things.. I would have them write down everything they have done so far and give that to the dealer, this will save you money
The next step in this process is to have a "leak down" test done. This is performed by using a differential pressure gauge, removing the cylinder's spark plug, making sure the valves are closed, and the piston is at the uppermost protion of its stroke. You then have the mechanic pump air in through the gauges and into the cylinder noting on the other gauge if there is a drop in pressure. If there is, you then listen through the exhaust or intake for air being pumped through which will tell you if(and which)you have burnt valves. If nothing is heard then look in the radiator for air bubbles. If bubbles are noted, you have a leak either in the headgasket or a crack in the cooling system. Let me know what was found. It is possible that the valves need adjusting also.
I also have a list where 32 is faulty MAP sensor circuit and 85 is throttle body service required. To do a leakdown test shouldn't cost more then an hour labor. This test makes sure you do not have any cracks or carbon build up on the valves. Did he give you the compression readings?
The idling screw is too low,, you need to adjust your rpm up a bit..
or there is a crack on the engine block (as he suggested) in which the block has to be replaced.....
Yeah but those error codes as well as the ones you listed before will noyt cause the problem your having.. and those can seimply be resolved by clearing them....
The one your having is motor problem..
You can turn the ignition and rpm up a bit and see if it helps.. but a cracked block means replace !!
The 4.5 engine in this vehicle has 8 injectors and from what I remember they had a problem with some of these and if there where more than 2 that were bad you are suppose to replace all eight.Before you do any of this check all the pcm grounds.They are very important.they need to be clean and tight.Also just because the check engine light did not come on always check for codes.This vehicle has it`s own on board diagnostic system.You don`t need a scan tool and almost all the test can be done with this system.But it takes a few years of training and I know you don`t have that long.But I can explain to you how to get the codes.On the heater a/c control push the off and warmer buttons simultaneously til all the light segaments on the dash and fuel data center.Then let off.All the codes in all the modules will be diplayed on the fuel data center.The computer codes will start with an E then the number.The history codes will be 2 EEs.Let me know what they are.Hope this helps.Good luck.
You hold the buttons down til the segaments come on.The cost of the diagnosis will depends on what they charge for by the hour and how long it takes them to find the problem.Also I don`t know where you got your info on the codes but the F codes they gave you are not correct.F codes are for the body computer E codes are for the computer for the engine sensors or what they call ECM OR PCM.The codes I get right out of the Cadillac service manual is.For F32 is BCM-PCM style="display:none;">You hold the buttons down til the segaments come on.The cost of the diagnosis will depends on what they charge for by the hour and how long it takes them to find the problem.Also I don`t know where you got your info on the codes but the F codes they gave you are not correct.F codes are for the body computer E codes are for the computer for the engine sensors or what they call ECM OR PCM.The codes I get right out of the Cadillac service manual is.For F32 is BCM-PCM data problem and as for the F85 well there is no F85.The body codes only go to 51.Make sure they are not E codes this would be the engine trouble codes.Yes this could be a computer problem but it could also be an egr sticking open or something else.The ignition module is in the distributor.This will usually cause a no start.
Sorry but you rejected my help.I am not going to waste any more time helping you.
If the motor had a crack he should of performed a leak down test to determine if you have a small crack. If he did then he's correct in his diagnoses. If you have a crack in the block then the motor will need to be replaced.
Also if the compression does pass then I would suspect you have a vacuum leak on the intake plenum. If only one cylinder is misfiring and has spark then its not the ignition module. Since the plugs have been replaced its possible you have a faulty distributor cap. It may look fine but internally it could be cracked.
Also these motor are notorious for head gasket issues. Did he do any test for this. Has the car been running hotter than normal or have you been losing coolant,.
Any good repair shop can diagnose this.. Plan on paying arouing 100 bucks depending how hungry the shop is.
A crack in the motor would make the oil turn milky. The way you describe it seem like an electrical problem. Make sure all the wiring connectors are plugged in where they are suppose to. Check also for loose wiring connection, corrotion etc.