1991 Cadillac 4.9 - 146,000 miles, Engine turns (Stalling) off just like you turn off the key. Starts right back up. It will happen at a stop light and while driving flat ground, making a turn foot up off the gas down hill. Never up hill while driving. Also the car will speed up (Flat ground) with out your foot on the gas, sometime as high as 40 mile per hour. At idle in drive it is not rough but it is not smooth. All the following has been completed the Cadillac service technician. 1. New spark plugs 2. New injectors 3. New TC Motor 4. Check computer (Rebuilt & marked used) OK 5. New thermostat. This has been going on for over 4 weeks. Last Wednesday I drove it home ALL THE ABOVE HAPPEN. Thursday evening I went for a drive NO PROBLEM. Help!!

Question, what would turn the engine off and not send a code? That seams to be the case.

 

it's been a long night so stay with me ...

what you described is an idle controller needing adjustment or failing.
i cant remember the acronym for the unit - need another cup of jabba.

there are many failing units out there as well as many defective units being sold.

to adjust it, refer to your factory manual for instructions.

 

Thanks, the 1st Idle controller motor that wasinstalled was bad andit was replaced.

Curtis3550

 

Hello All,
I read through all 39 pages Cadiullac problems like mind back to 2004 and made some notes. Just got off the phone talking to the Service Tech. This Friday he isgoing to check the fual pressure because he said it should not cut off going down hill. [sm=bicker.gif] If there is somthing else that you all think needs to be check please let me know.
[sm=feedback.gif]

 

hmmmm .... but you dont have a fuel pressure problem UPHILL?
i'm still stuck on idle controller, maybe timing or distributor, and
wondering about the ignition system ..

keep us posted

 

Hello Stealth and All::

I pick up the 1991 Cadillac 4.9 with 1460,000 miles this past Saturday; he had it for a day and a haft.
SealthYou were right, another “TCM”, That makes a total of two this time around, And one was replaced before I think see history that follows, all replacements with in 10,000 miles. Maybe a total of three.

It run’s better it does not stall; the speed up problems comes and goes. Also sometimes as I am stopping for a Red Light/Stop Sign engine speed will drop but not stall. I get 15 miles per gallen. Now has an engine miss at idle. It is no were near as smooth as it was just 10,000 miles ago.

A little history is in ordered here. At the time that I purchase it, from an individual, had 136,000 miles run just like a fine clock, I was not able to tell if the engine was running at a red light. All the problems started with the EPA test here in Hamilton County Ohio (Cincinnati). It would not pass. The dealer said all it needed was plugs and a wire was broken in the distributor. Did not pass. Back to the Dealer, something was in the tail pipe, a wade of carbon, you need a converter, No do not replace it. Back to EPA did not pass. They pass it after I showed them the bills. (So it did not pass the tests). After that I toke it to a shop that works on Cadillac (See problems 1st email, only did not stall at that time). They had it for 2 weeks I went down one time to see what was happening, the hood was up battery was disconnected, said he was resetting the computer and other systems. Week later he called me and said “I can not fix it come and get it”. No charge. By the way they were recommended by the EPA as one of the shops to take your car to for service if it did not pass there tests. In the mean time the EPA discontinues their EPA tests. Some months later I came across a used car dealer that sales high end cars and has its own shop with a crew of mechanics. So they looked at it. Replaced, TC sensor and I think the TCM. Also he said he replaced the chip in the distributor this turned out to not be true. It was ok for about a week or two. All total both shops about $1100.00. So I drove it for the next 14 months like it was, it did not stall it just speeded up.

In the mean time I needed to replace the water pump and have some work done on the air-condenser.

This last mechanic is a trained Cadillac technician “who specializtealthes in old Cadillac’s” has his own shop recommended by the dealer ship that he used to work for and does work for them now. In-addition to replacing the water pump and repairing the air-condenser the following has been completed: Plugs (2nd set with in 10,000 miles), injectors, distributor chip, and two TCM’s and checked the computer codies etc.A long the way each week for 4 to 6 weeks once a week I lost count, car down to his shop to see what is wrong.

I am thinking of taking it to “Steve Overbeck” who specializes in diagnostics of car engines at $70.00 hour “plan on two hours it will cost you $140.00”. I am not sure what to do I can sale it, it is a good looking car 2 door Fleetwood noon roof but I did not buy it to sale it. My 90 year mother can get in and out of it. I do not mind paying for service and repairs work. Count them 4 shops including two trained to work on theCadillac's that could not fix it. At this point I am an unhappy camper.


I need to replace the oil cooler lines. Is this a job I can do? I now have 1991 Cadillac shop manual.

Thanks, Curtis3550