QuestionQUESTION: Hi I saw some posts where you helped a guy with his ht4100
Well I have an 83 cadillac it was sitting for a year then when I started it it was running really rough so thinking it was a fouled up plug or something my father was giving it high rmp's while at idle then all the sudden the car shut off
Turns over fine
but is not getting gas
Fuse/ relays are good
Not getting any power back at the fuel pump connector by the tank
I ran my own power wire to the pump got the pump running car still wouldn't squirt gas into the tbi while turning over
If I spray gas into the tbi it starts right up but only runs while I dump gas into it
For some reason the computer or something is preventing the car from sending the proper signals or something
I took the computer apart and found a bad trace line on the board repaired that and as soon as I hook the battery up that trace blows out again and again
Could there be a sensor that's gone bad that tells the computer the motor is trying to start
Does the computer control the fuel delivery
Some people say there's a theft deterrent system on these and that could be it
Like I said it was running then all the sudden it stopped getting gas
I actually have a video of this very moment
Can you help ?!?
ANSWER: Hello,
Let me say that some people are showing their ignorance. CADILLAC DID NOT BEGIN STARTING TO USE VATS until 1989 in the Eldorado and Seville and all models in 1990. So, you have no so-called anti-theft system on this car from the factory.
The dealers in that era pushed Chapman alarms and they were true junk in which if the high beams were smashed out, it disabled the alarm.
You will know if Chapman equipped with the interior hood lock cable and a lock on the fender.
Who knows what some idiot did on the installs of these systems.
You always need to consider aftermarket installed junk because these cars could be stolen breaking the left side of the column with a screwdriver in 30 seconds by a teenager needing a ride to school.
Your fuel problem can be a multitude of problems, and when you get fuel, change the filter at minimum and hope you don't need to drop the tank to drain and clean. Also use one can of heat (no more) in a full tank.
Working without a factory service manual is chasing ghosts. You might be able to find one on EBay or Craig's.
What you are telling me is that the problem is on the other side of the computer fuse.
Car sat for a year. Could a rodent have chewed the wiring? I have run across that before.
You need a factory service manual to trace the wiring. The trace line should not be burning up! When you do find the problem and you have a dead short somewhere! Replace the computer after you repair, not before. With the factory service manual you should find the problem pretty quickly because you seem to know what you are doing.
Let me know what you find.
Http://www.autotheftexpert.com
---------- FOLLOW-UP ----------
QUESTION: I have the gm wiring diagrams and all there repair books they used from the 80s
I just don't know where to start
I'm guessing first thing is to find this dead short because the car was running then out of no where everything stopped
If you have an email address I can send you a video
AnswerHi,
Hee is the problem-I am not at the vehicle, nor do I have the manual.. Unless you have the factory service manual with re diagnostic flow charts, the wiring diagrams you have are out of context ad won't help.
I do not like guessing, but in your c case from your description, I would be looking under the dash from the harness running from the fuse box to tell computer.
Your problem is not common place in which an answer is not easy to come up with.
When I say this, examples would be where heater blower runs the battery down. Answer to that is you are screwed because you can not longer purchase the $500 module and you have to bypass. Trunk won't close, where you can manually adjust latch. Antenna keeps running, in which you would not replace antenna and just mast.
You have a unique problem in your car and the best place to start is with a diagnostic flow chart from the factory service manual which is step by step for fuel delivery. You say you have all the books from the 80s but you don't need all those books if you have the specific factory service manual for this exact vehicle.
To me anything else is worthless. Even Mitchell which was very good lacked information needed. Motors, Chilton, Haynes are worthless for this type of situation in my opinion.
If you need to pull the dash on this vehicle, it really is not too hard which will give you unfettered access to the wiring. It's a 3 piece dash assembly. The pad, the lower, and the main dash. I did so many dash replacements, I could have the dash removed in 15 min and another half hour to install.
The fact that the computer fuse has not blown is significant telling me that your problem is between the fuse box and the computer, but as I said, this is only a guess and I don't like guessing.
Good luck!
Http://www.autotheftexpert.com
