Car experts, help!!!!!?

Question

Hey... I've had on going problems trying to get my 97 Cavalier started and on the road again. (See link below, to read ALL details in two blogs) And.... I have hit a MAJOR road block, now.

Had my car towed to a Chevy dealership, with the mindset that they would run a diagnostic with the Tech 2, and find out the problem.

The car does crank, just not turn over... But....

They said they couldn't even use the scan tool on it, because the wiring as all wrong?

So... Questions:

#1 - Why couldn't they use the scan tool, if when the key was turned, all lights worked, and it cranked (just didn't competely start)? Does this sound right to you?

#2 - Is it true that I have to buy a BRAND NEW wiring harness from them? Everyone I talked to said that a wiring harness from the same year, same make/model, auto trans, same engine should work. The engine wiring harness I bought from a salvage yard was from the exact same type car (manufactured in 96, but is a 97 model I found out).

Answer 1

Okay, so you're getting the runaround on your car. Maybe I can help...

I, too, have a 97 Cavalier. Since purchasing it a year ago I've run into just about every problem imaginable...including your "no-start" problem. I know it sounds crazy and not logical in the least, but tightening the battery ground cable actually fixed this, and all of my other electrical irregularities. After tightening it down with a few washers and a bolt, it fired right off, and ran fairly well. In retrospect, my guess is that the loose ground cable made my car think the wiring was messed up, and somehow triggered the Theft System as well. Kinda strange but nothing with this model of car seems to make sense!

I hope this helps, though knowing Cavaliers, anything could fix it.

P.S.: Still to this day, however, I cannot get an OBD-II reading from my car. I'm not sure what that problem is but it now runs fine without it, so I deal with it. lol.

Answer 2

I think this Cav is going to get the better of you.

In retrospect a used wiring harness may not have been the best way to go.  I've not encounted this exact issue before on a GM but I can say I'm not too surprised they are having communication problems.  Some systems can be very sensitive to this sort of thing, others (like 90's Honda's) it doesn't much matter what you get from where.  My own car (03' Nissan Sentra) had a no-start problem and went in to the dealer for a recall which included re-flashing the ECM last Friday.  They could pull fault codes from the ECM but it would not accept the re-programming so they had to replace it (still under warranty thank goodness).  These things can happen. I've certainly encounted my share of unresponsive ECM's over the years.

If your ECM is new (I think it was, can't recall) then I would suggest the purchase of a new harness.  You may need the number off the ECM to match it.  With any luck it will fire right up after that.  There could always be a fault in the used harness that you don't even know about.

Answer 3

They are referring to the OBD2 connector harness... The only use for this harness is for using the scan tool on it.  A different year could have a pin in a different location.  Just let them fix it so its fixed right and if its not fixed then its on them.  Just get a quote.

Answer 4

ur anti theif light is supposed to blink.... mine does it all the time on my car.... u can unplug the fuse to it if it bothers u... lol   but if ur fuel pump doesnt come on then u need to replace that cause ur car wont start with out it!!!!!      My advice is to stay away from the auto mechanics.....    Alll u are doing is paying for their knowledge when they are really easy fixes.....  if u need a new fuel pump which it sounds like to me u do then u will probably spend 75.00 on the part and if u take it to the shop they will charge u probably 75- 150 to put it in 4 u when it is simple to do........

Answer 5

The lights, starter, etc. don't have anything to do with it.  If there are 200 circuits, 198 of them may be right, and 2 may be wrong.  You need to forget about that line of thinking.

It is possible to sort out any wiring problem, using your brain, a wiring diagram, and a volt meter.  However, you can't afford to pay dealership mechanics $100 an hour to do this.

We don't replace wiring harnesses when a car doesn't start.  That's NOT the first step to troubleshooting a no-start.

Answer 6

It is possible that the harness you put in is the correct harness for the car and that it is connected correctly. If the ecm was damaged when it "fell out" or if the replacement computer is not good the scan tool will not give a usable reading. The dealer claiming the wiring is wrong does not mean the harness must be replaced, just inspected to make sure all the sensors are connected to the right plug on the harness.

I don't use dealer mechanics for this reason, they tend to be "parts changers" who don't really understand the systems they are paid to work on. Unfortunately your only other option is to get a good repair book on the car and self educate yourself on the electrical system so you can slowly go over the whole thing and find the error. That is how I learned everything I know about these systems, it is a hard way to go but better than giving the dealer 3 or 4 thousand dollars.

Good Luck!

Answer 7

First mistake was taking it to the dealership. Have this looked into by an independent shop or mechanic. the dealerships will use tactics to get you to pay more especially now since their buisness is down.

As for the harness they aren't for a specific vehicle so one out of the same car with the same eng/trans will work.

Answer 8

??PCM Fell out of the Car???? Sounds like you may also have a "Major Rust Problem"! Fell out and Shorted out Almost everything. (Never "No Matter Old the Car) heard of a PCM "Falling Out??") Yes you can hook up a Wiring Harness so you can't get a Diagnostic Reading and the Lights still come on. Sounds like you have Ground Problems (IE; Rust!) and do need a "Completely New Harness!"

NOTE; They want you to buy the "New Harness" from them so they can Install it and trace & Check Everything while they are Installing.

NOTE 2; If a PCM (More commonly known as an ECM "Electronic/Engine Control Modual") falls out it does MORE then Rip the Harness and distroy the Module. New Harness must match with the Original Part Number.

Answer 9

To use the scan tool or decoder,the car needs to be running...The computer cannot detect whats wrong if it,s not running..Do you follow me?It,s like you can,t fix a bug in your home computer if you cannot turn it on...First always get a second opinion...You may have a shop that is trying to rip you off.You also have to make a decision,is the car worth fixing?It,s now 11 or 12 years old...Me i,d get a different car...The car isan,t worth much any way..

       L:ots of luck!!!!!