I have a 1989 firebird 2.8L with a couple issues I haven't found answers for. First, this car was bought new by a grandma, it quit running in 2008. It sat in a barn for 4 years and then I started working on it for my son to drive. Basically replaced the fuel pump and it fired right up. It does run and he is driving it daily for the last year. However, ever since we got it running it dies on the first turn of the key every time. Whether hot or cold, you turn the key and it starts to run a few seconds and then dies. The second turn of the key and it will usually run at idle. If you give it gas too soon though it sounds like it floods out and will about die so you have to wait 30 seconds or so and go easy on the gas to get going. Once running, it seems fine, but there is some hesitation when you give it gas.

Problem number 2 is that the 12 code flashes the entire time the car is running. If we jumper to ODB or not, it always flashes 12. Autozone tried a diagnostic on it an it said no codes.

I am not too electronically inclined when it somes to cars, but try to work on them myself. Haven't found any issues on here that sound similar. We have replaced the MAF, air filter, temp sensor, water pump, fuel pump and filter. Plugs, wires and distributor were all changed right before it died in 2009 so no age on them. I have rechecked the fuel pressure and it is 44 when not running and 38 while idling.

I wondered about a vacuum leak because the hoses are getting old, but replaced the main line at the back of the intake that runs to the brake booster. And a spray of carb cleaner on the lines seems to make no difference.

Any suggestions before I pay for a full diagnostic on it. Thanks

 

If your certain there are no short circuits between A and B on your ALDL (the test port) my only two thoughts would be either no distributor reference pulses making it to the ECM or that the ECM itself is faulty ....

 

I've wondered about the ECM, I think my mother-in-law says "They changed the computer when they did the tune up". This was before the fuel pump went out so a long time ago and no records. Elsewhere on this site, it says if the ECM isn't getting the Distributor Reference Pulses, then it shuts the car down. If that is the case, then would seem the ECM is bad. Can the ECM be tested? If it has to be on diagnostic machine to test it, then that would be $70 and a new ECM appears to only be $85.

 

They could have sold your mom in law an ICM instead of an ECM and would she have really known the difference ? You are right in that if no distributor pulses were getting to the ECM that it wouldn't spray the injectors but what about a messed up or somehow otherwise erratic signal ? I wonder if that would fire the injectors but trigger the code 12 ? Electronics can do some really illogical things at times when the failure mode is partial rather than total . Otherwise , I am kinda leaning tword your thinking of the ECM cause without a shorted A&B on the ALDL what else would cause it to call out code 12 like that while running ?

 

Yeah, but the ecm is different than the aldl port--at least on my car they are on opposite sides of the dash! Maybe the ecm is ok, but there is something grounding the aldl? Im a rookie at this, but the only way I know to get a code 12 is grounding the aldl. I also know you arent supposed to start the car when the aldl is grounded because damage can occur. This could be why. IDK....just ignore me if Im off base...lol

 

Have you actually read my two posts to him ? I've twice mentioned possible short between ALDL pins A&B and no one but you has mentioned any confusion as to which is the ECM or the ALDL ????

 

Yes, I noticed what you said, but HIS response to you mentioned only the idea of chagning the ecm after YOU mentioned the aldl. He said he wasnt the best with electronics, and when I first got my car I didnt know the difference myself. Thats why I said what I did. If he knows the difference he can say "oh yeah, I knew that" and nothing is lost, if he doesnt know, now he does. All I did was basically agree with what you said, seems like a strange reaction man, I never said you missed anything or were wrong. In fact, Im confident you know a lot more about it than I do.

 

Sorry , my post came out in print way harsher than I intended it to sound .

Also , our point of the possible shorted ALDL or it's harness would be a next thing for the OP to check before buying an ECM , and an easy quick check might be to unplug the ECM and use an Ohm meter on the A and B terminals of the ALDL to verify NO connection exists with the ECM unplugged . If he unplugs the ECM and has continuity between A&B it would have to be a short in the harness cause the ECM would be out of the circuit .

 

Hey no big deal man, crap happens. Btw, this is good advice I may pocket it for future use myself......

 

Thanks for the replies. Yes, I know which side ALDL is on and the ECM, but thanks for making sure. Actually you nailed down what my next step was going to be. I got the wiring diagrams and now going to try and track down the wires from the ALDL and the distributor/ICM back to the ECM and see if it shows any issues.

 

Good luck! I hate dealing with wiring issues. Let us know what you find, might be useful to us/anyone who reads this........