I already posted about my car problems once but since I was on vacation, and have to go to my sisters house to use the internet never got my problem solved through here.

I have since then narrowed my problem down a little bit. My car seems to be running in limp home mode. My symptoms are very little throttle, and idles bad. I just put the tpi on my car.

I took my stock chip out of the memcal long before I ever put TPI on my car. Since I no longer have internet I figured I would just go ahead and used the stock chip to see how it would work. It ran like crap. What was weird to me was how as soon as I would turn the key on the check engine light would flash on and flash right back off, then never come back on. I tried to pull codes off of the computer and it didn't flash any, including the normal code. So I burnt off a chip for an 89' 305(my setup is off of an 86' engine unknown) from a bin file I had saved from a year or so ago.

It runs the same, however now my check engine light comes on and stays on with the key, and never turns off, even with the car running. So I tried to pull codes again, and got nothing, again.

I put a spare chip of mine in the memcal that was blank, started the car. It ran the same and the light stayed on permanately.

So, I guess what I need to know is if my computer is bad or are my chips bad? Or, what all can cause the computer to go in to limp home mode? All my sensors and relays are new except for the TPS(which I have checked with a voltmeter), coolant temp sensor, intake air temp sensor, and the other sensor that goes on the front of the intake manifold, I can't remember what it's called.

I hope I didn't ramble on too much. Thanks for any help.

 

Well for starters it sounds like alots going on here and theres alot of background info that might be helpful. First off you may have changed the prom but are you sure that your working with a compatable ecm and correct pin out for wireing harness and all that? Next if you get no codes not even the code 1-2 then youve got another issue to explore. Ide start with pulling the TPS sensor plug or something just because that should set a code and it should be stored on the comp when you run the codes.

 

Well, I bought the set up off of ebay. The guy said it was an 86' set up, it has the large dizzy with the coil on top so I'm guessing that's right. When I tried installing it on my car the first time, I fried the computer by being in a hurry and not wiring the power wire, instead hooking it up to a jump pack.

I bought a reman computer from O'reillys, so that should be a correct 86' computer.

As far as the "pin out" I'm not sure what you are talking about, but I started with brand new Painless wiring kit.

Does anyone know of any way to test an ECU to see if it is bad?

Tried to pull TPS code, and I still got nothing.

Thanks for your help.

 

Well to my knolede there is no simple way of testing an ECM. Your best bet to be to call up an autoparts store and see if they could by chance. Beond that there are a few things to check electrically speaking that could cause a steady check engin light as it should always flash atleast code 1-2.

Step one

completely dissconnedt the ecm from the car. As result the check engin light should be off. If it is still on well have to look deeper into that. if it is off continue to step 2.

Step 2

Reconnect the ECM and carefully try and ground the diagnostic port at the ECM itself to chssy ground. If it flashes out a code now theres an electrical problem in the wireing to the diagnostic port. if you still dont get a code continue to step 3.

Step 3

Remove the prom completely and try to pull the codes. At this point if you see a code 51 its indicating a deffective prom. If you still get no code or got the code 51, replaced the prom with a new prom and dont get any codes again then its a bad ECM and the wireing should be check to prevent killing the ECM again and all solenoids and relays coil resistances should be checked. If less that 20 ohms replace.

 

Ok, from what you had me do, I have figured it out to be a bad ecm. I tested my resistance in my power to ecm relay. It is only at about 15 Ohms. I have bought a new relay and still have the same resistance. Do you know what I should do to fix this problem?

Thanks for your help.