88FormulaLS1

I'm having problems with my 87 Trans Am's 305 TPI ECM. I replaced the fuel pump when I bought the car. So my first guess was the pump came off the sending unit or wasn't getting juice. I took the fuel pump back out and ran a hot wire from the pump to the battery. It's still good.
When you turn the ignition to the 'On' position the 'Service Engine Soon' light does NOT come on. I took the guages out and replaced the engine light bulb. I even tried unplugging the ECM with the switch to the 'On' postion before I bought the ECM.
The car cranks, but doesn't start. All fuses are good. I've double checked them after everything. I put in a new ignition switch on the steering column. I put in a new ignition lock cylinder. I installed a new ECM.
All the electronics work like the lights, windows, etc. The engine will crank, but will not start. I tested the fuel pump pigtail and all the relays. None are getting power.
Does anyone have any clue or idea or know what is causing the ECM not to be working??? Considering all of it is new and it still has the same problem.

RBob

iTrader: (1)

Look under the hood for a heavy gauge wire that runs along the passenger side fender well. Inline with it, usually closer to the front of the car is a fuse holder. Looks like a small plastic square with a flip-top.

That fuse provides battery power to the ECM and the fuel pump relay.

Note that I am not positive that the '87s used this power feed to the ECM. If they didn't then need to check the fusible links off the starter solenoid.

RBob.

88FormulaLS1

Alright. I'll go try that now. Thanks alot. I'll let you know.

88FormulaLS1

Well i remember what wire you were talking about on my 86. But this TPI setup doesnt have it. The only relays on the passenger fender next the airbox was two 10038311 relays which one goes to the headlights and fog lights and the other was put in for the fans that are on a toggle switch. any other ideas? Or did i miss it completely?

red88tagta

iTrader: (14)

Takes 3 things to make any engine run. Air, fuel and source if ignition. Lets narrow it down and save some time, Check for power at the ecm with a meter to a good ground, If no power, follow circuit bacward to locate interuption of power. If you have power at the ecm, go forward to the fuel circuitry, if you have fuel, go to the ignition circuitry. Recommend you get a Chiltons manual with the wiring diagrams if you don't already have one.

RBob

iTrader: (1)

There aren't any relays involved with this power feed wire. The wire originates at the battery or a junction block (depends which side of the car the battery is on). Within a short distance there is a small plastic fuse holder with a cover. It then runs up to the passenger side firewall and disappears into the car.

RBob.

red88tagta

iTrader: (14)

Just looked at the schematic for your 305 TPI. On the DRIVERS side, mounted on the firewall behind and outward there are three relays. (MAF, MAF BURN OFF and FUEL PUMP relays) These relays AND your ECM are fed by an orange wire. On my 88 GTA, the INLINE fuse for this is by the battery. (Mine is on the drivers side) If you find this fuse and it is blown, LOOK for some burnt wiring around the above relay connections first before replacing the fuse.

red88tagta

iTrader: (14)

JUst look under my hood, first pic is the relays. Second is the inline fuse that feeds them and the ecm. Had to also use a flashlight so pic is a little fuzzy. If you want to reset your ecm without disconnecting the battery, this is the fuse to pull.

88FormulaLS1

Wow. that was easy. Thanks guys. red88tagta-- it was that fuse. Out of the 16 Firebird and Camaro's i've owned this is only the 2nd TPI car i've owned. This car sat from 2006 till a couple months ago. I saved it for $700. I can't believe it was that simple. I appreciate it dude. If you're looking for any random parts for a 3rd gen i might have them.

RBob

iTrader: (1)

I never knew that they also ran that fuse/wire on the drivers side. Thank you for letting us know.

My '92 has the battery on the drivers side, with the fuse/wire being run up the passenger side. It is connected to a junction block on the passenger side of the rad support.

RBob.

red88tagta

iTrader: (14)

I am glad to be of what little help I was in diagnosing your delema. If the fuse was defective, there is only one cause. Too much amperage for it to handle. Which make it a little more inquisitive. Are one or more components drawing too much power?
Did it fail due to a low battery or bad starter?

If the fuse stays in tact after a week of continued use, you are probably OK.
I would really look at the wiring harness to the relays, the wires are close together, maybe an intermittant short.

red88tagta

iTrader: (14)

Hey RBOB,
They made so many changes to these cars in the wiring, it's not funny anymore! No one can keep up with it. Let alone these cars are 25 years old! All in all start with the basics. Get the right schematic for your car. Use a meter, don't just swap parts out needlessly. And above all else PATIENCE and if you don't know ASK FOR HELP!
Thats what we are here for isn't it?