Title is weird, so I will be as descriptive as I can.

I have a 1985 Pontiac Trans Am, that I transplanted a 5.7 beating heart into. Learned for tuning and prom purposes, that a ECU from 86-89' would be better than trying to run it off the dinosaur 85' ecu. So I did an ecu swap following all the write ups to a T. Word for word, splice for splice. I of course wired in (per directions) a MAF Power Relay and a Burnoff Relay to replace the burnoff module. Now, I state that because it is one potential place to look for this issue. So, the issue at hand. 6 out of my 8 tail light bulbs are burned out, which I believe makes it so the turn signals stay solid, but my turn signals stay solid on the dash if I try to use them (replace the flasher maybe?) In playing with my turn signals, I noticed that the RIGHT turn signal, if I apply it halfway, not completely finishing the circuit, makes one of my MAF relays and my fuel pump relay CLICK, and the Fuel Pump primes the fuel system as if you turned the ignition on. Turning the turn signal all the way on the right of course makes then click and the fuel pump makes a noise, but doesn't do the whole prime cycle unless you hold the turn signal halfway.

Anyways, I have a high mechanical aptitude, but I am still learning the electrical side of automotive. The computer swap took me a week in itself because I double checked everything. So, where should I start looking? I don't understand why my turn signal would prime my fuel pump as the lights and fuel system are completely not related.

Any help would be appreciated. Thanks!

 

If your turn signal switch is controlling something as unrelated to it as the fuel pump , I'd say it's a pretty good bet that you've got at least some of the wiring wrong , pinout wise ....

 

Possibly grounding issues - sometimes electricity will find a path to ground through a different circuit or component.

I would guess that wherever you pulled power and/or ground from for the fuel pump and MAF relays is part of the turn signal circuit. Start with that - where did you get power and ground for these and did you also have to pull any additional power or ground for the new ECM?

GD

 

So I found out in the end it was a combination of issues. After I painted the engine bay, and had dropped the new engine in, I never hooked back up the headlight grounds, which I think made a feedback loop into the fuel pump as its part of the circuit deep in the wiring diagram. Which magically fixed even more issues. I then replaced my turn signal flasher and now everything works. Thanks for the reply guys!