novakm

A little help please...

I put TPI into my 71 Chevelle.
Engine has mild cam
I bought a nex AUJP chip from GM to start
Junkyard harness
new 24lb injectors

When I turn the key, it jumps to life and then immediately dies. Does not throw any codes. Since it fires, I know there is spark and the injectors work

If I keep the starter engaged, it sound like it is running, but dies when I let go of key

Opening throttle makes it jump to life at a higher rpm, but it dies just as fast.

I took out the Eprom to force limp mode, and it acts exactly the same.

Vats has been disabled..(by me, I have pocket programmer, Moats' adapter, and moates' scanner software.)
Tried messing with ve tables..+10 and -10 across the board

Nothing seems to make a difference.

Obviously either the ecu is fried or I hooked something up wrong.

Any ideas?

Thanks
Mike

david roush

iTrader: (1)

Did you check your fuel pressure ??

91banditt2

iTrader: (1)

what type of TPI is it?MAF or Speed Denisty?
sounds like a problem i had with my 91 Bird
check your vacume going to the MAP sensor.make sure you have a dedicated vacume sourse for the MAP.

novakm

Thanks...

I have not had a gage on the fuel pressure yet, But I can feel it in the hose when the pump goes on. I know some fuel is getting up, because of the initial VROOOM.. when I turn the key. As soon as I let go of the key it's like I shut it off. Just dies. I need to find a fuel pressure tester.

The intake is from an 87, but I am using a '730 SD ecm. Yes, the MAP sensor is on a dedicated line.

Watching vacuum on the scanner, it starts at 98 before I try to start. As it catches, it drops to about 40, but does not run long enough to draw more than that. With the carb, I would pull 15-18" vac.

jmiller

Do you have the fuel pump switch hooked up? It is a sender on the back of the block. If it is not hooked up, the ECM will see no oil pressure and will then shut off the fuel pump. The ECM ignores the oil pressure when in crank mode, allowing the engine to start, and run for a few seconds.
jmiller

91banditt2

iTrader: (1)

could be a bad IAC

92 zzz28

When you said that you tried to start it with the throttle open and it still died, did you keep the throttle open or let if go? I am just thinking about maybe the IAC or minimum air not set right. Sounds like a similar problem I once had. Good luck...

novakm

I found the problem!

I feel like an idiot!

ECM needs an ignition feed. I spliced into the distributor feed. Distributor is fed with a resistance wire that is bypassed when the key is turned for starting.

While cranking I had a solid 12v. soon as I let the key go, voltage dropped just enough to keep it from running. once the engine died, the coil was not drawing as much current, so I had 12v again, so no codes or other indication of problem...

Last question, Should I hook the coil to the resistance wire that fed the old distributor and the ECM feed to a good ignition source, or should I bypass the resistance wire and connect the coil to ignition with no resistance?

Do '90 TPI camaros use resistance wire in the ignition coil circuit?

Thanks guys!