Newbie GN Owner Motor dies when cruises

[Fattdragger]

I have a pretty new to me 87 GN with mods. Motor is fresh, upgraded pistons/cam, has new prescision turbo, has .009 injectors with chip, seventh injector, big fuel pump adjuable fuel pressure reg., adjustable wastegate, 3" down pipe and 3" exaust...Problem is you can hammer it around and it runs fine, but mellow out and just cruise around town and it will die. It will restart and basicly only idle. If you give it gas it loads up bad. Now here's the fun part... I now have the ECU sitting on the floor. When it dies I unplug the prom, reinstall it and were back to fine. Drive the pee out of it and it's good, cruise around slowly and it'll do the same thing. I also think it's idling a little fast. I assume it's a prom/ecu problem? Who do I send it to or ? Maybe another problem? Thanks in advance for the help.

 

[gn4u2c]

Well it should not be on the floor for the wires to get moved around constantly they could break internally.. the metal case is making static like you can't believe doing that. Mount it correctly. Do a TPS check .42-.44 base- 4.7 + full throttle. clean / relearn on the IAC and your most likely good to go.

 

[Fattdragger]

Ok will check. The problem was before I removed the ecu for easy access. I left it out so I could remove the prom and restart the car. No loose wires or static as a cause. Thanks

 

[turbo39151]

Do you have a scan tool?

If not, go buy a scanmaster so you can see what the car is doing. Might not be a bad idea to put the ECU off the floor...


In case you do not know what one is or looks like:
GBodyParts.com Online

 

[WhiteTtype989]

seventh injector ?

 

[Fattdragger]

Yes on the scan tool. No codes... It will die with the ecm mounted or removed. I only have it loose to remove the prom to reinstall it to make it home.

 

[turbo39151]

No Mal codes is a good start. What about your other numbers?

 

[mikestertwo]

Could be a lot of things....bad O2 sensor...IAC not set correctly...tps adjustment. Having the computer out on the floor won't hurt anything. Mine has been laying on the floor for the past year What chip is in it? By the way, the 7th injector is old school..I would take it off..get a decent chip like a turbotweak programmed for your setup.

 

[GN owner]

My car used to act up like yours only not as bad. I cleaned the TB and the IAC pintle and reinstalled. I also checked the TPS and the IAC for proper adjustment.
Go to this link to for TPS and IAC adjustments:
General Maintenance and Up Keep