timing trouble on 91 L98

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Jun 3, 2006 | 03:56 PM

revrun72

Thread Starter

3rd Gear

Joined: May 2006

Posts: 3

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timing trouble on 91 L98

I have a 91 L98 instaled in my 1972 vette. It pulses from 800Mv to 0 Mv on the OS sensor. The injectors are shutting off and on causing a surge and I believe causing the OS sensor reading. I have replaced ALL sensors TWICE and replaced the ECM and the chip. The problem still remains.

I had a Bullseye piggyback computer instaled to hopefully cure the problem. We live tuned the engine and it ran great for several hours and then began to do the dirty deed again. The tunning program showed all systems OK except the OS going 800Mv to 0Mv like every nanosecond. Something is causing the injectors to shut down and then back on.

Could the distributor be the problem? What controls the injectors? the ECM or the distributor? How do they interact?

HELP.......Glenn

Jun 3, 2006 | 04:20 PM

tequilaboy

Melting Slicks

Joined: Aug 2003

Posts: 3,403

Likes: 397

From: Lakeville MI

Could be your O2 shorting to ground. I've never seen 0 mv.

Injectors are controlled by the ecm. The ecm gets rpm info, via the drp (distributor reference period ) from the dustributor.

Jun 3, 2006 | 08:18 PM

rodj

Le Mans Master

Joined: Aug 2000

Posts: 8,838

Likes: 31

From: Australia

Post this question over in C4 scan and tune also.

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