Timing Q for 22RE
09-23-2006, 11:12 AM
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Timing Q for 22RE
I looked through 1 year of timing posts, didn't find an answer, so here goes:
Trying to diagnose a intermittant surge at idle on 85 22RE. Timing is set at 5 btdc with the connector jumped. Set the TPS and it is good at the TPS and at the ECU (shows that the harness is OK, too). All the TPS readings are per the FSM.
Most of the time, it idles fine. When is acts up, it will start surging up to 1300, down to 600, over and over. Eventually it dies at the lower end of the swing. When acting up, it may keep doing it for the rest of the day. Stop and go driving during rush hour is more like stop and restart engine. Really testing out the lifetime starter.
While trying to troubleshoot when it was NOT acting up, and watching the timing (not jumped...the ecu is controlling it), I noticed it is about 8, but as soon at the throttle is opened slightly (the TPS idle contacts open) the timing jumps to about 25. Close and it returns to 8. It this normal?!
I have not been able to work on it when it is happenning. The other day he said the throttle stuck at 5K when he came to the first stop sign out of our neighborhood
It is the OEM TPS, a used ECM (OE was shot....literally), and OE AFM.
I have 2 spare throttle bodies, 1 TPS, 2 AFM's and harness parts. Truck has arround 200K.
Any suggestions? Is that timing jump normal? I was expecting a gradual increase, not an instant jump.
Trying to diagnose a intermittant surge at idle on 85 22RE. Timing is set at 5 btdc with the connector jumped. Set the TPS and it is good at the TPS and at the ECU (shows that the harness is OK, too). All the TPS readings are per the FSM.
Most of the time, it idles fine. When is acts up, it will start surging up to 1300, down to 600, over and over. Eventually it dies at the lower end of the swing. When acting up, it may keep doing it for the rest of the day. Stop and go driving during rush hour is more like stop and restart engine. Really testing out the lifetime starter.
While trying to troubleshoot when it was NOT acting up, and watching the timing (not jumped...the ecu is controlling it), I noticed it is about 8, but as soon at the throttle is opened slightly (the TPS idle contacts open) the timing jumps to about 25. Close and it returns to 8. It this normal?!
I have not been able to work on it when it is happenning. The other day he said the throttle stuck at 5K when he came to the first stop sign out of our neighborhood
It is the OEM TPS, a used ECM (OE was shot....literally), and OE AFM.
I have 2 spare throttle bodies, 1 TPS, 2 AFM's and harness parts. Truck has arround 200K.
Any suggestions? Is that timing jump normal? I was expecting a gradual increase, not an instant jump.
Last edited by Yoda; 09-23-2006 at 11:13 AM.
09-25-2006, 11:59 PM
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Often the rpm up and down things is a Vac-leak. The computer richens up the mix ( higher rpm's ) then leans the mix ( lower rpm's ) it continues to do this searching for the right air/fuel mixture. But a vac leak letting in air is not letting the computer find the sweet spot. So it searches up and down.
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