Urgent timing quesiton

[0-60n4]

e-mailed Eric at turbotweak and waiting for his response but I need a quick answer. Can someone guide me. in the middle of this right now.


Got a question on timing:

I have been chasing some gremlins left from a previous owner (87 Grand National) with your chip in it.

The transmission had all the wiring removed for a non-lock up. So no signal wires to the ecm so I guess than means the ecm thought the car was always in 3rd or 4th gear and retarded timing accordingly. Although, I see high knock retard in the top gears and none in the low gears which seems backwards.


We are connecting the transmission wiring back the way it is supposed to be and going back to a lock up stall converter. But now we are wondering if the based timing may have been wildly altered to compensate for the wiring issue. How can I check to see if the base timing is correct? What is the procedure and what should it be?


Thanks,


Jim

 

[0-60n4]

After some more reading; if I understand correctly, if the car is running then the timing must be correct to whatever the chip is programed for. correct? And was I correct that if the ecm gets no signal from the transmission, it thinks the car is in 3rd or 4th all the time (or never thinks the car is in 3rd or 4th)?

 

[fastblackracing]

Ok lets have a go at this.....The trans connector has 4 wires in it. 2 of these are to run the lock-up solenoid valve arrangement for a lock up converter-----these 2 wires are purple wire on pin A [ +12 vdc], tan/black on pin D [- or ground by the ecm]. Then the other 2 wires are dark green/white pin C [third gear switch] and then Lite blue pin B [fourth gear switch]........ The 3rd and 4th gear switches close to ground when in 3rd and 4th gear....... Since none of your wiring was connected your ECM would never know that 3rd or 4th gear had ever happened always thinking it is first or second gear.....so any thing that would be in the chip that would need that may not work as designed by your chip guy........ Many guys that run 200r4 trannies in trucks street rods or whatever will use the 4th gear pressure switch to ground the lock up solenoid so they always have the converter locked in 4th gear.........Does this make sense?

 

[bison]

If you have Eric's chip it is burned using the VSS to schedule timing. You don't need input from the trans 4 pin connector unless you requested that it be used. If you have a knock retard problem id do the following:
-Verify timing (directions in the sticky in the tech section)
-be sure the chip is burned for the boost you are running.
-make sure there is no overshoot on ramp in.

I've seen a lot of overshoot with manual boost controllers over the years. This overshoot will cause detonation on ramp in. Looking at a gauge is unreliable for reference. The gauge can't keep up with the actual boost pressure. An accurate map sensor logged is the best. Timing should be at its lowest after the 2-3 shift


Sent from my iPhone using Tapatalk

 

[0-60n4]

thanks. Eric got back to me and explained his chip uses MPH to control timing and not the gear. But he also said 4th gear would reduce boost in his chip. Well this car is set up with manual boost control. Sounds like I have found the problem. I'm learning a lot. Thanks everyone.