4l80e swap issues
4l80e swap issues me and my friend just got done converting his '99 trans am from a 4l60e to a 4l80e. this was our first swap like this but we did our research and checked after ourselves over everything. we bought the conversion wiring harness, we measured our circle D converter and it didn't need to be shimmed so we just bolted it right up. one of our issues is that when the cars just sitting idling, the speedometer shoots up and moves with the tach. i was hoping it just needed to be tuned for the car but the tuner came by and did what he could but he told us he thinks we should have shimmed the converter because he thinks the converter's too far back and somehow causing the speedometer to think the cars moving and that's what's causing our issues. it just doesn't seem right because we measured and measured again before we tightened the bolts and it was within spec. any help would be appreciated, thanks.
Wow,
I'm not sure why a tuner would think the converter would have ANYTHING to do with the problem described. I would be looking for another tuner.
Look at the VSS and ISS wiring, you probably have them backwards.
I'm not sure why a tuner would think the converter would have ANYTHING to do with the problem described. I would be looking for another tuner.
Look at the VSS and ISS wiring, you probably have them backwards.
yea it threw me for a loop as well. i'll check the wiring for the VSS. it's possible i got the pins at the pcm reversed. do you think if the vss was just bad would it cause this problem? just wondering if the wiring is correct if we should just try a new sensor.
OK,
Speedo is being activated relative to the tachometer without the car moving...
That tells me that the VSS wiring is likely plugged into the Input Speed Sensor.
Speedo gets signal from the VSS normally. The ISS picks up forward drum movement, which would move in park and would accelerate when you rev the engine.
If they are reversed, you will get the symptoms you have now.
Check the obvious, all you have to do is swap the sensor plugs from front to back to see if this is the issue.
Speedo is being activated relative to the tachometer without the car moving...
That tells me that the VSS wiring is likely plugged into the Input Speed Sensor.
Speedo gets signal from the VSS normally. The ISS picks up forward drum movement, which would move in park and would accelerate when you rev the engine.
If they are reversed, you will get the symptoms you have now.
Check the obvious, all you have to do is swap the sensor plugs from front to back to see if this is the issue.
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i found it. i was looking under it and saw that the front sensor was plugged up so i was assuming we had it right but somehow we just had the factory 4l60 vss plug into it. i couldn't see that the rear sensor had the plug that should have been in the front sensor because it was covered in a bunch of jumbled up wires. thanks a lot for the help guys. sometimes it's just the dumbest little things.
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Verdad Gallardo the other issue we're having is that that tuner said he could hear a whine that he thought sounded like the trans pump. i listened and could hear a slight whine from the trans but it didn't sound too bad to me. he said we may not have shimmed the converter correctly. i don't remember the measurement but when i measured the space between the converter ears and the flexplate, it was right in the middle of where it should be so we didn't shim it. any thoughts on this? we just don't want to drive the car up to a tranny shop and let them hear it if we don't know if it's going to cause harm.
