AE86 Silvertop Misfiring Issue
Posted: Wed Oct 25, 2017 1:48 pm
Little bit of history:
-Bought a 1985 AE86 GT-S with a Silvertop swap (BT wiring, ecu, itbs)
-200 miles later engine spun a bearing.
-Had the engine rebuilt by a mechanic because I didn't feel experienced enough at the time to handle a job that big.
-Car returned but would no longer idle. Mechanic basically had a meltdown and said he was done working on my "crap nonsense engine."
-I start digging into the car myself and discover a slew of issues. He removed the vacuum line from the MAP Check Valve and capped it off so he could just put a T in another random line and connect it to the MAP sensor. He also removed the IACV for reasons still unknown to me. After spending a good amount of time sourcing a vacuum diagram I think I have it all hooked up right. That brings us to the title issue:
The engine now idles very rough. Very very rough. However, if you pull on the throttle it doesn't miss on the surge. It's only when its being held at a steady rpm. I've tried adjusting the timing (has a distributor relocation kit from Battlegarage/SQ), haven't been able to get it completely dialed in. Doesn't help the previous owner completely deleted the check connector so I can't put it into diagnostic mode. I discovered I can unplug the connector to Injector 1 and it makes no difference to how the engine runs. All four cylinders have spark, compression, and are getting fuel. The plugs all come out caked in a black soot almost but still dry. I swapped the injector to other cylinders and it seem the problem is locked into the first cylinder. I then put a pulse checker (name?) into the connector and it is in fact getting power and pulsing. At this point I have no clue what the issue is and I feel my only solution is to try and find an aftermarket ECU and wiring harness for large quantities of dollars.
Any help or insight into this matter would be much appreciated
Thanks!
Evan
-Bought a 1985 AE86 GT-S with a Silvertop swap (BT wiring, ecu, itbs)
-200 miles later engine spun a bearing.
-Had the engine rebuilt by a mechanic because I didn't feel experienced enough at the time to handle a job that big.
-Car returned but would no longer idle. Mechanic basically had a meltdown and said he was done working on my "crap nonsense engine."
-I start digging into the car myself and discover a slew of issues. He removed the vacuum line from the MAP Check Valve and capped it off so he could just put a T in another random line and connect it to the MAP sensor. He also removed the IACV for reasons still unknown to me. After spending a good amount of time sourcing a vacuum diagram I think I have it all hooked up right. That brings us to the title issue:
The engine now idles very rough. Very very rough. However, if you pull on the throttle it doesn't miss on the surge. It's only when its being held at a steady rpm. I've tried adjusting the timing (has a distributor relocation kit from Battlegarage/SQ), haven't been able to get it completely dialed in. Doesn't help the previous owner completely deleted the check connector so I can't put it into diagnostic mode. I discovered I can unplug the connector to Injector 1 and it makes no difference to how the engine runs. All four cylinders have spark, compression, and are getting fuel. The plugs all come out caked in a black soot almost but still dry. I swapped the injector to other cylinders and it seem the problem is locked into the first cylinder. I then put a pulse checker (name?) into the connector and it is in fact getting power and pulsing. At this point I have no clue what the issue is and I feel my only solution is to try and find an aftermarket ECU and wiring harness for large quantities of dollars.
Any help or insight into this matter would be much appreciated
Thanks!
Evan