Revving issues - 85' GT-S Redtop MAP setup

[souldrift86]

Club4ag,

My AE86 has a redtop with MAP setup and lately has been having issues when I rev passed 3000 rpm. When driving about 3200 rpm and letting off the gas before reaching a stop sign the motor would shut off. After starting it back up, I need to feather the gas at the stop sign since it won't idle at all. I had another enthusiast drive it around to see how it compares to other 86's and said it lacks power in the low end. Been a member since 2005. Had this 86 since 2007.

What the engine looks like for reference:



Things I’ve done to remedy the issue:

-New battery
-New spark plugs
-Replaced fuel inlet bolt
-Adjusted TPS
-Adjusted IACV
-Checked timing and distributor
-Inspected clutch
-New cat converter
-Checked vacuum leaks and replaced caps

[Jeonsah]

Do a compression test on it to make sure. I have had a blown head gasket that has had similar problems.


Also- how did you end up doing the wiring. I am curious because I am going to the MAP route as well!

[LongGrain]

i had a **** load of problems like this one when I did my map conversion too. I ended up selling it all because no one could figure out what the problem was. MAP is just a pain in the ass IMO.

[souldrift86]

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[souldrift86]

Do a compression test on it to make sure. I have had a blown head gasket that has had similar problems.


Also- how did you end up doing the wiring. I am curious because I am going to the MAP route as well!

Jeonsah, I was able to rent a compression tester today and the results were 190 psi across all cylinders. Built up pressure quickly with no issues. Also, I had someone else do the wiring years ago.

[souldrift86]

i had a **** load of problems like this one when I did my map conversion too. I ended up selling it all because no one could figure out what the problem was. MAP is just a pain in the ass IMO.

LongGrain, I never had this issue before. Its been running decent for years. I'm hoping I can figure this out instead of scrapping the whole setup back to AFM.

[ga_goosh]

could it be a vac leak at the injectors? iv heard of the injector seal kit leaking air and causinfg issues like this. also try cleaning your iacv too it could be clogged.

[MisterJerk]

How did the Fuel inlet bolt get burned?

Check the usual suspects, timing(cam and ignition), vac leaks(check all vac hoses), make sure there is water and oil(stupid, yes. you never know), check for vac leaks at injectors, if its still being a PITA, clean Throttle body and check TPS with multimeter.

[ronny]

check ur map sensor..
check ur intake air temp sensor
inspect your throttle body

i have ran map a long time ago for a few years.. never had many issues.. but sometimes this sort of thing does happen randomly..

what are ur codes saying?

[86_Chaser]

Low fuel pressure? Exhaust leak? Unplug tps. If that fix ur problem. Then ur tps is bad. The Ecu will go limp mood and will idle high too.

[souldrift86]

Forgot to update this...

After pulling the motor and looking at the engine harness it was apparent that the coolant temp sensor to ECU was in real bad shape. I believe this and the TPS was the problem all along.