Early EA82T TPS Issues .

[discopotato03]

I've been having a few problems with my 86 RX Turbo for a while , when it felt like it the thing would go into a lean mode and feel pretty flat under acceleration . When it was all standard it'd feel a bit flat occasionally then clear itself pretty quickly .

After the fabbed header and Garrett turbo install it would go into this lean mode at times and buck and kick unless driven flat footed . It never backfired or spat from the exhaust but the idle would get a bit rough while "mad mode" lasted .

I always suspected that early type twin switch TPS on the throttlebody so having a spare TB/TPS I decided to whip off its plug and start probing with a multimeter . Continuity testing proved the idle switch worked every time but the second on load one was doing silly things . At about the right point it had continuity but would then lose it past that point and regain it towards full throttle , sometimes there was no continuity at all . So I thought I'd test the spare TPS since it was screwed to a throttlebody and it worked every time . I noted where the throttle was when the idle contacts opened and refitted the spare TPS so it did the same thing .
So far my car hasn't gone into lean or mad mode and I can understand where having the on load contacts not close would cause issues .

I do have a printed copy of the 86 L EFI System factory WSM and it reckons that here in Aus the turbo and NA TPS is different in that the on load contacts close earlier on the NA one than the turbo one .

The figures it shows is:

Idle contacts closed from 0-2 degrees
NA both open ..... 2-22 .
Turbo both open ..2-47 .
Except aus open ..2-32 .

Obviously the second or what the WSM calls "full" contacts close from 22/47/32 degrees to full throttle for NA/Turbo/Except Aus models .

I don't suppose anyone has an NA 85/86 model MPFI TPS I could try to see what happens on a turbo engine ?

For the moderators , how would you feel about having an "Engine Electricals" section on this forum ?

Cheers Adrian .

[steptoe]

ask for a new section as I did for "brakes" and you will be made a moderator