LLman

My friend has 89 TII and revs are bouncing up & down when car is hot.
Revs are stable when car idles but when you try to get revs to 1500 then it starts to bounce up to2500 & down to 700 revs. Also the car idles poorly.

Any sugestions.
LLman

89turbo2dutch

Sounds like the same thing mine was doing when the BAC valve died. Will the car stall, at idle, with the A/C on ???

Do a search for BAC and Idle on this forum for more info!!

Mike

Josepi

Also search for TPS (Throttle Position Sensor), it too can cause similar problems.

DriftFC

if it's your TPS let me know, I had the same problem, and a guy I know, Mazda Guild Tech, re-built mine, because a used one is about $275... my car just died and i'm think about parting it out... so i may have one for SUBSTANITIALLY less than that

Josepi

89-91 TII have different TPS than NA's and especially the 86-88's. A brand new one runs around 260 at www.mazdatrix.com dealer is around 280.

NCsublime

I have the same problem. It's been like that forever. I have a new TPS to put on, but haven't gotten around to it yet. The screw on the bottom of the unit is a PITA to get off! Anyway, I think it is the BAC. I need to get a new one, but they are about $400 from Mazdatrix. I'll probably end up getting a used one.

-Derek

LLman

I have not got the time yet to deal with the problem but I think also that the problem is in BAC.

LLman

amemiya

I know this is not what you want to hear for such a small problem but get the AEM computer. it will alow the use of a delco tps like $35 and don't need the bac and get rid of the maf senser (adds 15HP). just my 2 cents.

amemiya

I think us americans are the only ones the call it RPM's and not rev's.. that is one of those pet peeves of mine "rev's uuhh".