Not sure what's going on here, wanted to see if anyone had this problem and had fixed it. This is on a 94 VTEC, OBD1. The idle speed was fluctuating up/down from 750 to 850. Happens about once every 15-30 seconds. When this happens you can watch the base timing vary about 20 degrees or so, enough that the "15" mark or TDC mark can't be seen.
We originally thought the dist. was damaged. The rotor screw came out and damaged the rotor button but taking it apart it seemed OK (sensors). Put it back together with a new cap/rotor. Problem didn't change.
Timing belt was recently replaced and verified OK. Cam timing is consistent and doesn't fluctuate.
All else I can think that would control advance is the TPS which (watching the VAFC) seems to be OK.
I'm thinking this is a timing issue since the timing is drifting. I don't think for this reason that it's a vacuum or idle control problem in itself.
my distributor is dying i know that, the tach just goes buck wild when the car is OFF. I doubt its my timing tho, my car run real good, and i have had my timing advanced to 29 for like 2 years, the response was really good when i did it, so i left it as is.
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I'm pretty sure you don't have to do anything with the ECU in order to adjust the timing.
However, you do need to jump the service check connector. It's a blue, two-pin connector down behind the centre console. (Somewhere near your feet when you're driving.) It has a little connector holder that it slots into, so you have to look or know what to feel for in order to pull it out. But it's quite accessible, don't worry. (There's also a three-pin diagnostic connector down there. Ignore that.)
So, once you've found the SCC, all you do is: start the car, let the idle settle down (~700 r.p.m.), jump the SCC (use a paper clip or something), then check/adjust the timing in the normal way.
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1994 JDM Prelude Si VTEC w/ 4WS
Sherwood Green Pearl (G-78P)
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92 Si Vtec, broken several times
Linear Mode
