rgordon1979

iTrader: (3)

I think my car is running rich. Last night I stopped to check my mail, left the car running. Walking back I noticed fire coming out of the tailpile every few seconds. I have been having trouble getting the car to idle smooth. It seemed like the fire would come out when the rpms would go low. Too much fuel for such a low rpm?? I had just been driving the car somewhat hard, nowhere close to redline or anything though. Was it running rich just because I had been exercising it or is something wrong. I have never seen this before. Also, I have a full RB exhaust, no cats and a cone filter, no other mods. Thanks for any help. Rob

Keith

As with all idle problems, the first thing to check is the TPS adjustment, on a warmed up engine the middle wire on the narrow range TPS should read 1.00V (engine off, ignition on). Adjust if necessary. Then, jumper the initial set connector (on drivers side of engine compartment, toward the front, single or double connector), and adjust the rich/lean screw on the other side of the engine compartment for highest rpm idle. This should fix the problem. If you do not have an ACV/air pump installed, you may have to lean this out slightly, since at idle the ACV directs pumped air to the exhaust ports to neutralize unburnt fuel from the rich mix required for a smooth idle. Good luck!

Irv, Keith's dad

rgordon1979

iTrader: (3)

Is the idle mixture screw on the BAC?? Is it on the end?? Sorry, I am new to the idle mixture screw thing. Also, if possible, can you describe which wire to test the narrow range TPS? I tested it the other day, can't remember what wire though. I tested the resistance. It went from about 1.06 to 4.5 or so. Is this what I should have tested? Thanks a LOT for the help. It is REALLY appreciated. ~Rob

Keith

Whoops! Sorry about that. What I call the idle mixture adjust screw is called the "variable resistor" in the Haynes manual. The manual goes on to state that this adjustment can only be done by a dealer (HeHe, guffaw!). On my '87 TII, it is mounted on the passenger side strut tower in front, right next to the pressure/boost sensor. It seems to me it was in the same spot on my '88 NA (my memory is not to reliable - what were we talking about???) LOL. It looks like this: <#>. The pound symbol represents a hole with a screw inside it. On one side of the screw hole is a little stencil that has L<---->R on it. Hope this locates it for you, what you are thinking of in your post is the idle SPEED adjust screw.

Oh yeah, your resistance readings on the TPS are good. Just be sure that as you slowly open the throttle, the resistance doesn't ever jump to 0 or infinity.

Any more questions, lemme know.

Irv, Keith's dad

rgordon1979

iTrader: (3)

I can't seem to figure this out. I have a 90 GTU, n/a. I am convinced that there is no idle mixture adjustment screw or variable resistor on my car. I have looked all around the passenger side of the engine compartment, can't find anything at all. Is it buried in all of the vacuum actuaters above the headers?? I am at a loss. Let me know if you know anything about them removing this from the 90 on. Also, I can't find ANYTHING in the haynes manual about a variable resistor. AHHHHHHHAHAHAHHHHHHH

*****90 GTU for sale, maybe.......******

Keith

OOPS! I am so sorry, please except my apologies. This adjustment only exists on 86-88 cars. I didn't know we were talking about a 90. You are not going nuts, they don't have one. At least I was correct on the TPS advice, though. Unfortunately, I don't have any documentation on the 90, and never owned one. Hopefully someone who knows this area will help.

Irv, Keith's dad

rgordon1979

iTrader: (3)

Ok, that makes me feel much better!! I am going to try to se the idle using the jumper today. If that does not work, I think I am going to take to a local shop that specializes in Mazda and RX7 work. Anyway, thanks for all the help, I am sure I will be in touch.
Rob