C. Ludwig

iTrader: (27)

Background is that the car runs great at 3/4 throttle or less. Has good power until you try WOT. Anything over 3/4 throttle gives a miss like it's lean. Checked the TPS today and the initial adjustment, when checking the terminals at the ECU according to the manual, and it was a bit off. When I set the TPS so that that checks out the idle surges. And when I check the TPS according to the lights both lights stay lit no matter what the adjustment to the TPS. Does this sound like a bad TPS? IS there anyway to verify the TPS independent of the electrics on the car? Thanks.

Chris

tesla042

What year is your car? The 86-88's have a funny TPS where it only registers between like 0% and 30% of throttle. So if your problem is coming on at 75%, it's prolly not the TPS..

...not that your TPS is okay.. you disconnected the wiring harness to the TPS before checking it, right? AND the car was warm, right? Try using a multimeter to check the resistance between (i think) green and black. Should be ~1k at no throttle, and sweep LINEARLY (no big jumps) up to ~4-6k at WOT (or, on the 88's, when the TPS is all the way out [~30% or so]).

-Tesla

C. Ludwig

iTrader: (27)

Hey TESLA, did you see we were right across the river from one another? Kinda cool. You don't autocross do you? There is a guy that brings out a blue 2nd gen every once in a while.

Anyway, the motor is a 90. Why would you disconnect the TPS in order to check it? Is that what you were saying in your post when you asked if it was disconnected?

Thanks,
Chris

Keith

OK, we are going off on a tangent here. On an 89-91 RX-7, there are 2 TPS's, one being a "narrow range" sensor, the other being a "full range" sensor. As far as engine performance is concerned, the only TPS sensor that affects this is the narrow range sensor. It's entire range is covered before the throttle even reaches half way (just like the 86-88 cars). The full range sensor was added only to run the electric OMP. So, although you are having an adjustment problem on the TPS, if it is the full range TPS you are playing with, you will never adjust anything. The narrow range sensor is the one that controls ECU functions like ACV and solenoids. It should be adjusted for 1 Kohm with the engine fully warmed up, using the rightmost pins top and bottom on the plug, facing the pins with the latch on top. Oh yeah, this would have nothing to do with your 3/4 throttle problem. Hope this helps.

Irv, Keith's dad

C. Ludwig

iTrader: (27)

Now we're getting somewhere! Thanks Irv. That makes alot of sense now.

Any other thoughts on what might lead to such a problem? All the other sensors check out. Haven't checked the timing yet but I'm leaning toward that. The only other things I could think of is clogged secondary injectors or a bad ECU. Anything? Thanks again.

Chris

Keith

This could be a fuel problem. I would replace the fuel filter first. I have also heard of a pre-filter on the fuel pump in the gas tank sometimes getting clogged. If this doesn't help, I would check fuel pump voltage at the connector on the back of the drivers side rear strut tower. If you have 9 volts or less, you either have a bad fuel pump resistor relay or a bad ECU holding this relay on all the time. If you are at less then 13 volts (like 11 or so), you are not getting sufficient juice to the fuel pump and it needs to be rewired. If all of this is ok, I would check the plugs for the secondary injectors, they sometimes corrode. If okay, I would get a hold of a fuel pressure tester, T in to the supply fuel line, and check to see if you are getting 40 psi with no vacuum on the fuel pressure regulator. If this is ok, I would leave the guage on and see if it holds 40 psi or so WOT at high rpm. If this is good, fuel system is likely ok.

If fuel system is ok, must be ignition. Check wires for wear/arcing. If ok, replace leading plugs and try again. If ok, check MAF. If ok, swap out ECU. If ok, I am stumped.

Irv, Keith's dad

C. Ludwig

iTrader: (27)

Thanks. The car is an ITS roadracer with custom fuel system. Pressure isn't a problem and the filter is brand new. The thought of a clogged secondary is coming to the top as my number one suspect. We ohmed out the MAF and I'm trying to get hold of a second ECU to try. Guess I'll grab some plug wires while I'm at it. Sounds like I'm on the right track. Just didn't want to be skipping anything obvious. Thanks again!

Chris