LambertZ6

So I've been having a very weird problem for a couple of months with my TPS. I've pretty tired everything except for replacing the ECU. About 4 months ago I started having a rough running from idle to 4K in my car. And after a lot of research, it narrowed down to my TPS. After checking it it was off and had a lot of dead zones between idle and full throttle. So I replaced it a new from AZ. They fixed it for about 2 days and then my problem got worse. The car wouldn't even fire right until I got past 4K. So I did the same thing, bought a new TPS sensor from Honda. This kind of fixed that problem, but I've got a whole new problem now. Now it feels like I have a hell of a dead zone until after 25% throttle. Feels like the ECU is not telling the fuel pump to pump gas until after 25% throttle until I get up over 3k rpm. It will just not go. You can feel and hear it doing this even sitting still with it not in gear. And throttle response is absolute ****. Literally a half second delay. You can hear the intake open and then a split second later feel the fuel come in. Everything is reading correct at the sensor and at the ECU with voltage, .5 at idle and 4.52 at full throttle. I've also replaced the dizzy, wires, plugs, fuel pump, filter, and regulator. I'm pretty much stumped at the moment. The last thing I can think of is the ECU. And btw, no CEL codes at anytime.

Also it doesn't run right after I'd say 80% throttle. You feel it just bog with that much throttle. And it feels like it's running rough until after 4K still at times

mk378

Check the timing. If the spark timing doesn't come in near the center of the adjustment range, cam timing may be off.

LambertZ6

Timing is in check, that was one of the first things I tested. It definitely feels like an electronic problem, rather than anything mechanical. I've adjusted all the valves just to be certain on that.

creizlein

It happen to me a few time ago with a p28 chipped ECU that it wasnt reading the TPS signal correctly, alltrough the voltage were 100% fine as you mention, .5v closed and 4.50v on WOT, the ECU (which had a s300 on it) was reading about 3-10% closed and only 50-60% when fully opened, and it was varing all the time as well, so i ended up changing the ECU and the problem went away.
I know this doesnt help much, but at least I can confirm that it might be possible that some internal components on the ecu are failing, see if you have the option to borrown another ecu and give it a try, Specially considering you have tried almost everything else.

LambertZ6

Appreciate the input, it's what I've been thinking. Just didn't know if anyone else has had this problem or not. I know had something similar with an AICV back in 2009 with my 93 del Sol I used to have. Ended up having to chance the ECU in that as well. Seems like when you get over 250,000 on original electronics in Hondas, they seem to go bad lol.

Badcopyinc

Not sure how much a new one is but its always worth it to take it apart and see if there's any corroded parts inside. Usually components don't go bad excluding caps and resistors which are cheap.

post pictures if there's anything worthy to see ill help with what i can if you decide to try to repair it.

truth is we don't get a lot of ECU's for hondas. which tells me whatever went wrong with yours was not because of natural causes.

LambertZ6

Sorry for the late bump, but I now have my problem figured out and fixed. First, I was right about the bad ECU, it has some black spots on the board close around the same spot. I plugged in the new ECU and drove it for two days. My hick-ups at first acceleration went away right at the start, no longer had that issue. But was still having the half to full acceleration problem, it just bogging. After the two days, I got a CEL, finally! O2 Sensor code. Replaced the O2 sensor, and boom, no more problems.

Stephen Wyckoff

I have a 94 del sol si and i have the same problem but if i dont keep it at over 3k rpms the rpms gose down to 0 but the motor dose not die and if i give it gas i can put the peddle to the floor and it will not do anything. Still dont know whats wrong with it.