RB25DET S2 hesitations , I dont know where to start....?

[240z4u]

Have you done a boost leak test?

[DrifterProdigy85]

I have. Tested to 30psi with no leaks.

[Carryl]

I noticed you mentioned you had changed the TPS, i had a similar issue. Have you adjusted your idle switch so that the ecu comes out of idle at the crack of the throttle? Its pretty easy if you have consult wired up etc. It fixed my problems which seem to be identical to the ones your having.

[ka24eracer]

I will take a look for sure , I hope I ll find the problem before sunday !!

[DrifterProdigy85]

I noticed you mentioned you had changed the TPS, i had a similar issue. Have you adjusted your idle switch so that the ecu comes out of idle at the crack of the throttle? Its pretty easy if you have consult wired up etc. It fixed my problems which seem to be identical to the ones your having.

What do you mean by the idle switch? The car revs and drives perfectly fine but steadily gets richer and richer as the rpms increase at WOT. Im gonna switch back to stock coilpacks and see if that changes anything.

[ka24eracer]

Im bringin back this thread because I did not solve my problem .

The engine is still bucking and I found out the worst case :

If floor it , then let go , then floor it , then let go ...rapidly It can take 10 second before I can gently get power again .

Sound like fuel , but I got a 255 , Nismo Fpr that I tried from 40 psi to 50 psi without improvement .

Oh and If I do like I said before , but going like 90% throttle , no problem at all ( I.E. 90% throttle , then 0% , then 90% , etc rapidly )

Its always the WOT that kill my engine HELP PLEASE

[ka24eracer]

If I unplug the TPS ( both plug cause I have a SII ) and it STILL hesitate , can I remove the tps from potential suspect ?

[DrifterProdigy85]

I just fixed mine. It was the electric fans pulling too much from the alternator making the electrical system weak. Im using the clutch fan now and drives beautifully. Only other thing im gonna change out is the Coolant Temp Sensor cause its cruising on the rich side, right around 13.0. You should definitly look into getting a Wideband. Knowing the AFR tells alot about how things are running.

[ka24eracer]

The hesitations I had were caused by the TPS , the car is just slower when unplugged but no hesitations !

The car ran fine for a day and then , its now running pig rich all over the rpm range but horrible at idles !

No leak , brand new coolant temp sensor .... I HATE THIS ENGINE

[DrifterProdigy85]

So your TPS is unplugged now?

[ka24eracer]

I plug it back on because the car is slower when unpluged , I learned to drift with the WOT hesitation I guess ...

The car also seem to run better with the O2 unplugged ...

Right now my theory for being rich is because the CTS was bad , I replaced it but now my plugs and o2 are dead , causing the car to still hesitate at idle and while cruising .

[DrifterProdigy85]

The car runs leaner without the O2. I don't have an O2 on mine right now and it cruises around 16.5 and goes down to 12.5 to 11.2 at WOT.

[FinkenS14]

Still having these same problems with my RB as well, made a post on it

When you wired your ahrness, or sent it out, how did you get pwoer to your injectors.

I know n a S1 RB25 into an S14 you need to give the grey wire for the injectors a key on 12v source. I sourced it out from my ignition relay. The ACTUAL relay. Kinda jus stuck the wire in there. So you could say its rigged. Maybe changing that will fix my exact issues your having.

[FinkenS14]

Still having these same problems with my RB as well, made a post on it

When you wired your ahrness, or sent it out, how did you get pwoer to your injectors.

I know n a S1 RB25 into an S14 you need to give the grey wire for the injectors a key on 12v source. I sourced it out from my ignition relay. The ACTUAL relay. Kinda jus stuck the wire in there. So you could say its rigged. Maybe changing that will fix my exact issues your having.

I also got a busted intercooler clamp, but this was happening before the clmap busted.

[DrifterProdigy85]

I had my wiring done by Mckinney. Everythings working great there. Injectors are all spraying and the fuel pump primes like it should. All thats wrong with mine is tuning at this point. Runs great on stock booost but hesitates over that which is probably just the ignition and fuel maps. No big deal anymore. Enthalpy said he can tune a Z32 ECU for me. Says he can roughly get 285-300whp with 1 Bar boost on stock setup.

[N!SMO SILVIA]

Im sure it has to do with your spark plugs. A day ago mine didn't have that problem and today that I changed the spark plugs mine started to hesitate when I step on it. I have the same spark plugs as you so that makes two of us with the same problem. Oh and my idle also went down so now it has low idle. Does anyone know if that problem relates to the spark plug problem?

[ka24eracer]

My main problems was the tps , even adjusted properly , its didnt work. I unplugged it and the car was almost perfect . The engine is out of the car now .

[DrifterProdigy85]

The only time mine misses is at high rpm with 10+psi. It just needs tuned at this point.

[opticnerv]

did you check to see if the throttle cable was sticking to the hood ?