Engine Cutting Out Randomly

[heycharger]

Hi all, I recently picked up a pretty worked R33 s2. Always been into Valiants/Chargers so this is a little different.

The car has been great but in the last 250km's or so it's developed a problem that seems to occur the more I drive it. At random times when driving, whether running low or high boost, whether the car has been running 5 minutes or an hour, the throttle simply dies. It feels like I've taken my foot off the accelerator pedal; it just looses throttle. Then 1~3 seconds later it kicks back in. Then dies again. etc. It mainly happens driving around town (low RPM), but has occurred on the highway too. Additionally a couple of times when I've started the car up it hasn't idled as high as it usually does and even after warming up for a few minutes it conks out when reversing out. I don't thrash the car (much...) and have only had it happen when doing normal driving, IIRC.

I checked the Power FC hand controller and when this occurs the InjDuty momentarily hits 0% (or otherwise decreases significantly) and IgnTiming drops significantly too (i.e. ~50% down?). The other stats on the 8-way readout appear normal. The throttle 'dropouts' only occur for a split second or couple of seconds then it's fine, then a couple/few seconds later happens again. Usually the problem disappears a minute or two later but it happened yesterday intermittently for about 20 minutes and today seems to be hanging around and showing it's head every 10 minutes for a minute. When the problem happens, there's sometimes (but not always?) a clicking at top of engine; unsure if related (only noticed that this morning once when I had the bonnet up, then it went away).

BTW car was recently tuned and runs very hard 95% of the time without ANY problems whatsoever, so I guess it can't be the tune. Knock is still very low (usually 1~10; hasn't changed since this problem started) and I'm strictly running BP Ultimate 98.

EFI/turbo's are new to me and I feel a little lost...what am I dealing with here?

Any help would be GREATLY appreciated.

heycharger

[GTR-N1]

Wondering if you've got a mate with the same ECU and do a temporary swap. > See if his car does it & yours doesn't.

[heycharger]

Thank you for the quick reply. Unfortunately I don't know anyone... For the record I think it's a Power FC.

Any other ideas? Could it be a vacuum leak somewhere...?

[-Jimmy-]

Very nicely explained, I'm having the same problem on my RB25DE NA... Got no idea what it is or how to test it? Some people say it could be a dodgey AFM but I have sprayed the sensor inside with carby cleaner as suggested, and resoldered all the joints tightly.

[wht510]

The best way of telling whether you have a problem is to plug the car into a laptop with diagnostic software (I bought some diagnostic software = "Nissan Data Scan" for my SR20DET for $40. You need a plug as well to plug into the OBDII plug on the ECU. which is under $100.

THEN you can find all the problems with the motor and see if all the sensors are ok! Easy!