Engine stalls on deceleration after high load and cluth in

[CHIEFAPONTE]

I need help sorting this problem out. My car has a rough tune that makes the car run well and idle well. accelation is much better as it reflects the mods below.

My car is a 1991 R32 GTR wit a nistune FP board.

I recently upgraded injectors from stock to 600cc and mafs from stock to z32's.

like I said, the car runs very well, AFR's and timing are close to the targets. My only problem is that when I clutch-in after a high speed run, the engine dies(RPMs fall to zero) my log does not show any crazy MAF voltage spikes.

Please see attached log and BIN. The rpms drop to zero at times 4:15 and 8:19.

Please help

[Matt]

The starting time of the problem is 04:01 where you cluctch in and then the load (MAF, TP) start dropping but RPMs are maintained around 3000rpm

When this happens the injection time drops a little until 04:03 where the MAF voltage takes a dive (whilst RPMs still around 3300rpm) which makes the injection time plummet (and AFRs start going south from 11.5:1 to 23:1 or leaner

Your injection is cut at 4:07 (to value of injection latency) whilst RPM keeps droping and then recovers 1150rpm.

However post recovery for some reason your AFRs are still showing super lean from 4:08 - 4:11 when the RPMs gradually die. This is despite there being about 1.8ms or so of injection at this point

Try increasing your Min Load (TP) values so that it does not cut injection as much around idle
Your latency is too low and is causing issues when it does its fuel cut. 400uS is very low compared to the 770uS factory value, so stick back with factory values and it wont go so lean. What is the advertised dead time @ 14V of your injectors?

[CHIEFAPONTE]

Matt. Thanks for the reply. The injectors i have are hks purple ones and the advertized latency is 402 . My wideband went bad on me in the middle of this trial which is the reason it reads so lean. It is a innovate with a new sensor and heat sink. I tried the calibration,re- wiring it and nothing. It reads ok at first and withing a few minutes the afr increases to 22.4.

I will adjust the latency and k and go for another run.

Thanks

[CHIEFAPONTE]

Matt. I adjusted the latency to stock and made adjustments to TIM.

on my run today the car still managed to stall after a hard acceleration. My MIN LOAD (TP) is set at 8 accross the board.

How high should i go to keep the car from stalling?


This time I lowered my boost to 8 psi. the load index never went above 69. One thing of concern is that I reached RPMs above 7000 but the NISTUNE log never shows RMPs going that high????

[Matt]

Replied to other post. Try latency around 700uS and the TPmin around 10 and then take another log

[CHIEFAPONTE]

Matt. I installed the R35 MAFs and the stalling is gone. The tubes I used are a kit from SPECTRE P/N SPE-9405. It is a universal kit that uses a 3" tube

[Matt]

Looks good!