Intermittent issues

[Crazy]

1986 nisan 300zx turbo with a nistune converted 88 non turbo ECU......Car runs good just sitting idling , then all of a sudden the engine shuts off. I figured out when it dies it went extremely rich. Nistune was not connected to the ECU for two years (the car ran 12.40s @ 114mph in the 1/4 mile on this tune). I connected Nistune to figure out why the engine kept shutting off.......

[Matt]

You will need to stay connected if possible and log until it dies. Then can see what is going on. Strange issue

[Crazy]

What do i log along with the wide band AFR, RPM, & water temp?
What is cylinder temp sensor listed under?

[Matt]

It will log everything which is displayed in the consult gauges (doesn't need to be displayed in the logger). As long as you have consult connected that should be enough

[Crazy]

I took a log. I didn't get the LM1 hooked up.

[Matt]

Thanks for the log. Some things I've noticed...

This is idling really right (should be about 800rpm) but I'm seeing quite an inconsistent around 1300rpm idle. Next there is no TPS idle indicator and timing is around 39 deg BDTC. Probably related to RPM issue. Check your TPS idle switch

Second part is the cut out 60 deg C coolant temp, end of log injection double when it dies

Related to this:
viewtopic.php?f=7&t=3153

5.23ms to 9.22ms after hitting 60 deg C and it dies. Something to do with switching to sequential injection and adding more fuel not working right with the injectors any more... not a tuning specific issue but would suggest fixing TPS switch and flow testing injectors

[Crazy]

The car stopped running good at all now. It runs bad all the time! I had a popsicle stick under the throttle blade adjustment to do the log because it runs so bad. I did buy a new board from Andy and installed and nothing changed! I will install the ecu in my stock Nissan 300zx 86 turbo and do a few tests.

[Matt]

Yeah I don't think its an ECU problem... something else has gone wrong

[Crazy]

Yeah I don't think its an ECU problem... something else has gone wrong

I installed the Nistune ecu in my stock Nissan 300zx 86 turbo with the correct image and the car runs great!

On the problem car I changed the coil, dizzy, new cap, rotor, wires. next is new CHTS and CTS I just ordered from Nissan....
Fuel pressure is at 40 psi...

[Matt]

I don't think the problem is sensor (temp sensor) or ignition (spark) related. Looks like a fueling problem with the injectors if it happens at that point. Hence checking flow testing

[Mercennarius]

Sounds like it has something to do with the injector recall/service campaign to me. In the US nearly all Z31s went through a service campaign in the mid-late 90s rewiring the injectors. See below:


NTB96-010a: March 15, 1996 (U11, Z31)
NTB96-010b: March 18, 1996 (U11, Z31, F31, S12-V6)
NTB96-052: May 17, 1996 (S12-V6)
NTB96-010e: May 17, 1996 (U11, Z31)
NTB96-024: May 17, 1996 (F31)
SBN-004: May 17, 1996
NTB96-010g: August 28, 1996 (U11, Z31, S12-V6)
NTB97-035: April 30, 1997 (Z31

"Nissan opted to install a new injector sub harness. Before the service campaign, the ECU had two firing modes, simultaneous and group. Simultaneous Injection mode means that all injectors fire at the same time. This mode is when the engine is over 3000 rpms, injection pulse duration is more than 6.5ms, or cylinder head temperature is below 60oC or 140oF. Group or Batch Injection mode means that the six injectors are divided into two groups. The groups are cylinders 1, 2, 3, and 4, 5, 6. These groups are fired once each engine cycle 180o opposite of each other. After the service campaign, the ECU still has both of these firing modes. The only difference is the groups. The new groups are 1, 3, 5 and 2, 4, 6. "

http://z31.com/wiki/doku.php?id=resourc ... _injectors

[Matt]

Thanks for the info. That confirms the 6.5ms change over time we see on these ECUs (and similar with the S13 CA18DET) and matches what we saw in the logs with the 60 degC

[Crazy]

Matt, I found the problem. I just kept replacing parts till I found the problem. The z32 MAF only wanted to work half of the time then died completely.....I got a used factory stock z32 MAF on ebay and the car runs great!

[Matt]

Good that you finally sorted it!