z32 rich and non matching dual wb during warmup, random miss when warm

Post here where your issue is not tuning specific but more of a sensor or mechanical issue
xlr8
Posts: 28
Joined: Fri Oct 12, 2018 8:27 am

Re: z32 rich and non matching dual wb during warmup, random miss when warm

Post by xlr8 » Tue Oct 13, 2020 2:58 pm

looks like i can rule out the ecm / nistune board.
with stock injectors / tune, it performed very similar to the same problems with larger injectors. mismatched banks during warmup...one side spot on stoic and other rich then snap closer to each other when warmer...then they flip flop and other side goes rich and opposite stoic at full temp. (as before the random misfire happens more often the warmer it gets) I logged it all but i updated nistune before doing anything and it gives some sort of log error and wont save it. i will fix that later and post the log.
anyway, i also bought another ecu (same jdm p/n) and it acts the same...pretty much ruling out the nistune ecu as the culprit !!
it is quite puzzling though, it drives fine off idle, it can keep a clean matching burn both banks, no misfire...but as soon as i snap back to idle its mismatched again. after a bit of a test drive it started to lean out again (not as drastic like with the larger injectors). and again...i turn on the a/c and they hit 14.7 matching banks at idle !! omg im going bald on this issue !!

Matt
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Re: z32 rich and non matching dual wb during warmup, random miss when warm

Post by Matt » Thu Oct 15, 2020 8:14 pm

That is kind of good that you eliminated the ECU with the factory injectors, and reduces the potential culprits but doesn't help you figure out why its doing what it is doing.

The only suggestion is look at everything which is changed from stock, or try and compare what you see against a stock 300ZX (if possible)

xlr8
Posts: 28
Joined: Fri Oct 12, 2018 8:27 am

Re: z32 rich and non matching dual wb during warmup, random miss when warm

Post by xlr8 » Sun Jan 03, 2021 8:56 am

just touching base here. no fix yet. setup is still stock ecu and injectors, with same symptoms. i finally got some garage time again, so i went back through all the wiring (even though everything under the hood is new.) all continuity's to ecu are good, no shorts to ground, all proper battery voltages are present when backprobing. did in line spark check on all 6 again, no irregular spark. soon as i can get back to it i will noid light all injectors, do another compression test...if all that passes, im going to rip off the exhaust and listen to tell if the miss presents itself in only one bank. this car just doesnt want to be obvious with its issues, very illusive. if i unplug any coil or injector, doesnt matter which one, there is no longer any audible miss. very tricky.

xlr8
Posts: 28
Joined: Fri Oct 12, 2018 8:27 am

Re: z32 rich and non matching dual wb during warmup, random miss when warm

Post by xlr8 » Sun Jan 03, 2021 3:17 pm

well this car is making a fool out of me yet again. was prepping to do the noid and compression tests, thought for kicks i would put the un modded ecu in again while doing the warm up. and just my luck the wb readings are spot on matching... there is still a slight rumble as it got warmer, but im amazed at how well its burning clean in both banks. i have a bluetooth nisbie and logging software on my phone and the stock O2 are fluctuating off idle 0 to .8 as they should? (this is how i tuned 3000gt years ago is so im thinking its correct). and injector pulse seems stable. i couldnt get to full warmup temp sitting in the garage so tomorrow i will do another warm up and drive it to get to full temp. wish me luck !!
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xlr8
Posts: 28
Joined: Fri Oct 12, 2018 8:27 am

Re: z32 rich and non matching dual wb during warmup, random miss when warm

Post by xlr8 » Mon Jan 04, 2021 6:11 am

pretty stoked after todays test drive. its driving like it always should have !!! burning clean in every gear every pull, both banks. at very first start up it was around 15 on one side, 14.5 on other, changed up in seconds and stayed 13.6 (ish) on both banks through rest of heat cycle. not sure how normal it is for the z32 to run slightly rich at idle, as this is my first one. Any input on this would be greatly appreciated. but every condition off idle, it fluctuated close to 14.7. so happy (knock on wood) that it has so much power now. i still dont suspect the nistune board, but maybe a problem with my original ecu like it cant properly translate either the stock o2 sensor inputs or injector outputs. when i got this car it was in horrible shape, injectors were all green corroded and all engine bay connectors just crumbled apart when touched. so there could have been some ecu capacitor damage or something (purely speculating) from struggling to keep continuity or proper voltage. i will daily it this week to make sure today wasnt just a fluke, and most likely send both ecu's to you for a board swap service, so we can (possibly) find out once and for all what the problem was, and so i can finish the flex fuel system and tunes. i appreciate your patience on all my rambling Matt. take care and happy new year !!

Matt
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Re: z32 rich and non matching dual wb during warmup, random miss when warm

Post by Matt » Mon Jan 04, 2021 1:26 pm

Thanks, happy new year for you it sounds like too!
i still dont suspect the nistune board, but maybe a problem with my original ecu like it cant properly translate either the stock o2 sensor inputs or injector outputs.
What are the part numbers of both ECUs? Maybe we could see from moving the original (working factory) ROM chip to the one with the Nistune board to see if there is a problem there

So you just need to get the current factory ECU socketed, and then can switch things over.

Perhaps there is an issue with the ECU with the Nistune board fitted

The Nistune board is loaded with factory firmware initially, so that should not run differently. Swapping it over still indicate if there is an issue, but should be the same with factory maps uploaded.

xlr8
Posts: 28
Joined: Fri Oct 12, 2018 8:27 am

Re: z32 rich and non matching dual wb during warmup, random miss when warm

Post by xlr8 » Wed Jan 06, 2021 1:31 pm

they are both the same jdm ecu
23710 41p13
a18-000 m05
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thank for the advice that makes sense. i will be doing a clutch upgrade when i get time, so while its down i will get the ecu's taken care of.
ive been driving it for a couple days now its doing good so far. still a little rich at idle (13.7) so i still need to track that down. but off idle or with a/c on at idle its perfect 14.7 !! i'm finally enjoying this car. no mismatch banks and i dont feel or hear any missing. i almost cant believe it haha.
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