SR Stutter and miss when engine is warm?

[1990 sr hatch]

Or if you have a voltmeter
A proper working cts reads at
°f 68 2100-2900ohms
°f 122 680-1000ohms
°f 176 300-330ohms
To test sensor, disconect sensor connector. See engine (coolant) temp sensor location table. Measure resistance across sensor connector terminals .if resistance is not as specified in engine (coolant) temp sensor risistance table, replace sensor

[BlackZenkiS14]

I already replaced the CTS with a brand new OEM unit.

The problem was there with the factory ignition as well as the splitfire. Upgrading to splitfire was one of the things I did to try to remedy it initially because my coils were all cracked.

[Mikester]

Kyle- did you say your plugs were a bronze/tan color? PLEEEASE tell me you don't use any additives.
I had a very nearly similar issue with my SR back in Okinawa... The short version of the story is that I swapped pretty much every fucking thing on the motor that you could possibly think of that could cause this issue... Of course thanks to that f####t Capt. Murphy the extreme last thing one tries is usually the thing that fixes the problem LOL- turned out to be my ECU warm loop was faulty... Brand spanking new power FC fixed it and I never looked back...

Given that power FC is pretty old and AEM infinity is modern and VERY AWESOME Albeit expensive... I think you need a new ECU (ahem... And dyno tune... Cough)

:-D

[quickdiversion]

I second Mike's opinion. At least try another know working ecu for testing.

[KoukiMonsta]

I'll third that opinion, cuz he said dyno!!!

In all seriousness if you can test a local ecu do it asap. This is starting to sound like the answer.

[BlackZenkiS14]

Its a tuned and calibrated JWT ECU, not something I can simply swap out.

[quickdiversion]

You call them all of you can send them the ecu for testing, or swap for one. You can also go through with them all that outs going wrong and what had been done. Tell them the ecu I all that's left and see what they offer?

[BlackZenkiS14]

Well, I back probed the ECU at the CTS signal and confirmed that I am getting the appropriate reading there as well....1.2V.

Also the problem is the same with the O2 sensor plugged in, and unplugged.

[cotbu]

I listened to your video and it sounds like spark is be cut out by something, fuel, water or oil maybe. Right after you get it to have the problem, shut it down and pull the plugs. I see you've pulled codes already. So it's not a true misfire or a misfire registered by the ecu or timing would be pulled and you said timing is still 15deg.

Disconnecting your tps, during your test should give the same results, a lazy throttle response. You could try clearing long/and short term fuel trims and set the tps to .445/.45v not .50v. That's an acceptable working range, only if it's registering closed and or the ecu has relearned.

The other option is to let the car get up to operating temp without touching the throttle, the first time you touch the throttle after completely warm, does it still stutter or miss?
If so, pull the plugs, do not idle excessively, you need to pull the plugs when the problem occurs.

[S14DB]

Originally Posted by BlackZenkiS14

I already replaced the CTS with a brand new OEM unit.

The problem was there with the factory ignition as well as the splitfire. Upgrading to splitfire was one of the things I did to try to remedy it initially because my coils were all cracked.

Spitfire doesn't replace the ignitor. It just bumps the power up on the constant.

[ultimateirving]

Originally Posted by S14DB

Spitfire doesn't replace the ignitor. It just bumps the power up on the constant.

Yup. The ignitor could still be heating up and failing. Have you tried a new one yet

[jr_ss]

I've been pointing at the ignitor since day one... Doesn't seem like he has looked into that aspect of it yet. In for updates.

[BlackZenkiS14]

I havent, as I dont have easy access to testing a new ignitor.

But I cant imagine thats the problem, because the car runs perfect until operating temperature is achieved, like clock work. like if I start it, let it idle until car is at operating temp, the issue will be there.

Its not like the engine bay needs to get hot, or the ignitor needs to heat up or anything, the ignitor is the in the very corner of hte engine bay on the intake side, away from all heat.

[jr_ss]

The ignitor still gets hot, regardless of its location. It's an electrical conductor with voltage constantly going through it.

PM me, I have a spare ignitor. I'll let you use it to test just send me a deposit. If it happens to be the problem you can keep it and we have the problem solved. If not you can mail it back and I'll return the deposit.

[BlackZenkiS14]

Originally Posted by jr_ss

The ignitor still gets hot, regardless of its location. It's an electrical conductor with voltage constantly going through it.

PM me, I have a spare ignitor. I'll let you use it to test just send me a deposit. If it happens to be the problem you can keep it and we have the problem solved. If not you can mail it back and I'll return the deposit.

Thanks a lot for that offer man, good dude. But I've got a couple friends within driving distance of me that I can probably try to snag one from, just haven't had time to get out and do it yet.

I've got my Nissan DataScan and PLMS cable coming in in a couple weeks that should help get it sorted out.

[jr_ss]

I'm sure Mike would be willing to let you "try" his if he is around. Besides, it sounds like he's going away for awhile.

[Mikester]

Originally Posted by jr_ss

I'm sure Mike would be willing to let you "try" his if he is around. Besides, it sounds like he's going away for awhile.

Yup- I will be home this weekend... Weather permitting, me & the 240 will be going on a date lol. Will be happy to meet ya Sat or Sun if you wanna give mine a whirl... Beyond that, get with Andy & tell him I said it's cool- he has my keys anytime I'm gone for more than a couple weeks & after this weekend, I will be gone till August.

I still suspect it's the ECU. JWT ECU's are still 20+ yr old SR ECU's... With a tune & maybe some copyrighted goodies added. Even if the whole board were brand new, they can still fail... Especially given Kyle's 'less than ideal' luck (much love broham lol)...

Had the same issue... Or at least a strikingly similar one.

Kyle- I sincerely hope it's the igniter.... But my gut still says ECU.


Mike

[quickdiversion]

I think I still have my old ignitor that I know works, cause I switched to ls2 coil packs. let me know if the ignitor fixes it, you can have it.

Mike, you being deployed again?
I texted you week, where ya been?

[Mikester]

Bryan- been at SNCOA in Alabama.

Kyle- fixed??? If so, do tell.

[BlackZenkiS14]

Well it wasn't the O2 sensor, I have the Nissan DataScan program, but I need a new laptop, mine shit the bed. And I need help translating the data, Cody has been helping but he's been busy lately.

I'm gonna try to get to the dyno soon and get a few pulls for more intel

[Mikester]

Did you ever get back with JWT? Why pay for dyno time when you know it stutters & misses when warm? I am off all next week, will be happy to watch your boost, AFRs etc. any evening on a long straight road :-)

[BlackZenkiS14]

Might take you up on that, but yea, JWT has been trying to help walk me through it as well.

[BlackZenkiS14]

Still no resolve. Same problem, gets worse in warmer temps as I noticed today.

Any fresh ideas?

[bataangpinoy]

This is happening to my s15 sr, but in reverse. It will randomly misfire and cut out as the temps get colder (ie if it gets cold at night). Sometimes it runs great, others, it will break up or cut IGN completely. In my car, it feels like IGN cut; fuel pressure is stable whenever it happens, as is boost level.
Leads me to believe its either a failing maf, or that I'm maxing my stock maf (if thats even possible).

In your scenario, being that it occurs when getting up to operating temp and its not your CTS, I am led to believe that a failing CAS is the culprit.I would open it up and inspect it...

[jr_ss]

Originally Posted by BlackZenkiS14

Still no resolve. Same problem, gets worse in warmer temps as I noticed today.

Any fresh ideas?

Can you update on what you have tried? That way people don't offer same advice, such as ignitor...

[BlackZenkiS14]

This week I am going to try to locate a new igniter and a new CAS to try. But here is what I have done so far.


I have cleaned the MAF, cleaned the IACV, and checked for vac leaks.
Plugs looked good, all a light brown/bronze/tan color, all equal across all 4 cylinders.
All the gaskets are quality OEM, all on the engine are less than 1200 miles old. All were attached using brand new hardware, locking nuts with locking tabs. Intake gasket is brand new as well.
Base timing is set to 15*, set just a couple weeks ago.
TPS reads .5v when closed and 4.1v when WOT
I replaced the Coolant Temp Sensor with a brand new OEM Facory Nissan part, and still the exact same thing. Revs great when cold, then begins to stutter and miss once it reaches op temp.
Checked codes, only code I get is the 55 "All Clear" Code.
I also checked BOV, BOV is in good shape.
I back probed the ECU at the CTS signal and confirmed that I am getting the appropriate reading there as well....1.2V.
Also the problem is the same with the O2 sensor plugged in, and unplugged.
Replaced o2 sensor with brand new OEM unit, same problem.

[KoukiMonsta]

Damn, was really hoping your post would be "I found the solution"

I am doubtful the CAS would be the culprit, based on its internals and design I don't exactly see temp effecting it.

I am still leaning towards ignitor, as it seems much more plausible especially with a past experience of mine. (pretty sure i mentioned it in this thread..car got hot...things went shitty)

Did JWT have any good leads for you? besides the stuff you posted?

I will be mind blown if its not ecu or ignitor related, considering all the testing and part swapping you have done. I just cant see what else may be the culprit - since this seems to be temp based...

That gives me a thought though, 'temp based' - as in temperature sensed by a sensor (CTS) or temp as in the engine bay heats up and components (ignitor) do weird things.

Just hoping to spark a thought or answer with some brainstorming, I kinda want to see that new turbo in action..

[BlackZenkiS14]

Tell me about it man, thanks for the intelligent thought!

I'm gonna start swapping things, and start logging some more stuff on Nissan DataScan and then go back to JWT if I am still having issues.

[BlackZenkiS14]

FML. Someone help me lol

Swapped ignitors with a known good ignitor, and then tested my ignitor on another engine...same problems persist.

Also, when you shift into the next gear, it totally falls out of the power band and has to spool back up from nothing and is very laggy on power. (it only does this when warm, when tested with a cold engine (before reaching op temp), it snaps into power immediately upon shifting into next gear and lights up tires)

[delado]

what do your AFR's look like when the break up happens? Maybe something to do with that tune?