Off Idle Hesitation Stumble

[Torinate]

Does this look dirty?

Can’t really get any better pics...

Are they supposed to be completely smooth?

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[kevinvan6000]

Hey Kevin.

Thank bud!

It’s pissing me off lol.

Been smoke testing the last hour and a half. Nothing! Not a bloody wisp anywhere. I keep taking more stuff off and pushing on stuff to try to find something but nada.

Compression test was great. Didn’t do a leak down. Guess I could borrow yours but honestly, if compression is fine and not showing anything not sure if a leak down would shown different.

I may borrow the borescope to have a look at the cats maybe.

I’m stumped and think I stumped even the smart guys lol.

I may take you up on the scope. I was hoping to find something with the smoke test but i think I’m going to call it - no vacuum leaks.

What’s your injector cleaner? Does it hook up on the rails or pull the injectors to do it? They were the single hardest thing to do on the whole install...

The injector cleaner I have, you need to pull the injectors out to clean them. I'll send you a dm with some info

 

[Torinate]

Sounds good.

There’s only a few thousand miles on the injectors but who knows. I may take you up on the scope and injector cleaner.

Got it back together but haven’t had a chance to drive it. Cleaned the MAF sensor but that data didn’t seem off in the logs.

 

[Torinate]

Just bumping this up. Hopefully someone can offer some ideas of possible causes and solutions.

Thanks guys.

Much appreciated.

 

[Torinate]

This is a custom tune. I haven’t had this issue in the past and it’s something new. It is getting really frustrating.

So far I’ve done a compression test and it was fine. Checked the plugs and they look new. Cleaned the MAF, changed the TB, did a smoke test and no vacuum leaks. I’ve logged the “events” but don’t see anything. Logged with Forscan and see many misfires but all random cylinders. Or rather, 1 2 4 7 and 8. Nothing to pinpoint anything specific. On logs where I take the rpm a little higher under boost afr stays consistent and. It leaning (other than the 1 episode where is dropped for 2 milliseconds).

Also did a KAM reset and crank relearn.

Plan now is to scope the cats and see if there’s anything. Change the plugs. Maybe change the fuel pump and try to clean the injectors but there’s only 4000 miles on them.

Anything else I should look at? I’m stumped! I can turn wrenches fine, but diagnostics is frustrating!

What else am I missing?

Thanks to Kevin for lending a few things. I think I’ve stumped his as well...

Thanks everyone!

 

[StangTime]

What was wrong with your old throttle body?

 

[scotty]

I was going to suggest to try cleaning the MAF, but looks like you already got that far... The only time I've ever experienced anything remotely similar is when I used to run the air filter open and it would get wet from water dripping through the hood vent .. I'd have to clean the contamination off of the MAF afterwards... but that would also be accompanied by the wrench light and limp mode.

Hope you get it sorted out and that there is nothing serious going on!

 

[downtoearth1986]

Just FYI. I was having some hesitation at various rpm speeds on my whipple mustang with the 1050x injectors. My car had similar issues as you have now including misfire codes on multiple cylinders. Long story short I ran e85 for about 5 months straight. Car sat most of the week. I ended up having a clogged injector plus a bad coil. I ran logs and sent the to palm beach dyno but we couldn't find the culprit. Car would take a unusual long time starting from a cold start. Car ran fine after I replaced my coil and cleaned the injectors. If you are having random misfires definitely check the coils and injectors.

 

[Torinate]

Just FYI. I was having some hesitation at various rpm speeds on my whipple mustang with the 1050x injectors. I usually ran e85 for about 3 months straight. I ended up having a clogged injector plus a bad coil. Amazon sell the injector pulsating kit for cheap that I used and it hooks up to any injector or carb spray can. Car ran fine after I replaced my coil and cleaned the injectors. The tool I got was called Allosun fuel injector tester and cleaner DYI tool set kit.

Thanks for that! How did you narrow it down to those two things? I’ve taken some forscan logs and I’m goi g to do one more right now. So far there’s nothing obvious at all. No codes etc.

Did you do logs and see something or just started throwing parts at it lol.

I’m going to clean the injectors (@kevinvan6000) has loaned me a kit similar to what you used. I’ve been dreading doing them unfortunately as that was the single most challenging part of whole installation.

Thanks!

 

[downtoearth1986]

Thanks for that! How did you narrow it down to those two things? I’ve taken some forscan logs and I’m goi g to do one more right now. So far there’s nothing obvious at all. No codes etc.

Did you do logs and see something or just started throwing parts at it lol.

I’m going to clean the injectors (@kevinvan6000) has loaned me a kit similar to what you used. I’ve been dreading doing them unfortunately as that was the single most challenging part of whole installation.

Thanks!

I first started with logging. Then I started throwing parts at it thinking what if lol. I replaced all 4 O2 sensors, rear crankshaft position sensor and those parts was never the problem smh. The car sat for a month because I was on travel assignment working so when I came back home to drive the car it took for ever trying to start. Then I noticed some weird hesitations when trying to get on the WOT. When I did the crank relearn was when my car finally threw a code and it narrowed my problem to the cylinders to check. I did almost everything including ohm my spark plugs to cleaning the maf sensors. I attached the codes my car threw at the time

 

[Torinate]

Thanks!

That's kind of where i'm at right now. This log I just completed with ForScan Mode$6. So I see misfires all over but still no codes and no direction to take.

Maybe someone here will see something and have an aha moment.

For now, my plans are the same. Scope the cats and see if there's anything amiss. Plugs have been checked and appear fine. But, will likely replace. Take out and clean the injectors when i've got a solid 2 days when I can do it. While out, I may as well replace the o-rings. Those that have installed the Edelbrock kit know the pain of installing injectors. Edelbrock does not feel it's the bypass valve as it appears to function correctly (but unsure if it holds vacuum to infinity) but opens and closes as it should. I do another fuel pump but AFRs have been fine and n sign of dropping off when logs run with the nGauge. STFTs appear the same as initial logs when tune was done. Hour and a half smoke test was negative.

This is the cylinder misfire counts. Anything else anyone want t see?

Misfire General Data A1
Total Engine Misfire and Catalyst Damage Misfire Rate A1 80 1.75 % 0.00 % 24.50 %
Total Engine Misfire and Emission Threshold Misfire Rate A1 81 0.20 % 0.00 % 1.00 %
Inferred Catalyst Mid-Bed Temperature A1 84 565.7 °C 0.0 °C 635.0 °C
Misfire Cylinder 1 Data A2
EWMA misfire counts for last 10 drive cycles A2 B 8 Counts 0 Counts 65535 Counts
Misfire counts for last/current driving cycle (calculated) A2 C 228 Counts 0 Counts 65535 Counts
Cylinder 1 and Catalyst Damage Misfire Rate A2 80 0.87 % 0.00 % 24.50 %
Cylinder 1 and Emission Threshold Misfire Rate A2 81 0.00 % 0.00 % 1.00 %
Misfire Cylinder 2 Data A3
EWMA misfire counts for last 10 drive cycles A3 B 3 Counts 0 Counts 65535 Counts
Misfire counts for last/current driving cycle (calculated) A3 C 47 Counts 0 Counts 65535 Counts
Cylinder 2 and Catalyst Damage Misfire Rate A3 80 0.00 % 0.00 % 24.50 %
Cylinder 2 and Emission Threshold Misfire Rate A3 81 0.00 % 0.00 % 1.00 %
Misfire Cylinder 3 Data A4
EWMA misfire counts for last 10 drive cycles A4 B 0 Counts 0 Counts 65535 Counts
Misfire counts for last/current driving cycle (calculated) A4 C 5 Counts 0 Counts 65535 Counts
Cylinder 3 and Catalyst Damage Misfire Rate A4 80 0.00 % 0.00 % 24.50 %
Cylinder 3 and Emission Threshold Misfire Rate A4 81 0.00 % 0.00 % 1.00 %
Misfire Cylinder 4 Data A5
EWMA misfire counts for last 10 drive cycles A5 B 4 Counts 0 Counts 65535 Counts
Misfire counts for last/current driving cycle (calculated) A5 C 20 Counts 0 Counts 65535 Counts
Cylinder 4 and Catalyst Damage Misfire Rate A5 80 0.00 % 0.00 % 24.50 %
Cylinder 4 and Emission Threshold Misfire Rate A5 81 0.00 % 0.00 % 1.00 %
Misfire Cylinder 5 Data A6
EWMA misfire counts for last 10 drive cycles A6 B 1 Counts 0 Counts 65535 Counts
Misfire counts for last/current driving cycle (calculated) A6 C 17 Counts 0 Counts 65535 Counts
Cylinder 5 and Catalyst Damage Misfire Rate A6 80 0.00 % 0.00 % 24.50 %
Cylinder 5 and Emission Threshold Misfire Rate A6 81 0.00 % 0.00 % 1.00 %
Misfire Cylinder 6 Data A7
EWMA misfire counts for last 10 drive cycles A7 B 0 Counts 0 Counts 65535 Counts
Misfire counts for last/current driving cycle (calculated) A7 C 36 Counts 0 Counts 65535 Counts
Cylinder 6 and Catalyst Damage Misfire Rate A7 80 0.00 % 0.00 % 24.50 %
Cylinder 6 and Emission Threshold Misfire Rate A7 81 0.00 % 0.00 % 1.00 %
Misfire Cylinder 7 Data A8
EWMA misfire counts for last 10 drive cycles A8 B 5 Counts 0 Counts 65535 Counts
Misfire counts for last/current driving cycle (calculated) A8 C 119 Counts 0 Counts 65535 Counts
Cylinder 7 and Catalyst Damage Misfire Rate A8 80 0.25 % 0.00 % 24.50 %
Cylinder 7 and Emission Threshold Misfire Rate A8 81 0.17 % 0.00 % 1.00 %
Misfire Cylinder 8 Data A9
EWMA misfire counts for last 10 drive cycles A9 B 15 Counts 0 Counts 65535 Counts
Misfire counts for last/current driving cycle (calculated) A9 C 63 Counts 0 Counts 65535 Counts
Cylinder 8 and Catalyst Damage Misfire Rate A9 80 0.00 % 0.00 % 24.50 %
Cylinder 8 and Emission Threshold Misfire Rate A9 81 0.02 % 0.00 % 1.00 %

 

[downtoearth1986]

Thanks!

That's kind of where i'm at right now. This log I just completed with ForScan Mode$6. So I see misfires all over but still no codes and no direction to take.

Maybe someone here will see something and have an aha moment.

For now, my plans are the same. Scope the cats and see if there's anything amiss. Plugs have been checked and appear fine. But, will likely replace. Take out and clean the injectors when i've got a solid 2 days when I can do it. While out, I may as well replace the o-rings. Those that have installed the Edelbrock kit know the pain of installing injectors. Edelbrock does not feel it's the bypass valve as it appears to function correctly (but unsure if it holds vacuum to infinity) but opens and closes as it should. I do another fuel pump but AFRs have been fine and n sign of dropping off when logs run with the nGauge. STFTs appear the same as initial logs when tune was done. Hour and a half smoke test was negative.

This is the cylinder misfire counts. Anything else anyone want t see?

Misfire General Data A1
Total Engine Misfire and Catalyst Damage Misfire Rate A1 80 1.75 % 0.00 % 24.50 %
Total Engine Misfire and Emission Threshold Misfire Rate A1 81 0.20 % 0.00 % 1.00 %
Inferred Catalyst Mid-Bed Temperature A1 84 565.7 °C 0.0 °C 635.0 °C
Misfire Cylinder 1 Data A2
EWMA misfire counts for last 10 drive cycles A2 B 8 Counts 0 Counts 65535 Counts
Misfire counts for last/current driving cycle (calculated) A2 C 228 Counts 0 Counts 65535 Counts
Cylinder 1 and Catalyst Damage Misfire Rate A2 80 0.87 % 0.00 % 24.50 %
Cylinder 1 and Emission Threshold Misfire Rate A2 81 0.00 % 0.00 % 1.00 %
Misfire Cylinder 2 Data A3
EWMA misfire counts for last 10 drive cycles A3 B 3 Counts 0 Counts 65535 Counts
Misfire counts for last/current driving cycle (calculated) A3 C 47 Counts 0 Counts 65535 Counts
Cylinder 2 and Catalyst Damage Misfire Rate A3 80 0.00 % 0.00 % 24.50 %
Cylinder 2 and Emission Threshold Misfire Rate A3 81 0.00 % 0.00 % 1.00 %
Misfire Cylinder 3 Data A4
EWMA misfire counts for last 10 drive cycles A4 B 0 Counts 0 Counts 65535 Counts
Misfire counts for last/current driving cycle (calculated) A4 C 5 Counts 0 Counts 65535 Counts
Cylinder 3 and Catalyst Damage Misfire Rate A4 80 0.00 % 0.00 % 24.50 %
Cylinder 3 and Emission Threshold Misfire Rate A4 81 0.00 % 0.00 % 1.00 %
Misfire Cylinder 4 Data A5
EWMA misfire counts for last 10 drive cycles A5 B 4 Counts 0 Counts 65535 Counts
Misfire counts for last/current driving cycle (calculated) A5 C 20 Counts 0 Counts 65535 Counts
Cylinder 4 and Catalyst Damage Misfire Rate A5 80 0.00 % 0.00 % 24.50 %
Cylinder 4 and Emission Threshold Misfire Rate A5 81 0.00 % 0.00 % 1.00 %
Misfire Cylinder 5 Data A6
EWMA misfire counts for last 10 drive cycles A6 B 1 Counts 0 Counts 65535 Counts
Misfire counts for last/current driving cycle (calculated) A6 C 17 Counts 0 Counts 65535 Counts
Cylinder 5 and Catalyst Damage Misfire Rate A6 80 0.00 % 0.00 % 24.50 %
Cylinder 5 and Emission Threshold Misfire Rate A6 81 0.00 % 0.00 % 1.00 %
Misfire Cylinder 6 Data A7
EWMA misfire counts for last 10 drive cycles A7 B 0 Counts 0 Counts 65535 Counts
Misfire counts for last/current driving cycle (calculated) A7 C 36 Counts 0 Counts 65535 Counts
Cylinder 6 and Catalyst Damage Misfire Rate A7 80 0.00 % 0.00 % 24.50 %
Cylinder 6 and Emission Threshold Misfire Rate A7 81 0.00 % 0.00 % 1.00 %
Misfire Cylinder 7 Data A8
EWMA misfire counts for last 10 drive cycles A8 B 5 Counts 0 Counts 65535 Counts
Misfire counts for last/current driving cycle (calculated) A8 C 119 Counts 0 Counts 65535 Counts
Cylinder 7 and Catalyst Damage Misfire Rate A8 80 0.25 % 0.00 % 24.50 %
Cylinder 7 and Emission Threshold Misfire Rate A8 81 0.17 % 0.00 % 1.00 %
Misfire Cylinder 8 Data A9
EWMA misfire counts for last 10 drive cycles A9 B 15 Counts 0 Counts 65535 Counts
Misfire counts for last/current driving cycle (calculated) A9 C 63 Counts 0 Counts 65535 Counts
Cylinder 8 and Catalyst Damage Misfire Rate A9 80 0.00 % 0.00 % 24.50 %
Cylinder 8 and Emission Threshold Misfire Rate A9 81 0.02 % 0.00 % 1.00 %

That is weird to have so many misfires in numerous cylinders like that.

 

[Torinate]

Exactly. Something globally causing it I would think.

Cylinder 1 is the worst followed by 7 and then 8. None of them are consecutive in the firing order so NOT playing off each other. Doesn’t point to a bad plug or coil. So with that info, does it point to fuel? Doesn’t appear to be a certain injector. So that leaves fuel pump. However AFR doesn’t fall off. I will say though, watching live data in forscan when idling and then driving, there are far more misfires at idle than anywhere else. Steady state cruising did not misfire. Under load up hill at lower RPMs did not misfire. Under load in boost showed a few random misfires. But idling they would pop up.

Frustrating!

 

[kevinvan6000]

Exactly. Something globally causing it I would think.

Cylinder 1 is the worst followed by 7 and then 8. None of them are consecutive in the firing order so NOT playing off each other. Doesn’t point to a bad plug or coil. So with that info, does it point to fuel? Doesn’t appear to be a certain injector. So that leaves fuel pump. However AFR doesn’t fall off. I will say though, watching live data in forscan when idling and then driving, there are far more misfires at idle than anywhere else. Steady state cruising did not misfire. Under load up hill at lower RPMs did not misfire. Under load in boost showed a few random misfires. But idling they would pop up.

Frustrating!

Wondering if it could be an intake manifold gasket gone bad?

 

[Torinate]

Wondering if it could be an intake manifold gasket gone bad?

Eek!

Maybe... guess that may be included when I pull the injectors. Everything is out of the way then so “easy” to get to the blower bolts to take it off. Big job though as it involves draining the intercooler and rad as well. No real way to lift the blower off without draining both.

Basically removing the whole thing. Was hoping for something a little less involved.

Any way to know for sure? Smoke tests didn’t show anything there.

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