Engine cutting out at 3k rpm in WOT

Venompower

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96' Cobra with 54k miles
- Procharger Stage 2 P-1SC with 3 Core Intercooler and Big Red Blow Off Valve
- VMP Blow through setup
- 42 lbs./hour injectors, unknown fuel pump
- NGK TR6 plugs gapped at .030 with less than 10 miles on them
- Stock Coils and Plug Wires
- Probably tuned by DynotuneMp based on stickers on the quarter windows, but since he saves tunes by owner name we cannot verify.

So finally got to take my first real drive in the car Sunday after getting tires, and attempted after warm up to do a short pull in first and experienced an abrupt hard cut out in power during WOT around 3k rpm.

Today I took it to a shop to schedule an exhaust installation and took these videos on the way home. Same thing WOT around 3k and the engine cuts out. AFR was in the 11’s when this occurred. My birthday is a week from today and I planned on picking up an SCT X4 so I can data log. In the meantime has anyone experienced this and can point me in the right direction?


 
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07GtS197

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What does the afr do after it cuts out? Just from the video I’d say it’s weak coil packs but could also be maf or boost related.
 

Shifty Powers

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So it was tuned by a shop and they cant tell you if they did it? Thats silly. Also the car didnt come with a tuner? That is just crazy to me.

Sounds like either something in the build but more likely the tune itself. You will need to get a tuner and have it redone quite possibly. Or have the asshat that did it fix it.
 

Venompower

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What does the afr do after it cuts out? Just from the video I’d say it’s weak coil packs but could also be maf or boost related.

When I was driving the AFR was fine, it went into the low 11's during the pulls. If it's ignition I'm guessing it's coils as well, because it's not the kind of stutter or break up caused by a single cylinder or even a few cylinders with bad plugs/wires. The plugs are all brand new NTK TR6 gapped at 0.030 with less than 10 miles on them. I've let it idle at night and no electrical show from arcing plug wires either.

MAF could definitely be an issue as it was converted to blow through and has a slot style VMP MAF soldered in, instead of the plug and play harness. I finally got my laptop, have Live Link Gen 2 downloaded with a config file from decipha on svtperformance. I'm going to make some logs tonight and over the weekend, idle log, rev log 1.5k, 2.5k, 3k holding each for 15 seconds, then a 5-10 minute drive log through town, and a WOT log. Hopefully between these, knowledgeable people can see areas to focus on with troubleshooting.

So it was tuned by a shop and they cant tell you if they did it? Thats silly. Also the car didnt come with a tuner? That is just crazy to me.

Sounds like either something in the build but more likely the tune itself. You will need to get a tuner and have it redone quite possibly. Or have the asshat that did it fix it.
The tuner is DynotuneMP which is locally known as the best tuner in the area specifically for Mustangs. I really don't have any reason to doubt the quality of the tune, but due to them saving their tunes under owner name I can't verify. It's their shop to run, but I think VIN or partial VIN would be better with these amount cars change hands. The SCT tuner that came with the car is long gone, my guess is a previous owner sold it separately. I did order a new SCT X4 and just received a new laptop in the mail, I will be datalogging. The plan is to potentially take it back to DynotuneMP for a few dynopulls to verify the tune is solid, to be applied to a retune if not. However, I'd like to get the cutout resolved prior as I don't want to waste expensive time trying to troubleshoot there and would rather have the time be spent polishing the tune.
 
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07GtS197

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I see your thread over on SVTPerformance there are some knowledgable people over there. Between here and there I’m sure you’ll figure it out.

Something I forgot about, did your tuner delete the knock sensors? You could be getting excessive or even false knock pulling timing.
 

Venompower

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I see your thread over on SVTPerformance there are some knowledgable people over there. Between here and there I’m sure you’ll figure it out.

Something I forgot about, did your tuner delete the knock sensors? You could be getting excessive or even false knock pulling timing.
Not sure... the logs should show if timing is being pulled.

Some people speculated bad gas as the car sat for reportedly a year with very low fuel. I filled up at Speedway with 93 octane because it was close, but have been advised to use Shell or another top tier gasoline. While I don't hear any detonation, it's possible that the PCM is sensing it and saying I don't think so... the cutout certainly feels like that, you feel it in the accelerator pedal similar to traction control where even though your foot is down the power just drops like your foot isn't doing anything.
 

07GtS197

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Could be bad gas or even water in the gas. You could drain the tank and start over if you feel advantageous.
 

ttocs

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I am not sure why bad gas would make it cut out at 3k but as he said if it is the motor pulling power it should show up on the logs.

I didn't know you have an aftermarket maf. Is it in a place where you can turn it and play with what angle its at? At higher rpms and with more air moving it could be in a bad place that does not register at higher rpms. I have read about people turning the maf to tune where it is in the flow of the air and it might be that simple.
 

Venompower

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I am not sure why bad gas would make it cut out at 3k but as he said if it is the motor pulling power it should show up on the logs.

I didn't know you have an aftermarket maf. Is it in a place where you can turn it and play with what angle its at? At higher rpms and with more air moving it could be in a bad place that does not register at higher rpms. I have read about people turning the maf to tune where it is in the flow of the air and it might be that simple.
Sorry yeah it's a VMP slot style MAF but it's in a straight VMP housing right before the throttle body pipe.
 

Shifty Powers

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Ok.. First you do not need a dyno tune for this car. Once you have a tuner and you actually know the parts on the car, you supposed best tuner in the area should be able to do so remotely. If not, since your MAF is VMP, contact VMP and they can send you a tune and i can bet it will work. THESE CARS DONT NEED A DYNO TUNE FOR BASIC SHIT. The computers are basic as shit.
-- Yes your shop is stupid for not being able to identify the car without the original owner(they should fix it). There are probably people on this forums, that for fun, could write a tune that could get the car running easy peasy to get it to a tuner for you if you really felt you needed to dyno it.
 
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Venompower

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Ok.. First you do not need a dyno tune for this car. Once you have a tuner and you actually know the parts on the car, you supposed best tuner in the area should be able to do so remotely. If not, since your MAF is VMP, contact VMP and they can send you a tune and i can bet it will work. THESE CARS DONT NEED A DYNO TUNE FOR BASIC SHIT. The computers are basic as shit.
-- Yes your shop is stupid for not being able to identify the car without the original owner(they should fix it). There are probably people on this forums, that for fun, could write a tune that could get the car running easy peasy to get it to a tuner for you if you really felt you needed to dyno it.

Knock sensors? Ignore that. Not sure why that is the first go to. But yes you can use the tables to basically turn them off. But that is not where i would start
Because the car has a Stage 2 Procharger P-1SC my preference would be to data-log and hopefully have someone read therm and point out any glaring issues. Then once the car is running decent have a full dynotune done so I know the tune is spot on and I know the power level as I believe im on stock internals.
 

ttocs

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I had a remote tune done on my car and the first thing he did was turn off the knock sensor that I installed. He said that you need to do some tuning and adjustments on it with datalogging for it to be helpful and with out doing that they are more trouble than they are worth. That very well could be the problem maybe try unplugging it and see what happens?
 

07GtS197

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My thoughts exactly. It could be pulling timing like a mofo from real or false knock. I’ve had that happen on my 07 Gt a few times and that’s what it felt like.
 

Venompower

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I had a remote tune done on my car and the first thing he did was turn off the knock sensor that I installed. He said that you need to do some tuning and adjustments on it with datalogging for it to be helpful and with out doing that they are more trouble than they are worth. That very well could be the problem maybe try unplugging it and see what happens?
Just sent a picture of the log to the tuner I’m hoping to use and he said the only thing that looked off was the battery voltage. He said it looked extremely low. He said before he would even do further diagnostic if i brought it he would need me to replace the coils with new OEM.

So I will likely order coils and plug wires, but I really need to figure out the voltage. I trickle charged the battery last night measured at the battery while taking the log and had 14.2-14.4v. When I had the bad negative cable connection I had a similar drop where the other fuses displayed 7v…
 
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Venompower

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The grounds in the engine bay are fine, and using the multimeter I'm getting 12.5v when I touch them with the negative lead. The ground by the PCM looks intact and completely untouched. The Battery Voltage PID is displaying 7.9375v with no cel or codes. Everything works... my idle is rough, the exhaust note is off, and I'm having the already reported cut out issue.

Going to check the PCM power output relay in the CCRM, and then try to check the VPWR pins at the PCM tonight. I have been unable to google and find any other Mustang with a similar issue. The friend who suggested the CCRM check, said they had an internal relay start to fail for their fuel pump and they were seeing a similar 7 ish volts at the pump.
 

ttocs

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ok wait a minute, how are you testing these grounds? Your getting 12.5v when touch the negative lead? Unless the positive lead is on the + of the battery you should be showing 0v if your testing grounds by touching one lead to one end and the other lead to the other. If your just going from + to - then that is not a good way to test. The best way would be to use an ohm meter and touch both ends of the cable and try to get as close to 0 ohms as possible. But with all this being said its NEVER a bad idea to remove the grounds, clean and then tighten them back up. This is really the only real way to "check" grounds imo.
 

Venompower

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ok wait a minute, how are you testing these grounds? Your getting 12.5v when touch the negative lead? Unless the positive lead is on the + of the battery you should be showing 0v if your testing grounds by touching one lead to one end and the other lead to the other. If your just going from + to - then that is not a good way to test. The best way would be to use an ohm meter and touch both ends of the cable and try to get as close to 0 ohms as possible. But with all this being said its NEVER a bad idea to remove the grounds, clean and then tighten them back up. This is really the only real way to "check" grounds imo.
In the engine bay I’m putting red test lead to positive terminal and the black test. Lead to each ground.
 

ttocs

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that is really only good for testing battery voltage and isn't a good test for ground. With a bad ground you can still see 12v, but it will not be able pass enough current if needed. You just can't look at a ground and see its good because the wire can corrode inside or even in between the connections. Like I said the best way to "check" grounds is to remove the end, clean the connection and then make sure its ugga-dugga tight and it can't wiggle/move at all. I know its a pain in the ass but ground problems can cause some silly issues.
 

Venompower

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that is really only good for testing battery voltage and isn't a good test for ground. With a bad ground you can still see 12v, but it will not be able pass enough current if needed. You just can't look at a ground and see its good because the wire can corrode inside or even in between the connections. Like I said the best way to "check" grounds is to remove the end, clean the connection and then make sure its ugga-dugga tight and it can't wiggle/move at all. I know its a pain in the ass but ground problems can cause some silly issues.
No I appreciate the advice, I’m willing to do whatever I need too…

Real question, one ugga dugga or two?
 

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