Engine cutting out at 3k rpm in WOT

ttocs

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a quick search for "where to mount a slot style maf" I came up with this from svt.com

"What ever you decide just know that the density of the air will increase in and right after the outside radius of a curve in the piping.
This can result in dangerously lean conditions if the MAF sensor is reading air in a section that is on the inside radius or just after.
The "stacked up" more dense air can sneak by on the outside radius, and not be fully detected.

The best placement will be in a section of pipe that has been straight for as long as possible so that the density has evened back out after the curve.

Don't place it close to a turn or even too soon after a turn."
 

Venompower

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a quick search for "where to mount a slot style maf" I came up with this from svt.com

"What ever you decide just know that the density of the air will increase in and right after the outside radius of a curve in the piping.
This can result in dangerously lean conditions if the MAF sensor is reading air in a section that is on the inside radius or just after.
The "stacked up" more dense air can sneak by on the outside radius, and not be fully detected.

The best placement will be in a section of pipe that has been straight for as long as possible so that the density has evened back out after the curve.

Don't place it close to a turn or even too soon after a turn."
Typically you want somewhere around 5-8 inches of straight pipe prior to the sensor so with the VMP housing I should be good.

Tuner recommended starting with cleaning the MAF and also speculated the wires may be the issue.
 

Venompower

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VMP suggested replacing the harness as a starting point. They advised you could see in the data log where the MAF data was intermittent which indicates a short.

I still think the MAF looks bad as well…

11088C50-BB9B-40EA-8F1D-EBC0FC8AEB6B.png
 
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Venompower

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So I received the VMP harness Friday evening, but have not yet had a chance to install it. I will be making some time tonight, and hopefully data logging it tomorrow.

In the meantime, can someone take a look at the attached excel file from my data log and help me out.

Knock Sensor Retard Increment is a flat 1.5 across most of the log, but in a small section it jumps to 1.75. Knock Sensor Retard Increment is also 0 across most of the log, but goes as high as 3 though it doesn't seem to correspond to timing being pulled.

I do see Spark PID dropping to 0, and it appears to start falling as the MAF count goes from 511 to 523, timing drops from 15.25 to 9.75, and then continues to drop to 0 for a period before bouncing between 3.75 and 8 eventually jumping back up to 18+. Some knock retard is listed during that stretch at the end but doesn't seem to correlate to timing being pulled.

I'm not sure if the misfire PID is not supported, but there is a PID for cylinders 1 through 8 and no misfires were listed at all in the log.

I really just want to make sure I'm seeing everything that looks off in the log, and addressing all the potential issues. I really appreciate everyone's help, wish I was smarter with this stuff.

datalogquestion.JPG
 

ttocs

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Are you replacing the entire harness or are you going to solder/shrink the connections?

can ya turn the knock sensor off in the tune, or can you just disconnect it and see what happens?
 

07GtS197

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What we’re you doing when the log was taken? The o2 sensor voltage is high, what was the afr?
 

Venompower

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Are you replacing the entire harness or are you going to solder/shrink the connections?

can ya turn the knock sensor off in the tune, or can you just disconnect it and see what happens?

So the current harness is the solder in kind, and that's what I ordered to replace it. I have the diagram and will just cut each wire and then solder the harness back in and heat shrink the connections. I'm probably going to clock the VMP housing to move the sensor and harness father away from the wheel.

I'm wondering about that, I read something earlier that it was possible to turn them off in the PCM while the SCT still shows the PID of what they are reporting? I would have expected timing to cut in correlation with the knock detection and it doesn't seem too... timing cut seems more related to the MAF. I also have LT's that are probably bumping against the strut towers, or potentially the steering shaft. The knock detection was so low in the rpm range, that I have a hard time believing it's any sort of detonation.

What we’re you doing when the log was taken? The o2 sensor voltage is high, what was the afr?

This log was driving through my neighborhood, to a 45 mph stretch of highway, and then back through my neighborhood. The AFR wasn't overly rich or lean during the drive, and went into the 11's a wot.
 
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ttocs

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I went through the trouble of installing a knock on my 5.0. The first thing my remote tuner did was turn it off saying that to use it I have to tune it and went through some procedure of how to do it. I have never done it. Disconnect it and see what happens.
 

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I went through the trouble of installing a knock on my 5.0. The first thing my remote tuner did was turn it off saying that to use it I have to tune it and went through some procedure of how to do it. I have never done it. Disconnect it and see what happens.
Once I get the data log with the new harness if the knock is still showing up I'll disconnect and try another log. It's certainly being turned off when the car gets it's new tune.
 

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So to many times have I found "the likely thing causing my issue," to say it again... however, I'm working remotely today and decided to install the MAF harness/connector and clock the pipe to hopefully avoid future contact with the tire and found this:

This is water that came out of the intercooler piping just below where the MAF sits.

IMG-4916.jpg

This is inside that coupler:

IMG-4917.jpg

This is the feed side of the intercooler from the Procharger:

IMG-4918.jpg

I'm currently in the process of removing the front bumper so I can take off the intercooler and make sure there isn't anymore water in there.

The day this started was the day I got my new tires installed, and on the way back home we had a monsoon... I was nervous because the previous owner had removed the fender liners and I have the Anderson Power Pipe which puts the filter right in front of the tire. I assumed it was fine, because I slowly made it home and it seemed fine at idle.
 

07GtS197

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Hmm that could definitely make it run like crap. The ecoboost motors are known to collect moisture in their intercooler causing surging and misfires. The diy fix is to drill a small hole in the bottom of the intercooler to alleviate the issue.
 

Venompower

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Last night I went with the family to a local cruise night, and despite being tired I was determined to get things fixed. Stayed up until almost midnight making sure all the water was taken care of, and all intercooler piping was well connected and tight. Then I removed the old MAF harness connector and soldered in the new one, I matched each wire in sequence based on the old connector since the new VMP connector used slightly different colors so it should be perfect but since it's all buttoned up and wrapped I'm paranoid I'll have to re-do it. I also clocked the housing to keep the sensor and wire away from the wheel.

I'm hoping to have everything wrapped up tonight, so I can test it to see if the issue remains. I'm still guessing that I may need a new MAF sensor based on what I found, but I want to get another data log first to see what the MAF is doing.
 

Venompower

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with that much water coming out I would double check every thing ,
The only water was inlet and outlet of intercooler at the low points in the piping. Intercooler had some water droplets and moisture but no significant water. Spent last night with a hairdryer and got everything dry and went through all the couplers to make sure they were well connected and tightened down.

Tonight I buttoned her up.

7C835817-F878-4AF7-B4E7-601C053CC658.jpeg
DEF324F7-303D-479D-83A5-A609BCCE55C8.jpeg
 

Venompower

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Well I’m sorry to say that this will be my last post…

In this thread because the Cobra is officially FIXED!!!!

I took it for a short cruise tonight and did multiple wide open throttle pulls and they were smooth as silk with no cut out at all!!!

Plan is to replace the rear shocks Saturday morning and if it doesn’t rain there a car show at my towns block party and then a cruise night in the evening! Man the sound of the BOV when you shift is amazing!
 

Venompower

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Awesome, you've been chasing this for a while. Now you can enjoy it.
This has eaten up the last two months of summer... cruise nights here run through the end of September, so I'll get a few more opportunities to show her off. To say I'm relieved is an understatement, now to get the suspension on point.
 

Venompower

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so do ya think it was the water or wiring?
Honestly the water... the wiring was more a maintenance issue in my mind. The connector kept the wires separated and the wire that had the worst rub through wasn't even used as it was for integrated IAT.

If I had to speculate the water sat in the pipe at low loads and part throttle, and as rpm increased under WOT it pulled water/water vapor onto the MAF sensor. Since the MAF is a resistor and makes measurements by how much the air passing over it "cools" it the water/water vapor was likely cooling it far more than the air and causing it to max at 1023 counts.

I can't say for certain, but between the two changes she rips now and accelerates smoothly. I will also note that the idle is much smoother now too...
 

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