Video of 2g DSM WOT

[KeelesKustome]

Need help diagnosing this.

DSM Stutter at WOT - YouTube

 

[KeelesKustome]

part #2


DSM stutter diagnosing part #1 - YouTube

 

[Imback]

Sounds like your maf could be going out on you but it's hard to tell with your video. Are you logging any of this ?

 

[broken_eclipse]

sounds like spark blowout. or a boost leak.
Same question as when you posted this on the Link forum, log?

 

[Frskrgps]

i was having a similar issue with my car. Turned out to be spark blowout cause of a weak coil. what are your plug gaped too? i swapped coils and now the car pulls all the way to red line.

 

[KeelesKustome]

If you click the youtube links I have better data on whats been done.

New spark plug's 7's gapped at .25
put a new maf on today,
wires checked out good,
fuel preassure is good.
changed to a brand new coil pack,

no boost leaks whatsoever, it hold's boost untill i release it.
Whatever the issue is only happens under WOT with boost over 10 psi.

I've ran 26 psi daily without issue. I am really stumped on this one.

 

[Frskrgps]

how new is the knock senor? and do you have a data log that will help out too?

 

[97ebaygst]

Isn't fuel pressure supposed to be set at 43.5?

 

[ramsack]

1. Fuel pressure should be 43.5 PSI unless you specifically tune for 50 PSI.
2. Testing the resistance of the wires doesn't matter much. Insulation can leak spark, and that absolutely won't show up on a multimeter by measuring resistance of the conductor.
3. Spray some water on the coil pack to see if that is leaking any spark. Use a spray bottle that does some fine mist action.
4. Revving in neutral is no indication of how good your ignition system is. Load needs stronger spark than idle revs. The more load you put on the engine (boost is load, and so are loaded RPMs) the stronger the spark has to be to jump the gap, and the more current will be drawn through the wire, which means more voltage needs to be pumped at the beginning of the path (coil) to push through those wires. More voltage being pushed through the wires with weak insulation is going to arc all over the place because it is finding the path of least resistance. Notice how the plug wires are several thousand ohms? Spark also gets weaker as revs climb.

It really does seem like spark blowout.

And do a thorough boost leak test.

 

[M4Dboost]

no boost leaks whatsoever, it hold's boost untill i release it.
Whatever the issue is only happens under WOT with boost over 10 psi.

Just to verify, you did do a boost leak test?


Last time I asked my buddy if it was holding boost he meant when the throttle was pressed, not the pressure from the BLT being released. So Im just asking for clarity.

 

[KeelesKustome]

Boost leak test holds perfectly and drops at a verry slow rate, maybe 1 psi per minute.
It then will not drop any lower than 10 psi untill i realease preasure on my tester.

I misted water and see or here no change, I can make a video if you so desire.

But i just put a new coil, new maf, new plugs gapped at .25, and yes my link is calibrated for the 50 psi,
To make things easier I put the FP back to factory settings and adjusted link accordingly.

It did not remedy the issue.

 

[snowborder714]

I'm hoping you meant .025 and not .25.

Can you post a log of this happening?

 

[KeelesKustome]

I did, and yes I will try to do so tonight.

 

[bryanwheat]

What is the a/f ratio like when this is happening?IF you know that the a/f is right when this is happening than you know that the maf and everything in the fuel system is correct. If that is the case than it is ignition related. How old are the plug wires? They can spec out right but have a pinhole in the wire or boot and arch over inside the spark plug tube.

 

[broken_eclipse]

Have you checked system voltage? when my alternator was on its way out a few years back it couldn't provide sufficient spark and resulted in a similar problem. you can log this with Link as well.

 

[GSX77901]

how new is the knock senor?

im with him? How new is it

 

[kthackst]

Sounds like its running pig rich with bad O2 sensor stuck at .9volts.

 

[KeelesKustome]

I still have boost way down, and listen to this.
Yesterday morning my starter took dump, it would free spin and try to engage but culdn't stay engaged under load, so it would just free spin.

I had it warrentied and went ahead and did a compression check.
#1 148 #2. 146 #3. 150 #4. 147 so it's all good.

I did another boost leak test, and took soapy water to it, no leaks at all anywhere, and my boost leak tester even with groves flared can only hold 25 psi before it blows off.
Timing is still set dead on.
Injectors are pulsing normally,
ISC has been recalibrated to the ecu' The long proper way.
AFPR, is set back to stock settings still,

Drove my car home from the shop and ran perfectly. I need to take the link for a log today and see if it's still good but here is my theory.

I think my abndix on my starter was faulty, I'm thinking under load it was sliding back onto my torque converter causing these crazzy issues.

At this verry moment for my car to begin working fine after replacing it, it seems it may have been the culprit, So I'm going to slowly up the boost again and see where I stand.
I'm thinking link was showing 395gms on most my good pulls before this happened.
I'll keep you updated with a better video I'm working on.

Cars still running good.

 

[dsm03]

I have similiar issues Im glad this post came.. Have yet to diagnose as my car is sleeping for the season.. but I have a few places to start now..

 

[KeelesKustome]

It's back, so new ngk wires br6 plugs and a AEM wideband setup is on the way.

 

[KeelesKustome]

here is 19psi fixed, 30 psi comming back soon.

dsm changed spark plugs and wires 19 psi - YouTube