mk4 8vt - MS2

[kevinescobar15]

hello fellas, i've been having a bit of issues with my 8vt on megasquirt 2 v3
background on the car,

AEG stock bottom end with head spacer 9:1
P&P with TT 276
42# greentops
50trim garret turbo .48ar
Custom SRI
MS2 v3

Currently the car is running great, ive had tons of help from a friend of mine but we can't seem to figure out whats wrong with the rev limiter. Rev limiter is set to 7300soft cut and 7400 hard cut but the issue is that when under boost (wot) it cuts out at 5800. however when under partial thrttole (45%tps or so) it revs all the way up to where its suppose to.
we are short of ideas of what could the issue be. if anyone has any input or anything it would be much apreciated it.

[kevinescobar15]

Also forgot to mention this but we were messing with the Accel enrichment wizard we managed to raise the limiter at WOT to 6500ish but we cant figure out what else we could do to make it rev to the designated rev limiter. i'm including a screen shot of what some of the stuff looks like.



thanks for any input

[ValveCoverGasket]

i still think youre having some sort of boost control issue...
the couple boost runs near the end of the file dont look right. boost drops off for no reason at 6100rpm. then the pull right after that it looks to me like youre hitting the boost cut.

have you tried running the wastegate just off spring pressure?

[need_a_VR6]

On that note make sure overboost fuel cut is off.

[kevinescobar15]

i still think youre having some sort of boost control issue...
the couple boost runs near the end of the file dont look right. boost drops off for no reason at 6100rpm. then the pull right after that it looks to me like youre hitting the boost cut.

have you tried running the wastegate just off spring pressure?

haven't tried running just the wastegate off the spring pressure(which is 15) and also the boost cut is on but way above the limit of the map sensor or the boost pressure set by boost controller(18-19psi)

On that note make sure overboost fuel cut is off.

Weird thing is it revs to 7400 if i do partial throttle and we managed to raise from 5800 to 6500 by messing with acell enrichment but we aren't sure what else could be causing this. but i Will try to just running wastegate pressure.


oh and when we were tuning we would hit boost cut and it sounded differently then when it drops once it hits 6500. It sounds more like if i was letting off the gas..?

[need_a_VR6]

Get some logs of it revving clean at part throttle and cutting at high load and post your msq as well.

Also make sure you are running a fairly tight plug gap on the stock coil.

[ValveCoverGasket]

Also make sure you are running a fairly tight plug gap on the stock coil.

forgot about that, good call

[kevinescobar15]

Get some logs of it revving clean at part throttle and cutting at high load and post your msq as well.

Also make sure you are running a fairly tight plug gap on the stock coil.

Currently running msd coil and gap is at 26... Is that good or should i go smaller?

[kevinescobar15]

I Will get some logs part throttle in 3rd and fourth.. Its strange though but when Im doing logs, everything seems to freeze and not the entire pull shows up. but i Will def try my best.

[ValveCoverGasket]

Currently running msd coil and gap is at 26... Is that good or should i go smaller?

id go smaller, if it clears things up then start opening it up until you run into problems again.

ive had to run some NA cars at 24...

try 22 to start and see what happens

[kevinescobar15]

id go smaller, if it clears things up then start opening it up until you run into problems again.

ive had to run some NA cars at 24...

try 22 to start and see what happens

Okay i will try that small. oh and quick dumb question need_a_vr6 said post the msq, Im not sure what that is and Im not really sure how to post the logs here but Im sure i can figure that one out.

[need_a_VR6]

The msq is the tune file, go to file, save as and BAM! there it is.

[kevinescobar15]

The msq is the tune file, go to file, save as and BAM! there it is.

oh yeah silly me. i have that already. so bad news, i did the logs today and car started throwing ALOT blue smoke. i might of done something to the motor. i know my valve stem seals are worn out and i get a bit of blue smoke in the morning but now its throwing smoke more often and it puffs blue smoke when cruising also, but it goes away something... could it be, cracked rings, or piston, or the valve stem seals just went out all the way?

[kevinescobar15]

I'm not sure how to upload the logs here, need_a_vr6 if you want i can email them to you.

[need_a_VR6]

Sure kandpperformance at gmail dot com.

[kevinescobar15]

Sure kandpperformance at gmail dot com.

email sent

[ValveCoverGasket]

the only thing that jumps out at me right off the bat on the part throttle logs is the ability of the thing to maintain boost and not spike when you do this at part throttle.

[kevinescobar15]

the only thing that jumps out at me right off the bat on the part throttle logs is the ability of the thing to maintain boost and not spike when you do this at part throttle.

Yeah. i don't understand..any ideas on what it could be? What i don't understand is why part throttle rpm is good but anything above 50% tps doesn't go above 6500.

[need_a_VR6]

Your MAP drops before the TPS does, most likely spark blowout as I don't see you losing sync or anything else odd there.

[kevinescobar15]

Your MAP drops before the TPS does, most likely spark blowout as I don't see you losing sync or anything else odd there.

How can this be corrected?

[ValveCoverGasket]

close up that gap, maybe try colder plugs for fun if that doesnt work...

[kevinescobar15]

close up that gap, maybe try colder plugs for fun if that doesnt work...

So its nothing ecu related then? Im using the bkr7e. i Will try to close that gap once i figure out what i blew out. Then ill get back to it.

[need_a_VR6]

There's nothing in the logs I see at all, it might be worth doing a tooth or composite log during a pull and see if there's lost sync that the ecu doesn't see. Also sent you a note over email about the AFRs, they are very strange.

[ValveCoverGasket]

yeah i had no luck getting the AFRs to show up in the logs... anything other than apparently random numbers

[need_a_VR6]

I was getting ~3-12afr in general, not sure why.

[kevinescobar15]

I was getting ~3-12afr in general, not sure why.

reason why is because the ground on the gauge is different than everuthing else on ms. however afrs under boost are good. varies from 10.8 - 11.7

There's nothing in the logs I see at all, it might be worth doing a tooth or composite log during a pull and see if there's lost sync that the ecu doesn't see. Also sent you a note over email about the AFRs, they are very strange.

When you say it might be worth doing a tooth what do you mean by that?

[ValveCoverGasket]

reason why is because the ground on the gauge is different than everuthing else on ms.

you need to fix that. the wideband stuff has to be grounded at the same spot as MS otherwise whatever numbers youre seeing can potentially be 1-1.5 points off...

[kevinescobar15]

you need to fix that. the wideband stuff has to be grounded at the same spot as MS otherwise whatever numbers youre seeing can potentially be 1-1.5 points off...

I understand but we have the tune only based off of tps and the ve table. for now we aren't using the afr table.. Although i am changing the ground once i pull the head out since i need to replace piston rings.

[ValveCoverGasket]

right, but the only way you know if that tune is correct is by either watching the AFR gauge, or using it as a feedback for autotune.
in either case it could be leading you down the wrong path if its off

[kevinescobar15]

right, but the only way you know if that tune is correct is by either watching the AFR gauge, or using it as a feedback for autotune.
in either case it could be leading you down the wrong path if its off

yeah we have been using the gauge and the gauge is good, the only down side to not having the ground where ms is grounded is that on the computer it shows something different. soon ill be fixing that, that way we can start using AFR's to tune better.

So, today i was checking what the issue was with the car throwing so much smoke after doing those logs and came up with this...

Comp test:
Cylinder one: 140
Cylinder two: 145
Cylinder three: 146
Cylinder four: 147

Also spark plugs come out clean, no oil residue.

So now, i'm thinking that the valve stem seals just went out on me all the way. The car was already smoking a little in the morning but now its more constant but it kind of freaked me out when i saw that much smoke after those few pulls.

Re-gaped spark plugs to 25 and now ill see what that does to the RPM

[need_a_VR6]

You wb cant even read 3afr on gas, something else is up. You using the narrowband output to the ms without changing it in lm programmer?

In any case without afr reading right in the logs its hard for random guys on the internet to help withkout asking, wtf is up with the afr a bunch!

[kevinescobar15]

You wb cant even read 3afr on gas, something else is up. You using the narrowband output to the ms without changing it in lm programmer?

In any case without afr reading right in the logs its hard for random guys on the internet to help withkout asking, wtf is up with the afr a bunch!

Yeah sorry about that.. ill fix it asap and get back to you guys, i just thought maybe there was something else up with it that you guys could see wrong with the msq

[kevinescobar15]

Hey, sorry for the delay in the response. so the issue wasn't anything ecu related. everything pointed out to be the wastegate. faulty wg. if i run it with out the boost controller, just off of the wg spring (10psi) then it revs smoodly up.to 7400. Currently im running 14psi and it seems to hold good but i can't go any higher. now is the time to buy a new wastegate.

Now my other question is, i have been looking into adding an idle stabilizer but im not really sure where to start from? From what car can i get it out of that is compatible and easy to use with ms. if you guys have any thoughts on this, would be great appreciate it.

[need_a_VR6]

2 wire from an aba or vr6 is about as simple as it gets.

[kevinescobar15]

Does it hook up straight to ms through a pin or how would that work? I'm clueless when it comes to isv's systems.