engine hesitation problems..

[JayRome]

Do the intake leak test as per VFAQ. Almost guarantee the TB will be pissing out air. The N/A tb seals are the wrong war around and only made to deal with vacuum and not internal pressure (boost). You'll either have to swap the seals and/or the TB. I'll try and draw a pretty picture in paint re: seals later when I have more time. You may also find a few other leaks here and there.

Nup, TB was fully reco'd when i supercharged my engine before i turbo'd... and actually the N/A TB are identical to the Turbo minus there is a required adaptor for the Turbo TB... i have inter changed parts between both over the years... no diff. even gaskets are the same, but the HG and HH TB's are different, they run different style ISC and TPS.. and the vac ports on the top are slightly different but they can be pluged up anyways....

no leaks in intake Mani either... all hole that are not needed are pluged up, EGR port on the Aspec Mani is welded shut.... i pressure tested before i installed it....

 

[trq-str]

yes base pressure is around 40psi....

So, this 40PSI is with a stock NA FPR correct? are these rising rate like the turbo's?

 

[JayRome]

So, this 40PSI is with a stock NA FPR correct? are these rising rate like the turbo's?

oops just check its around 34-36psi base.... depending on how old it is (spring can go soft after a while)

the stock FPR's should be the same.. between VR4 and N/A DOHC, only diff being is that, the ECU controlls the Turbo engines FPR via a solenoid valve usually located under the air box on the VR4 or on the fire wall on the EVO/GSR (someone correct me if i'm wrong on the positioning)

from memory the part numbers are the same..... (again someone correct me if i'm wrong here)...

 

[milkandoj]

Check the service manual out (downloadable on this forum) the base fuel pressures are stated, i know vr4's run 37psi base pressure with the vacuum source disconnected (so it see's no vacuum at idle.)
I’m not at home and cant check the manual myself, but look what the NA's run i think it was higher.

As for where you MAF starts to overrun here’s some good info. Im pretty sure the vr4 and 1g dsm amf are comparable, if so then it's limited to 28lb of airflow a minute so using 9.5-10hp oof power created per Lb/min of airflow thats only 260-280 crank hp. not much to play with.
http://www.ecmtuning.com/wiki/maffrequencylimits?s=overrun



Vote 1 for; 055 or 069 afm and ecmlink lite. and 510 or 560s injectors!
And then you can tune yourself, you build it man, so now have FUN tuning your high comp motor!
Why stuff around with an evo 6 ecu when you dont have to wire another ecu into you loom. id go the lite version first as its all you'll need for a while and can always upgrade easily.

 

[JayRome]

Check the service manual out (downloadable on this forum) the base fuel pressures are stated, i know vr4's run 37psi base pressure with the vacuum source disconnected (so it see's no vacuum at idle.)
I’m not at home and cant check the manual myself, but look what the NA's run i think it was higher.

As for where you MAF starts to overrun here’s some good info. Im pretty sure the vr4 and 1g dsm amf are comparable, if so then it's limited to 28lb of airflow a minute so using 9.5-10hp oof power created per Lb/min of airflow thats only 260-280 crank hp. not much to play with.
http://www.ecmtuning...imits?s=overrun



Vote 1 for; 055 or 069 afm and ecmlink lite. and 510 or 560s injectors!
And then you can tune yourself, you build it man, so now have FUN tuning your high comp motor!
Why stuff around with an evo 6 ecu when you dont have to wire another ecu into you loom. id go the lite version first as its all you'll need for a while and can always upgrade easily.

ah that link is a good read.. cheers bro..

 

[milkandoj]

Double check the service manual for the base fuel pressures for the GGSR and VR4. I really have a feeling the NA motors had a higher base pressure.
I’ve got my old vr4 fuel pressure reg, if i can find it in my garage (lol) you can have it, just pay for postage, and give it a go. Maybe the GGSR ones are different as the only operate in vacumm rather than rising pressure with boost, I would have no idea.

 

[trq-str]

Maybe the GGSR ones are different as the only operate in vacumm rather than rising pressure with boost, I would have no idea.

That’s exactly what I wanted to know, as the N/A FPR’s also have the vac/boost nipple.

I will have to check the manuals tonight.

 

[bazeng]

I've got a handful of stock VR4 fuel regs if you need them Jay,
Let me know

 

[Rockabilly]

Can't pass 65% throttle as the power will flat line but boost will continue to hold. Sounds like a split bov hose maybe.
Try Baz's VR4 fuel reg. A ggsr reg floods down low & flows like a vr4 at mid & then can't hold pres up top.
Cheers !

 

[JayRome]

half the problem fixed.....

tested for leaks... none...

swaped FPR to an evo 1-3 (i think) lying around... and same thing with hesitation

tested the electrical system... and found my TPS wasnt giving correct out put... changed with spare

so power is back but still topping out the MAF. so detuned even more on the timing and she runs sweet....

time for a bigger maf/injectors and a hell of a tune....... 560's and i might try the Evo 8 maf...

cheers for the suggestions everyone...

this is why we are Team4G/4GTuner! we can not put a price on the valuable collaboration of knowledge collected from everyone on this site!! :thumbsup:

 

[omad]

The A-Spec's run extremely rich stock FYI. Stock computer's tuned to 6-10 PSI (argueable) with a low compression engine. Easy to go over that with your high comp. You should be able to tune yourself to what you have with an ECMlink. First thing you'll need to change is the AFM. Some are using the evo8 or similar which is round instead of the oval 055 if you wanted to go that way. You should be abe to get a bit more out of those 450's though. Can put up a screenshot of the stock A-Spec map if you like, but the thing is rudely rich once on boost. Remember it was tuned for 91 octane fuel!

And seeing I spent so much time on my little picture, I'll post it for you anyway =)

PS - what'd you use for leak testing and to what pressure?

 

[kaotik]

I got an 055 and adaptor harness sitting in my garage if u want it jay

 

[TMAK]

my 1250's are going in on sat.. so guessing you'll be taking the 560's off me?
evo 8 ecu also going in.. so you taking my ecu too?
you better pay up biatch!

 

[JayRome]

my 1250's are going in on sat.. so guessing you'll be taking the 560's off me?
evo 8 ecu also going in.. so you taking my ecu too?
you better pay up biatch!

you stil owe me a steak dammit! lol....

yes 560's are mine!....