12v mod with walbro, now fuel cut and bad idle

[mk3tattoos]

so i have a 57trim ct-26 ,rc550,walbro 255, lexas v8 afm, perrin boost controller, turbo back titan down pipe, blitz nur spec exaust, titan meat hg, arp studs, all mandrell bent hard pipes, xs blow off vavle.boost was set at 12 and ran strong with no issues. i want to set boost at 15 psi, so i did the 12v mod with new relay and all new grounds 10g wires. go for a test drive and as soon as i come to a stop the engine dies. and when i go to wot it hits fuel cut. So my only gues is I'm running realy rich. is there anything i can do to lean it out, or do i go back to 6 volt to power the walbro fuel pump?

 

[str8_6]

6 volt? you mean rewire the resistor back?

you shouldnt be that much more rich because your fpr does most of that part. this is why i always recommend getting a quality wideband...so you arent taking guesses.

what are you using to tune if any? do you have an aftermarket fpr that you didnt mention?

what i would do before redoing everything is turn your boost down to where you had. then i would redo the 12 volt mod (which i honestly dont think is the issue because your fuel is regulated), then undo the grounds.

how did you rewire the pump with a new relay? when i did it, i just bypassed the resistor.

 

[grimreaper]

fuel cut has nothing to do with your af ratio being rich or lean. obviously something you wired in isnt correct, and why did you do this mod? The ecu will switch the pump from 9v to 12v when the conditions warrant.

 

[WhtMa71]

so i have a 57trim ct-26 ,rc550,walbro 255, lexas v8 afm, perrin boost controller, turbo back titan down pipe, blitz nur spec exaust, titan meat hg, arp studs, all mandrell bent hard pipes, xs blow off

Well there's your problem.

 

[mk3tattoos]

I do not have an aftermarket fpr, but its on the list. as far as tuning i was going to wait to get an Apexi SAFC or MAF_T. but i realy should get the wide-band.
the 12v rewire was from a write up i saw, they say the wires running through the car are not good. i will rewire the system and turn the boost down with the resistor bypassed. I used to get a red hot manifold after cruising 20 min. tonight i did not have that problem. So it would be safe to say i was lean and now im running rich?

 

[mk3tattoos]

Well there's your problem.

a meat hd is not going to hold up is it?..hahaha i better check on that:aigo:

 

[WhtMa71]

OK seriously though.. When you did the fuel mods did you bypass the J-tube on the block? You're probably just running extremely high fuel pressure if you have a 12v walbro and have the stock FPR and J tube.

Your setup should run fine as long as you have a adjustable fuel pressure regulator set at the the correct fp and have a the j-tube bypassed..It would probably still run a little on the rich side but not rich to the point its dieing out.

Get a fuel pressure gauge and see where its at @ idle with vacuum line off.

 

[mk3tattoos]

OK seriously though.. When you did the fuel mods did you bypass the J-tube on the block? You're probably just running extremely high fuel pressure if you have a 12v walbro and have the stock FPR and J tube.

QUOTE]
i never bypassed the j tube! So if i bypass the j-tube now without a new fpr it wont work right? I have a wide band on the way. one more thing, what kind of fpr do i get, and fuel pressure gauge. thank you so much for you help.

 

[Rennat]

did you up the boost? because fuel cut is based from air flow...

 

[str8_6]

just turn your boost down to 12psi and see if you still hit fuel cut. go on from there.

 

[supraguy@aol]

You want a rising rate FPR, or a 1:1 boost reference FPR(others please chime in) if I recall.
You can either bypass the J-tube entirely, or drill out the end to remove the restriction. I did this, as It was off the car and I didn't have to worry about metal shavings.

 

[mk3tattoos]

just turn your boost down to 12psi and see if you still hit fuel cut. go on from there.

ok i set it to 12psi. and there was no fuel cut. but it still run ruff at idle. i think the 12v is to strong but when i put on the resistor it runs lean, and the manifold and the back of the turbo get red after 20 min.

 

[grimreaper]

20 min of what? idle? cruise? boosting?

high egts = to much fuel/ to little fuel along with ignition retarding

 

[WhtMa71]

While running rough at idle does it smell like unburned fuel? Im betting your fuel pressure is too high. You can just drill out the jtube.
Most people use the aeromotive kit like the one from driftmotion http://store.driftmotion.com/Static/Itemafprkit7m-gte.php .
This kit also bypasses the j-pipe.

 

[mk3tattoos]

20 min of what? idle? cruise? boosting?

high egts = to much fuel/ to little fuel along with ignition retarding

20 min on the free way cruising at 70mph. the timing is set at 12. sorry i forgot. it did this before any fuel mods were done, which was realy weird. but after the 12v mod it stopped. i realy hate driving it when it turns red hot. thank for helping guys.

 

[grimreaper]

While running rough at idle does it smell like unburned fuel? Im betting your fuel pressure is too high. You can just drill out the jtube.
Most people use the aeromotive kit like the one from driftmotion http://store.driftmotion.com/Static/Itemafprkit7m-gte.php .
This kit also bypasses the j-pipe.

anything closed loop is controlled by the ecu. it will do what ever it can to put it at stoich. unless he is stuck in warm up enrichment, the ecu should compensate under normal part throttle (idle too) conditions. i dont know how the j tube affects this unless its open loop operation.

 

[mk3tattoos]

anything closed loop is controlled by the ecu. it will do what ever it can to put it at stoich. unless he is stuck in warm up enrichment, the ecu should compensate under normal part throttle (idle too) conditions. i dont know how the j tube affects this unless its open loop operation.

do you think my ecu is messed up, and i should get a new one?

 

[grimreaper]

no, i think your going off of bad data, or lack of actual data. "smelling" the exhaust is useless, as one person thinks it stinks, another smells no difference.

search the j tube and its affects with X setups... i havent had to deal with this so i dont know how that affects things.

 

[mk3tattoos]

no, i think your going off of bad data, or lack of actual data. "smelling" the exhaust is useless, as one person thinks it stinks, another smells no difference.

search the j tube and its affects with X setups... i havent had to deal with this so i dont know how that affects things.

we have a similar set ups. I'm missing the AFPR, and a few othere things. But if i get the few things to regulate and get data, do i need to bypass the J-tube? so your saying you did'nt, what did you do? sorry so many questions, i just think I'm close to running safely.

 

[grimreaper]

i didnt put it on, the car already had it bypassed.