500hp Fuel Pump With Stock Injectors & Ecu

[wlspn]

As Iv stated in a previous thread, Iv just fitted an RB25, R33 ECU & custom loom in my 32 & am having major overfuelling issues. I am running a custom GCG highflow, greddy-style plenum, GTR cooler & piping + some other bits & pieces so was planning on remapping the ECU. However I havn got around to remap but have fitted a 500hp walbro fuel pump. Seeming Im still using stock ECU, FPR, injectors, etc, could the pump be causing my problems? So bad I cant even drive it to mechanics for a fuel pressure check! Got told to remove fuel rail, turn IGN on & if pump is the problem my injectors should leak. Have done this & they dont leak. Just want some more opinions...

[paulr33]

it wont be the pump as that doesnt affect load, the throttle body changes, larger cooler, greddy plenum, larger turbo and pipework etc will certianly affect it and make it run like ass

you have way tooo many mods for a stock ecu. are you honestly suprised it overfuels? im surprised it starts given the amount of crap youve changed

sure they aren't critical sensor/interopabiltiy changes but certianly the volumes, load, and characteristics would be all over the shop

1) stop driving it

2) remap it

or

2) get a stand alone ecu

or

2) get a stand alone

or

3) get a stand alone

[FloydWestwood]

I like your style Paul.

[wlspn]

it wont be the pump as that doesnt affect load, the throttle body changes, larger cooler, greddy plenum, larger turbo and pipework etc will certianly affect it and make it run like ass

you have way tooo many mods for a stock ecu. are you honestly suprised it overfuels? im surprised it starts given the amount of crap youve changed

sure they aren't critical sensor/interopabiltiy changes but certianly the volumes, load, and characteristics would be all over the shop

1) stop driving it

2) remap it

or

2) get a stand alone ecu

or

2) get a stand alone

or

3) get a stand alone

Not driving it at all at the moment. It will hardly idle & the way its blowing black smoke Id be lucky to get halfway down the rd without getting EPA'd in my neighborhood... I know exactly where youre coming from but is there any way to confirm what youre saying? Willing to go aftermarket or remapped ECU but only if I can be 99% sure it will solve my problems. That has been the plan all along but didnt want to go for remap with an underlying problem.

Thanks for your input

[paulr33]

remaps are a bit of a dead weight, its one of those things you buy for $50

remap it for sub $500 and its worth $0, no one wants to pay any amount of money for it, as its got someone ele's tune on it

whereas a stand alone you buy for sub $1.5k ish and when you sell it, its still worth that $ amount

regardless of what you spend on the tune

[Moodles2]

All these mods on a stock R33 ECU hilarius

[Cjmartz2k]

So wait, you are trying to say his different intercooler, turbo, intake plenum, and throttle body with out being mapped would cause the car to idle like ass? Seriously, come on. WOT and getting into a bit of boost, sure, but those mods aren't going to make a car not idle or drive out of boost.

OP, did your car ever run well after the swap? I have seen walbro's over power a stock FPR before, but it was because the FPR was bad anyways. I had twin walbro's in mine and when I swapped it back to a stock RB25 to sell, it ran just fine on the stock FPR. I'd make sure you don't have a leak in your intercooler piping or something basic like that.

[wlspn]

Thats what I was thinking. Was expectin not to be able to boost it up but thought I would have been able to keep it under 3k rpm & at least drive it to tuners... No, car hasnt run right since 1st start with new engine. Put stock fuel pump back in yesterday & still having same problems. I have the whole R33 the engine has come out of & it drove fine last time it went. Problem is engine has been out on a stand for at least 12 months...

Thanks for your opinion

[paulr33]

and the other issue is you've changed a gazillion things at once

[msnismo]

So wait, you are trying to say his different intercooler, turbo, intake plenum, and throttle body with out being mapped would cause the car to idle like ass? Seriously, come on. WOT and getting into a bit of boost, sure, but those mods aren't going to make a car not idle or drive out of boost.

OP, did your car ever run well after the swap? I have seen walbro's over power a stock FPR before, but it was because the FPR was bad anyways. I had twin walbro's in mine and when I swapped it back to a stock RB25 to sell, it ran just fine on the stock FPR. I'd make sure you don't have a leak in your intercooler piping or something basic like that.

Please tell me you are not serious???

You can't change all that and expect the ECU to cope.... at minimum a SAFC is required to control the fuel situation to make it driveable...

The stock ECU is designed to cope with a standard motor meaning standard air flow and fuel delivery as per Nissan's years of R&D which ultimately created the ECU and engine package.

He has messed with alot of stuff within the key areas that the ECU does not have the capacity to deal with ... If the ECU was a person, it's head would be spinning and then suddenly exploding trying to cope with with the amount of mixed signals it is currently getting...

Pack it onto a trailer/tow truck, get an aftermarket ECU or at least a pi99y (keeps changing it!) back fuel computer and get the thing tuned.

** IF by some strange miracle this engine had all the mods on it in the donor car and was running, there would be a massive air leak (ie intercooler pipe) somewhere. I am a bit confused as to whether you have taken a stock running motor and done the mods.... or if majority of the mods were already on the motor and the fuel pump has been changed only (which is not your issue as you found out)

[grigor]

So wait, you are trying to say his different intercooler, turbo, intake plenum, and throttle body with out being mapped would cause the car to idle like ass? Seriously, come on. WOT and getting into a bit of boost, sure, but those mods aren't going to make a car not idle or drive out of boost.

Agreed.

For idle situations the only stand out problem area is the G-Reddy style plenum and the twin fuel pumps.

Try it with a conventional fuel supply to eliminate that from the equation.

[rb30_22]

have you had your ecu checked n tested? a frend of mine had over fueling issues one coz there was a faukt in the computer causing it to over fuel

[wlspn]

msnismo: No, RB25 was stock when in old car. Turbo was on my RB20 which ran fine with turbo, FMIC, etc. Only changes since then have been plenum, throttle body, swap to GTR cooler & piping, catch can & other small bits & pieces. Would these affect idle so badly?

grigor: Have gone back to fully standard fuel system with no change. Waiting on a mates FPR as its been suggested this could be contributing.

rb30 22: Who checks & tests ECU's? Trying to organise to use someones consult software. May be able to swap ECU's over quickly & see if that helps...

Car runs a lot better cold & gets worse as it heats up. Originally thought cold start was not turning off which is why Iv suspected the mentioned parts being at fault.

[msnismo]

msnismo: No, RB25 was stock when in old car. Turbo was on my RB20 which ran fine with turbo, FMIC, etc. Only changes since then have been plenum, throttle body, swap to GTR cooler & piping, catch can & other small bits & pieces. Would these affect idle so badly?

Cool... then I am in agreement with paulr33....

As per my original post... too many changes affecting airflow and fuel.. the ECU never had a chance. Had you done one mod, then run the car you would of noticed progressively the difference in the idle and behavior of the car... Would assume the throttle body and plenum are your biggest enemies at present without knowing every detail of the car. The turbo (assuming its not that big based on the specs) and FMIC would be minimal by themselves, but would still create a noticeable difference.

But all together.... no hope in hell of it running .. unfortunately

Try replacing the plenum and throttle body and see if runs better than present (making sure there are no air leaks at the same time) ... can always put this on at the tuners when you decide what fuel controller to use.

[Cjmartz2k]

Please tell me you are not serious???

You can't change all that and expect the ECU to cope.... at minimum a SAFC is required to control the fuel situation to make it driveable...

I'm serious, and you are wrong. So is Paul. None of those mods affect how the car idles. There is another problem here. Bigger injectors or a different MAF, yes, they would screw up idle with out a tune. Different intake, intercooler, turbo, ex manifold, exhaust, etc. have no effect on idle when it's still equiped with stock injectors, ecu, and MAF, especially with a MAF equiped car. Feel free to keep arguing and continue being wrong though.

Edited October 10, 2009 by Cjmartz2k

[FATGTS-R]

I think you are both correct but in relation to different situations.

If the car is at idle i.e not in motion and without load then the mods he has done should not affect the car. From my understanding it could have a T51 on there and a cooler the size of his bonnet and it should idle just like a stocker. The afm will read the air coming in at idle and supply fuel just like normal.

Once its on the move though its a different story as AFM maxes, injectors max etc etc.

You've done an engine transplant with a custom loom etc so your problem could lie anywhere. Could be a wiring issue with AFM, vacuum hoses, cooler pipes leaking etc etc.

[Cjmartz2k]

I think you are both correct but in relation to different situations.

If the car is at idle i.e not in motion and without load then the mods he has done should not affect the car. From my understanding it could have a T51 on there and a cooler the size of his bonnet and it should idle just like a stocker. The afm will read the air coming in at idle and supply fuel just like normal.

Once its on the move though its a different story as AFM maxes, injectors max etc etc.

You've done an engine transplant with a custom loom etc so your problem could lie anywhere. Could be a wiring issue with AFM, vacuum hoses, cooler pipes leaking etc etc.

Exactly my point, except even under light throttle loads, it'll still be fine. Now when you start moving enough air to notice the change in volumetric efficiency; that is to say, more than the MAF can cope with, it won't run right at WOT. The last bit you said about swapping an engine and all the things associated with it, that's the problem right there. It's going to be something basic like IC piping leak, or wiring, CTS got knocked off, or something basic along along those lines.

I understand why there is a tendency to just say "you need to get it tuned" since so many people post up on here that can't figure out why their car isn't running right after a new IC, exhaust, boost controller turned up to 16psi, etc. and didn't bother to tune it. You can't just always spout off the same internet rhetoric that is repeated over and over again however. This site is famous for that.

Edited October 10, 2009 by Cjmartz2k

[paulr33]

nothing wrong with being wrong

did he retain the std TPS?

[wlspn]

Have checked most of those things, besides wiring obviously. Hoping to have someone come around today with consult. Should this show any wiring problems? Like if AFM, etc was wired incorrectly or there was an ECU fault would it be immediately obvious with consult?

Yes Paul, running R33 TPS off donor engine

[SirRacer]

check the afm, my guess is its that