Problems with New Fuel System (Rewire, FPR, Injectors, SS Lines)

[Volume Eight]

I could use some help troubleshooting my new fuel system. The car doesnt want to run right after we installed it. Its bogging down as soon as you hit the gas especially if im about to build boost. Details are below.

Installed:

Walbro 255HP
AEM FPR (universal)
Denso 660s
Billet Fuel Pump
6AN SS Lines
Fuel Pump Rewire
ECU w/DSMLink

I had been waiting to install this system for a while since i had my dsmlink chip burned for the 660s. Well, i brought it to a friends shop, and we got started. Everything is connected properly, there are no fuel leaks. It just seems like the car is WAY to rich. Even though dsmlink is telling me it is lean? Here are some strange problems i have run into both during install, and while troubleshooting.

1) After installing fuel system, there was no power gettiing to the pump, so we ended up hardwiring the fuel pump. (ignition on source to relay to trigger new 10awg to power pump).

2) Set FPR to 37psi with vac source off at idle. Put the vac source back on, and the FP went down to 18?! Took it back off, shook the FPR a little, it went back to 37, so i attached the vac source again, and it stayed at 37.

3) During all the testing and trying to configure DSMLink to get the car to run properly, my Battery went dead (recharged it) and my ISC died on me. (replaced it)

Before i go through the hassle of putting the stock injectors and ecu back in, i wanted to see if any of you guys have had similar problems, or have any ideas as to why this install would cause my car to NOT RUN. It will idle, but as soon as you give it gas, it bogs down (like a choke on a lawnmower, too much gas). Any help here would really be appreciated.

Thanks!

 

[BoostedTalonTS]

I'm not using a DSMLink, but the last time I had something like what you are describing happen on my 1G, I had apparently popped the EFI fuse by accident, while moving some wires around near the ECU (LONG STORY, but it was during my EPROM swap, when I had the ECU out of the car). Once it was re-installed, it seemed like only part of the ECU was powered... Apparently it has more then one source of power, as when this happened, my fuel pump and AFC's power (along with the power that was sent out from the ECU to the MAS air meter) was non-existant.

For simple starters, I'd just start with checking that EFI fuse. If there was a problem with the fuel pump install and/or the relay wiring, you could have popped it... If I recall correctly, its a blue 20 amp fuse on the (+) battery terminal.

Other then that, I'd also check the factory fuel pump relay (under the radio, next to the ECU) and MAS, making sure that they are plugged in.

 

[Volume Eight]

I'm not using a DSMLink, but the last time I had something like what you are describing happen on my 1G, I had apparently popped the EFI fuse by accident, while moving some wires around near the ECU (LONG STORY, but it was during my EPROM swap, when I had the ECU out of the car). Once it was re-installed, it seemed like only part of the ECU was powered... Apparently it has more then one source of power, as when this happened, my fuel pump and AFC's power (along with the power that was sent out from the ECU to the MAS air meter) was non-existant.

For simple starters, I'd just start with checking that EFI fuse. If there was a problem with the fuel pump install and/or the relay wiring, you could have popped it... If I recall correctly, its a blue 20 amp fuse on the (+) battery terminal.

Other then that, I'd also check the factory fuel pump relay (under the radio, next to the ECU) and MAS, making sure that they are plugged in.

Thanks for the reply. The fusible link is ok, i already checked them. As far as the factory pump relay, i will definately check that out in the morning. However the new pump is hardwired and is definately running when the car is in the "on" position, so fuel is being delivered. Is the factory fuel pump relay set up to deliver power to the pump all the time? Or does it only supply power intermitently as needed? This is something im not too sure of. Thanks again. Any more help is appreciated.

 

[BreathinHeavy]

well i had a problem with mine and it ended up being the the wiring for the pump was backwards, not my wiring but the marks on the pump were. it might be somthing to consider i dont know why my car was like that but i had to do that.

 

[BoostedTalonTS]

The reason that I suspected the EFI fuse is that it has a lot on just that one circuit (well in a 1G anyways, I'm sure that the 2G are similar)... When I experienced the same rough idle/stumbling acceleration, I also had my fuel pump rewired, but the factory circuit that controls the 5volt power to the MAS (and consequently my AFC) was knocked out by having that fuse blown.

I bet that if can find out the cause of having the OE fuel pump circuit die on you, your idle/stumbling problems will go away after you fix it.

FYI, the OE fuel pump relay supplies power to the fuel pump, via the ECU's output (it works like a ignition power source, but has other built in safety behaviors that stop the fuel pump when the engine dies, and that sort of thing, to prevent the fuel pump being active in the event of an emergency shutdown. Otherwise, it will only supply power to the pump while the engine is running.

To test the OE fuel pump circuit, I think that the 2G have a fuel pump test connector in the engine bay... I know that the 1Gs have it... Basically you just throw 12v+ to the test terminal and it will activate the fuel pump. I would recommend that you look into finding this connector in your 2G and testing it. With the fuel pump rewired "correctly", it will also activate the relay that you installed on the OE fuel pump wire, and activate the fuel pump.

"Correctly" wirin gthe fuel pump relay would be like this:

Relay pins:
85 OE fuel pump 12v+ wire that was going to the fuel pump
85 chassis ground
30 fused 12v+ in from the battery (10 AWG wire or better)
87a not used
87 12v+ out to fuel pump

 

[project_tsi]

Are you global/ injector deadtime's setup up correctly? And base fuel pres. is correct also?When I installed all my fuel parts my car ran like shit too, b/c my tune was very much off, and yes w/ Link. Funny how there basic settings don't quite work right....

 

[Maglin]

Yes it sounds like your not getting power to the fuel pump relay. That relay supplies power to the ECU as well as mentioned above. It would be wise to check the actual relay if the fuse is ok. You can also try unhooking your MAS and seeing how the car runs. It will put it in limp mode and instead of being MAS based load it goes to RPM and TPS load mode. It's not safe but it does work. I have had a few bad MAS's and the easiest way to tell is just unhook it and see how it runs. If it runs really well then chances are the MAS is bad. But being as it happened right after all the install it's slim that it is.

 

[Volume Eight]

Are you global/ injector deadtime's setup up correctly? And base fuel pres. is correct also?When I installed all my fuel parts my car ran like shit too, b/c my tune was very much off, and yes w/ Link. Funny how there basic settings don't quite work right....

I agree, i had to compensate for the injectors with a larger than expected deadtime, and my fuel sliders are all at -15% roughly. Do you have a copy of your setup i can look at? Oh yeah BTW i got the car running. She pulls good, but the front o2 is reading .96 or so... definately rich still. Thanks for all the advice guys.

 

[sweet97]

Sounds like the FPR is acting strange. Why would the pressure stay at 37psi with the line on? First it dropped too much and then it did not drop at all when it should drop some. mark

 

[Volume Eight]

Sounds like the FPR is acting strange. Why would the pressure stay at 37psi with the line on? First it dropped too much and then it did not drop at all when it should drop some. mark

Mark, i suspected the same thing but now it seems to be working ok. Its been raining alot here, so i havent driven much today, but as soon as the weather is nicer im going to take it out and drive some more... i just need to get a sender so i can monitor my FP from in the car. I just dont get how a brand new AEM FPR would be bad out of the box... Im going to need to fine tune my DSMLink and see if this problem rears its ugle head again. Thanks for the input. Peace

 

[Volume Eight]

The reason that I suspected the EFI fuse is that it has a lot on just that one circuit (well in a 1G anyways, I'm sure that the 2G are similar)... When I experienced the same rough idle/stumbling acceleration, I also had my fuel pump rewired, but the factory circuit that controls the 5volt power to the MAS (and consequently my AFC) was knocked out by having that fuse blown.

I bet that if can find out the cause of having the OE fuel pump circuit die on you, your idle/stumbling problems will go away after you fix it.

FYI, the OE fuel pump relay supplies power to the fuel pump, via the ECU's output (it works like a ignition power source, but has other built in safety behaviors that stop the fuel pump when the engine dies, and that sort of thing, to prevent the fuel pump being active in the event of an emergency shutdown. Otherwise, it will only supply power to the pump while the engine is running.

To test the OE fuel pump circuit, I think that the 2G have a fuel pump test connector in the engine bay... I know that the 1Gs have it... Basically you just throw 12v+ to the test terminal and it will activate the fuel pump. I would recommend that you look into finding this connector in your 2G and testing it. With the fuel pump rewired "correctly", it will also activate the relay that you installed on the OE fuel pump wire, and activate the fuel pump.

"Correctly" wirin gthe fuel pump relay would be like this:

Relay pins:
85 OE fuel pump 12v+ wire that was going to the fuel pump
85 chassis ground
30 fused 12v+ in from the battery (10 AWG wire or better)
87a not used
87 12v+ out to fuel pump

Boosted, thanks for the reply. The relay is wired correctly, 85 is just coming from a difft 12v ignition on source, so the fuel pump is powered up when the key is in the "on" position. Do you know if this is alright to do with these cars? Is having the pump hardwired at ignition on bad for the FP? Thanks

 

[BoostedTalonTS]

Boosted, thanks for the reply. The relay is wired correctly, 85 is just coming from a difft 12v ignition on source, so the fuel pump is powered up when the key is in the "on" position. Do you know if this is alright to do with these cars? Is having the pump hardwired at ignition on bad for the FP? Thanks

It's not really a good or bad thing to have a true ignition lead feed your relay's coil 12v+... You are just bypassing the OE fuel pump control (and several OE safety-related fuel pump disable functions).

-Hypothetical Situation-
You end up in a nasty wreck... since you fed the FP relay off of a true ignition source, the fuel pump will continue to pump as long as the key is in the IGN position (provided that the battery is still connected). The way that the ECU controls the OE FP relay is that once is senses that the engine is no longer running, the ECU will cut the power to the OE FP relay, and thus the FP itself (even if it is rewired as previously illustrated. Leave it the way that you have it now, and the fuel pump will just keep on pumping).

Your way will work, but there is a definite reason as to why the OE fuel pump relay is no longer providing the fuel pump with 12v+ (before the rewire)... I still think that this is directly related to your drivability problem... As previously mentioned, the OE fuel pump circuit has more then just the power feed to the OE fuel pump relay on the same circuit. -Go and test the theory... As Maglin said, test the MAS. -Unplug the MAS and see if the conditions get worse. If they remain the same, then what I believe to be going on in your car is more likely the case. Otherwise, I'd also suspect the OE fuel pump relay, the 20 amp EFI fuse, and I'd also look into the OE fuel pump diagnostic connector in the engine bay. -Just make sure it wasn't shorting to ground or anything.

Let us know what you find out

 

[mirkoelek]

looks like your mas is bad, everything youre said leads to it....mas is bi*** ...

 

[Volume Eight]

I have thought about the possibility of a bad mas, and it is something i will definately look into. The only thing about the mas that i dont understand is that i am able to get the car running ok with DSMLink tuned a bit. However, with the stock ecu and the same fuel setup (660s) the car wouldnt rev past 3500 without bogging down. Does this sound MAS related, or is it due to just running 660s on a stock eprom?

As far as the OE fuel pump wiring, i want to look into it, i just dont know where to start. The fusible link off the + terminal is all good. No blown fuses there. I also checked the relay next to the ecu, and it is plugged in. Do you have or could you explain the signal flow/schematics of the OE fuel pump wiring/relay system? Im in the dark on this one.

Thanks for all the help guys, hopefully ill get this thing figured out, and get the car tuned right. This setup should be good for ~275whp... Next step is MAFT and FMIC. Just want to get this under control first. Thanks again.

Peace

 

[mirkoelek]

Yes mas would do that. please check it and let me know.