duranvw

iTrader: (2)

I have a problem with my fuel pump being shut off, I'm able to keep the car running if I run direct power to the fuel pump (hot wire) however the AFRs getting very rich once the car warms up, richer than 11:1.

I assume this is because I'm sending 12V to the pump at idle when it would normally only have 7 or 9 or whatever it steps it down to normally. I have the same fuel pressire 42PSI at 12V.

How would I tune to accomodate this at idle and cruise? I have ECUFlash and Tactrix cable, not sure if I just start changing the fuel maps in the idle tables?

Raptord

iTrader: (10)

changing the fuel map will have no effect in idle or cruise conditions since the car is running in closed loop.

duranvw

iTrader: (2)

Is the reason the car is being flooded possibly due to the contact 12V to fuel pump or is there another problem? Something with injectors?

90zcrex

iTrader: (11)

Personally I would fix the problem instead of hotwiring it. If you've got a problem with wiring to the pump then you could possibly have problems affecting other systems/ ignition/ sensors/ ecu. Get the actual issue fixed and you won't have to worry if things are right or not.

duranvw

iTrader: (2)

I agree 100%, I havent been able to identify the problem yet. However if I unplug the MAF (putting car into open loop) the car will run, however not very well.

My guess right now is that open loop is ignoring the problematic sensor/part? Anyone know what all is ignored in open loop? I know the o2 sensor is no longer used for sure.

90zcrex

iTrader: (11)

Sounds like a bad maf to me, seems if you unplug the maf the ecu will use predetermined values and this is whats keeping the car running. I would try swapping out a maf sensor if you have access just to try it.

duranvw

iTrader: (2)

That was my original thought as well, I've been trying to fix this for 6 months. I have already relpaced;

1) MAF sensor
3) Fuel pump
2) IACV
3) ECU (another EVO IX stock one)
4) Areomotive adjustable FPR
5) Swapped the two fuel pump relays under the dash
6) Fuel pump relay #3 and resistor on the firewalll
7) Crank position sensor

I throw NO SES codes, I was throwing rear o2 codes months before the problem occured but the rear has no control over this from what I understand.

90zcrex

iTrader: (11)

Do you have a voltmeter? I'm not exactly familiar with the evo's fuel pump system but looking at the wiring diagrams you can do some checks. Check for voltage at the resistor on pin 1, the power will go out after a certain amount of time so you may have to keep cycling the key to check.
If your getting power on pin 1, then plug the resistor in and backprobe the other pin and check voltage, you should have a lower voltage here but should still be something. If you've got voltage on pin 2 at the resistor, this wire runs straight to your fuel pump so you should have this same voltage at the pump, if not you have a bad wire.

If you don't have power on pin 1 at the resistor- then your not getting power through fuel pump relay 1 and 2. You will have to check power on pin 3 and pin 1 of relay #1 and power on pin 2 and pin 1 on relay #2.

Also did you swap the two relays under the dash as in put them both in each others places? or used known good relays in place of these? The power for the fuel pump has to go through both of these relays so if one is bad and you just swap them you still wont have power to the pump.

duranvw

iTrader: (2)

I do have a voltmeter, I can tell you I monitored the wires right at the fuel pump assemlby and I get 12V when the car starts but it drops to 0 after a couple seconds and the car dies.

I havent checked each relay pinout as you suggest, the fact that the car runs in open loop would indicate the wiring to the pump is good, right? It can obviously get power but I think the fuel pump relay#2 is not being grounded by the ECU and then pump shuts off

90zcrex

iTrader: (11)

Yea if you are getting 12v there for a minute and shutting off then the ecm is turning it off. You are reading engine speed in evoscan correct?

duranvw

iTrader: (2)

Do you mean RPM? I have recorded evoscan logs when having this problem... not sure what I can look for tho

90zcrex

iTrader: (11)

Yea engine rpm. You can try and disable the immobilizer in ecu flash, could be something funky going on there.

Jturbo86

iTrader: (1)

Im not sure that having 7-9 or 12v at the pump is going to change your fuel pressure, wouldnt that be dependent on your FPR? If you bought a used MAF you could have another faulty unit.

duranvw

iTrader: (2)

[QUOTE=Jturbo86;10460846]Im not sure that having 7-9 or 12v at the pump is going to change your fuel pressure, wouldnt that be dependent on your FPR? QUOTE]

Right that's what I figured so that should be the cause of running rich in openloop. Yes the MAF was a used one from the forums here.

When I swapped the ECU with a second one I disabled the Immobilzer to get it to even start, but same issue so I don't think that Immoblizer is the problem.

joseph143

iTrader: (8)

I run the walbro e85 pump, 450lph, hot wired to the battery. And i dont have issues with afr but my fpr is adjusted to manage it. If it runs in open loop its ignoring your o2 sensor inputs. Since it doesnt run in closed loop chances are its something to do with them or possibly an auxilary input that is also ignored. Can you log front amd rear o2 to see them in closed loop? If they are throwing bad info they might just be freaking out the ecu and it in turns shuts down the car. But i would think it would throw a cel or revert to open loop automatically.

Sorry for the brain storming. Check your cam angle sensors. They crontrol fuel systems for most cars. Crank controls ignition at startup but not after that normally. It switches to ecu control via various inputs. Were there any modifications, repairs, or damage that were prior to the hickup?