Fuel Pressure Issue?

bkrathwohl · Dec 6, 2009

Im having a strange issue. I have a 2g AWD with a 6bolt swap and cannot get my car to start anymore. My car was working perfectly fine one day, and then the next it would not start. It would crank and crank and then start for like 2 seconds then die. So i figured maybe the fuel pump went out, so I got a walbro 255 and put that in.
Now all my car will do is crank over and over and over. I pulled the plugs, and they are not soaked, they are still sparking. I changed the fuel filter to see if maybe it was clogged, still nothing. I took the fuel pump out to see if maybe I installed the o ring wrong, but it is installed right.
I checked the CAS to see if maybe it was still working. You can hear the injectors fire. So the only thing I can come up with is maybe a fuel pressure issue.
Do you think it could be a bad FPR possibly? I am about to change the o-rings on my injectors just in case they are leaking.

Im thinking about getting either an AFPR or making my own pressure tester to see whats going on. Do you guys have any thoughts on what the issue could be?

JamiesTSI · Dec 6, 2009

Can you hear the pump running?
Try swapping out the resistor pack on the fire wall.

bkrathwohl · Dec 6, 2009

I can hear the pump running when its cranking over, Is there any way to test the resistor pack? Or will I have to replace it.

I checked the ECU for leaky caps and there weren't any, on the top or the bottom.

I poured some gas into cylinders 2 and 4 and it started firing, I tried to give it some gas to keep it going and then it died.

I found a thread about a 1g resistor pack here would that test be the same on a 2g?

turbomatic · Dec 6, 2009

Check the CAS wires. I had the same exact problem. I was convinced it had something to do with the fuel, turned out one of my CAS wires had come loose. I wired it up and it fired right up.

bkrathwohl · Dec 6, 2009

The wires for the CAS look fine, I tested those yesterday and they checked out. Manually turning the end of the CAS you can also hear the injectors firing.

I will check the voltages for the CAS again though, should the plug be connected or disconnected to read the voltage, or does it even matter?

yoshi_tony · Dec 6, 2009

HELP ME I HAVE THE EXACT SAME PROBLEM :banghead:

WITH MY 98 TSI AWD MY FUEL PRESSURE READ 10-15 PSI I CHANGED THE ECU RESISTOR PACK FUEL FILTER AND MINE STARTS FOR A SECOND AND WILL JUST KEEP ON CRANKING :ohdamn:

... IMA SOUND LIKE IM STUPID BUT WHATS THE CAS? :confused:

PieEyedPiper · Dec 6, 2009

yoshi_tony said:
HELP ME I HAVE THE EXACT SAME PROBLEM WITH MY 98 TSI AWD MY FUEL PRESSURE READ 10-15 PSI I CHANGED THE ECU RESISTOR PACK FUEL FILTER AND MINE STARTS FOR A SECOND AND WILL JUST KEEP ON CRANKING... IMA SOUND LIKE IM STUPID BUT WHATS THE CAS?

The CAS is the thing that stops you from posting in all caps. Yours is broken.

CAS usually refers to Cam Angle Sensor, however Crank Angle Sensor is a common one too.

yoshi_tony · Dec 7, 2009

pieeyedpiper said:
the cas is the thing that stops you from posting in all caps. Yours is broken.

cas usually refers to cam angle sensor, however crank angle sensor is a common one too.

well their not broken i checked on the signals on both cam and crank and their good the hardness its like new...if i do the fuel pump re wire will that help?

turbomatic · Dec 7, 2009

yoshi_tony said:
well their not broken i checked on the signals on both cam and crank and their good the hardness its like new...if i do the fuel pump re wire will that help?

Rewiring the fuel pump shouldn't have anything to do with the car starting or not. It allows the fuel pump to get a constant 12 volts so your fuel pressure is consistent.

bkrathwohl · Dec 7, 2009

Is there any way that a failed FPR would cause this? I have a new pump, new fuel filter, CAS is firing the injectors, and fuel in the rail but my car wont start. Pouring fuel into the cylinder started the car for like 2 seconds before it died again. So the only thing I can come up with is fuel pressure is too low.

yoshi_tony · Dec 10, 2009

well mine turns on the problem i had is the way i put my fuel pump to the assembly i only had 10psi, theirs a little o ring rubber than goes all the way inside the assembly thenthe plastic that goes on the fuel pump push it inside then put the rubber on the bottom of the fuel pump and just screw everything back on together and you should get enough fuel pressure if that dosent work it could be your fuel pressure regulator...but now it flouds and idles bad :confused:

but good luck

bkrathwohl · Jan 20, 2010

Well I replaced the lines and added an AFPR to it. The AFPR is holding at 46PSI when cranking and she still wont start up. I am stumped on what the issue could be now. :hmm:

bkrathwohl · Feb 3, 2010

Alright so....
One day the car fired right up, the next it wouldnt start at all.
The car will crank and crank and crank, never try to start.

Fuel pump, lines, afpr were all replaced - fuel pressure is at 46psi right now
new spark plugs - spark plugs are indeed sparking
known good cas is in it
different ecu
injectors are firing with a noid light
compression is 130, 120, 120, 130

Now I am out of ideas and need some input. The only thing I can think of right now would be maybe the Coolant Temp Sensor, since that can cause starting issues. Do you guys have any other ideas? Anything at this point will be helpful.

standard235 · Feb 3, 2010

bkrathwohl said:
Alright so....
One day the car fired right up, the next it wouldnt start at all.
The car will crank and crank and crank, never try to start.

Fuel pump, lines, afpr were all replaced - fuel pressure is at 46psi right now
new spark plugs - spark plugs are indeed sparking
known good cas is in it
different ecu
injectors are firing with a noid light
compression is 130, 120, 120, 130

Now I am out of ideas and need some input. The only thing I can think of right now would be maybe the Coolant Temp Sensor, since that can cause starting issues. Do you guys have any other ideas? Anything at this point will be helpful.

The coolant temp sensor did the same thing on my 92 AWD. It would work sometimes, and wouldn't on others, shown by the logger. Replaced with OEM Mitsu and no issues.

spydreclips6 · Feb 3, 2010

I had issues with mine when my Coolent temp sensor when bad. I could get it to start, but as soon as I let off the gas it would die. Could be that, and I'm guessing you already checked your timing?

bkrathwohl · Feb 4, 2010

If it was my coolent temp sensor wouldnt it eventually start up?

ramsack · Feb 4, 2010

i would get a spark tester or noid light to see if your injectors and plus are firing. if neither are firing then it is your cas most likely.

bkrathwohl · Feb 4, 2010

The spark plugs are indeed sparking and we bought a noid light last night and the injectors are also pusling

ramsack · Feb 4, 2010

it would seem like something isn't timed correctly then. have you taken out the rail with injectors in it and see if they spray? you'll have to have somthing to hold them in place so they don't pop out.

bkrathwohl · Feb 4, 2010

I havent tried that yet, I was thinking about doing it this weekend. That seems like the best place to start right now.

ramsack · Feb 4, 2010

did you take out the cas? it could be 180º off of timing if you took it out.

Redwidow · Feb 4, 2010

I have had this problem before on an install of a 255. Pull the pump and make sure you have the positive and negative wires on the correct side of the pump. I had them backwards and I could here the pump running but wasn't getting any fuel to the rail. After pulling the pump and switching the wires, I realized that I had the wires backwards and the polarity was reversed, thus trying to push fuel into the tank rather than sucking it out. Try this and see if it fixes it.

ramsack · Feb 4, 2010

he says he has 46 psi of pressure at the rail.

bkrathwohl · Feb 4, 2010

I am getting fuel to the rail. I know its nothing in the fuel system, its just something that either controls fuel or spark, or its something electrical in the harness. Unless I am missing something that is super obvious.

ramsack · Feb 4, 2010

If you are getting fuel, spark, and compression, there needs to be timing of all of those. If you are getting fuel and spark, then it has to be compression and/or timing. Using a starting fluid won't tell you that all the timing is correct (180 off) because the spark plugs fire on 2 cylinders at once, so it is firing at the end of the compression stroke and the end of the exhaust stroke of a cylinder.

The Top DSM Community on the Web

Fuel Pressure Issue?

bkrathwohl

JamiesTSI

bkrathwohl

turbomatic

bkrathwohl

yoshi_tony

PieEyedPiper

yoshi_tony

turbomatic

bkrathwohl

yoshi_tony

bkrathwohl

bkrathwohl

standard235

spydreclips6

bkrathwohl

ramsack

bkrathwohl

ramsack

bkrathwohl

ramsack

Redwidow

ramsack

bkrathwohl

ramsack

Similar threads

Latest posts

Build Thread Updates

Vendor Updates

Latest Classifieds