Car bogs when gas pedal is pressed

[dreaMervaj]

Hey guys,

so I threw my old KA-T kit on my new 240. Relocated battery to trunk.

It ran fine for a few days then one night coming home it just shut off and wouldn't start up so I had to tow it home. Before it shut off oil pressure/AFR was normal and it drove fine up until the rpm's slowly started dropping and the car came to a halt.

The next day when I went to turn it over it would crank but not start up. So I proceeded to check the electrical components to find out all my grounds were loose. Therefore I check my negative cable in the trunk and it seem the strap (the strap that holds the battery box) touched the negative cable (where I had it grounded on trunk/the strap showed a little burn mark).

I proceed to check to see if there was any blown fuses and there was none (checked cabin and in engine bay) so I tighten all my grounds and started the car. It was doing the same thing as before it would crank and crank but not start up. I reset the timing back to TDC and it fired up. It fired up and idle fine (1000rpm or so) until I went to push on the gas pedal; when I pushed on the gas the car bogged down.

I've replaced my maf (Z32) thinking that may the problem and problem still persisted. Changed distributors and bought a new cap (no button yet) and still no luck.

What could've happened here? Bad TPS? Bad IACV? Fried ground wires?

Sorry for the long post but any advice would be appreciated. I hate looking at my 240 just sitting there...

Quite stump at the moment. Any advice would be greatly appreciated. Thanks!

[dreaMervaj]

any loose/not attached couplings?

I have yet to check for vacuum leaks but I've checked all my couplers and they are tight..

Boost gauge is pulling about 15 right now when it should be closer to 20 but would a leak cause it to do that at idle? The car bogs as soon as I press the gas pedal.

[jaxshawn]

Check your fuel system

[dreaMervaj]

Check your fuel system

What should I check for? I installed a Walbro 255 also before the kit went on. I know the pump is priming because I hear it...

[PedroJG]

Check fuel pressure?

[Kallixtos]

Check to see if the ECU is throwing any codes?

[quickdiversion]

I think I know your exact problem cause a similar thing happened to my while dicking around in the driveway. I have an SR, but I know the KA has a similar setup. The ground switch signal that turns on the fuel pump coming out of your ecu might be no good anymore. On the SR ecu it is pin #104, it is called ground switch.

This signal is sent from the ecu to the fuel pump relay. On the KA wiring I believe it is a black wire pink strip and it goes to pin #3 on the green fuel pump, or egi pump, relay. I had all the same symptoms and found this to be bad.


All you have to do to test it is pull the relay. Take a volt meter that has the little diode symbol, basically is makes a noise if the wires are touching (used to check connectivity) put one meter prob in relay pin #3 the farthest one back, aka closed to the firewall, but do check, and the other prob to ground.

Set it to the connectivity check symbol and turn the key to acc. If you get a tone that the signal is good and I am wrong. If you get no signal. Than you need to replace your ecu.

Or do what I did. Wire up your own ground switch and have a manual fuel pump switch.

Good luck

[dreaMervaj]

Check to see if the ECU is throwing any codes?

I've disconnected the battery multiple times and haven't had the car running for a long period of time but I checked and got a code 55 which means no faults.. but can't be positive cause I haven't had it up and driving around like I said...

When the car cranks over it will idle fine but if I shut it off and try to turn it back on it just cranks and cranks but doesn't start...

I'm pretty stump here. Not sure where to start.

[quickdiversion]

I've disconnected the battery multiple times and haven't had the car running for a long period of time but I checked and got a code 55 which means no faults.. but can't be positive cause I haven't had it up and driving around like I said...

When the car cranks over it will idle fine but if I shut it off and try to turn it back on it just cranks and cranks but doesn't start...

I'm pretty stump here. Not sure where to start.

Did you read what I wrote?
It might be the case

[dreaMervaj]

I think I know your exact problem cause a similar thing happened to my while dicking around in the driveway. I have an SR, but I know the KA has a similar setup. The ground switch signal that turns on the fuel pump coming out of your ecu might be no good anymore. On the SR ecu it is pin #104, it is called ground switch.

This signal is sent from the ecu to the fuel pump relay. On the KA wiring I believe it is a black wire pink strip and it goes to pin #3 on the green fuel pump, or egi pump, relay. I had all the same symptoms and found this to be bad.


All you have to do to test it is pull the relay. Take a volt meter that has the little diode symbol, basically is makes a noise if the wires are touching (used to check connectivity) put one meter prob in relay pin #3 the farthest one back, aka closed to the firewall, but do check, and the other prob to ground.

Set it to the connectivity check symbol and turn the key to acc. If you get a tone that the signal is good and I am wrong. If you get no signal. Than you need to replace your ecu.

Or do what I did. Wire up your own ground switch and have a manual fuel pump switch.

Good luck

So was the fuel pump relay bad or the signal to the fuel pump relay from the ECU? And from what you're saying I should test the fuel pump relay pin #3 correct?

Did the car start up and idle but bog when you press on the gas like what I mentioned in my original post?

I'll give this a try tomorrow if I get a chance.. My car's been down close to a month because of this..

[quickdiversion]

The car finally gave up starting, it would crank and crank forever cause no fuel.

The signal from the ecu was not coming through. something in the ecu went and it no longer sent the signal to the relay to kick over and turn on the pump.

If you have the car turned to acc and do a continuity test from pin 3 of the egi relay to ground and you get continuity, that it is good.



.....In your original post I thought you said it finally stopped starting altogether, it would just crank.

[dreaMervaj]

I've been so busy I haven't had a chance to work on the car until today.

I went to rent a fuel pressure tester from Autozone today and connected it like so:

http://i17.photobucket.com/albums/b77/PaOie-VaJ/fuelgauge_zpsce533996.jpg

From the fuel filter it goes to one end of the T rod that goes to the fuel pressure gauge and the other end of the gauge goes to my rail. When I turn the key to "ON" position the gauge isn't getting any kind of pressure; it sits at 0.

I can hear my Walbro prime. If I start the car and the car is running the gauge still reads 0. If I'm getting 0 fuel pressure how could it start?

Gauge malfunction?

[quickdiversion]

Did you pull the pump up and look at the strainer? Make sure that isn't clogged?

[dreaMervaj]

Did you pull the pump up and look at the strainer? Make sure that isn't clogged?

I don't want to pull the pump if I don't have to.. but I may when it gets cooler here.

I can feel the fuel coming through the hoses but no pressure reading at the gauge.. how is that possible?

[quickdiversion]

Are your feed and return switched up? Put the pressure gauge on the other side and test

[dreaMervaj]

Are your feed and return switched up? Put the pressure gauge on the other side and test

Feed and return are where they are suppose to be..

[quickdiversion]

Did you check?
Cause this is what's happens when they are not.

[S14DB]

Get a bucket, cup, ect. Point the line coming out of the fuel filter at / into it. Have someone turn the key to the ON position without starting. Fuel should spray into the cup for 10 secs. If it doesn't put the lines back and pull the return line off the FPR and do the same test. If you get fuel coming out the return line you have them switched.

Your lines should run: Supply, Fuel Filter, Rail, FPR, Return.

If you get constant fuel out of the filter for 10 secs while the car is turned to the ON position and you lines are correct like above. I would say your FPR is bad if you aren't building 43PSI during key on prime. Or the pump can't build pressure.

To test if it is the fpr or pump. Hook up everything then pull the return line out of the FPR. put the cup in front of the line out of the FPR. Have someone do the key on prime again. You should hear the pump run then a few seconds later the fpr will start returning fuel as it gets up to 43.5. Then is should stop right at 10secs when the pump turns on and hold 43.5 in the supply line. You may get a drip as the FPR weeps out the pressure but not a full flow until there is no pressure on the supply.

If fuel just pours out the fpr when you prime the car till the prime stops the FPR is bad. If no fuel comes out of the FPR at all the pump is bad or a line is leaking.

[dreaMervaj]

Get a bucket, cup, ect. Point the line coming out of the fuel filter at / into it. Have someone turn the key to the ON position without starting. Fuel should spray into the cup for 10 secs. If it doesn't put the lines back and pull the return line off the FPR and do the same test. If you get fuel coming out the return line you have them switched.

Your lines should run: Supply, Fuel Filter, Rail, FPR, Return.

If you get constant fuel out of the filter for 10 secs while the car is turned to the ON position and you lines are correct like above. I would say your FPR is bad if you aren't building 43PSI during key on prime. Or the pump can't build pressure.

To test if it is the fpr or pump. Hook up everything then pull the return line out of the FPR. put the cup in front of the line out of the FPR. Have someone do the key on prime again. You should hear the pump run then a few seconds later the fpr will start returning fuel as it gets up to 43.5. Then is should stop right at 10secs when the pump turns on and hold 43.5 in the supply line. You may get a drip as the FPR weeps out the pressure but not a full flow until there is no pressure on the supply.

If fuel just pours out the fpr when you prime the car till the prime stops the FPR is bad. If no fuel comes out of the FPR at all the pump is bad or a line is leaking.

Thanks for the detailed tips.

The lines are correct; when I turn the key to ON position fuel comes out of the supply hose (fuel filter hose). I can't seem to get the gauge to move yet the car is supplying fuel? I'm going to rule that the gauge is bad. I'll return it and rent another gauge I guess.

[dreaMervaj]

So I rented another gauge and it's still not reading anything.

Do I have it set up wrong? There are banjo fittings in the kit that I have no idea how to use and two GM/Ford schrader valve fittings. I use the T looking fitting and hook up the hose from the fuel filter to one side and the other side connects to the hose that goes into the fuel rail (as pictured above). Why am I not getting any reading with the car on the "ON" position or when the car is running?

I opened up my fuel tank to try to get a look at the Walbro I installed a month ago but can't seem to unhook it..

Heat + frustration is a bad combination....

[silverarrow27]

I'm getting similar fueling issues with mine too. Been battling it the last couple months on and off. My car is rough at first start up and have to keep the throttle open for several seconds until it catches and idles for a minute or so then stumbles and dies. I can't seem to rev past 3-3500 rpms on my car like a bad MAF, have replaced the MAF & FPR/gauge thinking it may have been a combination of all three.

Nope, fuel pressure still stays at 0. Previous gauge was a B&M and current gauge is a Marshall. Previous FPR was an Aeromotive A1000 & now have an Aeromotive 13129 EFI Bypass Regulator. Starting to think it's my fuel pump because I can't hear my fuel pump prime anymore when my key is at acc.

Thanks for the tips S14DB, done a couple of your suggestions already. Will do the other ones which I have not.

[S14DB]

Thanks for the detailed tips.

The lines are correct; when I turn the key to ON position fuel comes out of the supply hose (fuel filter hose). I can't seem to get the gauge to move yet the car is supplying fuel? I'm going to rule that the gauge is bad. I'll return it and rent another gauge I guess.

Did you follow my tips after that?

[cotbu]

I'm getting similar fueling issues with mine too. Been battling it the last couple months on and off. My car is rough at first start up and have to keep the throttle open for several seconds until it catches and idles for a minute or so then stumbles and dies. I can't seem to rev past 3-3500 rpms on my car like a bad MAF, have replaced the MAF & FPR/gauge thinking it may have been a combination of all three.

Nope, fuel pressure still stays at 0. Previous gauge was a B&M and current gauge is a Marshall. Previous FPR was an Aeromotive A1000 & now have an Aeromotive 13129 EFI Bypass Regulator. Starting to think it's my fuel pump because I can't hear my fuel pump prime anymore when my key is at acc.

Thanks for the tips S14DB, done a couple of your suggestions already. Will do the other ones which I have not.
Turn the key to on not acc!
If you have a fuel delivery problem, aka not enough then opening the throttle during startup only hinders the problem. Too much fuel on the other hand can be remedied by opening the throttle.
You have to determine what issue you have, before it can be fixed. Fuel issues not mafs related, usually appear around 4krpm, but if you continue to drive like this the rpm will tend to get lower, makes the issue look like something it's not
Resetting the ecu helps, but pull codes first.

Sent from my Highly Tuned Galaxy S3.4!!!

[silverarrow27]

Thanks, I was mistaken and I did turn the key to "on" and not "acc". Thanks for the correction. It seems the Aeromotive 13129 fpr is hooked up differently from the A1000 when comparing install instructions. I switched the fuel lines around per the 13129 instructions and my gauge finally showed fuel pressure. Unfortunately, the most pressure I built was 15 psi and then it just dropped to 10 psi and stayed there as I let the car idle.

Adjusting the fpr didn't help with the fuel pressure at all and then I clamped the return fuel line out of the fpr and built up a bit of fuel pressure up to 12 psi only. I'm guessing my 13 yr old Walbro 255 lph fuel pump finally gave out on me. I went ahead and ordered a Deatschwerks DW200 & oem Z32 fuel filter last night. Hopefully it'll come in before the weekend and I can install them to see if it resolves my issues.

[silva.240]

i'm hoping my issue is the same and my fuel pressure is low... btw i have a brand new dw200

[anti tyler]

Are you absolutely positive you're getting complete spark? I had an issue in later 2011 where my car would drive X amount of miles and die. RPMs would drop as it came to a slow stop. Spent 5 hours on the side of i95 in North Carolina to only find out it was the ignition coil intermittently failing. After 2 weeks of no results I replaced it with an MSD blaster 2 coil for $40 and that was that...

[silverarrow27]

Finally got off my lazy ass today and installed the DW200 fp. Upon taking the fuel pump assembly out, I discovered that the filter sock has disintegrated and the fuel line from the Walbro 255 lph fuel pump to the fp assembly started to disintegrate as well. Literally, my once tight fuel line can be slid up and down the fp assembly and the rubber fuel line has now become a gooey mess. I had to reach into my fuel tank and pick up as much rubber pieces as I could before reinstalling the DW200 fp. Went ahead and swapped out the fuel filter with a Nissan oem Z32 fuel filter as well.

Started the car up and it was idling nearly at 80 psi, readjusted the fuel pressure down to about 44 psi. I may bump it up to 50 psi since I'm running an HKS GTRS turbo. Revs freely now, although I think I may hear minor stumbles in the higher rpm range still, may have to double check my spark plugs. Probably fouled up from my troubleshooting.

[dreaMervaj]

Get a bucket, cup, ect. Point the line coming out of the fuel filter at / into it. Have someone turn the key to the ON position without starting. Fuel should spray into the cup for 10 secs. If it doesn't put the lines back and pull the return line off the FPR and do the same test. If you get fuel coming out the return line you have them switched.

Your lines should run: Supply, Fuel Filter, Rail, FPR, Return.

If you get constant fuel out of the filter for 10 secs while the car is turned to the ON position and you lines are correct like above. I would say your FPR is bad if you aren't building 43PSI during key on prime. Or the pump can't build pressure.

To test if it is the fpr or pump. Hook up everything then pull the return line out of the FPR. put the cup in front of the line out of the FPR. Have someone do the key on prime again. You should hear the pump run then a few seconds later the fpr will start returning fuel as it gets up to 43.5. Then is should stop right at 10secs when the pump turns on and hold 43.5 in the supply line. You may get a drip as the FPR weeps out the pressure but not a full flow until there is no pressure on the supply.

If fuel just pours out the fpr when you prime the car till the prime stops the FPR is bad. If no fuel comes out of the FPR at all the pump is bad or a line is leaking.

I haven't had a chance to work on the car due to unseen circumstances but I finally got to test the fuel flow according to S14DB yesterday... The lines were hooked up right and I found that my FPR was bad (fuel pour out of it as soon as the fuel pump came on). I replaced the whole fuel rail/FPR with another one I had laying around and swapped my 750cc injectors also. I had such high hopes that that would solve why my car would bog down when I stepped on the gas but my hopes were destroyed when it did exactly the same thing.

I'm pretty stump at the moment. No idea what is wrong with the damn car.

[dreaMervaj]

Any ideas what could be causing the car to bog down and stall when I press the gas pedal?

Vacuum is at 15-20 so I don't think it's leaking...

[EnnEssEnnKAT]

The timing could be off


Sent from my iPad using Tapatalk

[JSimpson]

dude its REALLY simple. You DON'T have fuel..... Pull the pump out, it takes 4 minutes or less, 10mm and 8mm deep socket on a 1/4 in. drive ratchet... MAKE SURE your filter sock is on it. Walbro 255s can do weird crap like this from time to time. PULL OFF BOTH FUEL LINES OFF THE RAIL AND FPR, put a long 5/16 rubber fuel line off the fuel supply hard line under the filter. run that into a bucket, or water bottle if you are feeling risky. Spray compressed air through the line to make sure it is free of obstructions/clogs/debris. Stick the pump back into the fuel and key it on and make sure fuel sprays out hard, it will spray pretty damn hard. If it doesn't, then your pump is done or at least needs to be cleaned out. You can revive these pumps more often than most like to give credit. I would also advise getting a clear return line from a hardware store. If you know much about boats, almost all marine fuel lines are clear braided lines so you can see the fuel return. This will also tell you when air bubbles are present. If you see lots of small bubbles like fizz then you have a leak. Lastly check the FPR, either get a simple reliable inline gauge or simply crack a line after the car has sat for a few minutes. If it still has pressure on the feed side after 10 mins or so, FPR is fine since it is after the injectors in the flow path. The walbro 255 has a built in residual valve that keeps pressure to the rail after key off to aid in startup...

Don't be lazy, do this.

[dreaMervaj]

The weather has been bad lately so I haven't gotten a chance to work on the car; not having a garage sucks.

So the first two times I rented the fuel pressure tester before I swapped the bad FPR out the key on PRIME didn't show anything and even when the car was on and running it read nothing on the gauge. Since I've ruled out the FPR I went out and rented the tester again; now on prime the car sits around 10psi-20psi and when the car turns on it sits right around 30psi. Isn't the car suppose to be at 40psi or so when the key is on prime and 34psi (with vacuum) at idle and 43psi without vacuum?

The fuel filter was one of the first things I swapped out after the car ran into this brick wall of a problem. I've narrowed it down to my brand spankin' new Walbro being a bad unit or maybe the sock on it is bad (I used the OEM sock since the install kit I got used the small sock)....

I haven't pressurized the system for fuel leak because I don't have a compressor; this could be the problem also!?

I'm going to place a order for a new Walbro unit on Monday and pray that solves this problem..

[dreaMervaj]

Any ideas?

This is all that I've done since last August when it went down.
Replaced fuel filter
Enthalphy sent me a new ECU with a new chip with the same tune
Changed fuel rail
Changed engine wiring harness
Changed distributor/spark plug/spark plug wires/distributor cap
Changed fuel pump
Replaced OEM FPR with another OEM FPR (used) then ordered a ISIS FPR (currently installed and reads 43psi like it's suppose to)
Replaced coolant temp. sensor with another one I had on a spare motor (used)
Replaced fuel pump relay

The car starts up fine and idles fine but when I press the gas pedal or pull on the throttle (inside engine bay) the BOV goes off and the car backfires/exhaust makes popping noises.

[dreaMervaj]

Still haven't figured out what's wrong....