Alright I have searched google quite a bit and cannot find a solution to my specific issue(s) Mods: evo3 16g, VRSF FMIC, 1g Bov, 2g Stock non eprom ecu, wally 255, stm fuel pump rewire, fuel lab AFPR, Stock 450cc injectors, I have a 97 GST

Ever since I installed the walbro I have had a problem with the car not going over 3k rpm it will free rev to 5500+ i just didn't red line it because I don't like to.. I set my fuel pressure with vacuum line off and covered (with my thumb) to 43 psi.. People locally say boost leak but I didnt have one before I changed the fuel pump to the 255 I recently changed the fuel filter thinking maybe that was it.. I am lost.. this problem is not being picked up by the ecu at all there are just my egr codes coming up that's it.. The boost gauge is picking up 10 psi at the manifold..

Best describing how the car acts at idle or revving the car it works beautifully.. once I get moving in 1st gear Ill try to get on it once the car gets just past 3k it just wont go.. it stutters halts It sounds like it wants to backfire it has once .. I can also hear boost building and it just feels like alot of pressure building once i let off I can hear the bov working but the car just wont push past tried 2nd gear and nothing as well I checked to see if it was my maf and thats not it the car barley runs unplugged.. Please help thanks

Also will be making a boost leak tester tomorrow. but i really feel thats not the issue but i am doing it for peace of mind

If all you changed was the walbro and now it runs bad I would say you haveca leak in the tank due to improper install. It will free rev because fuel pressure doesnt increase, no boost. Get it under boost and pressure rises. If you could see your pressure gauge you could verify pressure at least. Wideband would show it also, which is why you should already have one. Stock 450s?I hope you have a plan soon.

pauleyman said:

If all you changed was the walbro and now it runs bad I would say you haveca leak in the tank due to improper install. It will free rev because fuel pressure doesnt increase, no boost. Get it under boost and pressure rises. If you could see your pressure gauge you could verify pressure at least. Wideband would show it also, which is why you should already have one. Stock 450s?I hope you have a plan soon.

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Yeah Im on a e4 budget in the military and I have a non eprom ecu so the plan was to save the cash to get the non eprom converted to eprom and link v3 and then looking at 650cc injectors

Be aware they are back ordered. What did you find. Is what I described accurate?

pauleyman is more than likely correct pointing to a leak in the tank. You can easily pull the pump and check the O-ring.

There could also be a restriction of flow (something plugging the delivery line) at the pump outlet or a clogged fuel sock if you did not replace it and disturbed some debris in the tank.

To test, you just need to purchase a few fittings and plumb the gauge from your AFPR so that you can see it through the windshield. On second thought, use a camera or your phone secured under the hood to make a video of the gauge as its installed on the AFPR.

The pressure should rise 1:1 but my guess is like Paulyman, the pressure isn't there.

Slo2gn said:

Alright I have searched google quite a bit and cannot find a solution to my specific issue(s) Mods: evo3 16g, VRSF FMIC, 1g Bov, 2g Stock non eprom ecu, wally 255, stm fuel pump rewire, fuel lab AFPR, Stock 450cc injectors, I have a 97 GST

Ever since I installed the walbro I have had a problem with the car not going over 3k rpm it will free rev to 5500+ i just didn't red line it because I don't like to.. I set my fuel pressure with vacuum line off and covered (with my thumb) to 43 psi.. People locally say boost leak but I didnt have one before I changed the fuel pump to the 255 I recently changed the fuel filter thinking maybe that was it.. I am lost.. this problem is not being picked up by the ecu at all there are just my egr codes coming up that's it.. The boost gauge is picking up 10 psi at the manifold..

Best describing how the car acts at idle or revving the car it works beautifully.. once I get moving in 1st gear Ill try to get on it once the car gets just past 3k it just wont go.. it stutters halts It sounds like it wants to backfire it has once .. I can also hear boost building and it just feels like alot of pressure building once i let off I can hear the bov working but the car just wont push past tried 2nd gear and nothing as well I checked to see if it was my maf and thats not it the car barley runs unplugged.. Please help thanks

Also will be making a boost leak tester tomorrow. but i really feel thats not the issue but i am doing it for peace of mind

Click to expand...

Double check the wiring to your mas, your problem doesn't sound anything like its a fuel pressure issue. Pull the plug on your mas and see if it has any acid type build up on it and clean it with a can of sprite, all it takes is for of those wires not to be getting a connection to give you symptom as you have described. been there before.

Will try that it feels "gummed" I also got a 95 2g eprom ECU and changed to BPR7ES plugs changed the fire order.. still same issue I found an exhaust leak at the manifold to turbo gonna change the gasket to a thicker one we shall see how that goes. keep you posted.