fcs13

Heres what I have concluded about my latest car troubles. There is not enough spark happening when I turn the engine over. But wait, why would there not be enough spark? I never changed anything about the ignition system. Wait! I got it, too much fuel being added to the mixture, thats gotta be it right? am I wrong? When I first started my NA -> T2 convert I added a walbro 255 fuel pump and took out the stock NA fuel pump. Could this thing be giving it too much fuel? What should I do to make things work right? I understand an FPR could work but what do I do with it? How would I mount this to my stock fuel rails and where would I even begin to start the process besides buying the damn thing?



Also, what about just simply replacing the fuel pump with the stock NA pump? Would this then not give enough fuel? It is out of an S4 mind you all reading. I have also been able to get the car running in the past so I know the ignition system and the supporting systems function properly. Its just aggravating not knowing for sure what is wrong but I think I may have found the source of the gremlin machine. So someone, anyone, please help me! Thanks



-B.

DevilMotorSports

I would keep the Walbro pump in, you can never have too much fuel with a turbo car. Except for this



Do a fuel pressure test and see what type of pressure your getting from the pump. You want a pressure after the stock pressure regulator of 245.2-255.0 kPa and from the pump you want 490-637 kPa according to the FSM. Now thats with the stock pump. If the Walbro is off the charts than your going to need an adjustable fuel pressure regualtor to try and bring it in line.



A riseing rate adjustable fuel presure regulator is what you should get. It has an vaccum/boost attachment that will change the fuel pressure based off what the engine is doing. Most of them have an extra port on them where you can add a gauge so that you can monitor your fuel pressure; which is handy with trouble shooting



Did you hard wire the Walbro or did you use the stock wiring? The stock wiring has a resistor that changes the voltage to the fuel pump based off RPM and throttle position. You don't get a full 12+ Volts to the pump untill WOT. Having said that, if the Walbro pulls to much current though that resistor pack you could possiably burn it up. If you go with an adjustable fuel pressure regulator I would hard wire it for sure. Its much eaiser to set the presure base line.



I'd start witht he fuel pressure test and work from there.

fcs13

Well I knew the pump was working fine, I had it wired to the stock wires. I knew it was getting plenty of gas due to the smell of the exhaust. I knew I was getting spark because my tach needle was bouncing evenly and every once in a while the thing would start (when it was in the shop.) However, the more and more I worked on the car getting things finished and parts tied in here and there the car would no longer start or even try to start. Now, the needle wont bounce at all. not even a little until I turn the key off and there is only one little bounce at the end. other than that, nothing. I am still getting the fuel and also went ahead and tried swapping back in the stock pump and still have the walbro, not planning on getting rid of it :-P



This thing is just so aggravating is all. oh well, its long over due for a new pair of eyes to look it over anyways. Thanks for the advice though.



-B.