Walbro- good first upgrade, right?

[6SENSE]

Alright, I know a guy who has a '84 GN with rebuilt motor, everything stock. I had told him the first thing he should do before worrying about more boost is to upgrade the fuel system. He now has a Walbro340 pump and Kenne Bell adj fp regulator.
The car hasnt been running to great (missing) and is now blowing ALOT (I mean ALOT) of grey smoke out the pipes.
A couple of people have told him he shouldnt have put that pump in, he has "over-fueled" the motor (?!). He should have just put a Delco pump in (?!).
Correct me if Im wrong but it should not matter what pump you have in the tank, 34psi is 34psi, 38psi is 38psi, etc. What the regulator is set at is what you are running. Just because you have a pump that CAN push more fp doesnt mean all of a sudden your fuel lines swell up and youre flooding the engine with gas. There is no reason someone should not be able to put a pump that is capable of higher fp in place of a pump that may not be able to produce the fp that we need to run higher boost.
Its not easy working on someones car who has other people who think they know what they are talking about, or is trying to lead them the wrong way on purpose blowing BS in there ears, and then youve got to hear it.
Anyway, I was thinking the problem has to be somewhere else. Coil/ mod, plugs, wires ?. Iwas thinking that possibly an injector problem. Maybe cam sensor. Or even as a last resort, what about the ECM? I cant believe that with the way it is running, the ECM isnt giving out any codes.

Anyone have any ideas/comments? Please. Am I thinking right here or am I the one that doesnt know what Im talking about?! Thanks guys.

 

[Ormand]

Smoke?

Too rich should be black smoke. And the change in pump might affect mixture, IF the pressure regulator won't handle the higher flow. Pump is a constant volume pump, it pumps whatever the little electric motor will drive it to, and it starts out at max flow at low pressure. The regulator bypasses the excess flow back to the tank. Now if the Walbro 340 pumps more than the kenne-bell regulator will bypass, the pressure will go up, and you would see that as too rich, but you would also see the high pressure. I saw a post from someone who said that a Bosch 237 wouldn't lower pressure below 40 psi, with the Walbro 340, but don't know about the accuracy of the numbers. Short answer- if the regulator can be set at the desired pressure, the pump should not be causing a problem.

 

[1badTTA]

I agree 100% that it isn't the pump/regulator, as long as the pressure is correct, then it is something else. You said it was grey smoke, that sounds like oil. I would do a compression test to make sure the head gaskets are good. If not that then check the PCV valve and the turbo to make sure the seals are good (large quantity of oil in the turbo)

HTH

 

[Turbo 6 Justin]

I'll second that I believe that it is definitly NOT the pump/regulator. It may be rich but if that is true it is only cause the regulator is adjusted incorrectly. there are LOTS of people on this and other boards runnning the 340 with no problems from the 15's to the 11's