Car: 1988 Pontiac Trans Am ,
Engine: 5.0 litre TBI

The kit i am using is made by actron.
My question is , wich of the two fuel lines is to and from the tank " wich is wich ?" .

 

The larger 3/8" line is the feed (pressure) line. The smaller 5/16" line is the return.

Don't you hate that GM didn't put a simple schrader valve on the TBI engines where you could easily tap in to take a reading like on just about everything else?

 

yeah , there would be less fuel on the floor onthe enginebay ,and more fuel in the tank , so im assuming this test will only verify if the fuel pump isgood or bad ? will it let me know if my FPR is not working right ?

 

Both, really. If it reads low it could be either one. If it reads high that can only by the FPR or an obstructed return line.

If you can possibly rig it up so you can see the gage when you drive that's another test you can do. Proper pressure at idle is only one check. If pressure drops off when you put it under load (like making a quick WOT run through a gear or two) then the fuel pump isn't keeping up with demand. Clogged fuel filter, dying pump, inadequate voltage to the pump, etc.

 

did the test , 11psi @ idle , should be good . TBI's should be between 13 and 9 psi right?

 

With my TBI pump it put out over 15psi... That may be a bit low.

 

I wouldn't think 11 psi would be problematic on a TBI. BTW, if you ever do decide to replace your in-tank pump, just put a TPI pump in there. The regulator in your TBI unit will keep the pressure where it should be, and it shouldn't ever suffer from the pressure being too low. I ran a TPI pump in my TBI car for several years without any problems at all. I just recently swapped in a tuned port motor and it was nice to already have the higher pressure pump in the tank! If you went with a TPI pump, you could put in a high quality pump like the Walbro when it comes time for replacing it.

 

 

I want to check the fuel pressure on my L05 TBI (92 RMW) to set my EBL flasher properly.

Are there any kits existing that would bolt on simply on the fuel lines ???

if not how do you guys proceed ????

 

ooops

Found Sunpro # CP7817 GM TBI Tester.

seems perfect for the job !!!!!! (58 USD)