Fuel Pressure Tester

Hi Steve...

Once again, old retired electrical guy; take my thoughts with a grain of salt... but somewhat plagiarized...

Check the fuel line from the tank to the pressure regulator, looking for pinched or "improperly sharp bends" in it... Obvious, I guess - but also look for leaks.

Check the vac hose that feeds the regulator thoroughly, and it's source. Disconnect it (engine running) and verify there's vac.

If you have or can borrow a hand pump, suck the pressure regulator down to 10 or 12 inches. See if engine runs better. See if the vac will hold for at least several minutes without leaking down.

And yikes! Last resort, check for a leaking injector in one of the other cylinders.

All of this relative to "low fuel pressure"

And if that fails - dunno where you are other than Eastern Canada (I'm Winnipeg), but suspect it might be easier/faster/cheaper to let a mechanic who has one just check the pressure for you. Not fix it, just check the pressure. Buy him lunch :)

I'm real lucky; have a little tiny used car lot at the corner. Owned by a licensed mechanic. Fantastic neighbor. Works two ways I guess, went for a bike ride last summer, rode through his lot. Sat evening, threatening to rain heavy, and found an almost new Park avenue with the sunroof wide open. Couldn't close it, but phoned him at home.

Good luck, and take care.

Ken

Probably because GM fuel rail Schrader valve fittings are 1/4" inverted flare. The same size as what was used on R-12 low side AC systems.

So what should I call it? An R12 low side to 1/8 NPT or 1/4 NPT adapter?

Steve

As aarc... said: R-12 low side fitting is same as gm port injection large Shrader. Get a R-12 low side hose with female R-12 1/4" Schrader to 1/4" anything else (flare, NPT, etc.) and either use the other end or cut it off and use a hose barb. I suppose you could install an R-134 quick connect fitting on your car and use a R-134 hose. Get one that has a core and permanently remove the old core.

Hi Steve,

I made the following post back on Oct. 4, 2004. Sounds like we are having the same trouble. I rarely drive the car but was looking at buying a fuel pressure tester from NAPA for about $45.00. Let me know what you find out on yours.

Thanks, Jeff

The car is showing a miss on the #5 cylinder, occurs only when engine is under boost from the supercharger. Occasionally also shows miss on #4 and less frequently on #6. This was found by using a scan tool.

Have swapped plugs, wires, injectors, injector wires, and coils with those from either #3 or #1 cylinder, but problem stays on #5. Also tried a new ignition control module. Engine runs smooth in the driveway at all rpms. Only misses under load and only under boost conditions.

I'm thinking fuel pressure regulator?? fuel pump??

The fuel filter was recently replaced. I run 92/93 octane.

Problem occured after car was parked for several months with only being started every couple of weeks and idling to operating temp. The car has

Any help would be greatly appreciated.

Thanks, Jeff