Help Diagnosis EFI engine problem.

[canrel]

There should be a vacume line going to the fuel pressure regulator. Connect your fuel pressure gauge and check at idle. With the engine running remove the vacume line from the regulator, pressure should rise. Can't remember exactly how much but 50psi should work. Rev the engine to see if it drops. If it does you have a weak pump or a restriction in the supply line(s). First place to start is the filter(s).

 

[rjlougee]

At idle the Fuel pressure is 28 and drops to 23 when I rev the engine but with no load on the engine. From what I have read it should be holding at the upper 30's area.

It should be right around 40 PSI at idle and should rise as the RPMs go up (actually, as vacuum drops the way it really works). Do you have a vacuum source hooked to the FPR?

The pump should still push 40 PSI of pressure, unless the filter(s) are really plugged up. More likely you're looking at low voltage to the pump or a bad pump.
Joe

 

[67EB_in_619]

What does the FP show when you turn the key on but before you start it?
Should be at least 30psi... if it takes a few "key on/off" cycles to get there, you probably have an obstruction.

Have you checked/cleaned your grounds? These EFI systems are REALLY sensitive to grounding issues.

Bad ground at the pump and it might not run great.

Bad ground for the rest of the system and it might "lose" the TFI intermittently. etc etc etc.

The part that concerns me is that the pump "lost power" for a while... that sounds like a bad ground to me.

 

[Socal Tom]

If you don't already have it apart, check the pressure with the regulator hooked to vacuum and then not hooked to vacuum, at idle and reving.

If the pressure drops the same with and without vacuum, then you definetly have a fuel pressure problem. If the pressure only drops with vacuum hooked up then you could have an inaccurate guage, or your pressure regulator may be bad.

Is your check engine light hooked up? Does it come on after warm up?
Tom

 

[trailpsycho]

I know you 'think' that you have a new fuel filter, but replace it anyway. Disconnect the lines and blow them out. Then hook it all back up and see if the problem persists, if so, it very well could be the pump.

One way to see if its the TFI module is to get it running and then pull the SPOUT connector just distal to the TFI module, if it continues to run and evens out, then the TFI is bad. If it continues to do the same thing, then you likely have a fuel pump/accumulator problem and I would start by rexamining the way you have the accumulator plumbed.

You could try removing the accumulator altogether and see if that helps as well...but you did say that it was running fine before, right? I would try these things before I start dropping coin on parts.

FWIW, I am running the Carter 4070 with a section of hose to my E2000 pump for ~18 months and 16K miles without issue (due to the pumps or plumbing anyway). I had an obstruction(s) in the fuel pick/filter last year, that gave exactly the symptoms you describe. Hence, the comment about double checking the filter and lines. Just remember the KISS principle; it ridiculous sometimes how simple and stupid (it is or you are or both).

 

[RVH]

Galen - Did you ever resolve this one? Just curious what the root cause was for future reference.

Rob