Originally Posted by Jeffress77
Ok, I checked the fuel pressure today...
When the key was turned to "on" position the pressure tester read up to 30 PSI then dropped back down to almost zero. Each time the key was turned "on" and then "off" the pressure would go from zero to 30 PSI and then back to zero. When the engine was started, the pressure tester would read in between 45-50 PSI continuously.
This is exactly why I recommend testing before doing anything as this here, indicates a fuel delivery system failure and, the following are possible failure modes:
1. LEAKING INJECTOR:
Whenever an injector leaks, the valve remains stuck open thus, allowing fuel to pass through 100%. On a psi gauge, this represents semi pressure upon KEY <ON> event along with an immediate drop to zero once power has been cut to FUEL PUMP. This failure is quite common.
When running, the psi range will "bob" from low to high in rapid succession on the psi gauge.
I will describe in detail how to test and, how to isolate each injector to root out the problem injector/s down below in a bit.
2. PUMP LEVEL FAILURE:
This may be either a failing check valve at the regulator or, it may be a failed regulator altogether thus, the low psi and no pressure due to it bleeding back into the tank. This is what I had described yesterday in my first post on this. This is very common.
These are the first two that I would investigate as these two modes of failure are the most common occurrences.
FUEL INJECTOR ISOLATION TEST- W/O FUEL RAIL REMOVAL
--Tools and Materials
- --Long pry bar
While running, place pry bar onto the seam on each injector. Place the plastic handle up to your ear tightly. Note a steady tick, tick....in equally spaced timing. It must be in time. If it's intermittent tick, ____, tick, tick,____, you now know you've got an injector problem.
<IF> one is NOT opening and closing 100%, NO tick will be heard thus, isolating the problem injector to which, you will have to attempt to revive the injector by LIGHTLY tapping on it with a 1/2 inch wrench until it reactivates and begins to function again. Once it's alive, you can take five KEY <ON> event readings and note fuel pressure. I would take five cold KEY <ON> readings to ensure 100% function is restored.
ALTERNATE METHOD: PULLING FUEL RAILS
Pull the fuel rails but, leave the injectors attached to rails.
NOTE: PLACE SHOP TOWELS OVER FUEL INJECTOR PORTS TO PREVENT DEBRIS FROM ENTERING INTO INTAKE
TURN KEY <ON> then <OFF>
Get out and observe for signs of fuel. Note which injector/s is / are leaking.
Place rails and injectors back into the intake and secure everything. Using a 1/2 wrench, again, lightly tap the trouble injectors in attempt to revive them.
<IF> NO anomalies are discovered while testing the fuel injectors (all tick in succession and in time.), then, it may be safe to say that the problem is rooted at the FUEL PUMP LEVEL thus, requiring R&R (removal and replacement). On these, in-tank pumps, I remember reading that the regulator is not field serviceable meaning, a whole new fuel pump is needed.
Now, that's going by memory and, I may mistaken but, I'm almost 100% certain that this is the case. And oh, if it does come down to getting a new pump- GO WITH OEM. WHY? Well, I've gone through two aftermarket pumps (AZ and Pep Boys [carter pump] and, in both cases, both pumps failed prematurely. I only got around 10K miles off the Carter before it failed whereas, the OEM was a bit more but, it lasted to well over 100K miles. Trust, me, go with OEM on this one or, perhaps a high quality Bosch pump via online mail order. I've got no experience with Bosch pumps so, I cannot comment as to how reliable it is.