I replaced the junk plug wires, cap & rotor but the engine still wouldn't fire. I re-verified that I'm getting a spark and then decided to test the fuel pressure. The pressure with the pump forced on was 55 PSI, way above the rated 38-44 PSI. I can smell fuel when I crank the engine so I think the injectors are triggering (or perhaps just one is).

My manual says to replace the fuel pressure regulator. OK, I can do that - but would this problem be likely to suddenly cause my truck to quit running? I want to make sure I'm tracking down the right failure.

I'd try to fire it on starter fluid, just for grins.. Fuel pressure at 55 shouldn't prevent it from firing up.. Either you've got a situation where timing is way off or your fuel isn't right (injectors)?

Pulled more than one plug? IE pull plugs on opposite banks, make sure the plugs themselves fire.

I believe I have a decent grasp on the vaccuumm system here and maybe someone can chime in to verify or denounce. I'm thinking that one of your vsv's maybe took a dump or perhaps a vaccuumm leak great enough to not alow the engine to run. Have you ventured here yet? Have you pushed open the door on your air flow meter open w/ the ignition on to see if the fuel pump responds? You mentioned that the pump turned on when forced, did you jump connections or use the air flow meter trick?

Regarding to much fuel pressure, I would think that the computer would back off the duration of the injection. Maybe not but, there is also the bypass that allows extra fuel to return to the tank, I think some guys have spoken about this getting clogged and running rich as a result. So maybe you could have to much pressure, check the return line, maybe it's clogged and the ecu cannot compensate enough for the extra fuel???? Just brainstorming, any progress? <img src="/forums/images/graemlins/scared.gif" alt="" />

It's been a while since I had time to tinker with the truck, but the latest update is that I did re-verify that I have spark right at the plugs. Every plug was wet from fuel, so the high fuel pressure may be flooding the engine and preventing it from starting? I forgot to turn the engine to TDC and check the rotor position to try to see if the timing belt skipped a tooth, but I'll do that next.

In any case, I dove into replacing the fuel pressure regulator since I didn't see any obvious signs of a problem with the return line. I thought I could sneak it past the manifold, but no luck - so the intake manifold is off along with many other things while I go get some new hoses and gaskets.

Question - when I removed the EGR tube from the intake, I found that it was oily. I also found a small amount of oil before the throttle plate. It looks like some oil has been coming into the air intake from drivers side valve cover (a guess, but that hose is somewhat oily). Could this just be from the engine mis-firing or plain not starting, or should I be digging further into this while I have the manifold off?

How is the oil coming into the intake from the valve covers? Is there a noticeable leak from the plenum to the intake manifold? My egr was filthy when I first removed it, all oily and carbonated. I think this is fairly normal and should just be cleaned up. You could take the plenum down and have it cleaned out at a machine shop, or do it yourself, maybe even take off the intake manifold and have it cleaned as well. Put it back together in like new condition will probably give you a smoother idle and acceleration. I did not put mine back in clean at first and it still ran fine, could have been better though.

Well I finally got back to working on the truck.

I replaced the fuel pressure regulator (and several vacuum & water hoses while I had the plenum off). I put everything back together and ran the fuel pump (B+ to FP) to check for leaks and measure the pressure.

The pressure goes up to about 50 psi. Slightly lower than before, but higher than the specified 44 psi. What is new is that the pressure doesn't hold after I shut the pump off. It drops to zero over about 10 seconds - whereas before I worked on the truck it used to hold some pressure.

I can't find, feel or smell any leaks. So, I tried removing the fuel return line from the regulator and ran a short hose from there to a gas can. There was no change in the measurements, so there isn't a clog in the return line.

I haven't tried firing the engine yet, since I'd like to understand what these measurements mean, especially if I might have a leak someplace. However, a fuel leak ought to be obvious pretty quickly and I can directly see and touch the places that I worked on (the return line at the regulator, the regulator, the cold start injector banjo bolt and the return line connection near the firewall. The only thing I can think of to do is pull the plugs and sniff them to see if one of the injectors is now dumping fuel into a cylinder.

I have no idea why the pressure is still high unless my gauge is junk. This is the first time I have used it.

Anybody have any ideas?