Just an appeal for your wisdom with a 1992 5.8L that starts then dies within about 5 seconds. Replaced (so far) the fuel pump (was 20psi, now 45psi), fuel filter, fuel pressure regulator. Replaced the Distributor, Cap, Rotor, Wires and Plugs. The IAC valve, MAP and ICM sensors. The TPS sensor throws codes when WOT so it works and so, too, the ECM (probably). The only codes at KOEO are 55 (no or low volts (less than 7.5 volts) Key Power to ECM pin 5) and 56 (Vane Air Flow (VAF) or Mass Air Flow (MAF) sensor high - VAF MAF) although I have a MAP, not MAF, sensor in this year engine. The key ignition is broken so no key is needed to turn the ignition; but it has been like this for 6 months so it's an unlikely suspect. Spraying Starting Fluid into the throttle has no effect. I have a strong spark on all plugs. I can hear the new fuel pump engage when Acc is turned on.
I'm completely mystified and have no solutions.
Can you help?

 

When did the "no start" condition appear. Almost seems as if it's fuel related, but with your parts list and specs, that seems to rule that out. Another thought is exhaust restriction or air restriction. May also be contaminated fuel, but then it dies after 5 seconds or so.
Does the fuel pump hold pressure after its running or die? 45 psi seems high for this, as mine is only 35-38. I would check for return restriction from the fuel rail. Perhaps some of the wiser members can chime in with better ideas.

 

*thank you timbersteel for the timely response*

The "no start" condition started 4 weeks ago. One day it stalled for no reason while driving. Later that same day the van stalled while descending a mild hill and wouldn't restart. 20 min later I retried and it started and got me home. (btw: my ICM is fender-mounted, not distributor-mounted). Since then the engine dies immediately. I changed the fuel filter first. Found the fuel pressure at 20psi. Changed the fuel pump; pressure runs 40-45 psi with no leaking. Weak yellow/orange spark so today I'm replacing the ignition coil. That pretty much completes a new electrical system. New plugs are Platinum and Iridium (for the impossibly hard to reach #1 cylinder)...any concerns with extra resistance there? Will look at possible exhaust restriction tomorrow.
Any other 5.8L wizards out there with any insight??

 

Run the test for the PIP sensor in the distributor.That`s the thing that sends the signal to the computer to let it know when to send the spark.

 

I was thinking the PIP later, but didn't know fot sure if it would even allow the truck to start if it was bad. Definitely a good idea and place to start.

 

*thank you 393STROKER and timbersteel for your replies!*

Update to where I'm at with the engine:
Electrical: New Ignition Coil, Distributor (PIP), Cap, Rotor, Wires, Plugs, ICM, Ignition Switch, PCM Relay and Fuel Pump Relay
Fuel: New Fuel Pump, Filter, Fuel Pressure Regulator
Sensors replaced: ICM, IAC, MAP
Checked: Fuel Inertia Switch, Fuel Pressure @ 40psi, Fresh gasoline, No air restriction that I can see, all hoses connected, sprayed carb cleaner in Throttle neck.

Currently, it is now in a No Start condition. In the previous 3 weeks the engine would start for 6-10 sec then die. Now, it *almost* catches at WOT but will not not start at all, even with Starting Fluid (Ether).

Reset codes by disconnecting the battery for 10 min. Still generating only Codes 55 and 56 in KOEO since the engine will not start, much less Idle.

Amazingly frustrating.

 

have you thrown a can of heat in the gas tank to get the water out? I have seen this do what you are talking about? Or is it flooded? try releasing the fuel pressure at the valve that also might bring out an air bubble >simple and i hope you get lucky sooner or later!

 

Also your key switch that hooks through the ignition relay and runs dowm the back side of the steering colum via the accuator rod. Pain in the a-- to drop the column and then try to get it set in just the right place to line up with the accuator rod is a trick deal better done with two people! mine cracked right at the corner crimp, just as my ignition tumbler fell apart and would not hold the accuator in the run position? I have also heard that the accuator rod can bend or brake and then it wont make contact for continued ignition.

 

Bump for up dates? Any luck? I have a '92 Bronco with a 351 and it's doing pretty much the same thing.

 

kudos to Timbersteel for his insight on resolving my 5.8L No Start problem. Turns out that the front part of my Catalytic Converter melted inside with no visible damage to the outside of the unit. The resulting back pressure prevented the engine from idling and it immediately quit after initial start. We "rodded out" the Cat so it can breathe again. Turns out that with all the new parts my gas mileage jumped up 40%....no kidding! Figure that in a year I should break even on all the expense of this repair Drama.

 

Good info, I'll have to give it a try. We have already replaced about everything else. Was it fairly obvious to see when you cut the pipe?

 

Can you link to directions for running the PIP test? Thanks. (Or is that done by probing circuit #6 on the ICM?).