2.9L no-start, but it should

[CheapThrillB2]

okay brief history....

Use this truck for mud bogs, last oct i was boggin with it and slammed a rut hard and it stalled (inertia switch bypassed) and it wouldn't restart. So we pushed it on the trailer and brought it home. Its has now sat since Oct untouched until yesterday. Buddy is going to buy it but i want to get it running before he does. I started to check it out and found the lo psi pump in the tank to be dead so changed it out and working.

I have Hot Spark to the Plugs, Good clean Plugs.
40psi Fuel Pressure with KOEO
Inj Pulse when checking with my noid lights
Fuel Pump relay and EEC relay clicking and good
Tried a Different ECM (i have about a dozen various ECMs and tried them all)
Compression seems to be low at about 120-130psi (not sure where a average 2.9L lies)
I have replaced the distributor and TFI with known good ones
IT doesn't even act like it wants to fire at all. No pops or backfires when playing with the timing or adding a little either........

It ran great until i hit that rut last oct..............

any ideas

 

[Jorley]

You've checked all the usual problem areas. You've got fire, fuel and compression. About the only thing left is air. Is there anything that could be blocking the air into the intake?

 

[gbadgley]

If it won't fire on either, you have an Ignition problem. Greg

 

[Taragon]

This may be one of those unsolved mysteries.

I once had a 2.9 that backfired ONCE as I was shifting into 2nd gear. It went dead, and never started again.

I had fire, fuel, and a clean air path. Timing was dead on and not worn or loose. No coolant leaks and perfect compression with no leaks. No broken rods, valve springs, bend vavles, or holes in the pistons. No cracks in the block, or blown head gaskets. Neither the cam nor the crank was broken. No knocks when trying to start. No cracks in the heads, or upper or lower intake. No spun main or rod bearings.

So I replaced the motor. Use the EXACT same sensors and wiring from the "old" motor...none of the "new" motor wiring was used AT ALL! Fired right up, and has ever since.

So you tell me what may have went wrong. TO THIS DAY no one has been able to find the problem.

 

[CheapThrillB2]

well i am not about to just pull the motor and try another (even though i have one here)

anybody got an rough idea what nominal PSI compression is

 

[CheapThrillB2]

You've checked all the usual problem areas. You've got fire, fuel and compression. About the only thing left is air. Is there anything that could be blocking the air into the intake?

the tube is off the throttle body so i could spray either in it

 

[CheapThrillB2]

If it won't fire on either, you have an Ignition problem. Greg

thats what it seems

with the distributor in a good position, it cranks fine but doesn't even try top start with spraying either or carb clean. But if i advance or retard the timing a bunch, the motor with start to bind from the timing being way off while cranking, but still no pop or backfire.

i was almost thinking bad gas. It has a hlaf tank still in it from when i got gas last back in october. But even with the bad gas, when i spray either i should atleast get something as far a backfire or pop or something

 

[gbadgley]

You eliminated the fuel factor by spraying starting fluid, if it were a fuel problem it would have fired and quit.
Re check the timing, Is it possible the distributor off? Greg

 

[IMenriched]

Check ground wires & connections.


don't go put'n more flat spats on your forehead....Go back recheck everything....slowly taking special care...(not that you didn't before), but it is easy to miss something.

try disconnecting the battery over night, trickle charge it out of the truck. then reinstall & retry purhaps the engine computer needs to reset /codes erased.

was the sudden impact last fall enough to maybe shear the roll pin on the distributor gear..er at least enough to bend it?

just some thoughts

 

[CheapThrillB2]

i think its compression related......that motor has been run hard, long spurts of redline in 4-lo floating valves etc.....seems compression would be around 90psi, then with a little oil in the cyls it would come up to 120-140psi, i pulled all the plugs. Proceded to pour some oil in each cyl, then reinstalled the plugs and it almost acted as if it would start for a second. But then it went back to just cranking as if dead ign. Pulled the plugs and they were wet with gas again. I pulled the motor tonite and will be installing the other motor in the morning.

 

[CheapThrillB2]

installed the other motor today.....reused the old motors distributor and fuel rail. Set it to TDC and dropped the dist. in and it didn't crank for 5 secs and fired right up and idled.

 

[IMenriched]

That kinda of abuse...no wonder....be interested to find out what happened thou.

good to hear that you had a "spare" engine and with swap, got it running again.

was the oil in the pan kinda gassy ?? (the one that was removed)

bent valve...busted rings?? just carboned up? holes in pistons?

 

[Jspafford]

Yeah, you have to tear it apart, just so we all know what happened.

 

[CheapThrillB2]

i might if i get bored

 

[WildSide]

At least pull the timing and valve covers