A little history...
94 ram 4x4 5.2 auto. This is a rock crawler that sits idle over the winter normally. Usually starts no problem. Durning a coil over install it sat for about 18 months and hasn't been started in at least ten months. I had a kid in time too... Anyway...

It began with low fuel pressure- replace the pump and I have full pressure at the rail, but it was backfiring thru the intake and would not start even with ether.
Replace the crank sensor and the backfiring stopped. Would start briefly on starting fluid, but would not stay running.
Empty old gas and put 5 gallons of new gas in tank.
Check injectors for resistance- the two I checked were within spec.
Check Noid light- no light. Change cam sensor, cap & rotor. Noid light now comes on. Still nothing, but will still start and die with ether.
Pull spark plug- Very black and soaked stinking of bad gas. Replace all plugs and wires- still won't start. All plugs were wet.

I am at a loss... I pulled the injectors and fuel Rail off tonight. I have the injectors sitting in some gas and injector cleaner. Emptied fuel rail and there was a lot of seperated liquid.going to let the sit overnight and try to install tomorrow and see where we are.

It has fuel- if it starts with ether, it has spark and it has air. Any help would be appreciated. I am trying to get it ready to go on a ride for Memoria
Day weekend...

Thanks
Todd

 

Sounds like you got a good start on fuel issue as it appears to have crud in it...darn ethanol.

Bad upstream O2 sensor would also cause too much fuel. How is your plenum gasket?

 

No idea how the plenum gasket is... How can I tell if it's good or bad?

Any way to check the O2 sensor? They have been in there so long, doubt it would come out easy. Even if it were too much gas, wouldn't it run- even if poorly, once it started with starter fluid?

A couple other notes...
No catalytic converter to worry about
Ran fine when it last started
No codes
When fired with Ether, sounds normal- just dies quick.

Todd

 

O2 sensor won't affect starting...... I would be more inclined to look at engine coolant temp sensor. Being as it's a 94, you will have two. Single wire sensor for the gauge, two wire sensor for the PCM. If the sensor the PCM pays attention to has failed, or just has a poor connection.... it will DUMP gas into the cylinders. Try holding the throttle wide open while cranking. If it fires, and tries to run, but, dies when you let off the gas.... ECT is a good bet.

 

Hey Mountain Ram (I know your rig, sorta )

The plenum gasket topic can be read at your leisure here: https://dodgeforum.com/forum/2nd-gen...um-thread.html

It's located between the plate and the intake manifold. Since you have been sitting so long, it might be difficult to assess the gasket's condition, which is being blown out and thus failing to seal the manifold plenum from the top end. Some of the better ways is to completely remove the throttle body, flashlight, and look for evidence of oil pooling towards the back of the engine. Note, you will see oil residue and its normal in a brownie type of texture. If you've been losing oil over let's say typical interval (> 1 qt), then might be an indicator.

In addition to HeyYou's comments, what comes to mind to just getting cleaned up is the IAC sensor. It's located on the back of the TB....I believe. It is a pintle and gets coated in a good layer of carbon soot. The cavity of the TB really gets loaded up. Good to clean with carb or brake cleaner and more easily managed when taken off the intake manifold entirely. Treat the IAC like an egg though.

 

I could see the gasket being blown out with the age and abuse, but not keeping it from starting. Why would it fire with ether and not gas?? Good info though- I will put this high on the list to do...

As for the ECT sensor- could it really push enough fuel to completely flood the engine and have no attempt to fire? I would think the truck would at least attempt to fire- especially with new coil and plugs. I will pull one of the new plugs tonight to see how bad they are. I guess replacing the ECT is cheap enough too.

Any other sensors that could cause this? MAP? What is the likelihood that the Computer is the culprit?

Pic of my truck below

Todd

 

Check the fuel pressure with a gauge.

 

Failed ECT sensor makes the PCM think it is -40 degrees out.... so, yeah, it really dumps the gas, and, since it ISN'T really -40 degrees, you foul plugs in short order. Basically, the engine is flooded. Holding the pedal on the floor puts the PCM in 'clear flood' mode, and RADICALLY cuts back on fuel. Of course, if you plugs are wet, they aren't going to fire anyway.....

 

I have a gauge and it's a continuous 40+psi which is correct for the '94.

Picked up an ECT for under $20 and I'm headed out to put it all back together... Wish me luck.

Todd

 

Cleaned the injectors and fuel rail. Nothing.

Replaced the ECT- nothing.

Still starts with starter fluid and then dies.

Pulled a plug and checked it- moisture- gas and it still doesn't smell right.

Pulled a wire and I have great spark.

I drained all the gas I could and put 5 gallons of fresh gas on top of whatever was left. The old gas burns fine in my mower when mixed wi new gas 50/50.

I think I smell varnishy gas just after trying to start it... Can the little bit of bad gas left really cause this much trouble or is my computer shot? Any other sensors to try... Does the IAT affect this? About about the MAP sensor?

Todd