1990 2.9 - Engine Cranks, won't start - At my wits end!

[Munchie1615]

I forgot to put that in the first post, the first thing I checked was the inertia switch, as I had a 2004 Ranger Edge that always tripped and thought that has to be it! The inertia switch was good, and I definitely have fuel at the rail, when I depress the schrader valve it squirts out and also I did the fuel pressure test and was within a good range. Often times if I continue to try to crank after doing different things I'll get a fuel smell - that's why I thought "Man! Maybe it IS that ECT sensor!" but so far those ohm readings seem to be in range for the temp it was outside when checking. Now I'm scared to try the voltage test again since that's when my ECM went belly up! haha

I'm going to compile some more pictures from what I've taken out and I'll try the spark plug to ground.

I've been scratching my head for about 5months giving my brain a rest in between troubleshooting attempts, that's why I figured it was time to try and get some more opinions, suggestions, maybe find that one anomaly I haven't found or tried... I almost feel like it's an electrical gremlin somewhere but I swear I've checked everything that would STOP the engine from at least turning over.

More to come later today.

Mary

 

[RonD]

50/50 test takes fuel system off the table, it is testing the spark system and compression

Testing an individual spark plug doesn't give you much information
50/50 test tells you if you have strong enough spark and if its at the right time, or you don't

If starter motor is turning the engine and it doesn't start, then at least one of these 3 things is wrong
Spark
Compression
Fuel

50/50 test does spark, spark timing and compression at the same time
If there is a No Start then you know instantly to focus on spark or compression, forget fuel....for now
You can test a few cylinders for compression, need 130psi minimum, 150psi is expected
But its usually Spark that would be the issue with a No Start on a V6/V8 50/50 test

 

[Munchie1615]

Is there a different way you'd like me to try and test for spark? I'll take another video with whatever way you recommend....

Mary

 

[RonD]

Take the air tube off the upper intake, leave it off, just make sure the fan can't hit it
Open throttle manually and spray fuel(ether or gasoline) into the intake
Try to start engine

If it starts, runs and dies then you have good spark and at the right time(or close enough), but no fuel delivery
If it doesn't start then you have no spark or no compression
50/50 test

 

[PetroleumJunkie412]

Florida truck?

$500

 

[Munchie1615]

I did do that, in the video I had already sprayed inside the butterfly valve after i actuated it -- just couldn't do that and hold the phone at the same time. No start. I did the spark test with the test light inline with cylinder 1 spark plug - showed it sparking.

PetroleumJunkie - NOT selling. But you offering makes me think you know something I should check and you're just not saying...

Mary

 

[RonD]

Then you don't have compression or spark is at the wrong time

Its not complicated
Doesn't matter how many electronics are added to the outside of a gasoline engine, its still a gasoline engine
Spark, at the right time
Fuel, with some air
Compression, above 130psi

And it starts

 

[ecgreen]

Then you don't have compression or spark is at the wrong time

Its not complicated
Doesn't matter how many electronics are added to the outside of a gasoline engine, its still a gasoline engine
Spark, at the right time
Fuel, with some air
Compression, above 130psi

And it starts

Thats some Yoda advice right there...

Have these things, and start it will...

 

[RonD]

Thats some Yoda advice right there...

Have these things, and start it will...

LOL

May not stay running but at least you are past the No Start point and can proceed to diagnostics

 

[bobbywalter]

I did do that, in the video I had already sprayed inside the butterfly valve after i actuated it -- just couldn't do that and hold the phone at the same time. No start. I did the spark test with the test light inline with cylinder 1 spark plug - showed it sparking.

PetroleumJunkie - NOT selling. But you offering makes me think you know something I should check and you're just not saying...

Mary

Know this.....if you gave me your truck....I would throw all of the rangery engine parts away.....and likely axles...


And make it rangerish.....with different engine problems.

 

[PetroleumJunkie412]

Know this.....if you gave me your truck....I would throw all of the rangery engine parts away.....and likely axles...


And make it rangerish.....with different engine problems.

Florida truck with 2.9.

I have one 1988 that needs a cab, and another that needs.... parts.

I saw it first.

 

[PetroleumJunkie412]

PetroleumJunkie - NOT selling. But you offering makes me think you know something I should check and you're just not saying...

Mary

"It's not paranoia if they're genuinely out to get you"

- Nixon, probably

 

[Munchie1615]

lol

I guess back to the drawing board....I'll keep checking and continue to hunt this down until I figure it out. My new ECM should be here tomorrow to match the original P/N. Compression checked good with the pressures I posted when creating the thread. *sigh* tomorrow is another day.

 

[bobbywalter]

Hopefully it was just a bad pcm ..

 

[RonD]

As far as I know a bad PCM can't cause a No Start with 50/50 test on a 1994 or earlier Ranger

1994 and earlier have a separate Spark system, the 60-wire PCM is only used for Load spark advance

In 1995 and up the spark system was in the new 104-wire PCM