90 MJ 4.0/5spd Rust Bucket- No Start

[scottsdale1977]

I posted before with pics of my rusty floors.. besides that I'm battling a no start issue.  Bought this truck with hope of fixing it up to make it a cheap DD..though it looks like I'm in for a lot more than I bargained for. lol  

 

When I first had it dropped off (had to be towed) it was running smoothly, then it sputtered/died & wouldn't restart.  I could smell gas in the oil (i assume from cranking it so much), and the tank is fairly rusted/leaking.  I changed the oil, put in a little fresh gas and tried again.  The fuel pump primes (haven't checked fuel pressure though) and it's started a few times..run for a few seconds then died.  Most of the time it just cranks but won't fire.  Can the fuel pump be bad even though it's priming?  I replaced the relay and it sounds louder when it does prime (was kind of a low hum before, now it's more pronounced).  I checked for spark & all plugs are getting spark.

 

It might be completely unrelated, but in looking over the wiring I noticed this disconnected.  Any idea what it goes to?  I know the orange/black is for the fuel pump.  

 

[SVPete]

In that area, it kind of looks like the blower motor connector on my truck, although mine doesn't have the blue cap. So I'm not sure.

[scottsdale1977]

In that area, it kind of looks like the blower motor connector on my truck, although mine doesn't have the blue cap. So I'm not sure.

Haven't even tried ac/heat honestly.. I'll see if it kicks on or not.  

Any thoughts on the no start?  I know I should probably check fuel pressure... though if I keep the truck, I would just be replacing the tank & pump anyhow (came with new parts).  I did replace the fuel filter just to see if it'd make any diff, no luck.  

[SVPete]

It could be quite a few things. Start with Cruiser54's tips first, if you haven't already. 1,3,4, and 5 are kind of "musts" (or "haftas" to quote Cruiser) Go to Cruiser54.com. Many of his tips will help you confirm functionality of several components which can cause your problem and avoid parts swapping. Agree, fuel pressure check is needed along the way. There are many members smarter and more experienced than me, but most will direct you to Cruisers tips first also.

 

To relate a problem I experienced for years.....Truck would die (at an inopportune location, like an intersection during rush hour), injectors would fire a few more times flooding the engine. So I had to wait it out for 10+ minutes looking like a lame gebronie who should just get a new car. Sometimes I could be driving a 45 mph and it would just die electrically, and the injectors would fire some more, flooding the engine. Popping the clutch would make the truck run all out of time it seemed like. So again, pull over and wait out the flooding. Not sure exactly what part(s) was the culprit. I know the EGR had an issue, I replaced it and the coil at the same time (it was the original from 1988, this was 2015) and presto! problem solved.

 

Why does this matter and how does this relate to your situation? I followed many of Cruisers tips while I worked on this late last summer. What his tips did for me was save me money from just buying parts and then being aggravated when they didn't solve the problem. Start with his tips.

 

This is not a paid testimonial.

[SVPete]

As a quick follow up since I was at Cruisers website......check the vacuum line running from the throttle body to the MAP sensor.

[scottsdale1977]

SVPete, thanks for the help, and the story! I've taken a peak at Cruisers tips & will do those & post my results, as well as check the vacuum line.