Running rich.

[Jeepjunker]

I got my 1990 4.0 with a no start condition. Well sort of . It would start then die immediately . I went to replace the 02 sensor broke it off . So once i fixed all that up pulling the intake and header . It runs . But it runs extremely rich . Backfires and smells of gas . The previous owner bypassed the EGR system . If someone could point me in the right direction I’d be much appreciative. It’s been one thing after another with this one . 

[CrustyBoy]

I could be wrong but usually a consistent start followed by a stop is caused by a bad fuel pump ballast resistor.

 

There's a part in this video where he starts the engine prior to fixing the problem to show you the symptoms. Watch and see if yours is behaving the same way.

 

 

Edit: Sorry I missed the part where you said it's running after the O2 sensor was fixed. Still probably worth it to confirm that resistor is good but maybe it isn't your problem.

[Jeepjunker]

I appreciate the input . Initially the resistor was bypassed when i got the truck . But after getting it running . I’ve rehooked it with no change to running condition before or after

[Jeepjunker]

It Also has a new fuel pump and 4 hole injectors . Did a tune up new plugs and wires . Check distributor index it was dead on. Map line was previously replace with a hard steel line so no cracks there . 

[JustEmptyEveryPocket]

11 minutes ago, Jeepjunker said:

4 hole injectors

What part number on those injectors? Also, where did you purchase them from?

[Jeepjunker]

Part number : 0280155746

i bought them off kSuspension 87-90 range

[cruiser54]

those are the correct injectors. 

 

Pig rich is generally caused by a faulty MAP sensor reading. 

 

Any change if you unplug the MAP sensor vacuum line or electrical plug? 

[Jeepjunker]

Cruiser . I would say you’re spot on to something . Went out played with the map connector it killed the truck . Then went right back to the original no start issue i was having . The previous owner was a bit of a get er done mechanic from what i can see . 

[Jeepjunker]

Started stripping back wiring and found this . After just pulling back the amount of electric tape it started right back up and is running smoother but any idea what they’ve done here ? 

[cruiser54]

It all needs to be redone with soldering and shrink tubing. 

[Jeepjunker]

Looks like learning to solder is this weekends project . Should i go ahead and put a new map on it since I’m doing all this? thank you for the quick diagnosis and pointing me in the right direction 

[cruiser54]

No need to replace the MAP sensor. Buy shrink tubing and a lighter.