I have a 94 Cherokee that I bought with a bad engine from an auction. It ended up having to be rebuilt so I rebuilt it. Now with it together again and pretty sure that all the sensors are hooked ul correctly it won’t start. Replaced coil, crank pos sens, plugs, distrib cap and distrib rotor.
It seems to backfire through the throttle body when cranking.
Have fuel pressure with and without vacuum hose
New injectors, tested pigtails with noid light and all but #6 is firing.
Frustrated and hoping for help thanks!

 

The distributor is likely installed incorrectly.

Some of the manuals have this wrong. This is the one to use.

 

Pay very close attention to the location of #1 on the distributor. That's where Chilton & Haynes are wrong, and it has tripped up many of us. I'd say there's about a 99% chance that's where your problem is.

 

where is the Haynes wrong and what is the right way?

 

You can rotate the engine to TDC #1 cylinder (compression stroke, not exhaust) and make the rotor point to the #1 contact. There should be a 1 on the cap somewhere.

 

This is at tdc of what I believe is the compression stroke(the stroke after air comes out of the plug hole)

Wait that’s wrong isn’t it

 

Cruiser posted the correct diagram. If you compare than to Haynes you should see the error. Again, it's not in the ORDER, it's where they start on the distributor.

 

It was 180 degrees out. Smh

I’m we got is started but turned it off after a few second as we haven’t put the coolant in yet

still wondering how to fix the #6 injector firing

 

So the injectors have 12v constant to them when the key is in run or start. The ECU pulses ground to them. You either have a bad wire, connector, or a bad ECU. I have seen an injector transistor on the ECU give up before. I was able to repair it by soldering on a new one, but it takes some fancy soldering skills. You most likely just have a broken wire somewhere.

 

Is there any way you recommend to test for these various problems?

 

Do a visual inspection of the wiring and use a multimeter to determine if you're getting +12v or not. If you're not getting +12v, trace it back to the splice. If you are, check continuity of the trigger wire going back to the ECU.

 

I will give this a test this weekend

thank you for the help

 

A bit of work but you can also swap #6 to another position and see if the problem move with it. You can also apply 12v to the injector directly and hear if it clicks. I know you said you have new injectors but "stuff happens".

 

Yeah, check the wiring and swap injectors or injector connectors to see if the problem moves. If those "new" bosch injectors were under $80 for the set, they are most likely fake chinese knockoffs. Those are notorious for problems including poor patterns, mismatched flow rates, and dead out of the box.

 

did the break in 20 min and it seemed to run fine

the injector had 12 to it so pretty sure it’s fine