91 yj no start>>>

87XJBEAST

Well-Known Member
Joined
Oct 26, 2008
Location
Raleigh NC
i have a 91 yj with the 2.5. i just rebuilt it less then 5,000 miles ago. bored out .60 over. ran strong with no engine issues, just fuel pump is going out. i went on vacation and jeep sat, my buddy drove it around evey 3 days or so and on the last drive he went to start it ran fine but he got half way up the street and it just died. as if the key was turned off and just rolled in gear.

things i know
*coil is good
*crankshaft sensor is good
*has fuel pressure not sure amount but if i push the valve in fuel comes out
*if i disconect the ecm nothing changes
*if i pull spark plugs and turn it over nothing is sprayed out of holes>>>assuming no injector pulse
*if i pull the number one wire insert a screw drive and turn it over no spark
*while turning it over if i step on the gas pedal it sounds like there is a "pop" in the intake but if i cover the intake hose it wile collapse it
*battery is good
*the was one blown 20 amp fuse in the under dash fuse box replace it and nothing
*all fuses in under hood fuse box are good
* if i switch the relays around nothing changes but fuel pump kicks on with each>>>assume all 3 relays are good


please some one help i miss my jeep...is it safe to think that my ecm is bad. any one know how to test it other then puttng my ecm in another jeep and seeing if it runs
 
distributor maybe?? I had this same problem with my jeep last september, but my problem ended up being the coil. I thought the coil was good, I checked it and it checked out fine, but apparently it wasnt putting out enough spark, this is what I was told by a friend, so I changed it and all was good. That was of course after I had already changed plugs, wires, rotor button, cap, and distributor :rolleyes:
 
i put a new coil in it and no change. i don't think i'm getting injector pusle either...the plugs wires cap and rotorhave less then 5,000miles s i believe they ate still goof checked the cap and button and they looked fine
 
With the distributor cap off, have someone turn the motor over while you look at rotor button. Make sure it turns with the engine. If not, it's either the timing chain, gears or distributor drive gear.
 
I'm working on a similar problem. A '95, 2.5L, won't start. Not getting fire. On the coil plug that has two wires, both have 0 volts with the key off. 6.25 volts with the key on. Thsi is at the plug and at the computer. Check against a running engine shows 0 volts on both key off/key on, 12 volts on both engine running. I think I have a bad computer so far but still trying to diagnose it correctly.
 
thats what i had originally thought but some one told me to check my cam shaft sensor and that since i can here my fuel pump start when i turn the key that my ecm is probably fine. im trying to find someone local to swap ecms with and see if anything changes
 
12 battery recently disconnected

33 ac relay

54 camshaft signal

55 end diagnostics

I'd be looking at the distributor/camshft sensor signal
 
Is the coil itself getting power, are you sure its gettin gas, did you try spraying it with starting fluid?
 
try useing a noid light on the injectors or test the fuel pressure with a gauge make shure the jeep is getting pressure ive seen a few have fuel spray out but only run 8psi when 28+ was spec

but if its throwing codes use those to base ur diagnosis but the code is a starting point not a answer also make shure the airgap is correct with the cps or it will act up or not run at all
 
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