Buggy won't start

stadlermco

NAXJA Forum User
Location
vail co
I've posted this before, but got some new info. I had this pos(90 xj 4.0)running around easter and after towing it through a snow storm and power washing it won't start. It will crank just fine, but won't turn over. At first I thought it was spark and replaced the worn dist. cap and got some new plugs, no change. It will run on starter fluid so spark isn't the prob and I don't think that it is the cps(well over 200 ohms). So it's a fuel issue, I have 39 psi at the rail and the fuel pump is wired directly to the ignition switch. I don't believe that the injectors are doing anything, I pulled the plugs and it seemed like there was only residual gas from the last time it ran. I replaced the ballast resistor cause the old one was trash, nuthin. I suspected the Cam Pos sensor so I switched to a spare dist. that I had laying around, still no worky. I have found that the Cam Pos Sensor in the dist. is only running at a little over 3 volts. I found that the blue and grey wires on the harness side of the 4-pronged plug both have little cracks in them and the copper is exposed. Neither show any signs of arcing though and are shiny. They are continuous to the ecu and the ground is also continuous. What's wrong? Please help, kinda pissed. thanx
mike
 
If it runs on starter fluid it has spark, so I don't think it's the distributor. When you say the ohm reading on the CPS is "well" over 200, what does that mean? I'm not sure if the resistance goes up or down when they fail. Frankly, your problem sounds like a CPS problem.

Do you have a "noid" light for testing the injectors? They're cheap at any parts house. You plug it into the injector wiring connector to see if the injector is receiving a signal. I'd suggest trying that.
 
it looked like 270 or so. I thought that if the cps was bad that there wouldn't be any spark? Is there a better way to test it while the engine is cranking.
mike
 
A bad CPS may produce a weak or erratic spark, but the CPS also tells the injectors when to inject, and that's why I'm leaning toward the CPS as the culprit. I'll have to poke through some books, but I think other than testing the resistance you can also check it while cranking to see what voltage it produces. I just don't remember what the number is supposed to be. Maybe somebody with a better memory than mine will chime in.
 
I think that I shorted something in the ecu. It got wet when I was towing. There is no pulse at the injectors, but the cam pos sensor is sending one. I'll try to test the pulse on the crank pos sensor. I'm gonna get my hands on a donor ecu and see if that makes a difference.
mike
 
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