Mack4194 Posted January 2, 2011 Share Posted January 2, 2011 I have Spark, I have fuel. I made sure rotor is pointing to number one at proper time. Everything sounds normal it just won't start running. My father in law is a mechanic and we looked at it for about an hour testing everything. I didn't want to take to much of his time so I told him I would figure it out. But I'm stumped. Any ideas? I've checked every conection I can think of, cleaned them, and even put a little electric grease on them. I'm sparking and fuel pressure is good. Link to comment Share on other sites More sharing options...
bottomline89 Posted January 2, 2011 Share Posted January 2, 2011 maybe a sensor.. check your vacuum lines too Link to comment Share on other sites More sharing options...
MJCARENA Posted January 2, 2011 Share Posted January 2, 2011 Did you try putting a little gas down the throttle body. Maybe your injectors are not working. Also where did you check for spark, at the coil or at the plugs. I have seen bad rotors short out to ground and not let the spark reach the plugs. Link to comment Share on other sites More sharing options...
Geonovast Posted January 2, 2011 Share Posted January 2, 2011 Where are you grounding to when checking for spark? The grounding strap from the head bolt to the firewall might be shot. You could be getting spark outside the block, but not with the plug in the motor. Link to comment Share on other sites More sharing options...
Mack4194 Posted January 2, 2011 Author Share Posted January 2, 2011 I did not try putting a little gas down throttle body, spark plugs come out with fuel on them. I tried drying them and putting them back in. I checked for spark at plugs by pulling a couple out as my brother cranked it over. I will check the grounding strap. Bought a new CPS yesterday just in case that could make this happen, but man, I can barely get my finger on it let alone a wrench. Link to comment Share on other sites More sharing options...
Automan2164 Posted January 2, 2011 Share Posted January 2, 2011 The CPS, as I have found it is incredibly easy from the underside of the truck, using a couple of extensions and a union. I can change one in 10 minutes. Rob L. Link to comment Share on other sites More sharing options...
Mack4194 Posted January 2, 2011 Author Share Posted January 2, 2011 Really? I am getting ready to cut through the floor. I'll try your way first. Link to comment Share on other sites More sharing options...
Automan2164 Posted January 2, 2011 Share Posted January 2, 2011 Yeah, don't cut through the floor. I use some 1/4 and 3/8th's unions wrapped in electrical tape to keep them stiff but flexible, get enough extensions to get you there. Then take out the bolts from the bottom, unplug the sensor from up top and pull it out. Then fanagle the new one in, and start the bolts, and tighten 'er up. Please note that you should leave the card board or paper stock on the tip of the sensor. Its a spacer to make sure you have it properly gapped from the Flexplate or flywheel. Tighten it with the paper resting on the wheel, and the first start will rip the paper away leaving a perfect gap. Rob L. Link to comment Share on other sites More sharing options...
Geonovast Posted January 2, 2011 Share Posted January 2, 2011 Is it 4wd? If so, drop the front driveshaft!! I've been able to change the CPS on an 88 4.0/auto/4wd by dropping the front shaft and making friends with a 12 pt 11mm wrench. And no, I don't have small arms. If you're feeling lucky you can get a jack on the trans, and pull the crossmember bolts out of the framerail to lower it down. If you're feeling really, really lucky, that is. Link to comment Share on other sites More sharing options...
Automan2164 Posted January 2, 2011 Share Posted January 2, 2011 Why does it seem like I am the anomaly here? Granted, I have only changed one IN the vehicle, and it was a '91, AW4, NP242 XJ... So I would think it's the same as any other... Only thing I had on my side was a drive on vehicle lift, but I could have just as easily been on my back in the driveway... Am I missing something here? Rob L. :dunno: Link to comment Share on other sites More sharing options...
Geonovast Posted January 2, 2011 Share Posted January 2, 2011 Rob, I've used your method for breaking them loose and torquing them down, but it's been easier, at least for me, to do it with the front shaft out and with a wrench. Luckily most of my CPS changing history has been on a HO 2.5, which is freaking cake. Link to comment Share on other sites More sharing options...
MJCARENA Posted January 3, 2011 Share Posted January 3, 2011 Sounds like it is flooding if the plugs come out wet. I think if you hold the pedal down all the way when you try to start, the computer takes this as a flooded engine condition and will not fire the fuel injectors until it reaches a certian rpm. You might also try new spark plugs, sometimes when plugs get wet fouled they just don't arc the gap like they should even if you dry them off. Unless you clean them real good (sand blast type sparkplug cleaner) Link to comment Share on other sites More sharing options...
Geonovast Posted January 3, 2011 Share Posted January 3, 2011 You can use an in-line spark tester to see if they're sparking in the motor. Link to comment Share on other sites More sharing options...
comanche12 Posted January 3, 2011 Share Posted January 3, 2011 You can use an in-line spark tester to see if they're sparking in the motor. that tester would be come in handly to me someday. Yeah, don't cut through the floor. I use some 1/4 and 3/8th's unions wrapped in electrical tape to keep them stiff but flexible, get enough extensions to get you there. Then take out the bolts from the bottom, unplug the sensor from up top and pull it out. Then fanagle the new one in, and start the bolts, and tighten 'er up. Please note that you should leave the card board or paper stock on the tip of the sensor. Its a spacer to make sure you have it properly gapped from the Flexplate or flywheel. Tighten it with the paper resting on the wheel, and the first start will rip the paper away leaving a perfect gap. Rob L. :agree: electrical tape wrapped union sockets are really come in handly as I had experience with it for years. :thumbsup: AND :agree: Don't cut the floor. Its easy to reached the Crankshaft position sensor. P.S. That time was when I'm able to reached the CPS was when the front DS was dropped and jeep was already lifted. I would test the spark first before do the CPS. :thumbsup: only think simple before do things. Link to comment Share on other sites More sharing options...
Mack4194 Posted January 3, 2011 Author Share Posted January 3, 2011 Installed new CPS. No change. Took off cleaned and put back on ground strap. no change. Have already used in line spark tester. Sparking. Still no start. Completely Stumped and Frustrated. Link to comment Share on other sites More sharing options...
Automan2164 Posted January 3, 2011 Share Posted January 3, 2011 What happened leading up to this? Rob L. Link to comment Share on other sites More sharing options...
Geonovast Posted January 3, 2011 Share Posted January 3, 2011 You said rotor is pointing to #1 at the correct time. If you mean TDC, that's not correct. It should be pointing just past #1 at TDC. Also, are you sure it wasn't indexed on the exhaust stroke? Did you ever have the dist out? Link to comment Share on other sites More sharing options...
kyleag89 Posted January 3, 2011 Share Posted January 3, 2011 :agree: I have replaced distributors many times, but I have also thought I had it in the right place after a motor swap. I once spent 3 hours messing with my Jeep only to find out I had the dizzy in 180 out! :dunce: Link to comment Share on other sites More sharing options...
comanche12 Posted January 3, 2011 Share Posted January 3, 2011 hmm what did you do before start the engine? replace any parts? just try get more info. like maybe got wrong kind of distributor? ecu? flywheel? I'm just asking to see if you/someone did something before try to start the engine? Link to comment Share on other sites More sharing options...
pederl Posted January 3, 2011 Share Posted January 3, 2011 Did you check the ballast resistor? Link to comment Share on other sites More sharing options...
Mack4194 Posted January 3, 2011 Author Share Posted January 3, 2011 K complete story, by the way thanks for all the interest :) K I'd spent the day waterproofing electrical components by un-clicking and cleaning everything and putting dielectric grease on them. It went fine, I felt good about it, and the truck drove fine for a few trips afterwards. Then, and here comes the embarrassing part, I took off the distributor cap and put a little silicone around them rim, then here comes the really embarrassing part, I put a little silicone inside where the vent is, then I put it on and put some around the top on the vent whole, then to top it all off I didn't wait to drive it. It imiediately began to missfire/run rough, after I completed the 1 or 2 mile drive I had to do I got back took off the cap and saw the silicone had gotten on the rotor and all 6 points, so I drove it to auto zone 3 miles-ish and got a new cap and rotor. Then I put it on right there in the parking lot and drove a few blocks to my brothers house. It ran a little better, but still not the best. When I got to my brothers house I checked all the cables, pulled the off looked up firing order just to make sure I hadn't goofed somehow, and put them back on again. It hasn't started since. I took the new cap and rotor back to auto zone and had the replaced. No effect obviously. So my first thought of course was distributor, but it didn't appear that it wasn't working because it's sparking and everything as normal. So there you have it, I hate to admit it but I goofed a little bit, I was overzealous and probably a little bit cocky :doh: Thanks for you help once again. Pederl I will check the balast resistor Link to comment Share on other sites More sharing options...
kyleag89 Posted January 3, 2011 Share Posted January 3, 2011 Sounds like you should try a new distributor. Link to comment Share on other sites More sharing options...
comanche12 Posted January 3, 2011 Share Posted January 3, 2011 Sounds like you should try a new distributor. :agree: and make sure you do the right timing after install it Link to comment Share on other sites More sharing options...
Mack4194 Posted January 3, 2011 Author Share Posted January 3, 2011 ok guys, will do... Man I wish I was independently wealthy!!! Link to comment Share on other sites More sharing options...
kyleag89 Posted January 3, 2011 Share Posted January 3, 2011 Go to a junk yard and pick up a used one from an 87-90 MJ or XJ 4.0 and try that first. It will save you some $$. Link to comment Share on other sites More sharing options...
Recommended Posts
Create an account or sign in to comment
You need to be a member in order to leave a comment
Create an account
Sign up for a new account in our community. It's easy!
Register a new accountSign in
Already have an account? Sign in here.
Sign In Now