1987Comanche Posted November 18, 2012 Share Posted November 18, 2012 I finished wiring everything up and got my new 4.0 to run!! It was, however, not without some drama. I ended up having to crank it a total of 8 or 9 times over the course of the day while troubleshooting/replacing various components. The wiring on the CPS was loose (hit the firewall during engine install?) so I replaced that and it still wouldn't fire. I pulled plugs 3 & 4 and they were gas soaked so I knew the problem was spark. I swapped out the distributor with my old one and then verified timing. It turns out the dizzy was 180 degrees out. When she first fired up I only let it run for 10 sec as it sounded really rough (popping, etc). After giving it some thought I put the new distributor back in, verified timing, and tried it again. This time she ran well enough that I was able to bring the engine to 2000 RPM and held it for 15 min to break in the cam (as per rebuilder's recommendations). I changed the oil, added more ZDDP (again as per rebuilder's recommendation), and checked her at idle. The idle is pretty rough (fluctating between 650 and 950 RPM). I'm planning to check TPS voltage and make sure all the vacuum lines are connected. What am I missing?? Link to comment Share on other sites More sharing options...
ComancheKid45 Posted November 18, 2012 Share Posted November 18, 2012 Your on the right track. Definently check out the TPS real good, and the vacuum system. Both can play big roles in a smooth idle. Link to comment Share on other sites More sharing options...
cruiser54 Posted November 18, 2012 Share Posted November 18, 2012 Did you get those 3 or 4 ground wires back on at the dipstick tube stud where all the fresh paint has been scraped off? Link to comment Share on other sites More sharing options...
1987Comanche Posted November 19, 2012 Author Share Posted November 19, 2012 Yep, sanded the dipstick and block in that area and reattached 4 ground wires (3 small, 1 large). Also sanded the Driver's rear head bolt and attached the braided ground strap. I checked TPS voltage and it was nearly perfect (0.82V). I looked at all the vacuum lines and didn't see any obvious issues. I did find that my catalytic converter has apparently split at the seam on the driver's side (aftermarket replacement by PO). Could this be the source of my issues? It seemed quiet before the motor swap but bear in mind my manifold was almost 100% cracked around cyl 5 and the rear stud was broken off in the head (no retention of manifold by cyl #6). Link to comment Share on other sites More sharing options...
1987Comanche Posted November 21, 2012 Author Share Posted November 21, 2012 Finally got her running well :banana: I found an exhaust leak (welded it shut), a vacuum leak (made a new harness), discovered the fuel pressure regulator was shot (dumping tons of gas into the intake via the vacuum harness), and threw on a new fuel filter for good measure. She runs!!!! :MJ 1: Link to comment Share on other sites More sharing options...
meljr Posted November 22, 2012 Share Posted November 22, 2012 Congrats for staying with it and your tenatious diagnostic skills. Link to comment Share on other sites More sharing options...
ComancheKid45 Posted November 22, 2012 Share Posted November 22, 2012 :thumbsup: Link to comment Share on other sites More sharing options...
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