misfire

[lucky14]

Ok. Did you pull the rocker cover and check broken valve springs, cracked or broken rocker arms or collapsed lifters?

 

[Turtle]

Ok. Did you pull the rocker cover and check broken valve springs, cracked or broken rocker arms or collapsed lifters?

No I did not pull the valve cover, that was my next step. But it runs great, with and without load. If I had a broken valve spring, collapsed lifter, broken rocker, or worn cam lobe it would not run this good.

 

[Turtle]

Ha! 2+ years later, wow I need to get this thing on the road!

Pulled valve cover and everything is fine visually while turning the motor over. So I put it back together a couple months ago.

Yesterday I moved it out of garage and drove to gas station with no issues. But took it back out and at WOT it acts up, so I pulled over let it sit for 30 seconds, re-started and still ran crappy, shut it down and waited another 30-40 seconds and it fired right up and ran great driving mellow through the neighborhood. I can always get it to act up when I hit the highway at WOT.

While it was running good I decided to disconnect the camshaft position sensor, took it back to the highway and WOT with no issues, pulled over and started out again at WOT and no issues, I could not get it to act up no matter how hard I tried.

Does the CMP sensor do anything while running? Will be able to do more testing tomorrow, but it is looking like it may be the CMP sensor acting up while running. It's like it is messing with the timing of the injectors causing it to run rich and miss when it acts up.

 

[Turtle]

Just did another test drive. First start it was doing the mis-fire thing when trying to rev the engine, idle is ok, so I shut it down, waited 30 seconds, and fired up and ran great. Disconnected the ignition pick up sensor and went for a drive, it run great with no issues.

It appears this sensor does affect the injector timing while driving. Any issues with aftermarket pick ups? The sensor alone is $38, and the complete distributor is $50 for a Cardone unit for the newer 94-99 which appears will work on the earlier 91-93 4.0 engines. This is a 93 so the complete distributor has to come out to change the sensor.

Is it worth going to the newer style distributor/sensor for $12 more dollars?

 

[Turtle]

Just thought I would post a follow up. It was the distributor. You could see where the rotor was contacting the cam sensor. This was a remanufactured distributor. New distributor installed and no issues, runs as it should now.