Engine pings - intermittent-diff rpms

1266 Views 5 Replies 2 Participants Last post by  bycmike
1st drive on replacement enigine. All good. After approx 20 miles, the engine now has intermittent pinging UNDER LOAD at different RPMS.
The truck has thrown no codes. I had swapped intake/injectors and all other related electrical. I MAY HAVE installed the ign coil that came with the engine. It will ping under load and I know to back off as I don't need a holed piston. I have for testing, kept on it and in diff rpms it will dissappear. It's got new crank sensor, new water temp sensor, cap/rotor/plugs.
Any other thoughts other than swap out the coil ?
This thing always ran on reg. The replacement motor is from 96 Jeep.
Warlock -- thoughts ?
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You swapped intakes but did you replace the plenum gasket?
yes, complete intake set, wp gasket and new rear main seal/pan gasket. Why put a motor in with out spending the coin on gaskets and have a weeper of an engine.
The plenum plate gasket was blown out when I took it off to do the swap. I sealed both sides of the new gasket as well.
Do they cause this when they blow?
You'd be amazed by the number of people who drop a chunk of money on something big and skimp on the small stuff. The devil's in the details. Yes, they will cause pinging when they leak. However, in your case, since it's all new, and I'm guessing you knew to reset the computer, it could just need some running time to settle in. I'd bump up the octane in the short term as insurance. Could be anything. Running lean is usually related to some sort of vacuum leak or insufficient fuel. I'd run some Seafoam through it for a couple tanks. If an injector is not closing fully because of deposits, it'll dribble fuel, which causes a rich condition. The computer will pick this up and lean things out, which will then be too lean, and cause pinging. Mainly, get some miles on it. It's fresh and tight, needs some miles. Down the list, could be a failing fuel pump. A weak coil won't cause pinging, it'll cut out and generally make the engine feel puny. Run temperature look OK?
Temp is great ! Just drove it to work and NO PROBLEM.. I did drive it 2 days ago for an extended period. It then started to run erratic/poor idle. Shut it off,started back up immediately and the thing ran fine.. Ughhhhh I see electrical issues on this. I guess I will go thru all the connectors again UN-REPLUG EACH ONE. Then do an ECU reset with pos removed and short to Gnd. Damn cause when its right, it runs pretty good for a 318..
UPDATE !!! I installed the plug wires in a neat fashion when I originally put the engine in. Now, I separated them per the TSB and Voila ! The truck runs GREAT with NO PINGING ! Wow... I sure hope that this was the cure.. Will post back if it returns but it sure seems like I got it solved.. Will put some LONG TRIPS on the odometer before I uncross my fingers..
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