WesM228

Hi. I'm Wes in Florida and I'm new to the forum but figured I'd start with a problem I've been having for months. I need to get this resolved so I can enjoy driving my Jeep instead of worrying about blowing the engine.

My '93 2wd Cherokee with around 170k miles will ping on acceleration or any time under load such as an incline. It has done this since about two weeks after purchasing it late last year. I had made no changes up to that point other than adding Lucas fuel system cleaner, which I really regret. It makes zero noise cruising or at idle so I'm pretty sure it is pinging (pre-detonation). I have replaced the fuel pressure regulator with a Napa (Echlin) unit, the fuel pump, fuel filter, oil/filter, spark plugs (stock Champion), air filter (K&N), and cap and rotor. I switched to 93 octane for two tanks. Pinging disappeared and then I went back to 87 and pinging resumed. I have also tried sea foam slowly poured in the intake. In addition I used Lucas fuel treatment in the tank. Still to no avail.

I don't know what the hell else to try. I have the stock cat converter still and I have read it's a troublemaker though could it cause pinging? It rattles a little but doesn't seem to be blocked up as the exhaust comes out the tailpipe forcefully when gas is pressed.

All suggestions/advice is appreciated. I may try a few more things and if still no fix then take it to a shop and shell out a few hundred or more so I can enjoy the damn thing already.

Thanks so much guys!

freegdr

have you checked it for trouble codes even if there no check engine light?

freegdr

you might have a bad knock sensor

ken72

Are you using the same brand of 87 each time? I know this sounds crazy but I put a tank of Marathon gas in my tank one week because they told me it was ethanol free and my engine pinged liked crazy. I put some octane booster in it to relieve the pinging and went back to Shell 89 on the next fill up. Checking the knock sensor is not a bad idea as these can cause pinging when they go bad. Does it ping while it is still warming up or only after it has warmed up. If only after warming up I would also check your O2 sensors.

KD3NE

Yeah I was wondering the same thing since it started not long after he got it.

Maybe the change in brand of fuel is causing it to ping, under load.

I was always told that pinging under load, go up to the next octane level first and run a tank of that.

imthehink

Mine did the same thing. I filled up with 91 and drove it to almost empty, filled it back up with 87 and the ping went away.

tjwalker

I think you have excessive carbon deposits in the engine.

By switching to a higher octane and the pinging went away, that pretty much verified it. In fact, that is the test I try or recommend whenever the symptom of "pinging" comes up.

Seafoam was a good thing to try, but you may have a large amount of carbon and the Seafoam didn't do the trick.

I think I'd try decarbonizing again though, unless you want to tear the engine apart. This time, use MOPAR top end cleaner.

WesM228

I usually only get gas at Tom Thumb (Citgo). I think I tried 87 from Shell and it didn't help. I ran two full tanks of 93 until empty and then switched back to 87 a few days ago and the pinging returned. I had also tried 89 before the two 93 octane tank fulls and it seemed to lessen the ping, but it was still there.

The thing about the Sea Foam in the intake that had me baffled is when I watched a bunch of Youtube videos of people doing it their vehicles smoked like crazy. The first 1/3 of the can I used as directed it didn't smoke hardly at all. And I did wait the recommended time before restarting. A few days later I poured the rest in extra slow and again did not get the huge smoke show I was expecting. It actually was about an hour or more later that night when I started it again that it smoked decent so maybe the carbon on the internals is really tough.

I will have to check for codes and replace the knock sensor just to eliminate that and try the Mopar top end cleaner. I'm pretty sure it pings soon after start up before the engine is even warm. Obviously while under load though, not idling.

tiwvr1

worn plugs, distributir cap, anything ignition related will cause it, or dirty fuel filter, worn fuel pump, there are so manythings that can cause detonation.

Willys55

Tell her to get out, then try that hill again.

WesM228

Did you even read my first post? I've already changed out everything you mentioned.