89 Jimmy V1500 pops or pings ! code 43

I have an 89 Jimmy, V1500, 5.7, 4X4 with 161,000 miles on it ! About a month ago, it started popping under acceleration ! If I accellerate slowly, it's ok, if I floor it, it may "pop" but then takes off like a raped ape ! I changed the dist cap & rotor, tested the TPS, temp sensor, and the MAP sensor ! Got NO READING on the MAP, so I replaced it ! I cleared all the previous codes, and now am getting a code 43 !?? The distributor had been replaced about 15 months ago ! I tried playing with the timing, but it either pings, or pops through the TBI ! Any ideas ??
THANKS !!!

Making the engine "Ping" is NOT a good idea. It's the fuel air mixture exploding at the wrong time, trying to make the engine run backwards. There is a risk of holed pistons with this condition.

Popping back means the ignition timing is really overadvanced; a spark while the cylinder is charging, inlet valve open.


Code 43 is an ESC fault. The age and mileage of your Jimmy indicates that the knock sensor and/or the ESC is failing.

To change the knock sensor, you'll have to drain the cooling system. When you've removed it (have fun), make sure that there is no rust scale inside, covering the hole it screws into. The sensor tip should be in the coolant like a hydrophone listening for the "ping" of an over advanced ignition.

Check the ignition timing, preferably with a inductive pickup timing light. There should be a VECI label near the radiator with specific requirements for the vehicle's timing check. Likely you'll have to disconnect the ESC for this.

You should make sure that all electrical connections are sound; clean metal and in contact. Coating the contacts in a film of petroleum jelly prevents oxidation. resistance buildup and hence false signals to the ECM. Make sure the Chassis grounds are good too (especially the O2 sensor). I cleared a load of codes just by doing this.


Teaman3 :o)

Making the engine "Ping" is NOT a good idea. It's the fuel air mixture exploding at the wrong time, trying to make the engine run backwards. There is a risk of holed pistons with this condition.

Popping back means the ignition timing is really overadvanced; a spark while the cylinder is charging, inlet valve open.


Code 43 is an ESC fault. The age and mileage of your Jimmy indicates that the knock sensor and/or the ESC is failing.

To change the knock sensor, you'll have to drain the cooling system. When you've removed it (have fun), make sure that there is no rust scale inside, covering the hole it screws into. The sensor tip should be in the coolant like a hydrophone listening for the "ping" of an over advanced ignition.

Check the ignition timing, preferably with a inductive pickup timing light. There should be a VECI label near the radiator with specific requirements for the vehicle's timing check. Likely you'll have to disconnect the ESC for this.

You should make sure that all electrical connections are sound; clean metal and in contact. Coating the contacts in a film of petroleum jelly prevents oxidation. resistance buildup and hence false signals to the ECM. Make sure the Chassis grounds are good too (especially the O2 sensor). I cleared a load of codes just by doing this.


Teaman3 :o)
Thanks ! I did have a bad knock sensor ! That made it run a LOT better, just a little "chug" on take off ! LOL Then the infamous EGR code came up, so, after replacing that, too, ALL IS WELL with old boy ! LOL But THANK YOU for your help ! Now if I can find a cure for the trucks "cancer",.....;-) I know PATCH PANELS !! LOL Hey, have a GREAT DAY !!!

Glad you're rolling.

Good idea to get to know a welder. :o)

If you get a chance check underneath the carpets for damp. If they are there's water getting in and you may have some rust that will need to be dealt with PDQ.