2005 Chevy Uplander, had pinging issue when under load and at operating temp for a year and a half now....new plugs, wires, new coolant temp sensor, new coolant, new air filter, a couple bottles of techron, seafoam, and shell premium 93 octane gas and it still pings when at operating temp under load. It wont ping when cold only when the engine temp needle is in the middle (operating temp) timing is correct, no check engine light and no codes...i dont know what else to do. It has the 3.5 V6 engine and it just hit 100,000 miles...I bought some MAF sensor cleaner and cleaned my Accords MAF sensor today, im going to try and clean the MAF sensor on the Uplander as a last resort, but i have no idea how to remove it, my accord had two screws i removed with a screw driver but the uplander has no screws...how do you remove the MAF on the uplander with the 3.5???
Chevy Uplander MAF/pinging issue
- Thread starter gregk24
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Originally Posted By: itguy08
Why the reluctance to replace the most likely culprit, the $5 knock sensor.
i have no idea where the knock sensor is and im not mechanically inclined at all...i figured out how to remove the maf sensor and its drying off as i type. where is the knock sensor anyway?
Why the reluctance to replace the most likely culprit, the $5 knock sensor.
i have no idea where the knock sensor is and im not mechanically inclined at all...i figured out how to remove the maf sensor and its drying off as i type. where is the knock sensor anyway?
the MAF sensor is located in the air intake tube that connects from the air filter box.
just loosen the clamps and take the airbox lid off and the MAF sensor will pop out of the hose.
After you spray the sensor wires then let it air dry for about 10 minutes before you start the motor.
Your Van doesn't need 93octane fuel. 87 is more that adequate.
The timing is computer controlled and there isn't any physical adjustment you can make.
What brand plugs did you by, and did you gap them to .060" ?
Are you 100% sure the plug wires were put back on the correct cylinder? a crossed wire will wreck havoc as well.
I would definetely look at the knock sensor. If I am reading the diagram right, it would be on the right side of the engine under the cylinder head. (if you are facing the front of engine where drive belt is, so it should be on radiator side)
It's held down with a single bolt, and an electrical connector.
the knock sensor listens for pinging and then tells the car computer to retard the timing.
the car computer "should" be monitoring that sensor and a engine light should light up for it. But if it's faulty in the gray area then Yeah I can see the light not working.
I would replace the knock sensor myself.
just loosen the clamps and take the airbox lid off and the MAF sensor will pop out of the hose.
After you spray the sensor wires then let it air dry for about 10 minutes before you start the motor.
Your Van doesn't need 93octane fuel. 87 is more that adequate.
The timing is computer controlled and there isn't any physical adjustment you can make.
What brand plugs did you by, and did you gap them to .060" ?
Are you 100% sure the plug wires were put back on the correct cylinder? a crossed wire will wreck havoc as well.
I would definetely look at the knock sensor. If I am reading the diagram right, it would be on the right side of the engine under the cylinder head. (if you are facing the front of engine where drive belt is, so it should be on radiator side)
It's held down with a single bolt, and an electrical connector.
the knock sensor listens for pinging and then tells the car computer to retard the timing.
the car computer "should" be monitoring that sensor and a engine light should light up for it. But if it's faulty in the gray area then Yeah I can see the light not working.
I would replace the knock sensor myself.
What about EGR system? I chased down a pinging issue on my 2001 Taurus for YEARS. Probably spent $1000 or more replacing parts, cleaners, premium gas, etc. ... couldn't get it to stop pinging
I bought 93 octane once (usually we have 87, 89, 91) and it still pinged. There were times it would ping going 55 down a flat highway and have a slight mis fire at part throttle cruise. I considered getting a tuner to retard the timing further than stock, or offsetting the camshaft sensor to make it stop pinging.
One day I set an EGR code. Replaced the DPFE sensor and it NEVER pinged again!
Obviously DPFE sensor problems are exclusive to Ford, but maybe it could be something odd like that? Mine was out enough to cause SEVERE pinging for a few years.
I bought 93 octane once (usually we have 87, 89, 91) and it still pinged. There were times it would ping going 55 down a flat highway and have a slight mis fire at part throttle cruise. I considered getting a tuner to retard the timing further than stock, or offsetting the camshaft sensor to make it stop pinging.
One day I set an EGR code. Replaced the DPFE sensor and it NEVER pinged again!
Obviously DPFE sensor problems are exclusive to Ford, but maybe it could be something odd like that? Mine was out enough to cause SEVERE pinging for a few years.
the EGR valves on these engines are electrical, and I would say that if the EGR valve had any issue the CEL light would light right up and place a code.
The knock sensor (IMHO) makes sense.. however, upon staring at the diagram a bit more in depth, the motor has 2 knock sensors, and according the AC Delco site, the knock sensor is a fast moving part, which makes me think we're all on the right track.
I have a picture I can fax to you or maybe email it..?
The knock sensor (IMHO) makes sense.. however, upon staring at the diagram a bit more in depth, the motor has 2 knock sensors, and according the AC Delco site, the knock sensor is a fast moving part, which makes me think we're all on the right track.
I have a picture I can fax to you or maybe email it..?
Clogged EGR passages will cause higher combustion temps and part throttle pinging.
A bad knock sensor SHOULD cause the ECU to revert to base timing, resulting in no pinging.
A bad knock sensor SHOULD cause the ECU to revert to base timing, resulting in no pinging.
ok guys i cleaned the maf sensor and no change at all...i also found the knock sensor, im kinda proud of myself im not mechanically inclined at all..anyway i unplugged the knock sensor and as soon as it pinged the computer cut the power and IT STOPPED PINGING!!!! i plugged it back in and sure enough the pinging came right back. Does that mean that the knock sensor is bad??? i just scanned it no codes at all. no CEL either. PLEASE HELP! i dont want to replace it if its not the problem. i dont have any extra cash.
Sounds like the knock sensor is bad to me. KS in not sensing knock, however ECU thinks the KS is still good for whatever reason. Or unplugging the KS caused it to go to full retard as it should and cover up the root cause. Im still guessing EGR passages. There should be a EGR testing procedure.
The KS sounds like it is cheaper than the can of MAF cleaner was, so it's cheap enough to call "troubleshooting".
The KS sounds like it is cheaper than the can of MAF cleaner was, so it's cheap enough to call "troubleshooting".
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a knock sensor from Standard Motor Products is like $17. p/n: KS211
an AC Delco sensor: 213-1576 is about the same price.
Here's the catch.. you have 2 of these sensor, on on each engine bank. I would buy 1, and put it in. If nothing changes, put it on the other side of the engine.. OK.. you're gonna not have fun on the firewall side..
BUT, you might be able to get it from under the car. Put the new sensor on the other side. If the issue still remains, then I'm sorry, but you'll have to send it to a Tech who can diagnose.
There's only so many suggestions..
but plugged EGR passes is something you could do, the valve sits on topside of the engine, all you have to do is remove it and use your MAF spray and spray the valve and down the holes. And maybe at worst buy a new EGR Valve gasket.
You mentioned you ran Seafoam.. that's a great start, however, it busts up carbon on the topside of the intake manifold, doesn't really get to the EGR ports.
(I have an 06 Relay, same engine, same van).
an AC Delco sensor: 213-1576 is about the same price.
Here's the catch.. you have 2 of these sensor, on on each engine bank. I would buy 1, and put it in. If nothing changes, put it on the other side of the engine.. OK.. you're gonna not have fun on the firewall side..
BUT, you might be able to get it from under the car. Put the new sensor on the other side. If the issue still remains, then I'm sorry, but you'll have to send it to a Tech who can diagnose.
There's only so many suggestions..
but plugged EGR passes is something you could do, the valve sits on topside of the engine, all you have to do is remove it and use your MAF spray and spray the valve and down the holes. And maybe at worst buy a new EGR Valve gasket.
You mentioned you ran Seafoam.. that's a great start, however, it busts up carbon on the topside of the intake manifold, doesn't really get to the EGR ports.
(I have an 06 Relay, same engine, same van).
On alldata, there is an TSB for a recall reguarding PCM replacement. It says it may have been damaged and the part that is damaged controls the fuel pump and EGR controls. Worth a look.
Could still have some caked on hot spots on the pistons. Curious, what are intake air temps when it detonates?
Have you checked proper fuel delivery pressure and volume?
Could still have some caked on hot spots on the pistons. Curious, what are intake air temps when it detonates?
Have you checked proper fuel delivery pressure and volume?
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Originally Posted By: mattd
On alldata, there is an TSB for a recall reguarding PCM replacement. It says it may have been damaged and the part that is damaged controls the fuel pump and EGR controls. Worth a look.
Could still have some caked on hot spots on the pistons. Curious, what are intake air temps when it detonates?
Have you checked proper fuel delivery pressure and volume?
not sure about air temps and not sure about fuel pressure...going to try another bottle of techron. How long will an engine last that only pings when hot on acceleration. It only does it at 2500 rpm and above, and only when up to operating temp. Will it last? or will the engine blow up? it sounds just like the marbles in a tin can
On alldata, there is an TSB for a recall reguarding PCM replacement. It says it may have been damaged and the part that is damaged controls the fuel pump and EGR controls. Worth a look.
Could still have some caked on hot spots on the pistons. Curious, what are intake air temps when it detonates?
Have you checked proper fuel delivery pressure and volume?
not sure about air temps and not sure about fuel pressure...going to try another bottle of techron. How long will an engine last that only pings when hot on acceleration. It only does it at 2500 rpm and above, and only when up to operating temp. Will it last? or will the engine blow up? it sounds just like the marbles in a tin can
if its that loud it will eventually burn a hole in a piston from high temperatures. Look into that other stuff, including the PCM recall.
IMO you are wasting your time with techron. You need to have someone look at it with a brain and a scan tool, not someone who can just R&R parts.
IMO you are wasting your time with techron. You need to have someone look at it with a brain and a scan tool, not someone who can just R&R parts.
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Originally Posted By: mattd
if its that loud it will eventually burn a hole in a piston from high temperatures. Look into that other stuff, including the PCM recall.
IMO you are wasting your time with techron. You need to have someone look at it with a brain and a scan tool, not someone who can just R&R parts.
burn a hole after how long though? 30 years of driving? or soon? its been pinging for 2 years/20,000 miles now and no change in drivability. just that rediculous pinging noise
if its that loud it will eventually burn a hole in a piston from high temperatures. Look into that other stuff, including the PCM recall.
IMO you are wasting your time with techron. You need to have someone look at it with a brain and a scan tool, not someone who can just R&R parts.
burn a hole after how long though? 30 years of driving? or soon? its been pinging for 2 years/20,000 miles now and no change in drivability. just that rediculous pinging noise
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