85' vette pinging problem...Still :(
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85' vette pinging problem...Still :(
My 85 is still having a pinging/knocking problem. Here is a list of what I've tried.
-New plugs, wires, cap, and rotor
-New Fuel, and air filters
-New knock sensor
-New ESC module
-Checked the timing, and adjusted to 6* BTC...it was at 2*BTC (I think someone tried to fix it the "cheap way")
I don't have a scanner yet so I can't pull any codes, but I will get one soon. I am out of ideas though. The plug for the fan switch was sitting on top of the header, but someone had installed a new switch/sensor with a 2 wire plug so I guess the old plug wasn't needed. I thought that this might be the knock sensor plug but there was already a plug on the knock sensor (The wire on the knock sensor is blue, can anyone confirm that this is the right wire?) The fans work fine. And another thing. When I pulled the old knock sensor out, no coolant came out. What Gives!? I thought I remembered someone saying that the sensor screwed into the water jacket. Anyone have any suggestions???
-New plugs, wires, cap, and rotor
-New Fuel, and air filters
-New knock sensor
-New ESC module
-Checked the timing, and adjusted to 6* BTC...it was at 2*BTC (I think someone tried to fix it the "cheap way")
I don't have a scanner yet so I can't pull any codes, but I will get one soon. I am out of ideas though. The plug for the fan switch was sitting on top of the header, but someone had installed a new switch/sensor with a 2 wire plug so I guess the old plug wasn't needed. I thought that this might be the knock sensor plug but there was already a plug on the knock sensor (The wire on the knock sensor is blue, can anyone confirm that this is the right wire?) The fans work fine. And another thing. When I pulled the old knock sensor out, no coolant came out. What Gives!? I thought I remembered someone saying that the sensor screwed into the water jacket. Anyone have any suggestions???
Racer
Joined: Jan 2005
Posts: 315
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From: tomahawk wisconsin
well do you have a check engine light on?if so go to your local parts store and get a gm key and pull the codes yourself.If you have a auto zone in your town go there and they will pull them for free and look the code up and tell you want you need.
And the knock sensor is in a water jacket in the side of your block and if no coolant came out then either you pulled the wrong sensor or your radiator is dry.The knock sensor is about as round as a 50 cent peice and its about 1/2 inch thich with 3/8 thread that screws into the side of your block.anyway good luck.
And the knock sensor is in a water jacket in the side of your block and if no coolant came out then either you pulled the wrong sensor or your radiator is dry.The knock sensor is about as round as a 50 cent peice and its about 1/2 inch thich with 3/8 thread that screws into the side of your block.anyway good luck.
Thread Starter
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Yeah, I'm sure that it was the knock sensor. It's the only sensor that is that low on the block, on the passanger side. It's the one right in front of the starter. Oh, and the check engine light isn't on. Only when I turn on the key. I'm sure it has a stored code from when I adjusted the timing
Intermediate
Joined: Jan 2005
Posts: 36
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From: Clearwater Beach Fl
Did you disconnect the ECS wire (near the brake booster) before you adjusted the timing? yeah... maybe im the only one on here that ever pulled that one but that little error cost me about 300 bucks in parts when the original trouble was simply the pickup coil that was replaced (hence dicking with the timing in the first place!) and 2 months of driving around in a corvette that ran so poorly it was emberassing... you know its bad enough that YOU know its missing slightly but when you have high performance exhaust and its LOUD EVERYONE knows its missing slightly lol
Grant
Grant
Originally Posted by kcpaz
My 85 is still having a pinging/knocking problem. Here is a list of what I've tried.
-New plugs, wires, cap, and rotor
-New Fuel, and air filters
-New knock sensor
-New ESC module
-Checked the timing, and adjusted to 6* BTC...it was at 2*BTC (I think someone tried to fix it the "cheap way")
I don't have a scanner yet so I can't pull any codes, but I will get one soon. I am out of ideas though. The plug for the fan switch was sitting on top of the header, but someone had installed a new switch/sensor with a 2 wire plug so I guess the old plug wasn't needed. I thought that this might be the knock sensor plug but there was already a plug on the knock sensor (The wire on the knock sensor is blue, can anyone confirm that this is the right wire?) The fans work fine. And another thing. When I pulled the old knock sensor out, no coolant came out. What Gives!? I thought I remembered someone saying that the sensor screwed into the water jacket. Anyone have any suggestions???
-New plugs, wires, cap, and rotor
-New Fuel, and air filters
-New knock sensor
-New ESC module
-Checked the timing, and adjusted to 6* BTC...it was at 2*BTC (I think someone tried to fix it the "cheap way")
I don't have a scanner yet so I can't pull any codes, but I will get one soon. I am out of ideas though. The plug for the fan switch was sitting on top of the header, but someone had installed a new switch/sensor with a 2 wire plug so I guess the old plug wasn't needed. I thought that this might be the knock sensor plug but there was already a plug on the knock sensor (The wire on the knock sensor is blue, can anyone confirm that this is the right wire?) The fans work fine. And another thing. When I pulled the old knock sensor out, no coolant came out. What Gives!? I thought I remembered someone saying that the sensor screwed into the water jacket. Anyone have any suggestions???
Racer
Joined: Jan 2005
Posts: 315
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From: tomahawk wisconsin
Originally Posted by kcpaz
Yeah, I'm sure that it was the knock sensor. It's the only sensor that is that low on the block, on the passanger side. It's the one right in front of the starter. Oh, and the check engine light isn't on. Only when I turn on the key. I'm sure it has a stored code from when I adjusted the timing
Thread Starter
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I did unplug that plug when I set the "base" timing. And I don't know why I didn't get any coolant. Maybe the hole was corroded and plugged up. But I'm 100% sure that it was the knock sensor. I increased the timing because it's supposed to be 6* BTC. Putting it at 2*BTC just to try to make the knocking stop would just be a Band-aid. I need to fix the real problem, not just cover it up. Anyway, Could it be the PCV Valve??? The radiator is full also, I checked.
Last edited by kcpaz; Jan 22, 2005 at 10:55 PM.
Melting Slicks
Joined: Jun 2004
Posts: 3,032
Likes: 4
if you pull the knock sensor, and coolant doesn't rush out, you need to get your system powerflushed... something is really wrong there....
I suggested putting you're timing back because a "band-aid" won't ruin your engine with detonation until you figure out whats wrong
I suggested putting you're timing back because a "band-aid" won't ruin your engine with detonation until you figure out whats wrong
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Thread Starter
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When I changed the timing it didn't make a difference. It pinged/knocked just as much at 2*BTC as it did at 6*BTC. BTW, I just ran a code scan, and all I got was #42. and the only reason I got that is because I checked the timing. If I had gotten a #43, then it might all make sense but no such luck 
Intermediate
Joined: Jan 2005
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From: Clearwater Beach Fl
Originally Posted by kcpaz
When I changed the timing it didn't make a difference. It pinged/knocked just as much at 2*BTC as it did at 6*BTC. BTW, I just ran a code scan, and all I got was #42. and the only reason I got that is because I checked the timing. If I had gotten a #43, then it might all make sense but no such luck
Racer
Joined: Mar 2004
Posts: 311
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From: Oakley Ca
No coolant just means the hole is cruded over. Check that the harmonic balancer hasn't slipped. Most likely culprit is the EGR valve isn't working for what ever reason, maybe the passages in the intake manifold may be plugged with carbon. If the engine has been altered, the compression may be too high. Have you tried higher octane gas? Just my ramblings.
Last edited by olman; Jan 23, 2005 at 02:58 AM.
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I'm not doubting that the lack of coolant is a problem...maybe even a big problem. Infact, I'm probably going to put the car in the air again tomorrow, and pull the sensor out. Maybe poke something through the hole and see what's up. I'm sure that the cooling system needs a GOOD! flushing. I'm also going to try some SeaFoam...or similar product. Maybe it is just a matter of carbom build-up. But I am still open to any other suggestions of course
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What is the testing procedure for EGR valve/system??? I have heard a few people give this suggestion. BTW, I'm running Chevron 91 octane. It's the best stuff we can get here in Arizona other than race gas.
Le Mans Master
Joined: Jul 2001
Posts: 8,183
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From: Santa Maria, CA
Can you tell us when it pings/knocks?
Like when it's cold, first thing in the morning? Or when it is idling in park, or idling in D, or under WOT or part throttle? Upon start up regardless of engine temp? When it's up to op temp?
Is the sound a hard, mechanical knock like rod knock or is it in the cylinders?
Does it follow RPM?
Can ya tell approx where the pings is located in the engine bay?
The EGR valve, you can put your fingers into from underneath it and push up on the diaphram and see if it moves easily. It should also hold a vacum if applied to it. EGR valve operates only under certain times and conditions(hence all the temp/time questions above).
Have any mods or changes or parts replacements taken place recently?
Sorry for all the questions.
Like when it's cold, first thing in the morning? Or when it is idling in park, or idling in D, or under WOT or part throttle? Upon start up regardless of engine temp? When it's up to op temp?
Is the sound a hard, mechanical knock like rod knock or is it in the cylinders?
Does it follow RPM?
Can ya tell approx where the pings is located in the engine bay?
The EGR valve, you can put your fingers into from underneath it and push up on the diaphram and see if it moves easily. It should also hold a vacum if applied to it. EGR valve operates only under certain times and conditions(hence all the temp/time questions above).
Have any mods or changes or parts replacements taken place recently?
Sorry for all the questions.
Last edited by pablocruise; Jan 23, 2005 at 05:09 AM.
Race Director
Joined: Aug 2000
Posts: 11,506
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From: Vancouver,Wa.
Mine did the same thing..
Here is what to look for. Make 100% sure that the balancer has not spun on the rubber gromet.
Make sure that your EGR valve is working.
This is what I think is wrong though, Your car I bet smokes on start up.. after a long time of this you get a build up of carbon on the pistons. The carbon get so hot that it will actual ignite the fuel before the spark plug does. The cure is run the car though a motorvac system.
One more thing make sure that the TPS is set right.
Here is what to look for. Make 100% sure that the balancer has not spun on the rubber gromet.
Make sure that your EGR valve is working.
This is what I think is wrong though, Your car I bet smokes on start up.. after a long time of this you get a build up of carbon on the pistons. The carbon get so hot that it will actual ignite the fuel before the spark plug does. The cure is run the car though a motorvac system.
One more thing make sure that the TPS is set right.
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okay, I will do my best to answer all of those questions, and BTW, as far as I know, the car is completely stock...accept for the aftermarket fan switch set to go off at 190*. The car only does it under this scenario. If I am driving down the highway ~60-70mph, and I mash down on the throttle, the car will downshift, and I will get a ignition, not mechanical ping/knock until the car get's to ~3500rpm and higher. FYI the ping sounds like it's coming from the drivers side. It will also do if at 1/2 throttle in 4th gear right before it down shifts. It will NOT ping/knock in first, or second gear...or under 60mph. Even under hard launches, it's fine. All of this is happening at operating temps (180*-190*)...obviously I'm not revving the engine while it's cold. The outside temps here in AZ are starting to go up a little 80* high 55* lows 
and I noticed when it was really cold outside 35*-45* it wouldn't do it some times. I am going to the auto parts store again today to try to find some SeaFoam (or similar product) and maybe de-carbonize the engine. I will also check the EGR Valve...however, I'm not getting an EGR code at all. About the TPS, wouldn't an out of adjustment TPS set off a code???
and I noticed when it was really cold outside 35*-45* it wouldn't do it some times. I am going to the auto parts store again today to try to find some SeaFoam (or similar product) and maybe de-carbonize the engine. I will also check the EGR Valve...however, I'm not getting an EGR code at all. About the TPS, wouldn't an out of adjustment TPS set off a code???
Last edited by kcpaz; Jan 23, 2005 at 01:06 PM.
Race Director
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From: The Top of Utah
Originally Posted by kcpaz
I don't have a scanner yet so I can't pull any codes, but I will get one soon. I am out of ideas though.
Originally Posted by kcpaz
I will also check the EGR Valve...however, I'm not getting an EGR code at all. About the TPS, wouldn't an out of adjustment TPS set off a code???
What concerns me most is that you can hear the knock. It's one thing to see timing retard on a scanner caused by knock counts, but the ESC should retard the timing before you actually hear it.
Originally Posted by ar91c4
if that was the right sensor you pulled then you absulutely should of had coolant flow out.
RACE ON!!!
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So I tried some SeaFoam and it helped out quite a bit...actually ALOT!!!! Now I only get a ping/knock for a second while the transmission is downshifting...almost like the ESC is working, just not instantly. Once it settles into gear, it's fine. Still haven't checked the EGR Valve yet. That's next. 