85' Vette Pinging Problem...STILL!!!
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Instructor
Joined: Dec 2004
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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???
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Instructor
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no the converter isn't plugged. I just passed emissions, and the car has plenty of power. BTW, I forgot to mention, the ping only happens under heavy load like downshifting to 3rd on the highway, and it will go away once I get over 3500 RPM or so.
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carbon build-up in the intake?? or in the combustion chamber?? It doesn't do it all the time, just under heavy load. Like when I am going down the freeway, and I floor it. It will downshift to 3rd, and it will ping like hell until I get to 3500RPM's or higher. From a stand still, I can floore it and it will pull hard in 1st. and 2nd. with no ping
Drifting
Joined: Nov 2000
Posts: 1,428
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From: Jacksonville FL
What grade of fuel are you using? What is the heat range of the plugs you installed? Have you verified TDC on your engine? Did you change the knock module on the heater/AC box? Does it appear that the harmonic balancer is undisturbed?
Racer
Joined: Jan 2005
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From: Tucson, AZ. L98-85 AUTO COUPE: 120k MILES: daily driver. SOUND OFF IF YOU'VE BEEN THERE. Ex-Jumpin' Junky-82nd Airborne-2/505 PIR: 1st ID-1/16th Inf: Recon Marine Retread. GOD BLESS GRUNTS.
if you've got no coolant in the block, and you're pinging; it could be as simple as a seized thermostat causing the head to overheat and cause detonation. maybe.
frog
frog
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Yeah, the news is that I'm frusterated as hell. I have tried everything I can think of. I'm almost 100% sure that it's not an electrical problem. I have no stored codes, and the check engine light doesn't come on ever. I have replaced both the knock sensor, and the ESC mod. with no change. I have tried probably 6 SeaFoam treatments and have no consistant results. Sometimes it seems like it helps, and sometimes it seems like it makes it worse. I would take the heads off and check out the combustion chambers, but at that point, I would rather throw in a new ZZ4...wich I'm actually seriously considering. . I have changed the base timing from 8*BTC to 0*BTC with no real change. Either way I still get the ping. 
ANYONE HAVE ANY MORE IDEAS???? I love the car, but hate the sounds it makes when I get on her 
Could it just be that there is so much carbon buildup from the car sitting so long??? Should I keep using the SeaFoam to try to clean things up???
ANYONE HAVE ANY MORE IDEAS???? I love the car, but hate the sounds it makes when I get on her Could it just be that there is so much carbon buildup from the car sitting so long??? Should I keep using the SeaFoam to try to clean things up???
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Not yet, what should the preasures be at idle and under acceleration??? Also, wouldn't a Lean Burn show up with a code??? Oh wait, is that only on the OBD2 stuff??? Anyway, I will try to check tonight.
Melting Slicks
Joined: Dec 2004
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From: Obama=death for America
Just a thought, but have you ensured that you have the correct spark plugs in use? The wrong plug with the wrong heat range can cause all sorts of problems, including pinging. And also make sure you're running super unleaded. Running regular can cause pinging.
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I used some Bosch Platinum plugs. I don't know the heat range. I asked the guy at the AutoZone counter for plugs for an 85' Vette and those are what he gave me. Granted those guys aren't the brightest (no offense to any AutoZone guys that may be on the list) but I doubt that that could be the problem. I would think that if that were the case, that the problem would have gone away with the timing adjustment. and BTW, I use Chevron Super Unleaded, It's the nicest stuff we get here in AZ. I also tried some Race gas (101 octane) and it didn't really help. I mixed it 1:1 with the chevron super stuff.
Drifting
Joined: Jan 2002
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From: Middle River MD
Originally Posted by kcpaz
Not yet, what should the preasures be at idle and under acceleration??? Also, wouldn't a Lean Burn show up with a code??? Oh wait, is that only on the OBD2 stuff??? Anyway, I will try to check tonight.
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okay, I just checked the fuel preasure. Everything checked out fine. 35PSI at Idle, 39PSI when I get on it. I have heared a few people suggest the EGR Valve, and that's one of the things that I haven't checked...I figured that I would get a code if there was something really wrong, but I guess that might not always be the case. SO... How do I go about checking the EGR Valve function??? Thanks for all your help.