Knock Sensor issue on my 87
Thread Starter
Instructor
Joined: Jun 2002
Posts: 231
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From: 80/680 junction Ca.
Knock Sensor issue on my 87
Since I've had the car I've had to set initial timing to 0* with the wire disconnected, just to be drivable without detonation when under moderate excelleration.(usually drive very mellow, putt-putt)
I started thinking that there must be a problem with the knock sensor since the ESC should be backing off the advance.
Checked all the wires to the ESC and they check out.
Did the hammer tap test for the KS and nothing, no change in voltage at the ESC and the timing doesn't retard when I tap with the hammer either, but no code 43.
I run to the the parts store and pick up a new KS and install, and SES light now comes on and there is a 43 stored. Clear and start several times with no change.
Put the old KS back in and clear code, and no SES light, but still nothing indicating that the sensor or ESC is working properly.
I figure I'll try a new ESC.
Timing sits at about 12* at idle with wire plugged in from the initial unplugged wire 0*.
I started thinking that there must be a problem with the knock sensor since the ESC should be backing off the advance.
Checked all the wires to the ESC and they check out.
Did the hammer tap test for the KS and nothing, no change in voltage at the ESC and the timing doesn't retard when I tap with the hammer either, but no code 43.
I run to the the parts store and pick up a new KS and install, and SES light now comes on and there is a 43 stored. Clear and start several times with no change.
Put the old KS back in and clear code, and no SES light, but still nothing indicating that the sensor or ESC is working properly.
I figure I'll try a new ESC.
Timing sits at about 12* at idle with wire plugged in from the initial unplugged wire 0*.
Thread Starter
Instructor
Joined: Jun 2002
Posts: 231
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From: 80/680 junction Ca.
Just picked up a new ESC, bolted it up replaced the old KS with new, now no code 43.
Reset initial timing to 6*BTDC with ECM wire removed.
Test drive.
Anything over 15* throttle is straight up pinging.
So bad I'm afraid to drive it.
Do you think anything will change that much by the end of the 20 min. ECM relearn period?
I just spent $120 to make it worse.
Fuel pressure is normal.
Balancer is new and timing mark was checked during installation 6 months ago.
I'll take it out later tonight when the temps drop outside.
Reset initial timing to 6*BTDC with ECM wire removed.
Test drive.
Anything over 15* throttle is straight up pinging.
So bad I'm afraid to drive it.
Do you think anything will change that much by the end of the 20 min. ECM relearn period?
I just spent $120 to make it worse.
Fuel pressure is normal.
Balancer is new and timing mark was checked during installation 6 months ago.
I'll take it out later tonight when the temps drop outside.
Thread Starter
Instructor
Joined: Jun 2002
Posts: 231
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From: 80/680 junction Ca.
Plugs are fine, no non-foulers.
If you can call what we have here in Ca. premium. Thats what's in it. I doubt the engine has any mods.
I was putting a tranny in it about 6 months ago, the balancer needed to be replaced because it was grooved from the seal and the timing cover had been ground down by I guess a previous balancer and had a pin hole in it leaking oil everywhere, so I put a new cover and seal on as well as a new Crane timing chain, the one special made for the L98 with the roller cam. Pulled the valve covers, very clean inside and degreed all to make sure the cam timing was on and the balancer mark was correct with the new cover.
Since I was in there I dropped the pan and replaced the rear seal and pan gasket and took a look at the bottom end which also looked very clean, there was still cross hatch in the cylinders, so maybe the previous owner wasn't feeding it to me when he said it had been rebuilt, sure didn't look it on the outside.
It doesn't feel like a nasty motor running on crap gas. It feels like a stock engine running on crap gas.
My womans Mercedes CLK500 eats this thing like candy.
My old Dodge 4x4 has a 10:1 comp. 440 in it with a crap junk yard Thermoquad 4:10 gears and 38.5" tires and screams on the same gas, but it runs alot cooler.
If you can call what we have here in Ca. premium. Thats what's in it. I doubt the engine has any mods.
I was putting a tranny in it about 6 months ago, the balancer needed to be replaced because it was grooved from the seal and the timing cover had been ground down by I guess a previous balancer and had a pin hole in it leaking oil everywhere, so I put a new cover and seal on as well as a new Crane timing chain, the one special made for the L98 with the roller cam. Pulled the valve covers, very clean inside and degreed all to make sure the cam timing was on and the balancer mark was correct with the new cover.
Since I was in there I dropped the pan and replaced the rear seal and pan gasket and took a look at the bottom end which also looked very clean, there was still cross hatch in the cylinders, so maybe the previous owner wasn't feeding it to me when he said it had been rebuilt, sure didn't look it on the outside.
It doesn't feel like a nasty motor running on crap gas. It feels like a stock engine running on crap gas.
My womans Mercedes CLK500 eats this thing like candy.
My old Dodge 4x4 has a 10:1 comp. 440 in it with a crap junk yard Thermoquad 4:10 gears and 38.5" tires and screams on the same gas, but it runs alot cooler.
Thread Starter
Instructor
Joined: Jun 2002
Posts: 231
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From: 80/680 junction Ca.
This thing is a pile.
When I picked up the ESC at Napa earlier, I bolted it up there in the parking lot and drove it home. Mine you that the timing was still at 0* at this time , but I was mashing the skinny pedal and no pinging that I could notice, sounded great but just like always feels weak, like any car with the timing set so retarded.
I just went out there and reset the timing back to 0* so the only differance between now and the ride home earlier is the new KS, and it's a bit cooler outside now, about 75 to 80.
It's pinging about the same as when the timing was set at 6*.
I just checked and there are no codes stored at all.
Water temps varied betweed 200 and 220.
When I picked up the ESC at Napa earlier, I bolted it up there in the parking lot and drove it home. Mine you that the timing was still at 0* at this time , but I was mashing the skinny pedal and no pinging that I could notice, sounded great but just like always feels weak, like any car with the timing set so retarded.
I just went out there and reset the timing back to 0* so the only differance between now and the ride home earlier is the new KS, and it's a bit cooler outside now, about 75 to 80.
It's pinging about the same as when the timing was set at 6*.
I just checked and there are no codes stored at all.
Water temps varied betweed 200 and 220.
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Thread Starter
Instructor
Joined: Jun 2002
Posts: 231
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From: 80/680 junction Ca.
Went to Napa and picked up an EGR valve this morning, got home and decided to hook up my hand vac pump to the the EGR on the car again to make sure it wasn't holding vac as I saw last evening, and as last evening nothing. Put the vac pump on the new one and the same thing, won't hold vac, won't open.
Run back to the store the kid pulls out another, and the same thing!
I ask the kid to bring me any EGR, he does and I hook up my vac tester and it hold vac fine and opens right up.
Another counter kid there says "Your not supposed to test those with a hand pump!" I ask him what he's talking about, and he answers the phone and ignors me.
I get a refund and run to another parts store and the lady brings out one in a Borg Warner box. I plug my vac tester up and this one won't hold vac either.
So now I leave and start thinking that maybe these are temp sensitive? I've never heard of such a thing.
I hit up 3 more stores and no one has one and then the 4th try they don't have one either but the guy says that some GM EGR valves need back pressure to hold vac.
What!
Is this right?
I've never heard of this.
Run back to the store the kid pulls out another, and the same thing!
I ask the kid to bring me any EGR, he does and I hook up my vac tester and it hold vac fine and opens right up.
Another counter kid there says "Your not supposed to test those with a hand pump!" I ask him what he's talking about, and he answers the phone and ignors me.
I get a refund and run to another parts store and the lady brings out one in a Borg Warner box. I plug my vac tester up and this one won't hold vac either.
So now I leave and start thinking that maybe these are temp sensitive? I've never heard of such a thing.
I hit up 3 more stores and no one has one and then the 4th try they don't have one either but the guy says that some GM EGR valves need back pressure to hold vac.
What!
Is this right?
I've never heard of this.
Racer
Joined: Oct 2002
Posts: 416
Likes: 2
From: Westfield MA
Originally Posted by Maximus9000
Went to Napa and picked up an EGR valve this morning, got home and decided to hook up my hand vac pump to the the EGR on the car again to make sure it wasn't holding vac as I saw last evening, and as last evening nothing. Put the vac pump on the new one and the same thing, won't hold vac, won't open.
Run back to the store the kid pulls out another, and the same thing!
I ask the kid to bring me any EGR, he does and I hook up my vac tester and it hold vac fine and opens right up.
Another counter kid there says "Your not supposed to test those with a hand pump!" I ask him what he's talking about, and he answers the phone and ignors me.
I get a refund and run to another parts store and the lady brings out one in a Borg Warner box. I plug my vac tester up and this one won't hold vac either.
So now I leave and start thinking that maybe these are temp sensitive? I've never heard of such a thing.
I hit up 3 more stores and no one has one and then the 4th try they don't have one either but the guy says that some GM EGR valves need back pressure to hold vac.
What!
Is this right?
I've never heard of this.
Run back to the store the kid pulls out another, and the same thing!
I ask the kid to bring me any EGR, he does and I hook up my vac tester and it hold vac fine and opens right up.
Another counter kid there says "Your not supposed to test those with a hand pump!" I ask him what he's talking about, and he answers the phone and ignors me.
I get a refund and run to another parts store and the lady brings out one in a Borg Warner box. I plug my vac tester up and this one won't hold vac either.
So now I leave and start thinking that maybe these are temp sensitive? I've never heard of such a thing.
I hit up 3 more stores and no one has one and then the 4th try they don't have one either but the guy says that some GM EGR valves need back pressure to hold vac.
What!
Is this right?
I've never heard of this.
Race Director
Joined: Sep 2003
Posts: 16,838
Likes: 341
From: Database Error Indiana
EGR does have its own temp sensor of sorts. It screws into the EGR pipe near the distributor and senses exhaust temp. I doubt this has anything to do with the situation you have though. 
1st Gear
Joined: Jun 2006
Posts: 1
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I'am not sure what sensors your car is equipped with since I have had only third generation cars, however the pinging problem on a 4-cly Ford ranger drove me crazy for several years-NO CODES-ran good in cool weather ect....A friend who works for a Ford dealership even ran a computor update with no success-so after running HIGH TEST GAS for the past year, I read a article on how MAF senors can become dirty and can be cleaned by simply spraying them with electrical cleaner- IT WORKED no more pinging. If your car uses this sensor give it a try-CHEAP FIX!!! good luck.
Le Mans Master
Joined: Oct 2003
Posts: 6,130
Likes: 2
From: seattle WA
Trying to recall my long term memory 
but I've had my 87 for 7 years now,and it seems to me shortyly after owning it I recall some pinging. Well, then I would have the SES light come on....then go off, an itermittent thing, but I pulled the codes and found a code 32 EGR.
I had been on the forum for just a short time, but had read several posts that said 95% of the time it was caused by the EGR switch..so, I replaced it, that took care of the code and I believe the pinging. Other than that I advanced my timing to 8*, mine seems to like that better than 6*. As far as vacumn goes the FSM gives a detailed outline on how to check it.Rather drawn out and I don't know how to post it...but you might want to email Agent 86, nice guys and always post these type of things for others.
but I've had my 87 for 7 years now,and it seems to me shortyly after owning it I recall some pinging. Well, then I would have the SES light come on....then go off, an itermittent thing, but I pulled the codes and found a code 32 EGR.I had been on the forum for just a short time, but had read several posts that said 95% of the time it was caused by the EGR switch..so, I replaced it, that took care of the code and I believe the pinging. Other than that I advanced my timing to 8*, mine seems to like that better than 6*. As far as vacumn goes the FSM gives a detailed outline on how to check it.Rather drawn out and I don't know how to post it...but you might want to email Agent 86, nice guys and always post these type of things for others.
Thread Starter
Instructor
Joined: Jun 2002
Posts: 231
Likes: 0
From: 80/680 junction Ca.
Originally Posted by lhaslup
I'am not sure what sensors your car is equipped with since I have had only third generation cars, however the pinging problem on a 4-cly Ford ranger drove me crazy for several years-NO CODES-ran good in cool weather ect....A friend who works for a Ford dealership even ran a computor update with no success-so after running HIGH TEST GAS for the past year, I read a article on how MAF senors can become dirty and can be cleaned by simply spraying them with electrical cleaner- IT WORKED no more pinging. If your car uses this sensor give it a try-CHEAP FIX!!! good luck.
Originally Posted by SS409 425HP
1987 used a "negative backpressure" EGR valve. Do a Google search on negative backpressure EGR valve and you'll get lots of info on how it functions.
When it's cool I can accelerate without any pinging and grab a big tire bark when shifting into second. Just replaced the thermostat with a 160* but the radiator still can't keep up in 90* weather, running between 200* and 230* with both fans on constantly (I installed a bypass ground switch), it has an Edelbrock water pump also. It will actually get below 200 when sitting at an Idle. Still too hot to run right. Maybe time for a Dewitts?
Originally Posted by Spankyellow
EGR does have its own temp sensor of sorts. It screws into the EGR pipe near the distributor and senses exhaust temp. I doubt this has anything to do with the situation you have though.
I should have left it alone this weekend because it seemed like it was running better before I fiddled with it.
Thread Starter
Instructor
Joined: Jun 2002
Posts: 231
Likes: 0
From: 80/680 junction Ca.
Originally Posted by lhaslup
I'am not sure what sensors your car is equipped with since I have had only third generation cars, however the pinging problem on a 4-cly Ford ranger drove me crazy for several years-NO CODES-ran good in cool weather ect....A friend who works for a Ford dealership even ran a computor update with no success-so after running HIGH TEST GAS for the past year, I read a article on how MAF senors can become dirty and can be cleaned by simply spraying them with electrical cleaner- IT WORKED no more pinging. If your car uses this sensor give it a try-CHEAP FIX!!! good luck.
Just pulled the MAF and it looks pretty dirty. I don't know if today is a good day to find electric contact cleaner, but I will clean this thing up soon and see what happens.
Instructor
Joined: Dec 2003
Posts: 103
Likes: 0
From: Stockton CA
K&N and dirty MAF
OK "you all" I am really in CA., I have the post a few above this one with a nasty ping. I have a 96 LT4 done every thing but this dirty MAF with my K&N filter has some "ditto". Go to Kragen, I will go to my shelf in may garage and get some electric contact cleaner, I am going to pull the MAF and clean that puppy and see if what you have mentioned below "rings the bell" Thanks for the input even thought this is not my thread!!!!
