Last night I checked the ohms for both the wiring harness and the knock sensor.
Wiring harness: 558Knock sensor: 557
Wiring harness was checked while it was connected to the ks, and the ks was checked without the harness connected. (obviously) One connector on the harness gave no readout, while the other jumped all over the place until it settled in at 558. According to another post on this site, that's exactly what should happen because I hit the correct pole.
When I re-connected the ks to the ECU, the car still ran like garbage. I loosened the bolt on the ks because my neighbor said it was way beyond 15lbs of torque. He said that 15lbs is just over hand tight.
When I re-connected the resistor to the ECU, the car ran like a champ.
Any suggestions? It seems as though I'm doing everything right, but missing one thing.
knock sensor ohm test
Re: knock sensor ohm test (mej30guy)
If you measure the resistance between the two leads of your 500 ohm resistor, it should be somewhere near 500 ohms (probably +/- 1% or 5%) and resistors are not directional/affected by polarity. Think of the KS as a replacement resistor. With the sub-harness connected to the KS, but not to the Main harness, have you simply checked resistance between the two open pegs on the end of the connector?
Modified by GerryO at 10:01 AM 9/30/2008
Modified by GerryO at 10:01 AM 9/30/2008
Re: knock sensor ohm test (GerryO)
No I didn't. Do I just lay the lead from the ohm meter across the 2 connectors of the harness? What kind of readout should I be looking for? And if I don't get the one I should, does that mean I have a bad sensor?
Oy! The resistor I'm using is a 1megohm 1/2 watt.
Modified by mej30guy at 9:52 AM 9/30/2008
Oy! The resistor I'm using is a 1megohm 1/2 watt.
Modified by mej30guy at 9:52 AM 9/30/2008
Re: knock sensor ohm test (mej30guy)
OK, I see what you've done and why, based on these instructions that I found on-line:
To test the Knock Sensor:
1) Disconnect knock sensor harness connector. 2) Check resistance between terminal 2 (the one on the left) and ground. It should be approximately 500 - 620 k Ohms at 25° C (77° F)
It is necessary to use an ohmmeter which can measure more than 10 M Ohms.
You might need to confirm that both terminals of the KS are isolated from ground, just like in the case of the resistor? As a test try connecting the KS without it bolted to/contacting the engine?
There is no conductive copper lubricant where it doesn't belong?
To test the Knock Sensor:
1) Disconnect knock sensor harness connector. 2) Check resistance between terminal 2 (the one on the left) and ground. It should be approximately 500 - 620 k Ohms at 25° C (77° F)
It is necessary to use an ohmmeter which can measure more than 10 M Ohms.
You might need to confirm that both terminals of the KS are isolated from ground, just like in the case of the resistor? As a test try connecting the KS without it bolted to/contacting the engine?
There is no conductive copper lubricant where it doesn't belong?
Re: knock sensor ohm test (GerryO)
When I test the ks, I'll just hold it by the edges in my hand.
What kind of a reading am I looking for to know whether it's good or not? Is it grounding itself out somewhere?
Also, where is the best place to relocate it? No place I've tried has had any success.
The lubricant is just on the bottom contact area. The last time I tried the ks with poor results, I hooked it up without any lubricant is case that was a problem. Where shouldn't it be?
What kind of a reading am I looking for to know whether it's good or not? Is it grounding itself out somewhere?
Also, where is the best place to relocate it? No place I've tried has had any success.
The lubricant is just on the bottom contact area. The last time I tried the ks with poor results, I hooked it up without any lubricant is case that was a problem. Where shouldn't it be?
Re: knock sensor ohm test (mej30guy)
Read this:
http://www.wellsmfgcorp.com/pd....pdf
especially the part about installing them in their as-received condition.
Mechanically you want the KS to be able to detect vibrations (securely mounted to the engine) and electrically you want it to affect voltages communicated to the ECM similar to what the resistor is doing, and provided that the engine isn't knocking.
Modified by GerryO at 9:27 PM 9/30/2008
http://www.wellsmfgcorp.com/pd....pdf
especially the part about installing them in their as-received condition.
Mechanically you want the KS to be able to detect vibrations (securely mounted to the engine) and electrically you want it to affect voltages communicated to the ECM similar to what the resistor is doing, and provided that the engine isn't knocking.
Modified by GerryO at 9:27 PM 9/30/2008
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yodawill2000
- Posts: 3888
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- Car: 94 Infiniti J30
- Location: Grand Prairie TEXAS
Re: (yodawill2000)
Yodawill2000- I hope the family is better than ever, and soon.
Wish I'd known more about the KS when I had the plenum and EGR valve both off of the engine a while back. It looks like it may have been accessible at the time.
Wish I'd known more about the KS when I had the plenum and EGR valve both off of the engine a while back. It looks like it may have been accessible at the time.
Re: (GerryO)
I hope that's the stock location. I can't imagine me having to put it there!
Anyway, last night I was again checking the ohms on the ks and the harness. Both checked out fine. (557 and 558) But I did notice something strange. The wiring harness has 2 pins on one end that insert into the lead going to the ECU. The other end of the harness has only one slot in which to insert the 2 pins from the ks. Is this right? One side has the little metal clip that sits tight against the pin, and the other has just a hole in the plastic where the pin should be. Do I have a faulty harness?
I would think that if the harness was missing a metal clip for one pole of the ks, the circuit would not be complete. Therefore not sending the proper signal to the ECU.
Please say that this is my problem. Otherwise, I am completely stumped as to why this isn't working.
Anyway, last night I was again checking the ohms on the ks and the harness. Both checked out fine. (557 and 558) But I did notice something strange. The wiring harness has 2 pins on one end that insert into the lead going to the ECU. The other end of the harness has only one slot in which to insert the 2 pins from the ks. Is this right? One side has the little metal clip that sits tight against the pin, and the other has just a hole in the plastic where the pin should be. Do I have a faulty harness?
I would think that if the harness was missing a metal clip for one pole of the ks, the circuit would not be complete. Therefore not sending the proper signal to the ECU.
Please say that this is my problem. Otherwise, I am completely stumped as to why this isn't working.
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Q45tech
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1995 G20t 5 speed 334,000 miles 16" 2002 wheels - 205/50/16 Sr20ve vvl
Re: (mej30guy)
The plastic KS housing is VERY temperature sensitive [plastic cracks, resistance and sensitivity curve changes]. It was designed this way so replacement would be required when cylinder head became overheated-------AS A WARNING to techs to analyse more things.
The max limit is 300F and even 250F will crack after years and years.
My feeling is just like plugs, the KS should be replaced periodically.
We must do a few hundred per year between 3 shops.
The max limit is 300F and even 250F will crack after years and years.
My feeling is just like plugs, the KS should be replaced periodically.
We must do a few hundred per year between 3 shops.
Re: (Q45tech)
But are the harnesses missing what I've described? If so, how is the circuit completed?
Re: (mej30guy)
Check for continuity between the unused termial on the KS and ground/one of the exposed metal surfaces on the KS that is in contact with the engine or the mounting bolt that runs through its' center. The unused pin is probably just a ground connection and "one side" of the KS is otherwise grounded by contact.mej30guy wrote:But are the harnesses missing what I've described? If so, how is the circuit completed?
The other pin should probably slip into the little metal clip, not just sit tight against it, and there's no chance of connecting things the opposite way?
Are connections to the Main/ECM harness OK on the other end and how did you attach the resistor when you had it in place?
Best of luck! You are so close!
Re: (GerryO)
Wow! Love the info.
I figured that it was a grounding issue because when I did the ohm test, it took a little moving around of the ks on the block to get a consistent readout.
The resistor is tight inside the female clips of the ECU harness, and the ks end of the sub harness looks like it can only attach one way. The ks pin is tight inside its opposing clip. It was the fact that one side of the sub harness had a good clip and the other had nothing that freaked me out.
One other thing. Should I check the bottom of the ks to see if the surface is flush? There may be a spot on my ks where the housing is a little lower than the contact surface and covers a small part of the copper ring. Can that be fine grit sanded so it's flush without any damage?
I figured that it was a grounding issue because when I did the ohm test, it took a little moving around of the ks on the block to get a consistent readout.
The resistor is tight inside the female clips of the ECU harness, and the ks end of the sub harness looks like it can only attach one way. The ks pin is tight inside its opposing clip. It was the fact that one side of the sub harness had a good clip and the other had nothing that freaked me out.
One other thing. Should I check the bottom of the ks to see if the surface is flush? There may be a spot on my ks where the housing is a little lower than the contact surface and covers a small part of the copper ring. Can that be fine grit sanded so it's flush without any damage?
Re: (yodawill2000)
yodawill2000
Please try to check this weekend where the best place would be. I'm currently running it on the resistor bypass and don't want to do that any longer than I have to.
Remember, I'm not that bright so please try to be as simple yet specific as possible. I have blown up the pitcure of the entire j30 engine that jertapper posted a while ago. It's the one looking in from the front, with the engine cover still on it. Maybe you can use that as a reference.
Thanks in advance. I'm so close to getting this thing licked thanks to you all.
PS Do you have a good brisket/beef rub recipe?
Please try to check this weekend where the best place would be. I'm currently running it on the resistor bypass and don't want to do that any longer than I have to.
Remember, I'm not that bright so please try to be as simple yet specific as possible. I have blown up the pitcure of the entire j30 engine that jertapper posted a while ago. It's the one looking in from the front, with the engine cover still on it. Maybe you can use that as a reference.
Thanks in advance. I'm so close to getting this thing licked thanks to you all.
PS Do you have a good brisket/beef rub recipe?
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yodawill2000
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Funny you should ask !!!I'm famous round here for my Brisket.I'll post the rub here shortly
for each pound of Brisket
1/2 tsp cumin " Granulated Garlic " Salt " Chili Powder " Corn Starch1/4 tsp Black Pepper
Rub 2/3 on Fat side, and 1/3 on meat sideChar on medium Coals 10-30 mins or until dark and crusty
Wrap in foilput in oven at 200 degree's cook one hour per pound fat side up.Save the Juice that it Renders . Fantastic to pour over the meat after slicing.Be sure and put the foil wrapped Meat in a deep pan because it will render a WHOLE lot of A Jue'
It will make you tongue slap yer forehead !!!
Modified by yodawill2000 at 8:23 AM 10/3/2008
Modified by yodawill2000 at 8:43 AM 10/3/2008
for each pound of Brisket
1/2 tsp cumin " Granulated Garlic " Salt " Chili Powder " Corn Starch1/4 tsp Black Pepper
Rub 2/3 on Fat side, and 1/3 on meat sideChar on medium Coals 10-30 mins or until dark and crusty
Wrap in foilput in oven at 200 degree's cook one hour per pound fat side up.Save the Juice that it Renders . Fantastic to pour over the meat after slicing.Be sure and put the foil wrapped Meat in a deep pan because it will render a WHOLE lot of A Jue'
It will make you tongue slap yer forehead !!!
Modified by yodawill2000 at 8:23 AM 10/3/2008
Modified by yodawill2000 at 8:43 AM 10/3/2008
Re: (yodawill2000)
Who loves ya!!!
Thanks. Hopefully this will work as a steak rub as well. We can't get any real brisket up here, just that flat crap. But this method should work well with it because of the foil wrap to keep it tender.
My daughter went to UT-Nebraska last year and called me from Rudy's. (she's a brisket freak) I was in heaven, she didn't have a clue. Too bad I didn't have a "smell-o-phone."
Thanks. Hopefully this will work as a steak rub as well. We can't get any real brisket up here, just that flat crap. But this method should work well with it because of the foil wrap to keep it tender.
My daughter went to UT-Nebraska last year and called me from Rudy's. (she's a brisket freak) I was in heaven, she didn't have a clue. Too bad I didn't have a "smell-o-phone."
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yodawill2000
- Posts: 3888
- Joined: Thu Mar 24, 2005 4:10 pm
- Car: 94 Infiniti J30
- Location: Grand Prairie TEXAS
Re: (yodawill2000)
I do the same thing with my guy, only with pulled pork and back ribs. Do you think I get a deal on the meat after doing that a few times?
You betcha!!!
He's got a great little butcher counter in the back of his corner convenience store. His rib eyes are so good, they'll rip your face off! That's why I need a good steak rub too.
You betcha!!!
He's got a great little butcher counter in the back of his corner convenience store. His rib eyes are so good, they'll rip your face off! That's why I need a good steak rub too.
Re: (mej30guy)
OK, I've passed the rub recipe along to my brother Bob. I'll let you know if he gives it a try or if he knows of or uses something similar.
200 deg for one hour? Putting it on top of my J30 engine before taking a one hour drive should about do it...
Thanks!
200 deg for one hour? Putting it on top of my J30 engine before taking a one hour drive should about do it...
Thanks!
Re: (GerryO)
I'm sorry if this thread has morphed into something out of Rachel Rae, but when I saw the man was from Texas, I couldn't resist!
About my knock sensor grounding. Can I sand the bottom of it with 220 or higher grit, to get the surface even? Like I said, it looks like a little of the ks casing has overlapped the contact area. (the little copper ring around the surface) Maybe that's why I'm not getting a consistent ground.
And yoda, don't forget to look for the best spot to place this thing. I'd love to get this wrapped up. And I'm sure you guys would too!
About my knock sensor grounding. Can I sand the bottom of it with 220 or higher grit, to get the surface even? Like I said, it looks like a little of the ks casing has overlapped the contact area. (the little copper ring around the surface) Maybe that's why I'm not getting a consistent ground.
And yoda, don't forget to look for the best spot to place this thing. I'd love to get this wrapped up. And I'm sure you guys would too!
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yodawill2000
- Posts: 3888
- Joined: Thu Mar 24, 2005 4:10 pm
- Car: 94 Infiniti J30
- Location: Grand Prairie TEXAS
Re: (mej30guy)
I'm both sorry and happy to report that I don't have as much first-hand knowledge of the KS I'd like to have in this case, as mine hasn't failed...yet.mej30guy wrote:About my knock sensor grounding. Can I sand the bottom of it with 220 or higher grit, to get the surface even? Like I said, it looks like a little of the ks casing has overlapped the contact area. (the little copper ring around the surface) Maybe that's why I'm not getting a consistent ground.
We should still determine what KS terminals/outer contact areas are connected to which and I am puzzled why the instructions don't simply call for checking the resistance between the two terminals, if in fact one of them is connected to ground/the other contact areas. I'm not sure if the Piezoelectric element can be damaged by too much voltage. Also, the center/brass mounting opening that a bolt runs through is clean, right?
Also, have you measured the resistance of your old unit that's still connected to your old sub-harness? Does an infinite resistance reading/open circuit indicate a bad KS or sub-harness? It would also be good to know that the terminals on all of the connectors are matching up correctly too. Since there's only one clip in the end of the sub-harness, is it connecting to the terminal that's yielding the good resistance reading?
Re: (GerryO)
The old unit did not register. It was deader than Elvis.
As far as the sub harness is concerned, it looks like there is only one way it fits onto the ks so that pain in the @$$ little wire clip thing fits around the end of the harness to help secure the end of the ks. Fear not, I'll try it again with the harness reversed at the ks.
I would think that the live ks terminal should insert into the femal end of the subharness with the metal clip, and not into the empty side.
As far as the sub harness is concerned, it looks like there is only one way it fits onto the ks so that pain in the @$$ little wire clip thing fits around the end of the harness to help secure the end of the ks. Fear not, I'll try it again with the harness reversed at the ks.
I would think that the live ks terminal should insert into the femal end of the subharness with the metal clip, and not into the empty side.
Re: (mej30guy)
It certainly should.mej30guy wrote:I would think that the live ks terminal should insert into the femal end of the subharness with the metal clip, and not into the empty side.
Re: (GerryO)
I finally got back to my ks issue last night after a weekend of body work on my truck.
It only hooks to the sub harness one way, so it can't be screwed up. I tried placing it on the ground contact where the ground strap is connected, between the infinity logo on the engine cover, and the cross over tubes. I relocated the original ground strap to another spot, cleaned and sanded the contact area, and tightened the ks.
When I took a test drive, I was amazed at the performance. Just like new! About 10 minutes later, no more new. It reverted back to running like crap. My guess is, again, a grounding problem.
Tonight I'm going to have the kid next door bring over his ohm meter and do the following. We'll leave the ks on the same spot without the harness, and move it around until we get a good reading on the ohm meter. That's where it will be secured. Then we'll connect the sub harness and take another reading. If both readings are within the 500-600 ohm range, I would think we'll have a good contact and be ready to go.
One other thing. The new grounding spot is only 6mm, where the ks is 10mm. could that be a problem? There are no 10mm holes in the block, the biggest being 8mm.
Frustrating!
It only hooks to the sub harness one way, so it can't be screwed up. I tried placing it on the ground contact where the ground strap is connected, between the infinity logo on the engine cover, and the cross over tubes. I relocated the original ground strap to another spot, cleaned and sanded the contact area, and tightened the ks.
When I took a test drive, I was amazed at the performance. Just like new! About 10 minutes later, no more new. It reverted back to running like crap. My guess is, again, a grounding problem.
Tonight I'm going to have the kid next door bring over his ohm meter and do the following. We'll leave the ks on the same spot without the harness, and move it around until we get a good reading on the ohm meter. That's where it will be secured. Then we'll connect the sub harness and take another reading. If both readings are within the 500-600 ohm range, I would think we'll have a good contact and be ready to go.
One other thing. The new grounding spot is only 6mm, where the ks is 10mm. could that be a problem? There are no 10mm holes in the block, the biggest being 8mm.
Frustrating!
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