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Speed/ reference sensor gapping

I am trying to get my car starting, but I am having some doubts. I know that the Speed sensor (rear sensor closest to firewall) has to be a .8mm gap. I beleive that I have that. The reference sensor doesnt have a spec, correct? I had a stripped mounting bolt,so I had to play surgery on my car in the summer. I had to drill from the engine side through the wall and drill the mounting bolt out. I didnt drill a perfect tunnel to the bolt, and I think that the mounting bolt right now isnt lined up as it was originally, but it is very close, if not the same as it was. This is just a thought. Just wondering if the refernce sensor had to be within a certain gap-spacing range. I have a tool and old sensors to get the .08 gap for the speed sensor, but if the mounting bolt isnt lined up right, that could lead to having the speed sensor at an angle where only part of the speed sensor is at a gap of .8.

Future Reference: Talking about speed and reference sensors.
"The factory spec is .8mm +/- .3mm, so anywhere between .5 and 1.1mm is ok. maybe find yourself a 1mm washer and barely tap on the bracket afterwards" Rennlist member- V2Rocket_aka944

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Last edited by thekidd; 11-28-2009 at 06:12 PM..
Old 11-28-2009, 01:09 PM
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I think they are the same gap. also use a scope if you can get your hands on one. Not sure if angle will matter , it may
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Old 11-28-2009, 03:53 PM
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OK thanks. I dont think that mine are the same gap. I measured the (front) reference sensor (with a screwdriver) from the top of the bracket to the flywheel (I think thats whats down there). Stuck the screwdriver down as far as it could go and put my thumb at the top of the bracket. I then took my gapping tool (an aluminum shaft the size of a sensor) and put it up to my thumb and screwdriver. The speed sensor (rear sensor toward the firewall) was gapped with the tool. There was some good difference, Id say between 1/2'' to 3/4'' between the size of the tool and to the point where my thumb was on the screwdriver. I have more space between the reference (front engine side) sensor than I do the speed sensor (rear sensor). You might be right that they both have to be .8mm, but she runs. Thats right, SHE RUNS! Ill give it a month or so and let you know if the spaceing matters.
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Old 11-28-2009, 08:53 PM
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I need to revive this thread with the same question re: reference sensor gap.

The positioning pin is threaded, so is it adjusted inward and outward? I have the .8mm gap in the speed sensor, but have an intermittant problem of unstable idle and hard starting. Also, sometimes the fuel pump runs with the key in the "run" position with the engine not running. The fuel pump/dme relay is not supposed to receive power from the DME unless the DME is getting a signal from the reference sensor. So, I'm wondering if my reference sensor is sending a weird signal to the DME.

I have a spare, new DME. I tried it, and same thing. Also, sometimes the engine cranks more before it starts. Weird.
Old 02-06-2011, 08:23 PM
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Quote:
Originally Posted by rusnak View Post
I need to revive this thread with the same question re: reference sensor gap.

The positioning pin is threaded, so is it adjusted inward and outward? I have the .8mm gap in the speed sensor, but have an intermittant problem of unstable idle and hard starting. Also, sometimes the fuel pump runs with the key in the "run" position with the engine not running. The fuel pump/dme relay is not supposed to receive power from the DME unless the DME is getting a signal from the reference sensor. So, I'm wondering if my reference sensor is sending a weird signal to the DME.

I have a spare, new DME. I tried it, and same thing. Also, sometimes the engine cranks more before it starts. Weird.
Do you mean the pin in the flywheel?
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Old 02-07-2011, 05:49 AM
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Maybe...

This stud can only be loosened by heat/propane torch---super Permatex used




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Old 02-07-2011, 07:00 AM
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rusnak,when you adjust your gap you dont touch the pin, you loosen the bolts on the bracket and one of the bolt holes is slotted allowing it to raise and lower. When you gap the rear sensor the front one automatically is set correctly
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Old 02-07-2011, 07:52 AM
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That's what I thought too, so I left the reference sensor alone.

I checked and set the speed sensor gap to .8mm measured with a feeler gauge.

I noticed that this gap is substantially smaller than the old gap with the old sensors. The car was running great before. If I remove the sensor holder, can I measure the height of the reference pin?
Old 02-07-2011, 10:35 AM
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Quote:
Originally Posted by rusnak View Post
That's what I thought too, so I left the reference sensor alone.

I checked and set the speed sensor gap to .8mm measured with a feeler gauge.

I noticed that this gap is substantially smaller than the old gap with the old sensors. The car was running great before. If I remove the sensor holder, can I measure the height of the reference pin?
Yes, but I didn't think the pin was adjustable. I see the drawing and it clearly says adjust to 5 mm, but I think that is just a indication of how much it "should" stick up. IMO..... others here may have more input regarding this.
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Old 02-07-2011, 11:31 AM
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Quote:
Originally Posted by rusnak View Post

I noticed that this gap is substantially smaller than the old gap with the old sensors. The car was running great before. If I remove the sensor holder, can I measure the height of the reference pin?
Make sure you have the spacer washer on the rear most sensor..

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Old 02-07-2011, 11:40 AM
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spacer washer?? omg that's a new one. Now I have to go back to PET.

Today:

The car would not start. So, I get my old sensor out, plug it in to the reference sensor harness, and pulse the old sensor against the fender while running the starter with a remote starter button. Bingo, car runs perfectly.

So, I'm thinking I had either a bad sensor (not likely, brand new) or there is something wrong with the sensor spacing or perhaps the reference bolt is somehow not magnetic.

I'm going to take the sensor holder out, and bump the flywheel around until I can see the flywheel sensor bolt. If it's not magnetic, then that's the problem.

Does anyone know why the fuel pump would run with the key in the "run" position? It's not supposed to run, and the dme relay not energized, unless there is a signal from the dme reference sensor. But the dme relay is energized with the key in "run" and the engine stopped.
Old 02-07-2011, 03:41 PM
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It turns out the new flywheel came with a non-ferrous bolt. There was no way the car was going to start. Time to put the old reference sensor bolt in there and start it up.



Old 02-07-2011, 08:03 PM
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Rusnak,

Where does that pan head bolt go??

I am either very tired or completely confused.

I thought we were talking about the flywheel stud that is magnetic and is used by the sensors-----3 total Part 23 in photo

I am only familiar with the use of 3 "studs" on the flywheel---not the old sensor bolt in your photo

Pelican Parts - Product Information: OEM-477105276

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Old 02-07-2011, 08:44 PM
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