Testing coils on a coil over plug system?

[Pat Cook]

Art, is this a speed density or mass air system?

[art leong]

Originally Posted by Pat Cook

Art, is this a speed density or mass air system?

Pat I believe it is Alpha N


I think (HOPE) I found the problem. I took off the cam sensor to check an see if the magnetic was still there and didn't move. When I put it back and tried the test the coils.
I had no spark at all from the coils. through the tester. I noticed the light was off I rechecked the connection and it was tight. I put 12 volts to the sensor and the light remained off. It is normally on when the ignition is on, when the motor spins it flashes.
I just ordered a new one I should have it Wednesday. I hope I still have circulation in my body by then. Because I'm crossing my legs, arms, and fingers that, that is the problem.

[Adger Smith]

Art,
Remember: It is always the last thing you check that fixes a problem.
OK you found one thing...
While you are all wound up with fingers, toes, arms, legs, ect, ect all crossed
It might help to un wind and go ahead and check the other sensors and the coils like you intended to do. :~)

[buzzinhalfdozen]

Art, most of those hall sensors will not tolerate 12 volts... most run on 5 or 8 volts. You may want to read back thru you instruction manual for your system.

[art leong]

Originally Posted by buzzinhalfdozen

Art, most of those hall sensors will not tolerate 12 volts... most run on 5 or 8 volts. You may want to read back thru you instruction manual for your system.

The MSD 2348 sensor is supposed to work on 8 to 18 volts. I was powering it with 8 volts.
I'm going to try it as is to make sure it's the cause of the problem. Then I plan to power it up with 12 volts.
I'm thinking using the bottom of the allowable voltage might not be the best for the sensor.
Am I right?

[buzzinhalfdozen]

Art, the sensor should work correctly using any voltage within it's operating range, in this case more is not realy a good thing. You can test this sensor very easily... take your volt meter hook into the sensor signal wire( the one sending voltage back to the ECU) hook other meter lead to ground. Power up system so sensor has power, next pass a metal object by the sensor, you should see the signal voltage "toggle" switch from 8 volts to 0 volts. I've found it's best to check this at the ECU to verify the signal is getting to the ECU. If you see no voltage switch at the ECU, next try the same test at the sensor connector, if you now see switching then you have a simple wiring issue between the 2 devices. Please try this test and let us know the results. By the way I also noticed that you need to set the "trigger pull up resistors" in your trigger1 and trigger2 sub menus, this is set correctly?Another consideration is the polarity of your crank sensor, being a VR type sensor you really need it wired correctly, I know from experience that they will work even if polarity is reversed however not correctly. To figure out the polarity requires the use of a "scope" unless of course the sensor supplier supplied this info to you.

[art leong]

Originally Posted by buzzinhalfdozen

Art, the sensor should work correctly using any voltage within it's operating range, in this case more is not realy a good thing. You can test this sensor very easily... take your volt meter hook into the sensor signal wire( the one sending voltage back to the ECU) hook other meter lead to ground. Power up system so sensor has power, next pass a metal object by the sensor, you should see the signal voltage "toggle" switch from 8 volts to 0 volts. I've found it's best to check this at the ECU to verify the signal is getting to the ECU. If you see no voltage switch at the ECU, next try the same test at the sensor connector, if you now see switching then you have a simple wiring issue between the 2 devices. Please try this test and let us know the results. By the way I also noticed that you need to set the "trigger pull up resistors" in your trigger1 and trigger2 sub menus, this is set correctly?Another consideration is the polarity of your crank sensor, being a VR type sensor you really need it wired correctly, I know from experience that they will work even if polarity is reversed however not correctly. To figure out the polarity requires the use of a "scope" unless of course the sensor supplier supplied this info to you.

Thanks. the polarity on the crank sensor was checked on a scope whe we put the system in. It was a 50/50 shot of getting it right. and I got it wrong.
The cam sensor I have now shows nothing when I pass a magnet past the eye. It shows no voltage when I connect the postive to my tester and the neg to the ground. Soo it seems shot.
I will check the lines leading to the sensor. But I think the sensor was the problem.
I do everthing by myself on the car and could not watch the light on the sensor and put it in gear alone. On hindsight I could have rigged up some mirrors like I do to see if the wheels are turning, when on the jackstands.
I'm going to get a spare crank sensor. Have it's polarity checked and put it on to make sure it works. The wiring from both sensors is shielded and not grouded seperately (it's grounded in the ECU). So it isn't an antenna.
I'm hoping the changes in vibration on the motor when putting a load on it caused the sensor to fail, then correct itself on restarting. When I jiggled the wires. I made the problem permanent instead of intermittant.
Is there any benefit to running 12 volts, from the on switch. Instead of the 8 volts from the ECU?

I want to thank all that have helped so far. My understanding of the entire engine control system has progressed a lot. The first year and a half my ECU was a mystical majic box. That I had no idea about anything to do with it. I made some attemps to tune it, but usually forgot to press the enter button or the save button. While there is still an awful lot I don't know about it. Now when I read the help section on my ECU I can understand a lot more.
Like when I was thinking about changing the voltage to the cam sensor. I went to the wiring diagram and didn't see a 12 volt supply (there are 5 and 8 volt supply's). I realized that the 12 volt positive going to the ECU could be used.
Sooner or later I'll learn.

And Adger. I'm keeping my limbs crossed till I get the sensor. But I will trouble shoot everything else that I can just to have some info to go on if I have another problem. Thanks.

[buzzinhalfdozen]

Art, you have my utmost respect on this most would have simply thrown in the towel. No one knows it all if they ever say they do you can call em a liar. Prolems such as what you're dealing with is what I do everday, however I find it more difficult to strategically diagnose it over the internet. I believe you have proven that you have a failed sensor, and I must apologize about comments made to disregard them all together, as most systems I work on only use them for starting purposes only.After googling your system and quickly reading some of it's operational characteristics I believe it requires a constant cam sync input. Good luck with this and let us know if the new sensor fixes your issue. Joe Oh almost forgot, I looked for your sensor part number2348 on MSD's website but could not find it with a number search, however if it's stated you can use between 8-14 volts then it wouldn't hurt to hook 12 volts to it I just don't think it will make any difference. By the way does your sensor have voltage when you crank it and when it's running cause I noticed the ECU is responsible for supply voltage? Just another thing to think about.

[art leong]

Originally Posted by buzzinhalfdozen

Art, yes hook up your meter and check the resistance, then switch meter to AC volts and crank the engine, you should see Approx. 1 volt AC give or take it depends on the cranking speed the faster it turns the higher the voltage. You said you moved some wires around... anything near the crank sensor or it's wiring? As I said these type sensors are quite sensitive to interference. By the way is this sensor shielded? Also as Ed stated there's no real replacement for proper diagnsis, I realize not everyone has a scope on hand... however by simply replacing a part you could be missing many things, poor connections broken wires ect. that's why that strategy sometimes back fires on people. We see alot of vehicles from other shops that have had large amounts of parts hung only to find simple wiring issues as the source of the problem. We have alot of customers balk at our charge to diag. their veh. however with a proper diagnosis a sucessful repair is almost guaranteed.

Back to square one.
I checked the coils they are all able to jump the gap at 40K the spark doesn't look very healthy to me but I don't have anything to compare it with.
I checked the voltage across the crank pickup and on my volt meter set on ac I get .4 volts with the starter turning the motor. I have a 20 tooth wheel on the crank. I triple checked the timing, Put a new cam position sensor on.
And I still have the problem

[buzzinhalfdozen]

Art, I'll assume the cam sync lite blinks now? Do you mean it still doesn't start, or it starts and stalls when put into gear? I'd say if the coil is capable of jumping at 40,000 volts it's sufficient. So we're back to the basics, Air, Fuel, Spark. Perhaps we could try this test, hook your meter to the wires crank sensor wires @ the ECU, assuming the engine starts, set to AC voltage and start engine if possible raise RPM, the voltage should increase with rpm. The .4 volts AC seems pretty low to me however I'm sure different sensors can produce varying amounts of voltage. IF in fact the engine does start now you must have at least some trigger input to the ECU.By the way what supply voltage did you decide on for the cam sync? Also how much timing do you have ?