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Can you have spark with bad crank sensor?

51K views 36 replies 8 participants last post by  aerhed 
#1 ·
Is it possible to have either a profile ignition pickup (P.I.P.) on your distributer or a crankshaft sensor on your more modern engine that have failed yet still provide good spark? And does that basically amount to spark not occuring at the right time?
 
#2 ·
NO and NO. If the PIP is bad ,how could it signal to provide spark? If it is sparking , the PIP must be OK.
The ecm could provide spark at the wrong time, but while cranking the timing is at base timing through the ignition module,not the ECM. Also not likely to be your problem.

1: do you have hot blue spark while cranking the engine? Also have you verified Ignition timing?
2: Have you verified Fuel Pressure?
3: Have you performed a compression test?
 
#3 ·
of course i have the 3 things for start up thats why my focus has been on electronics and computer parts. its been put in time various times, fuel preassure is in specs. the problem is the car is acting like it cant tell i put it in time or something. both icm's pass their test at the store. i wasnt saying the PIP was blocking spark i was saying since it is a crank sensor maybe its not seeing my crank shaft in its actual position. and i know its not off the compression stroke either when i tdc it. it has no mechanical reason to be behaving like this. ive traced alot of wires and didnt see any damage either. two good ICMs, two good ECMs, new plugs, good wires, spark isnt orange, two good coils also. the best i could think was the ECM relay has gone bad but i cant even locate the relay unless its relay is in the main relay box above the engine fan. chain is new, old one really wasnt too bad honestly.

has to be something that appears to be working but isnt like maybe a weak coil or a sensor. again though i cant even run codes because my cel wont turn on anymore.
 
#6 ·
have you checked to see that the injectors are firing. If you have crank no start and everything is working the plugs should be soaked. Have you tried a little fuel in the TB. have you checked the fuel to make sure it is gas and not full of water.
 
#7 · (Edited)
One More Time - I remember you saying a guy at the Taurus website told you to move the dizzy, and you did, and said it ran one time then puked.
That tells me your timing chain either jumped, or the roll pin in the dizzy has sheared, and is catching in the right spot some times making it run.
Now you are saying there is no check engine light.
Have you checked for power at the ECM?
Have you checked Grounds to the ecm and the 2 little grounds at the batterynegative?
I have also seen ignition switches come apart, not powering up some of the circuits.
It sounds to me like you have a timing chain/distributor problem and have now developed an electrical issue as well.
Just because the check engine light doesn't come on , does not mean you have a bad ECM. If it has no power or a bad ground it may also not illuminate due to that.
Check the basics. Verify powers and grounds at THE ECM CONNECTOR.
Then check the roll pin in the dizzy as it may have sheared. I have seen that happen.
Also a 3.0 liter ( engine VIN "U") Overhead valve (pushrod motor) is not an interference engine. They have a sensor in the dizzy that is called the crank sensor.There technically is no cam sensor.
A crank and cam sensor will be used on a more sophisticated EFI ,that employs Sequential injection.Your old 3.0 doesn't use a "cam" sensor, and therefore is a "Batch fire" injection system
 
#13 ·
One More Time - I remember you saying a guy at the Taurus website told you to move the dizzy, and you did, and said it ran one time then puked.
Yes it ran good, well sufficient. After I drove it a few hundred feet then returned to my lot and parked I came back the next morning to the same issue. I put it back in time manually by turning the engine by hand, that got it to work two or 3 more times then after awhile that wouldnt even work. Even then I would label it an inconsistency because doing the exact same thing ten times might get 2 or 3 good results.
That tells me your timing chain either jumped, or the roll pin in the dizzy has sheared, and is catching in the right spot some times making it run.
Odly I got the most consistent cranks with the timing cover off which may just be a coincidence. But old chain was kinda decent, gap wasnt ridiculous but I just replaced it anyway so the chain is good. Both gears looked nice.
I am not sure what you mean by roll pin? The pin in the gear? How do I check to see if it rolls because everything seems tight and solid and not broken but I cant see how the gear acts once I place the dizzy back in I suppose.
Now you are saying there is no check engine light.
Have you checked for power at the ECM?
Have you checked Grounds to the ecm and the 2 little grounds at the batterynegative?
I have also seen ignition switches come apart, not powering up some of the circuits.
I started talking about the CEL due to me deciding I would try to use the paper clip to get some codes. Thats when i noticed the light not coming on anymore but actually dont know when it stopped lighting up period. I checked a few of the pins in the ribbon connector going into the ECM/ECU/PCM most came up good based on the numbers one site said they should be but that site clarified nothing in regards to what readings meant or what the pin hole pertained too so I'm not sure about those results.
I have not done the grounds test yet though.
It sounds to me like you have a timing chain/distributor problem and have now developed an electrical issue as well.
Just because the check engine light doesn't come on , does not mean you have a bad ECM. If it has no power or a bad ground it may also not illuminate due to that.
The head light dash lamp doesnt light up either so it might be bulb issues. I know that the coil, chain, ICM, Timing gears, injectors, fuel flow, compression, spark, are all activating. The only thing I havent done is look at the PIP sensor/crank sensor. I thought maybe a symptom of it being bad would be spark at the wrong moment skewing timing. I believe its one in the same as the hall effect sensor. Me changing the dizzy back the morning after itt ran did not fix anything again so maybe it is damaged where you said?
Check the basics. Verify powers and grounds at THE ECM CONNECTOR.
Then check the roll pin in the dizzy as it may have sheared. I have seen that happen.
Also a 3.0 liter ( engine VIN "U") Overhead valve (pushrod motor) is not an interference engine. They have a sensor in the dizzy that is called the crank sensor.There technically is no cam sensor.
A crank and cam sensor will be used on a more sophisticated EFI ,that employs Sequential injection.Your old 3.0 doesn't use a "cam" sensor, and therefore is a "Batch fire" injection system
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Again how obvious is the damage to the naked eye if the roll pin has sheared? i know it didnt have a counterpart to the cam sensor but confusion was created with multiple names for multiple parts then some people and sites calling the PIP a type of cam sensor or its forerunner. if i see that the dizzy isnt sheared and the ecm is grounded and connected then what? I have taken the liberty of buying a scan tool since the shop its at said some of my wiring splicing confused them even though it was just connecting three grounds wires directly too the battery ground instead of their old connector which done the same thing. When I tow it to my home I will investigate your ECM procedure.
 
#8 ·
Terminal 40 and 60 in the ECM connector will be grounds.
Terminal 1 will be Battery 12 volts with key off.
Terminal 37 and 57will be hot with the key on.This circuit powers through the EEC IV relay, be sure it "clicks" when turning the key on.The fuel pump relay will also cycle on at that time and will cycle back off after 2 seconds.That is the fuel pump prime circuit.Be sure they are working.
 
#9 ·
These are the 2 grounds I was talking about.They break out of the harness near the battery negative.They absolutely need to be connected to the ground terminal.
Check them well.If needed put a ring terminal on each and secure them under the nut/bolt on the negative cable
you can see someone has already cobbled these 2.
 

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#16 ·
I did not read through all of this but to answer the OP question. Yes you can have spark with a bad crank sensor. It happened to my 98 Tahoe with a Vortec engine. It had spark, blue spark too with a spark tester, but it would crank and crank and kick back like pull starting a gravely tractor and kicks back.I had 62 psi of fuel pressure so the fuel was good. The crank sensor was bad. There was a GM TSB on this as it gives the wrong reading to ECM and advances the timing to over 50 degrees. This could also cause starter and flywheel damage. Put the crank sensor in and it runs like new. Again, this was a GM.
 
#18 ·
I did not read through all of this but to answer the OP question. Yes you can have spark with a bad crank sensor. It happened to my 98 Tahoe with a Vortec engine. It had spark, blue spark too with a spark tester, but it would crank and crank and kick back like pull starting a gravely tractor and kicks back.I had 62 psi of fuel pressure so the fuel was good. The crank sensor was bad. There was a GM TSB on this as it gives the wrong reading to ECM and advances the timing to over 50 degrees. This could also cause starter and flywheel damage. Put the crank sensor in and it runs like new. Again, this was a GM.
While I wont dispute the plausibility of this on your GM, the OP has an 87 Taurus, with a 3.0 batch fire type injected motor with only a trigger wheel in the dizzy.
I guess it all comes down to how you define "Bad".
Intermittent signals from a crank sensor on the OP car could cause a backfire etc. I guess we all assumed "Bad " meant inoperative and not intermittent which is possible. Good post.:thumbup:
 
#20 ·
You have to determine if it is intermittent or completely bad. If you crank the engine and you have a spark then not and then again ..that is intermittent.
The PIP in the distributor can be intermittent as the module can also be.
But if that was the only issue, turning the distributor and getting it to run a while is not what your symptom would be.
If you have turned the distributor in the past and then it ran, but then it wouldn't restart without moving the distributor again, then you either have a timing chain problem or the distributor gear is spinning freely from the distributor shaft at times...ie: sheared roll pin. Not an intermittent crank sensor.
You may have a handful of issues making it very confusing for you.
I remember you said you had the timing cover off.Was the chain good?Replaced ?
 
#21 ·
like i said the chain had slack in it but it wasnt gap city or anything. I could line the marks up and not see the chain jump when it was turned over manually or by the engine running. none the less i replaced it just to get it out of the way so it has a new solid slack free chain on it. im certain my issue is timing i just wondered what created the timing issue. the only thing i could do before to get it running was mess with the dizzy or the crank pully to get results until even that stopped working. Again I ask you what am i looking for as far as a sheared pin? would that bhe a case of the gear going over the pin and moving freely, would the gear looked cracked, what am i visually looking for in my inspection?
 
#22 ·
Look around for a video on how to change the gear on the distributor.
You just need to use a small punch to move the pin to see if it the pin is intact. Just drive it out.If it is in one piece you are good to go. Put it back in,Then move on.
Chances are when you get to looking you may see a problem.
 
#25 ·
Why? Is your original distributor cracked or something. All that is in these are the hall effect/pickup/stator (all the same thing) and the module, cap and rotor of course. Be careful of aftermarket overseas distributors. Just use the factory ford dist. housing and knock the roll pin out of the gear, remove the gear (mark original location) and then pull the shaft out to get the stator out. Remove the stator, replace with new, reverse repeat. You may need to wd-40 the shaft a little when pulling it up. Putting the distributor in a vice with alum. jaws helps with this process.

Again, use motorcraft parts, module and stator. Replace them both. You are in there anyway.
T.J.
 
#29 ·
i finally got around to getting a new dizzy. i had began rebuilding my old one and had gotten a good new pick up installed and ran into too much trouble getting the gear off and then ordering a new one and finding a spacer. i retook the timing cover off ust to make sure the chain wasnt slipping and it looks good but now every spark plug period is weak. all orange and one barely sparked. They were blue when i had the old dizzy on them but i also had checked them months ago. im wondering if the "new" dizzy made them weak or if they just degraded naturally from sitting for 2 months? i put one of the plugs in my blazer and it wasnt missing or anything but the other 5 probably compensated for it too. im wondering with all 6 plugs conveniently faltering at the same time if i should just replace them all and see if that gets it cranked or what? i doubt looking at the coil or the plugs is really necessary again. iTS just all six at once?? and 4 or 5 of them are pretty fouled too, alot of black..
 
#31 ·
Maybe the issue has nothing to do with the distributor but more to do with you moving it . have you taken a good hard look at the wires surrounding the distributor both primary and secondary.
I am wondering if when you are turning the distributor you are moving a wire that has a bad connection or a short and allowing it to start. You didn't say what year it is but if it has a separate coil I would look at that wiring as well. The distributor triggers the coil and usually either it works or it doesn't if all power and grounds are tight and up to spec
 
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