Cranks but won't fire

ruswin

Registered User
Ok people, My 95 auto recently decided to quit again. I have recently removed my clogged cats and installed downtubes. Ran fine for a couple of days and then it just quit. Cranks fine, fuel pressure 40psi. Changed out the ignition coil module with one from my 93sc. I am suspecting that the ICM is NG. Unfortunately, the 93 and 95 years used different styles of ICMs. Is there any way to test the ICM? I also suspect that the cam or crank sensor is no good. Would either of them completely prevent the engine from starting? I have not changed either and the car has 110,000 miles.
:mad:

On a good note, my 90 aniversary SC just arrived, (now i have 3) and it looks and runs great, only has 52,000 miles.
:)

Any help will be appreciated... I love my SCs!

;)
 
a bad crank sensor will cause the car not to start. It could also be related to the dampner since the pickup point is located on the dampner. As far as I can recall the only thing the IRCM does on the 94 is the fuel pump relay, and since you have fuel pressure I don't think that would have anything to do with your no start condition.

Jeff
 
DIS or Crank Position Sensor.

If the upshift light flashes while the engine is cranking, it's telling you it's not getting a signal from the CPS.

The CPS can fail due to a failing balancer allowing the sensor to come into contact with the vane on the balancer.

The CPS may be good and their is a wiring issue.

The CPS may be good but the DIS is failing to function.

The DIS and CPS on the 95/94 cars is different than the 93 and earlier cars. It's actually called an "EDIS".
 
Thanks for the quick suggestions, here is some more feedback. The balancer seems to be OK, no movement. This is an auto trany, I don't see any upshift light? Am I missing something? I pulled a couple plugs, seems to have a spark, don't know if it is a timing issue. Atomized fuel was being blown out of the open spark plug hole when cranked. There does not seem to be any water in the oil. Headgaskets were replaced 1500 miles ago.

Now here is my biggest concern, all three of the plugs I pulled had a fresh coat of oil on them and they looked nasty will a heavy coat of carbon build up. Keep in mind this is a fresh block rebuild with less than 1500 miles on it. Here is some additional info from my teenage driver. And I quote, "I took it to school and parked it. When I was leaving, it started and I began to back up and it just died." When it was towed home, we began trying to figure out the problem. It cranks fine but doesn't even sputter. Once while cranking, it created a large backfire and coated my driveway with black oily residue that is still there after a week. One other thing we found that there was almost a full quart TOO much oil in her. I drained it down but I'm wondering if too much oil would cause it to flood the cylinders? What should I do next. I am starting to have a sinking feeling that it is not a simple ignition problem.
I broke my own rules letting my son take it to school... guess I'm not as smart as I thought I was. The last time he drove it was 6 months ago when the head gaskets blew. I excused that one cause it had over 110,000 on the originals and they were on their way out anyways. He may have beat on it a bit this time because it is a straight shot on the highway out here in rural AZ on the way to school. Would high speed high RPM cause oil to enter the cylinders? Is excessive oil enough to stop the sucker from firing at all? Would I even have a spark if either the crank or cam sensor was no good?
Come on SC people... HELP!
 
If the crank sensor is out it will not fire, if the cam sensor is out it will still run.

The upshift light is the yellow one with an arrow pointing up (in the tach).

Check to see if the Large bolt is in the middle of the dampner. Also look at the crank sensor and see if it is in line with the teeth on the dampner.

Jeff
 
It could be your ignition module went bad but keep in mind that these are about $525.00 from Ford and $410 from Napa. If it were me I would have some one run a code scanner on it before guessing. Could save a ton of money. I had 2 94`s that had fuel pumps go out early. Not totaly but enough to make the car run some of the time. Fuel pressure was fine on both but when I took them out you could tell from test runnig they were bad.
 
i had a problem like that. when u crank it do u smell gas but it still wont start? try turning the key on like ur going to start it but before u do press the gas petal all the way down then start it. if this works the mechanic that fixed mine said it was the temperature sensor and the cam sensor. i know he knows whats hes talking about cuz he comes highly recomended here in houston when it comes to thunderbirds.
 
ruswin said:
Ok people, My 95 auto recently decided to quit again. I have recently removed my clogged cats and installed downtubes. Ran fine for a couple of days and then it just quit. Cranks fine, fuel pressure 40psi. Changed out the ignition coil module with one from my 93sc. I am suspecting that the ICM is NG. Unfortunately, the 93 and 95 years used different styles of ICMs. Is there any way to test the ICM? I also suspect that the cam or crank sensor is no good. Would either of them completely prevent the engine from starting? I have not changed either and the car has 110,000 miles.
:mad:

On a good note, my 90 aniversary SC just arrived, (now i have 3) and it looks and runs great, only has 52,000 miles.
:)

Any help will be appreciated... I love my SCs!


;)

Here's any easy and FREE test you can try, so don't blow it off. Unplug your MAFS and try to start the car. If it starts then that means your MAFS is bad. If not, then you ruled out 1 more thing. Let me know what happens.
 
Disconenecting the MAF did not change anything. I still have to question why all of the plugs have fresh oil on them? I occasionally get a backfire out of her but that is it. Timing problem? How do I test?
I do not seee any upshift light on my 95 auto. Are they only used on the 5-speed? Otherwise, how can I check the function of the crank / cam sensors.
The HB bolt is in place and there is no "play" in the pulley. I can't see whether the crank sensor is lined up with the teeth on the gear, but I can't imagine why it wouldn't be.
If I am getting a spark, does that mean the ICM is working correctly? I may end up bring the car down to my local mechanic, I just don't think he knows as much as all you people here at the best car forum in the world. I just have to keep telling myself, I love my car, I love my car... Help?
 
Oil on the plugs is a sign of no spark. You will always get some oil in the combustion chamber when cranking but it's usually kept off the plug just from the sparking and then running.

I don't know the details of the EDIS system, but typically the Crank is one of the major inputs that prevents spark. Have you verified the lack of spark at all?

I'm not sure what you're calling a ICM. There is a ICRM (Integrated Control Relay Module) but that isn't involved in spark control. Really you're going to need to trouble shoot the no start condition following the Ford manual. You'll need a special sensor that can read the basic signals comming off the various sensors.

I jotted down this page that goes through the DIS no start condition on the earlier model SC's. It may help you a bit in trouble shooting yours.

Some other basics. Check the EDIS module, that I believe is mounted on the passenger fender, I think is also grounded via one of the screws that attaches it to the fender. Take each screw out and inspect it for corrusion, make sure the holes are all clean. You could have a bad ground.

If that's not it, verify you have a Crank signal being sent. If it's being sent and still no spark, then I'd have to point to the EDIS module. If you can find another similar car in town maybe than can swap modules with you.
 
I AM getting a spark, I just don't know if it is consistant. When I pulled a plug and rested it against the valve cover, I WAS getting a spark. I was saying ICM (ignition control module) I guess it is the EDIS module. Yes the module I am talking about is mounted to the passenger wheel well. I will pull the screws and make sure it is getting a good ground. The EDIS module on my 95 is different than the one on my 90 and 93. Is the EDIS I want the same for a standard 6 cylinder from 94-97 or is the SC module "special" like everything else on these cars?

What is the best way to test the crank sensor? It is a magnetic sensor that simply picks up the "notch" on the crank gear correct? Is there a point on the module that receives the signal that I could check with a multi-meter? It looks like a PITA to get to?

Thanks for trying, I appreciate it.
 
You can use a timing light to verify spark. If you have spark and fuel pressure but no fire, then you injectors must not be firing. Do you notice any fuel on the plugs? Basic small engine tech, if you have fuel, and you have spark, you're going to have ignition. If you don't have ignition and yet have all the others it could be an issue with timing, but typically you will get a backfire everyonce and a while if that's just it. Check the plugs for fuel. If no fuel, then it may be injector issue. That points to a cam sensor problem, or anything else that would prevent the injectors from firing. Other than the cam sensor, I'm not aware of what else might prevent the EEC from firing the injectors.

Here is a thread I made with a link to DIS trouble shooting for no start. But it's 89 through 93 specific. Some of it may apply to 94/95. Some may not. it describes how to make a tool to sense the signals from the DIS and crank sensor.

http://www.sccoa.com/forums/showthread.php?t=25523&highlight=DIS

I don't know about any LX modules. I didn't think they used the EDIS as it's specific to a V6. At least our EDIS module. Thus the only EDIS years for SC are 94 and 95.

The crank and cam sensor are Hall effect sensors which generate a voltage in relation to a magnetic field. The vanes in the stators that they sense against cause the magnetic field to fluctuate creating a voltage waveform. This isn't something a V/O meter is sufficiently sensitive to measure without influencing the measurement and possibly putting a voltage onto a circuit that could damage the circuit.
 
When I pulled one of the plugs, I had atomized fuel coming out in burst. Is it possible that for whatever reason only that one cylinder was getting fuel?
This is a frustrating problem because I seem to have spark and fuel but NO FIRE! I don't even get a sputter.

As for the sensors, the crank sensor being a hall effect switch should allow me to at least test whether or not it is turning ON and OFF or not. I realize I can't see it on a meter because of the high frequency of the square wave it would generate. Cant I stick a screwdriver in front of it when it is over the missing tooth and check it when it is just sitting there not cranking? If I knew what wires came up to the EEC or EDIS from the crank sensor, I should be able to check continuity right?

Thanks for the help, you obviously know these birds and a thing or two about electronics. Thanks Mike... and others.
 
Check whether your multimeter can measure frequency. Mine has a little button labelled Hz.
 
Yes, I have an Extech 380288. It can measure hz. Can you tell me where the best place to connect to the signal from the sensor? I will go look at the connector to the sensor. I guess I will need to leave the sensor connected (to 12vdc) and just check for frequency that way? What (hz) should I see when the car is cranking?
 
Cranking speed is 140-220 rpm.
Leave the sensor connected and check pin 4 (crankshaft sensor input) at the DIS (see attached pictures).
Connect the positive lead of the multimeter to pin 4 and the negative lead to ground - you won't get a frequency reading if you switch them. My Fluke multimeter needs to be set to measure DC volts and then the Hz button is pressed once (pressing it each time cycles between a few different functions).
 

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Keep in mind this is a 95, the DIS module does not look like the one in the drawings. It is mounted to the wheel well, not on top of the AC. It has a single connector. I have the Ford CD rom, I am trying to find the correct pins. You mentioned to check between the signal (pin4) and ground. Is ground and the sensor common the same?
 
The correct pin numbers from the crank sensor to the ICM on the 94-95 SC are #6 (pos) and #5 (com). When I crank the car with my meter connected to pin #6 and ground, I was getting around 94HZ. I would assume that the problem is NOT the crank sensor. I am begining to believe something else is affecting the timing, maybe the ICM itself? How can I test it? Too bad Ford had to change the design of the ICM between 93 and 94 cause I have two other SC that have the old style ICM.
 
Sorry about the mixup with the model year. How about checking the other signals - tachometer, ignition coil primaries, etc. (I don't know what exactly you have at the EDIS).
 
I think I may wait until tommorow and try to find a used module locally. Or I will bring it to a local mechanic for him to troubleshoot it. What a freakin PITA. I have owned this 95 for almost two years and it has run for a total of 4-months over two years. Hate to sell it though cause I have so much into it already. Keep fighting the good fight. Should I check the cam sensor function just for the hell of it? If you have any other ideas let me know.
 
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