Won't Start? Try This->

Mike8675309

Registered User
I spent much of Sunday watching the rain fall and typing up the pinpoint charts for a DIS no start condition. I picked that one because there are some good diagrams with it as well as coverage on some testing of the failure conditions of the Crank Sensor, the DIS and the Coil Pack. The Cam sensor isn't covered because the CAM sensor isn't required for the engine to start. But the Crank Sensor, DIS and Coil Pack are required.

Note for most tests on the DIS you need to use a LED tester, not a 12volt test lamp. This is because the 12volt test lamp can create a load on the DIS system causing starting problems, or throwing off readings. Here is how you make a LED Tester:

A LED test lamp can be created with some simple parts from Radio Shack. You need 2 resistors, and one dual LED.
2 of the Radio Shack 271-019 470 ohm resistors.
1 of the Radio Shack 276-012 Red/Green LED.

Hook 1 lead of the LED to one resistor, hook the other lead to the other resistor. You now have two leads to test from. Power one way will turn the led red or green. You can use a 12v source to test and then label one lead - and one lead +. Thus you'll know which color lights up for power going which direction.

Below is the link to the pinpoint chart, I hope it becomes useful:
DIS No Start Troubleshooting
 
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Okay I just tried this on my car. I made the LED test light per the instructions and it worked well. By the way the 470 ohm resistor is not listed under 271-019 anymore. I bought a pack of 5 470 ohm resistors for about $1 (just look through their resistor drawer for it).

Here's what I got:

N1: I'm getting a code 542 (fuel pump circuit open; ECA to motor), but I'm dismissing that for now since I have good pressure on the rail and the injectors (at least #1 and #2 are firing according to the noid light)

N2: I seem to be getting spark off of the coil pack. (go to N3)

N3: Test lamp blinks during cranking. (go to N4)

N4: Didn't check yet due to not feeling like ripping into the interior of the car just yet.

N5: No (go to N6)

N6: Plug wires look good and plugs are brand new (tried two sets with same results)

N7: LED comes on (go to N8)

N8: Getting 0.5 ohms resistance (go to N10)

N10: LED comes on for all three connections (go to N15)

N12: LED light on (probably don't need to check this but I did)

N13: no LED on for any connectors (probably don't need to check go to N14)

N15: LED blinks during cranking (go to N16)

N16: LED blinks during cranking (go to N17)

N17: LED did not blink (go to N18)

N18: no lights (replace DIS module???? it was okay before I changed the HG)

N19: did not test yet (see N4)

N20: LED is on with key on (spout is shorted to battery??)

N21: LED off with key on; LED is on with key off (replace DIS???)

N22: LED blinks during crank (replace DIS???)

N23: LED on (go to N24)

N24: 0.3 ohms (go to N25)

N25: LED blinks during cranking (check connectors and service or replace harness

N26: LED not on (go to N27)

N27: LED not on (go to N28)

N28: did not test (see N4)

N29: LED not on (go to N30) (crank sensor was properly gapped when replaced last year. crank dampener looked to be okay last time it ran)

Okay so potentially the SPOUT is shorted to battery. I got several tests telling me to replace the DIS even though it was fine before I tore the car down for the HG's. Sorry for making this so long. I also did try to start the car with what appears to be a parts store DIS module that was in the back seat when I bought the car. It appears to be new but I have no idea if it is any good or not. Sorry for making this so long. Anybody have any suggestions?
 
Did you remove the DIS from the accesory bracket or leave it attached?
If you removed it, it's possible that the heatsink wasn't done properly or maybe a wire in the harness going into the DIS or coming out has come loose or broken.

If you have these parts on your other car, you might try them before buying new ones.
 
Which car is this? Your 93?

I'd find someone locally you can switch the dis with. I'm thinking dis from reading all that, but considering the work you've done it makes me think that there could be a harness problem.

Is it possible any odd voltages might have gotten thrown through the system? No welding? Coincidences bite, so a suddenly bad DIS could really mess with ya.

Note my 93 guide shows a slightly different test program that I'll try to transcribe if I get time tomorrow.
 
Yes this is on my '93. Both DIS's I tested were properly bolted down with heat sink compound and good grounds. I don't think the system would have seen any weird voltages. The battery was out of the car until I went to start it and there wasn't any welding. Unfortunately the good DIS that I was running on my '93 came off of my Cougar. I have no other good DIS to reference. Does anyone know if VatoZone can properly test our ignition modules?

I certainly hope it isn't somewhere in the wiring harness. After looking at it it could take weeks to sort through all of that.

Mike if you do get a chance to transcribe the '93 test procedure that would be great!
 
You'll have to stop in to your local Zone and ask them. I had to go to 4 different stores before I was able to get someone to test mine. Good luck
 
Mike8675309 said:
Is it possible any odd voltages might have gotten thrown through the system? No welding? Coincidences bite, so a suddenly bad DIS could really mess with ya.

Funny you should say that Mike, I accidentally touched the alternator feedback wire to the XXIC on my car and I have a miss (as you know). Does the DIS either work or not work? Maybe the arc I created did something to the coil pack or DIS?
 
Mike, thanks again for the informative post. (I know it's a big thread bump, but the info in Post #1 is worth seeing again.) I used this recently and isolated the crankshaft position sensor as the cause of my no-start condition. I was leaning toward it anyway because the upshift light was sometimes on while cranking.

One note is that I misled myself when I first ran the test because I tested the crank sensor signal using the frequency mode of my voltmeter. That was the wrong thing to do. I should have used a test lamp or the DC volts setting. When I used frequency, I got a definite fluctuation at about 160 Hz, so I thought the sensor was working. But when I switched to DC volts, I saw that the voltage was stuck up in the 10V range and never switched more than 1/10 of a volt either way. Due to the bad signal, the computer couldn't figure out which cylinder was up, and wouldn't fire the coils. (Also note that the AC voltage setting will not work. It gave me all sorts of crazy numbers when I tried that.)
 
I should mention as well. I have found odd ignition problems are not always easy to track down. What may seem to be the dis, often isn't. On the other hand, sometimes it is. Items will test o.k, but when running down the street they will act up.

One item to never discount is wiring or connectors. Working on my car this weekend I noticed a harness to the coil pack not quite in a perfect spot. So while the engine is warming up (waiting to set a cooling fan start point) I try to push the harness into place. wiggle.. wiggle, push.. engine starts to stumble like it might shut off. I let go , it does fine. I wiggle the harness again, stumble.

I spent some time wiggling various areas and came to a conclusion that I needed to just let the motor cool down and review the entire harness. So the next morning I pulled the tensioner off the passenger side, remove the belts and fish the entire harness off the coil pack, from under the blower, disconnect the cam sensor, and the short harness piece that goes to the crank sensor. Pull the connectors off the DIS.

I took the connectors apart as much as possible and sprayed them with contact cleaner and enhancer. I replaced the connection to the ground wire that goes to the crank sensor (and into the harness) as the factory spade wouldn't stay in the connector housing properly. (snipped the spades off and used a posi-lock connector to replace it) I cut back some of the plastic harness cover that seemed to be pinching the wires slightly at the cam sensor and the coil pack. I put it all back together and started it up and did the wiggle test again. Didn't appear to have an issue.

I'm going to check it from time to time, as it's possible a wire internally has an issue and me just moving around got it to make a better contact. Vibration over time will separate such a connection again so I'll try and stay on top of it.
 
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