96 XP with no spark

[BCRSKI]

I was having an intermittent problem where I would loose spark and the XP would stop running and not start. Sometimes I would have a blown fuse in the box and it would fix it but then it would happen with fuses good and then fire again at another time. Then recently it died and will provide spark at all. No fuses, no self healing. In the service manual I see there is an adaptor needed to test the trigger coil. Is there a way around that? If I test for continuity between the yellow and white wire and the black and yellow wire, which per the wiring diagram go to the trigger coil, should I get continuity? I took the plug off the CDI module where the yellow and white wire goes in and tested the plug end of that wire to the ground in the box where the black with yellow wire mounts and did not get continuity.
I also see in the manual that the rev limiter can cause no spark condition. But the test for the rev limiter is done while the engine is running. Any other test for this part?

Any other suggestions on what to check for cause?

 

[BCRSKI]

I went through the continuity tests on the MPEM and CDI per the shop manual. The MPEM checked out, but the many of the resistance readings on CDI did not match the manual. Is this confirmation of a bad CDI? Also the holder relay measured at 350 ohms vs 104 ohm spec.

I also found that there was a 15A fuse in the 5A holder. I think the 5A blew with my son and he only had a 15A fuse.

 

[artr]

I had a problem with holder relay dropping the 12V to the CDI intermittently when trying to start. Since yours reads a high resistance it could be doing something similar. Put a volt meter on the 12V output from the holder relay an see if it is dropping when you lose spark. I had tested several CDIs for resistance that did not match the manual but it turns out they were all fine after replacing the holder relay.

 

[BCRSKI]

Measured the primary winding of the coil. Supposed to be .34 -.62 ohms and measured 1.1. So that is 3 components out of spec. Can't think they are all the cause. Have seen other posts on the DC-CDI having out of spec measurements and still being good?

 

[artr]

Do the measurement. No 12V to CDI, no spark.

 

[BCRSKI]

How do you measure that? When will 12V flow to the CDI? When DESS is on the post? Push start?

 

[artr]

When you put the dess on the post, 12V will be there for about 30 seconds. If you press start, the 12V will be there to allow it to start. If you think you have no spark, measure If the 12V is there. If the 12V is not there while cranking, there is something wrong with the holder relay. You can bypass the holder relay by shorting the 12V to the CDI and see if it starts. Don't leave it like that because it will eventually drain the battery.

 

[BCRSKI]

Turned over the engine with a meter on the signal wire to the coil. It was getting voltage when turned over, but still no spark. Bad coil?

 

[artr]

There are a bunch of ground leads that connect to a screw or bolt on the coil. Sometimes the bolt and/or connectors on the wires corrode. take them off and clean them and the bolt and reattach. There are also probably resistance tests for the input and output of the coil in the shop manual.

 

[BCRSKI]

Yes I cleaned them up and posted in an earier thread are the resistance results I got on the coil.

 

[peppawutz]

I had a problem with holder relay dropping the 12V to the CDI intermittently when trying to start. Since yours reads a high resistance it could be doing something similar. Put a volt meter on the 12V output from the holder relay an see if it is dropping when you lose spark. I had tested several CDIs for resistance that did not match the manual but it turns out they were all fine after replacing the holder relay.

where do I find this holder relay . I believe, I got the same problem?!

 

[BCRSKI]

But I am getting signal at the coil from the CDI via white wire. There is no spark at all. Not intermittent spark.

 

[artr]

But I am getting signal at the coil from the CDI via white wire. There is no spark at all. Not intermittent spark.

There is not much left if you are sure there is a signal from the CDI to the coil. Check that the small black wire that runs from the battery negative to the rear electrical box with the coil is providing a good ground to that post on the coil. You can also try trimming back your plug wires about 1/4 inch as described in the manual.

 

[artr]

where do I find this holder relay . I believe, I got the same problem?!

The holder relay is mounted on the MPEM board in the front electrical box. It is a small module with 4 wires attached to it and a single 5A fuse mounted on it.

 

[peppawutz]

The holder relay is mounted on the MPEM board in the front electrical box. It is a small module with 4 wires attached to it and a single 5A fuse mounted on it.

ok, thank you

 

[BCRSKI]

I installed a new coil and still no spark. I again tested voltage from the CDI to the coil and the reading was .12 - .13v, not the 12 - 13 volts I thought I read earlier. I must have misread the scale. I then checked the voltage going from the holder relay to the CDI and it was fine at 12.5V.
The CDI had some readings that did not meet speck in the manual. I have seen other posts were the CDI readings were not reliable for indicating a bad CDI. Could the CDI be bad or is there a possibility the signal from the stator is bad? It is sending a very low voltage to the coil, so not sure if that would happen if the signal from the stator was not there.

 

[artr]

Here is a very good youtube video I used to help me find out what was going on with intermittent starting problems on my 96 GTX. The engine on the 96 XP in the video and electronics are basically the same.

 

[BCRSKI]

Great video of all the shop manual tests. I had done all of them prior except the stator because as he noted that is the biggest pain. The lower two bolts suck to get to, even with the engine mount removed you still can't get a socket on one of them. Well that is where I found my problem. The trigger pickup that is attached to the cover broke off.

 

[artr]

Glad you got to the bottom of the problem.