88 XR2 150hp no spark

[chadbenton]

Hi, I have a 1988 xr2 150. I ran it last weekend and it ran fine up until it was time to leave. Completley gutless, would plane out or reach any high rpm. Checked it tonight, had to cool off for a week, was ready to sell the darn thing, but my wife talked me out of it. Checked for fuel issues, no problems, ran compression test all is good. Checked for spark and found no spark on the two bottom holes, no.s 5 and 6. These are each on seperate switch boxes. I have a seloc manual, but it is a little vague, and would like to know where to go next. Is it possible to loose a circuit on two different switch boxes at the same time, or do they share a common ground, or common input source from the trigger assembly. Any help would be greatly appreciated....

 

[Laddies]

Re: 88 XR2 150hp no spark

5 and 6 make your proiblem the trigger, if you ck with a ohm meter you will find it's open

 

[chadbenton]

Re: 88 XR2 150hp no spark

Thanks, going to check it right now, by the way could this affect my tach, it is showing a lot higher than it should. Also, mine has a idle module on the port side and one of the wires going to the switch box is toast. Can I just do away with the little black box, or is it a neccessary evil..Thanks.......

 

[chadbenton]

Re: 88 XR2 150hp no spark

Just did a stator and trigger check and they both ohmed out fine. Did some looking and the wire from the module had arched to a switch box. So, I put everything back together, and left the module disconnected. Now it is only missing on no. 5. I guess now my only choice is to swap switch boxes and see where the miss goes from there. The no. 5 coil ohms ok and the ground ohms good as well. Still wondering about the black box, if I do away with it, do I need to reset timing..

 

[j_martin]

Re: 88 XR2 150hp no spark

Still wondering about the black box, if I do away with it, do I need to reset timing..

Most consider the advance/idle stabilizer module to be surplus. Set your timing where you want it depending on compression, fuel, etc.

hope it helps
john

 

[chadbenton]

Re: 88 XR2 150hp no spark

Thanks, I think I will take it off and chunk it. I was mainly wondering if I can just remove it and run the engine as is, without changing anything. I figure I can since the module is disconnnected during sync and linc right! One more thing about checking the switching box. Could I not pull all my plug wires and ground them, and reverse my coil leads on the box itself to verify a failed circuit. Sounds easier than swapping boxes..

 

[j_martin]

Re: 88 XR2 150hp no spark

Thanks, I think I will take it off and chunk it. I was mainly wondering if I can just remove it and run the engine as is, without changing anything. I figure I can since the module is disconnnected during sync and linc right! One more thing about checking the switching box. Could I not pull all my plug wires and ground them, and reverse my coil leads on the box itself to verify a failed circuit. Sounds easier than swapping boxes..

There are several versions of the advance, or idle stabilizer, or combination module. Each modifies timing slightly by messing with the bias on both switch boxes. Looking in the charts for yours, max advance setting is 20*BTDC, and final advance is 26*BTDC. The switch boxes normally do about 2*, and the advance module wrings out another 4*. I'd set yours at about 23* - 25* BTDC, which is probably about the max mechanical limit anyway.

Mine is similar. I noticed the other day when I was both overloaded and overpropped, going at half throttle, I had enough detonation to notice the engine was unhappy. Didn't hurt it, but I have to pay attention to it, and put on a lower pitch screw when I want to do the Beverly Hillbilly thing. I'm going to also look into something to manually retard the timing if needed with a toggle switch, or a circuit operated by a detonation detector.

On swapping the boxes. You can swap coils around to see if a coil is bad. If the misfire stays with the switchbox, you then need to swap switchboxes to see if the trouble is in the switchbox or in the trigger or stator. They are stacked up, and there are 20 wires to move, so the easiest way is to do it without messing up and frying something is to just swap them physically.

hope it helps
John

 

[chadbenton]

Re: 88 XR2 150hp no spark

Well, this evening I removed the advance module and swapped switch boxes and it ran fine. I am getting good fire on all cylinders. It seems to run a little rough at idle on the muffs, but it always has. I can pull indidual plug wires to check spark, but is hard to notice it affecting the powerbalance, seems to be slight on some and more pronounced on others, especially the center holes no.s 3 and 4. The red wire on the advance module was cooked all the way up to the module, and it had rubbed against the inner switch box. Could this have caused all of the problems...