The first "bad" Matchbox!

[Rays74]

Well, just figured out why my daily driver '74 620 was acting strange........the matchbox had gone bad! Never seen one this in 15yrs of using them and 4 different Datsun's running them. Back in the day when they were plentiful in JY's I would harvest a couple most each visit....glad I did now.

Here's what the symptoms were....

 

Idling ok but did die randomly twice at a traffic light, accelerating WOT it would pop snap and cough and generally act like it was tune up time. Mileage had steadily declined as well.

 

The fix....

 

Change plugs (NGK BPR5ES) wires cap and rotor and although better, it still would not go through the gears with the same pull it had before, and refused to wind up past approx 45oo rpm. Checked all my wire connections along with the coil and all seemed well.......

 

Changed out the matchbox module (we always keep one known good one in each vehicle for emergencies) and life is good again :D

 

--Ray

 

[Pacific coast Datsun]

This is the 1st one ive heard that went bad. Glad you figured it out.

[bonvo]

this doesnt surprise me ive had 2 die on me in the time ive been running ei granted one wasnt in my car but still 

[ggzilla]

Is your matchbox turned away from -- or facing -- the exhaust manifold. I've heard of them overheating.

[Rays74]

Is your matchbox turned away from -- or facing -- the exhaust manifold. I've heard of them overheating.

 

Good question, but I've always set mine and the ones I've built (Yeller's twins :)) with the "box" opposite the exhaust manifold. I too have seen a few that were set up with the module facing the heat and wondered just how long it would last that way? Ugh.....

Thanks Mark, yeah me too.

[ggzilla]

So the symptoms of a bad matchbox were: Idling ok but did die randomly twice at a traffic light, accelerating WOT it would pop snap and cough and generally act like it was tune up time. Mileage had steadily declined as well.

 

This can also be caused by slightly corroded connections to the matchbox.

[Rays74]

The symptoms of this particular one.......yes. Connections were pulled and reset during the tune, no change.......I try and be as thorough as poss :)  

[datzenmike]

Usually heat causes electronics (at least old electronics) to fail but they come back 'on line' as they cool down below the problem temperature. Temps would have to get above 500 F to melt solder so that only leaves vibration.