96 GTX CDI Module - do these things go bad?

[chrisjkelly]

I have a 96 GTX that runs like a jet fighter sometimes - then putts along like a Piper Cub. This is intermittent and can not be predicted. When I brought it into my local shop (Deep Creek, MD) they rebuilt the carbs. for $450. That didn't fix the problem so they then told me it was the CDI module and needed another $950 to get it done.

Does a CDI Module show these symptoms when it's bad? I figured electronics were either good or bad and should not be sometimes good /sometimes bad.

I thought about opening it up and re-seating and checking connections. Is that a waste of time? I'm not sure of what diagnostics checks are available to a shade tree machinic like myself.

I'm not afraid to tackle anything - including getting a used CDI and installing it myself - understanding there are chalanges - including matching keys, etc.

With the colder weather already here I can tackle it this winter but will not really be able to test it until spring.

This is a fantastic machine (when it's running properly) and I hate to give it up.

Any suggestions from the more experienced team about suitable approcah>

Many thanks ~~ chrisjkelly

 

[6KJR]

Id stay away from the dealer, those prices are retarted. 450 for a carb rebuild? Geez..

Can you describe exactly what the machine is doing when it acts up? What happends when you give it gas, ect.

 

[chrisjkelly]

Thanks 6KJR - yea, I hear you. This summer I had more $ than time - not anymore. Now I have none of one and a little of of the other.

The machine starts up fine. When the problem shows itself (unpredictable and doesn't seem related to temp, being wet, fuel level, time running, or phase of the moon) the engine runs very rough and kind of sputters - even at idle. When you give it gas the RPMs go up slightly and it runs even rougher. Alternatively going between full throttle and idel many times will sometimes "fix" the problem but only shortly. When it does fix it - the machine runs like a rocket ship again. There is not way to predict how long this will last - anywhere from 30 seconds to 15 minutes.

When the problem isn't present, idle sounds smooth and steady. Accelaration is immediate (no hesitation), and top speed is awesome.

I have checked the fuel line and replaced the fuel filter as it sounds like it is being fuel starved. Since the carbs were just rebuilt (I hope) I didn't go any further in that department.

I also have a GTi that had similar (although not identical) symptoms last year. My local shop (same one) rebuilt the pump and that machine works great.

I bought this machine used - as is - 2 years ago. So far I have about $3,500 into it and love it when it runs well. I don't have another $1,000 to invest into it but have some time.

Final note - one of the guys at the local shop offered to buy it from me - as is. I'm thinking that maybe he's trying to put me in a position to sell it to him.

What do you think? Is it worth giving re-seating and checking connections in the electrical box? Should I give changing the CDI a try? How about changing out the whold electrical box? Are there any diagnostics I can do without any super special tools or testing setups?

I appreciate you taking the time to take a look at this problem and providing your feedback - thanks.

~~ chrisjkelly