Advice - Alot of Changes newbie errors and getting desperate

[JohnD]

Hi,

I am a long time owner of a 1971 fiat 124 spider.

Current specs
1608 with high compression pistons (newly installed)
34 DMS carb
Fireball ignition - installed 14 years ago but purchased in 1998

Recently I had new pistons and a rebuilt head installed on my 124 Spider. It does run but it does backfire through carb and runs rough. It backfires when I push on the accelerator. I have checked the timing and my friend who is a mechanic confirmed it also. He also checked the compression and it is good even though I don't have the exact specs.

Additionally, I have a fireball electronic ignition that bypasses the points and condenser. When the car runs it will run for a bit and then the plugs are fouled (as if running rich, brownish). In other words, I get the car running and then when I shut it down it won't restart unless I pull and clean the plugs. Even then it can be difficult to start.

Also, when I pull the coil the spark from the coil seems very strong but when I pull a plug (sparkplug attached) and crank the spark seems much weaker. Any thoughts or input would be appreciated. I would love to know more and a goal is for me to be able to maintain this car myself. Any thoughts, direction or guidance would be appreciated. I am thinking it is the ignition module. My car has been down for 2 seasons and I am getting desperate.

Thanks,


John D. Nicosia

[klweimer]

I would start by checking the cam timing and making sure the cam wheels are on the right cams. Lots of threads here on this topic.
Kirk

[johndemar]

Any possibility the carb is running rich?

[lglade]

I'm with Kirk. The fact that you recently had head work done suggest a possible issue with cam timing. Verify that the cam wheels are on the correct cams and verify the cam timing (e.g. one cam could be off by a single tooth). There are several great postings here that describe what to do or a good shop manual will describe how to do it. Do you still have the original distributor? If so, I'd then temporarily swap back to it, or another known good distributor, to cross it off the list of potential suspects. It's possible that your distributor has a bad module.

It sounds like you've made several recent changes to your engine, and I would verify that all of these are fully functional before looking for a different root cause. You'll find your problem if you keep looking. Don't get discouraged...we've all been right where you are now. It's not always practical, but try to change only one thing at a time and then confirm success before moving on to the next change. When things don't go as expected, it's much easier to diagnose the cause.

[JohnD]

I am including images of my timing marks. The car starts but continues to back fire through the carb. As stated earlier I have a fireball points replacement ignition. I get tons of spark ouit of the coil but a very weak spark from the ignition wires. The installation manual for the fireball states that you should time the ignition from the #1 piston. Does that make sense?

http://s1293.photobucket.com/user/JohnD999/media/Both%20Timing%20Marks%20Cams_zpssdb7vw13.jpg.html?filters[user]=140741462&filters[recent]=1&sort=1&o=0

[url]http://s1293.photobucket.com/user/JohnD999/media/Exhaust%20Timing%20Mark_zpsntvnxfnm.jpg.html?filters[user]=140741462&filters[recent]=1&sort=1&o=1[/url]

[url]http://s1293.photobucket.com/user/JohnD999/media/Exhaust%20Timing%20Mark_zpsntvnxfnm.jpg.html?filters[user]=140741462&filters[recent]=1&sort=1&o=1[/url]

[RRoller123]

Maybe this will help.