Hello, hello

[TinycarGo]

Hello all, My name is Travis and i'm new to the forum and to Fiats but I'm liking them both so far. My girlfriend and I have recently purchased a 1979 spider 2000. It runs and drives but has a couple small issues idling, running rich and backfiring on deceleration.

I have set and re-set the specs on the the adha multiple times but i'm still getting random backfire with a rough idle and it smells rich even when the mix screw is all the way in. it will also occasionally stall when reaching a stop because of what seems like the transfer back to the idle circuit. In addition to that my rotor is hitting the posts on the cap. one of the posts was at a 120ish degree angle as opposed to a straight up 90 and there were some metal shavings in the cap, this is a problem i have seen a few people have throughout the fiat forums.

maintenance completed by myself or PO as follows

Me:

New plugs (fouled from running rich) replaced before and after drive home post purchase 2nd set already black while i fix the richness
set and re set carb to factory baseline then adjusted

PO:

Had carb rebuilt by "the carburetor shop", installed himself and never tuned it, mix and idle speed screws weren't even set to keep the car idling.
new wires
new cap
new water pump
new v belt
new timing belt
had timing checked
had mechanical inspection performed and they found the rotor hitting the cap and replaced it, also noted loose ball joint, oil change, fluid top off

I'm wondering if the rotor and cap is causing my issue because the plugs aren't firing appropriately and that is causing the unburnt fuel and carbon fouling i'm experiencing, or if it's something in addition to that, like maybe something with the carb.

One other small thing to consider is that i'm in the Colorado High Rockies at 8600 ft elevation.

Any input or potential solutions/suggestions would be greatly appreciated.

Thanks,
Travis

[azruss]

backfiring on decell can come from the plug not firing..maybe sucking oil in thru the valve seals enough to foul the plug. this should cause serious smoking out the back on decell. also check leaks at the exhaust manifold. can get back firing from sucking in cold air. Are all the plugs uniformly black.

[TinycarGo]

all plugs have the same amount of sooty black carbon. I haven't noticed much smoke since i tuned the carb a little bit, it was a white smoke before that was really fuel rich.

[kilrwail]

Have you cleaned all the jets? Particularly the idle jet? You should set the idle mixture on the rich side, so there won't be a great emptiness when you lift off the throttle. The transition from main jets to idle jet must be fairly smooth, or it will backfire. Been there, done that on the Porsche - backfire is gone.

[RRoller123]

Welcome aboard! You will find plenty of knowledgeable and friendly people here.

Here is a thread on how to post pictures to the forum:

http://www.fiatspider.com/f08/viewtopic.php?f=4&t=21014

Pete

[focodave]

Welcome, and it's great to hear that there is another Spider in Colorado.
Where abouts do you live?
I'm in Fort Collins.
Your description of your backfiring requires one to make some assumptions in order to offer any effective help.
I wonder if your carb float level is set properly, since you indicated that "the carb shop" rebuilt it. Whenever a stranger has been poking around inside your carb, that is always a reason to suspect the worst.
I would start working on one thing at a time, and observe the results, so that you can effectively pinpoint the problem -- as opposed to "fixing" multiple things all at once in an attempt to stumble across the solution to the problem.
I would also double-check everything, even if you think it is OK.
For instance, I would check the ignition timing again. It is easy to do, but you must make sure it is correct. If the timing is too retarded, that may cause backfire.
I would then look at the carb.
Could the float level be set incorrectly? That one isn't as easy to check, but it is something to keep in your mind especially of you think "the carb shop" could have been dubious.
Definitely make sure that you are getting good consistent spark, as intermittent spark would cause backfire.
Good luck with it, and let us know what you find.
As others have said, there are lots of knowledgeable people on the forum who are eager to help.

[TinycarGo]

So I looked and found this, the shop is 20 minutes from his place and they seem reputable. While it is slightly reassuring, the claim could still be entirely false... but i'm going to ignore that possibility for now because i can hear the rotor continuing to make contact with the cap.

http://www.thecarburetorshop.net/index.html

I pulled the rotor off and upon inspecting the pickup and gear i didn't find any play in the gear and they actually look to be semi-recently refurbished. I'm wondering if maybe the cap was a Marelli and maybe the rotor was a cheapie. I ordered bearings, seals and the o ring to rebuild the dizzy as well as a new cap and rotor. I'm going to compare the rotors and caps when they arrive and look for design differences and flaws and then decide if the rebuild is necessary. I hope it all turns out well, i'd rather not mess with the carb at all until the end of May when i switch it for a 34adf and 1800 manifold. between now and then i'm going to replace my control arms, bushings, and shock/springs and u-joints, i just have to hope for the weather to do it.

As far as location i'm in Fraser, CO which is next door to Winter Park, thanks for the greetings and advice everyone.

[jmonreal0928]

Another CO Spider here, 1st Spider too, we have a 1980 and by we, it is my girlfriends car that I plan to fix up I have a lot to learn about these spiders and look forward to it. I may be having some similar issues but I really haven't been able to investigate yet. I'll keep an eye on what you come up with. I have to get emissions done down here in Lakewood, wish I didn't have to worry about it like you mountain counties.
Ayone know of some Fiat gatherings/shows nearby this summer? I missed the Broomfield one in June.