Now what

manoa matt · Post by **manoa matt** » Mon Jun 11, 2007 7:28 pm

Here's the story.

Well I'm getting married next month (7-7-07) so I HAVE TO get my spider finished and fine tuned for the big day. Last week I was close to having it done, but it just didn't run right. Sputtering, knocking, coil flashover, missing, etc etc.

I conceeded defeat and decided to enlist some professional help, I made an appointment for Saturday June 9th to take it to a local guy that has plenty of fiat spider experience. The guys shop is 4-5 miles of stop and go traffic up and down hills, so I wanted to make shure it got there.

Durring the week, after work I double checked everything, switched the plug wires to copper core and drained and refilled the tank with fresh gas. The old gas looked like cloudy urine, as it was sitting there for at least 3 months in a tropical valley, the ethanol had absorbed alot of water. The old gas was causing my sputtering and knocking, and the copper core wires cured the coil flashover at the tower.

Saturday morning It started right up and sounded great, the best I've ever heard it sound. It sounded so great I had to take it for a spin. My first run was a blast, I was so happy that I did it, and it was finally done after 9 months of constant work. It was then that I decided that I didn't need to take it to the shop, since it was running so good.

When my fiance came home I had to show off my handywork, since she's been so patient. We took a drive around our neighborhood, and on the way back, we go up a hill, after it levels off the car sputters a bit and backfires once or twice, I think it was out of the carb. Then dies, and won't restart, even after it cools off.

Durring the drives the car had good acceleration and good performance up to 3000 rpms. In between 3000 and 4000 rpms the car occasionally looses power and sputters or misses some. If I shift right at 3000 then there are no problems.

All the ignition electrials check out OK. The one thing I did'nt check was the plugs as it was too late and too dark. I'm thinking my air/fuel is not adjusted properly and that the plugs are carbon fouled. I think this is why it is not starting.

As for the 3000 to 4000 rpm loss of power/sputtering/missing:

My coil requires an external ballast resistor, which I have. The ballast resistor is a .50 - .60 ohm. When the key is on there is 11.75v going into the resistor, and 9v comes out and goes to the coil. When the car is started and idling at 800-900rpm there is 13.75v going into the resistor and 11.75v coming out. When I rev the engine to 3000-4000rpms there is 14.3v going into the resistor and 12.3-13v going to the coil.

When I get more than 12v to the coil it starts to miss and flashover.
I've tried a ballast resistor with a higher resistance, but with the key on there isn't enough volts coming out to get it to start, even with a jumper wire.

I still can't understand why the bosch blue coil won't work. Also my electronic dizzy and coil from a 79 won't spark either.

Matt

So Cal Mark · Post by **So Cal Mark** » Tue Jun 12, 2007 12:30 am

how certain are you that it's an ignition problem? 3-4k rpm is about where the carb switches from the low speed jet to the main jet. Maybe your carb main circuit has a problem

manoa matt · Post by **manoa matt** » Tue Jun 12, 2007 4:01 pm

I'm pretty shure the no start is from the ignition. I get a steady spark from the coil, mostly blue but there is some amber in the spark color.
The spark at the plugs is intermitent. I thought it was a points condenser, but after switching with a new one, still no go. The plugs were fine, no carbon fouling

Its intestering you say that about the jets. When I rebuilt the 34 ADFA carb I figured the primary jet was the larger of the two, and that it went in the primary stack (drivers side) I put the secondary jet (smaller diameter) in the passenger side stack.

drivers side jet is 185-180 (sorry, memory not so good)
passenger side jet is 175

Are my jets backwards? I could see what effect of switching them would have, but I can't get it started.

Fortunatly I did pull and push it back to in front of my place.

Matt

So Cal Mark · Post by **So Cal Mark** » Tue Jun 12, 2007 6:57 pm

the sizes you mention sound like the air corrector jet

manoa matt · Post by **manoa matt** » Wed Jun 13, 2007 2:56 pm

Mark,

You are exactly right, as usual. Air corrector jets. From my desk at work I'm trying to remember specks for work performed months ago.

Now a two part question: Do I have them reversed? and will reversing these jets effect performance in the 3k to 4k rpm range?

Haven't had a chance to get to the points ignition problem, I did find that my electronic dizzy had a bad rotor button. Switched to a good spare one and will try later this week.

Matt

So Cal Mark · Post by **So Cal Mark** » Wed Jun 13, 2007 3:36 pm

by placing the larger air corrector in the primary you've leaned the main circuit out. But that wouldn't cause an intermittent problem, just poor perf in the range you quoted.