Ignition or Carburetor

[TommyClocks]

I bought this Spider in August of 2009, it ran OK but didn't have much power. One day it didn't start so I decided to roll up my sleeves and get to work. I did the normal stuff, points, plugs, condensor, rotor, cap, plug wires, distibutor (it leaked oil) and got it running. Still needed some more help so I rebuilt the carb and got even better performance. I upgraded to a Pertronix ignition and Flame Thrower coil and saw some more performance gains. The car was running really sweet by December of 2009 and that is when I turned my attention to the front suspension and brakes because now I am going a little faster with this car. I replaced all four calipers, rotors and pads, now it stops straight too. The front suspension looked ratty so I replaced ball joints, and all the control arm bushings along with the outer tie rod ends. With the new tires and alignment I drove the car with a lot more confidence. I also drained and filled the trans (5 speed) and rear end because who knows when the last time this was done. I drove the car during the week and did some longer trip on the weekends, what a joy to drive. I was starting to feel like a real Fiat mechanic.

Last month the Spider went on strike, the car would start and run for about 5 minutes and warm up and then the engine would begin to miss. I noticed that the miss would become worse when the radiator cooling fan turned on. Eventually the motor would stall. At this point I couldn't restart the motor until it cooled off. I removed the Pertronix and the Flame Thrower and installed the original points, condensor and coil but that didn't help. I still had the same miss and eventually the motor stalled when it became warm. I read the posts about the bad ignition switches and decided to replace all the connectors on the ignition switch. I was able to get the car running and it ran pretty well but not a lot of power like before. I noticed that the air cleaner had a lot of oil in it, makes sense since oil doesn't burn as well as gasoline. I removed the oil vapor separator and cleaned it really well and reinstalled it with a new elbow hose. I also put a new air filter on since the old one was full of oil. It started to run pretty well so I took it to Ventura, about a 150 mile round trip, it ran OK. Looked like it was the ignition switch connectors, so I reinstalled the Pertronix and it wouldn't idle again. I installed a new set of points and now it idles but it has a terrible miss while driving. I set the timing at 14 and the dwell is at 49. When I bring the timing down to 5 or 10 dgrees the motor stalls. I replaced the ignition switch tonight with a used unit but the car still misses under acceleration. I know that this car can run really great but I am running out of ideas. I know this is a long post, but I wanted to bring you all up to date. Any suggestions or help would be greatly appreciated.

Thanks,
Tom

[So Cal Mark]

wow, you've been swapping lots of parts. Have you tested the coil or plug wires? How are the bushings in the dist? You may need to put it on a scope to look at all of the ignition events.

[TommyClocks]

I checked continuity on the plug wires, even though they are only a few months old. While the car runs I pulled each plug wire off one at a time and saw the rpm drop. I checked the resistance on both of the coils that I have, they check good. I rechecked the float adjustment and set it to 7mm. I replaced the wiring to the cooling fan, it appears that someone by-passed the fan relay and used lighter gauge wire in that process so I corrected that. I checked the points again and set the dwell to 55 on the nose. The car still started and idled fine until it warmed up, at that point it would miss-fire and eventually stall. Towards the end of the day, the fuel pump quit. No fuel was getting to the carburetor. I'll need to order a fuel pump, any recommendations on a good brand to buy, my car uses an electric pump. I'll have to replace the fuel pump and continue troubleshooting or maybe I had an intermittent fuel pump causing all my problems?

[TommyClocks]

I checked the distributor bushings, no play in the bushings, this unit was replaced in March and worked well after installation. I have a question about carburetor idle solenoid. This solenoid deoesn't seem to do anything whether it is connected to power or not. The power wire to the solenoid comes from the positive terminal of the coil. What does this solenoid do and what happens if it doesn't work?

Tom

[TommyClocks]

I'm still plugging away with my sick Spider. Some good news, some not so good. I replaced the fuel pump last night and now I have lots of fuel in the clear filter. The car started fine and when it warmed up to 195 degrees, it stumbled and stalled. This morning so far I rechecked some basics. Initial static timing with the crank at zero and the cam timing marks aligned, the rotor points to #4. I checked compression with all plugs removed, the reading were 95, 95, 92 ,90. Not sure if these reading are high enough but at least they are within 10%. I found that the idle cutoff solenoid was not working at all, it made no diference if I had it connected or not. I cleaned it out and now it appears to be working, I can hear a click with power applied. The car idles better but still stalls when warm. I have the ignition timing set at 30 degrees BTDC, any lower and it won't idle. Vacuum gauge reads 17" at 1,000 rpm. I think I am making progress, but I am still missing something. I have a spare carb that I may rebuild and try next. I sure could use some good advice. Maybe it is time for a beer.

Tom

[majicwrench]

That's not near enough compression if your gauge is accurate. Check cam timing.
30 deg is WAY too much befreo TDC . Check cam timing.
Idle soleniod, my 72 doesnt have one, but on most carbs, pull wire care should die if everything working well. Idle passages easy to plug on these carb. But CHECK CAM TIMING FIRST
Keith

[TommyClocks]

I've never checked cam timing before, I did some reading last night and I want to make sure that I do it right. I notice that the backs of the cams have dots on them and the cam housings have pointers. Are these valid check points or should I remove the timing belt cover and use the pointers in front of the motor?

Thanks,
Tom

[md88plt]

I purchased a new cap from local foreign parts store and expierienced very poor running issues with the engine warm.It would occur after about 20 minutes. Absolutely no symptoms until the point that the cap was getting warm enough to expierience resistance brought on by the heat from the engine. At the time I did not know it was the cap but by the process of elimination and utilizing my ohm meter I found that the cap was bad.

[rlux4]

I stopped by yesterday and met Tom, and had a look at the car. My car is FI so I'm not up on the possible carb issues, what with the relays, a pot on the side, and a push button on the firewall??? But we did verify that the cam timing is dead on. It's got to be heat related, you can set your watch by when the car will drop RPM and want to die. Fuel pump relay maybe?
We did notice that the timing belt was loose when the engine was off, and that it wandered accross the cam pulley when running, so a new tensioner bearing is in order. What I'd like to do is get some guys together when the new belt and bearing get here and meet at Tom's house. We could check the valve clearances at the same time.
Ron

[TommyClocks]

Sure was nice to meet Ron, his red Spider is a really nice ride, very well cared for car. Thank you for stopping by Ron, I'm glad we verified that the cam timing was correct and we found that issue with the timing belt tensioner. I will order a new belt and tensioner and "recore" the radiator prior to installing the timing belt, the rad has a small leak. I'll make sure that I have some burgers and plenty of gas in the BBQ grille in case you all want to drop in for that.

The suggestion about the cap is a good one, I had a distributor cap go bad on a BB Chevy, couldn't see any obvious defect but it was a bad cap. I ordered a new cap and rotor for the Spider also. I can monitor the voltage to the fuel pump today to make sure that the relay is OK. If I finish rebuilding the carb today I will install it and see if there are any positive results.

I'm being lazy today because we hiked Mt Baldy yesterday and I'm moving a little slower today. If anyone is interested in a great Fiat ride, the road to Baldy is winding and made for open sportscars. Mark, I think this is in your backyard, sure would be nice to organize a ride and get to meet everyone.

Tom

[So Cal Mark]

we do the Baldy run then over the Ridge Route on Sunday following Thanksgiving. This year will be the 4th annual Turkey Trot

[rlux4]

Right! Good idea Mark. We'll have to make sure the car is ready by then so you can join us Tom.
Ron

[TommyClocks]

The "Turkey Trot" sounds like fun, I'll keep working on making my sick Spider well again.

I rebuilt and installed the spare carb that I had. The idle rpm increased quite a bit so I know the old carb has some clogged idle passages. I could probably take some timing out of it and put it back to 14 degrees BTDC. Unfortunately the motor stumbled and stalled after about 15 minutes of idling. Wanted to thank Keith for suggesting the cam timing. Although the cam timing was dead on, that check made us inspect the timing belt closer and we were able to conclude that the pulley is probably bad, thanks Keith. I'll change the timing belt and tensioning pulley as soon as I get the stalling problem sorted out. I am waiting for a new distributor cap and rotor, keeping my fingers crossed. Thanks again for everyone's input, I appreciate the support.

Tom

[majicwrench]

The odds of a distributor cap causing an engine to stall after idling a few minute slim to none.
Do watch voltage at electric pump when engine dies, or even better, T in a fuel pressure guage. If engine dies like clockwork after a set time, this should be easy to figure out. When engine starts to stumble, squirt some carb cleaner into carb, see if it recovers. If it does, is a fuel issue. Look down carb venturies as engine stumbling and make sure fuel is not visably pissing into venturies.
TBelt can have loose spots with engine off, that is normal.

IS YOUR COMPRESSION UP NOW????? 90 is not near enough, nothign you do will make it run right till compression is up to snuff!!!

[rlux4]

There is normally play in the belt. But this is way too loose. Not only that, but as we said, you can watch the belt wave accross the pulleys as the car runs. We did watch down the carb as it went into sputter and die mode and didn't see anything abnormal. I'm almost positive it's fuel related. We're going to look at the fuel pump relay. It could be going faulty after it heats up. Obviously it's not time related, it's heat related. But it does take time for the component to heat up to the point where the car want to die.
Ron