car more difficult to start and bucks when cold

[btoran]

recently, my 1975 (carbed with a fuel pump) spider became more difficult to start. it used to start after a few pumps of the gas pedal and then i would engage the throttle for a min or two before taking off. until the car was warmed up (about 10 mins of driving), the rpm's would be high but a quick tap of the gas would settle the rpm's down at traffic lights. after 10 mins of driving, the rpms would drop to normal on their own.

now, the car starts for a moment and then dies and i have to give it lots of throttle to get it started again and keep it idling. if i don't wait untilt he car is fully warmed up, it will buck like crazy in 3rd and 4th gears as the engine is revved. down shifting seems to temporarily cure the bucking, but it will repeat until the car is fully warmed up.

it seems like a fuel delivery or carb problem, but only until the car gets warm. so what's happening and what should I check?

[johnsje6]

I would suggest a choke/fast idle problem. When the car is cold, you should be able to push the pedal to the floor and let up slowly, which sets the fast idle if the choke is working properly. Then the idle would stay high and it would run ok till it warms up, when the idle would drop to normal.
It sounds like your choke is not closed when cold and/or your fast idle is not being set. Next time before you do a cold start, take the air cleaner cover off and look to see if the choke is closed, if not, you either need to adjust it or fix it. Brad Artigue has some great information on carbs - is it the stock carb for a '75?

[btoran]

john - thanks. yes, it is a stock 1975 engine / carb.

[johnsje6]

Here is the link to Brad's info, there is some really good stuff on carburetors in there.
http://www.artigue.com/fiatcontent/Arti ... 124_MM.pdf

[btoran]

thanks guys. i tweaked both the idle mixture as well as idle set screws and she runs much better now.

i am still getting the hesitation and bucking, but only when going up a fairly steep hill. interestingly, i first noticed the problem going up a hill, but then then it started occuring on all streets (flat and hilly). now, it's only happening going up hills.

i checked the fuel filters at the electric fuel pump and by the carb and both are clear.

at this point, i'm thinking the fuel pump may be the issue. it looks to be original (see below picture) and has some very thin wiring.



ideas?

[TStark]

Your orig pump is gone, and that style pump is notorious for having weak lift.
Your inlet line looks original, and likely dryrotted, and slightly kinked by the inlet filter.
Consider bending some hard line in and using minimal length, new soft line to connect it.

[btoran]

thanks. will replace pump, filter, inlet line, and any others that are suspect.

[RoyBatty]

Once you have verified the fuel delivery is working in proper fashion, you may want to look at your ignition system too.
Are you still running the stock dual point distributor setup? My '75 came stock with the dual points distributor.
If so, there is much to be gained by doing away with the dual points and even switching the points out for a simple pertronix module.
Once set of points is set for warmup of the engine and then a coolant temp switch triggers a relay to switch you over to a second set of points that actually runs with less advance for when the engine is warmed up.
I know that I had experienced some issues with my stock ignition setup before I switched things out to first of all just go to a single point setup and then the pertronix module.
Good Luck
And just and FYI to add on,
I installed the pertronix module more than 4 years and at least 30 thousand miles ago and have not had to touch ANYTHING inside the distributor cap since then. It works so well I went ahead and installed the same module to the 1600 in my '71 Coupe.
As for the distributor seal. Research it here on this forum. It is an easy fix. Toughest part is extracting the drive gear retaining pin.

[btoran]

roy - i am running the original distributor setup and have the common distributor seal leak. was contemplating switching to electronic ignition rather than fixing the seal issue, but unclear on the total benefits (aside from a non-dripping dizzy). .

[azruss]

to solve the leaking dizzy seal problem once and for all requires a solid state ignition that doesnt use a dizzy. The biggest advantage of a non-points system is you dont have to goof with the points anymore. I went with Marks computronix system and have been very happy with it. Cleaned up the engine compartment. gives a very strong spark and fires twice per cycle. I like the fact that it is maintenance free.

[majicwrench]

GUESSING that it is fuel pump related is a good way to throw money at car. Would not be a big deal to T a pressure gauge in to fuel line, secure gauge at windshield and go for a drive and really see what is happening.

Nothing wrong w points distributor, easy to work on, can get parts anywhere (sorta).
Mine do take some maintenance tho, I look into dist at least once a year, yep, they are still there.
Folks that like spending money on their cars can certainly install diff systems, tis their choice.

Dualm points, if both sets still working, you may want to consider doing the change to a single set.

[btoran]

update: i changed the fuel pump, as well as the fuel filters (one connected to the fuel pump, the other by the carb). i also changed out 4 original fuel lines (the supply line to the pump and 3 lines from the tank to a valve/canister thing). the car no longer bucks going up hills and has noticeably more power on flat ground. thanks for the suggestions.