Rough Idle and dies at stoplights - No More!

[fiasco]

Basic problem: my '76 (32 ADF Carb) idles rough and dies at stoplights.

More info: To start, whether warm or cold, I have to hold the gas pedal to the floor and turn the key until it fires, then feather the gas to keep it at high enough RPM (1000 - 1500) to keep running. When cold, if I let off the gas, RPMs slow quickly until the engine dies. Once warm I can let my foot off the gas for a short time and it will idle at about 1000 for about 30 seconds, and then fluctuates wildly, and gradually slows until it dies. When it is sitting at idle, and when I am starting out in 1st gear, I get occasional, slight backfire sounds and I get 'hesitation' (not sure that is the right word) at lower RPMs in 1st, 2nd and 3rd.

What I've done: I have adjusted both the mixture screw and the idle screw. I leaned the mixture because it smells like too much fuel, and I screwed in the idle screw to increase the idle to keep it from dying at stop lights. I have also replaced a very dirty air filter. These measures resulted in a slight improvement when warm (now I get slightly longer at stop lights before it dies), but overall, the problem persists.

I have read through some old threads on rough idle, and was mostly lost. I'm hoping I can get some advice on things to check and work my way through them one at a time - first learning how to do, and then doing each one. Check timing, compression, points, plugs, vacuum, etc. Never done any of those things, but am generally good at figuring things out with a little nudge in the right direction.

Don't know if it makes a difference, but I have a plan to get some fellow spiderians to come over and help me replace the timing belt and do a valve adjustment in February.

So, ready, fire, aim!
-- se

[SpiderHead]

lol... I'll bring you the carb.

If it fixes it. buy it. if it doesn't.. then I'll buy the beer as we put yours back on.. lol

-Ryan

[fiasco]

lol... I'll bring you the carb.

If it fixes it. buy it. if it doesn't.. then I'll buy the beer as we put yours back on.. lol

-Ryan

Beer's in the fridge - come whenever you're thirsty! In fact - come Sunday afternoon if you don't have anything better to do.

-- se

[SpiderHead]

You got it mate.

I'll come up Sunday afternoon.

my cell # is 714-396-4589

-Ryan

[fiasco]

You got it mate.

I'll come up Sunday afternoon.
my cell # is 714-396-4589
-Ryan

PM sent - anyone else care to join for some wrenching?
-- se

[fiasco]

. . . and for everyone else. . .
while Ryan and I are putting in a new carb, what else should I be looking at?

-- se

[manoa matt]

Has the carb ever been rebuilt? Install a new fuel filter. Check the tip of the jet on the idle solenoid for wear, it should be perfectly conical. A local VW place should have the jet if you take it with you. Do the check in the workbook for the idle solenoid, make sure it clicks. Check choke housing index marks. Remove and check all jets and air correctors for dirt/debris/clogs. Adjusting the high idle diaphragm will help with the backfiring/popping.

76- how is the ignition/fuel pump relay? installed/ bypassed with jumper wire? What are the markings on the relay?

What type of ignition system are you running, stock? Do you know the condition of the parts?

If you need the 76 wiring diagram or the correct ignition/fuel pump relay imprint numbers send me an email.

[JimM]

Just a thought on the tough starting--have you checked the Dwell. If set correctly it should fire right away.
Good luck -- Jim

[TulsaSpider]

It could be a great many things, but it sounds like a vacuum leak to me. I doubt a new carb is in order but it's possible. These carbs are extremely reliable. Backfiring or popping on deceleration is a lean condition which could indicate too lean a mixture or a vacuum leak or possible bad choke adjustment as Matt said. I am sure you guys will figure it out on Sunday.
You Californians are so lucky! The nearest Fiat mechanic I can find is about 8 hours away in Kansas!!
Good luck

[racydave]

It was runnin kinda foul with the oiling issue, get the NGK's...

[fiasco]

Thanks guys. That gives me a lot of things to work on. I'll let you know how it turns out.

-- se

[SpiderHead]

Project report.

Met up with Steve, and saw his lovely project. Its a decent survivor, with a fantastic looking interior, and everything else looks redoable.

Sat patiently and watched him try to start it. That bit didn't go well at all.

So we took off the air cleaner to watch what was happening. His automatic choke unit is perished... not knowing the specific cause of failure, we took his carb off, and started to install one that I had professionally rebuilt 5 years ago. (the carb only had about 35 miles on it 5 years ago when my transmission exploded and I went off a ravine) My old 76 was a champ organ donor. Thank God I wasn't.

...anyway back to the tale of two carbs. The little temperature unit on the side of the carb (all these years I thought it was an O2 sensor) wasn't the same. Mine wasn't wearing one and his wouldn't fit mine. Odd isn't it? Same carb, same year of car, same stampings.. almost. Everything about these two carbs was identical except for this one thing... Either mine was aftermarket, Steve's was.. or they were seperated by enough manufacturing time, that there was a change.

So a few phone calls later, and we decide to take a ride... so Steve, and his son Zac, and I all pile into my '74, and we head down the road to talk to someone that sounds like he knows what the heck he is doing. He certainly knew Webers, but couldn't help us much as the Weber 32 ADFA wasn't something he had parts for.

Steve is putting his old carb back on for the moment, and I will dig through my stuff to see if I do indeed have this sensor somewhere in my stuff. Chances are that I do. Keep those fingers crossed everyone!

To Be Continued....

-Ryan

[fiasco]

Well this phase of the saga at least, appears to be done.

Took the car to Mark Allison (So Cal Mark) and he fixed her right up for me.

• Took the carb out and apart, cleaned the jets, and some vacuum ports, adjusted the float, and put it all back together.
• Replaced the vacuum tube from the front of the carb to the air cleaner.
• Gapped the points.
• Tuned it for smog, got a smog certificate and tuned it back to a racing setup (ok a good driving setup)

I picked it up this afternoon, paid a surprisingly small amount of money, talked a little soccer with Mark, and drove back home in a dream! Seriously, the car runs superbly now, and I am very happy. Next up brakes, then electrical gremlins.

This is the time of year I'm thankful that I work in higher education. The university is closed until Jan 5, so I have a bunch of wide open wrenching days ahead of me.

-- se

[mdrburchette]

Glad to hear you have your problems solved. Must be nice to have Mark so close by!

[ventura ace]

Accolades to Ryan and Mark, and congrats to you, Steve. Glad to hear you got it running great!

Alvon