Engine want s to die when put into gear

[jlw35]

Long title, sorry.
My '75 is roadworthy, but the one issue dogging me is just what the title says.

1800 motor, stock carb and intake.

Timing (static and running) is set. When I engage the transmission with clutch pedal still depressed (either first gear or reverse, doesn't matter) the rpm drops to the point that the engine will die if I''m not quick enough to give it some gas.
I have the idle set a little high, the mixture is set (plugs burn clean) and the motor runs pretty smooth at idle.

Hopefully there is a simple fix or at least a bit of troubleshooting suggestions, I'm open.

Thanks
Jeff

[Odoyle]

Jeff, what did you adjust the timing to and did you use a timing light? It could be the throw-out bearing is worn out, also could be that the clutch cable might need to be adjusted. You can inspect the bearing and clutch fork behind the dust cap on the driver side of the trans. Having the car on jacks and a second helper could help you see what is going on with the clutch when it engages.

[jlw35]

I did use a timing light and set it at 0 degrees. I suppose I could tinker with the timing a bit and try it at 10 degrees, just not sure what the relation is to the problem. That's due to my lack of understanding of course.

Thanks for the input.
Jeff

[ORFORD2004]

timing is 10 degrees and distributor vaccum unplug from distributor but line plug.

[samakijoe]

Jeff: We could use a little more info on the situation.
Does the car cut off like you are turning off the ignition key or does it sputter and die?
Is the engine warm when it happens?
Does it stall after pushing on/in the clutch pedal or only after you put it in gear?
And most importantly, (I learned this from many years of listening to "Click and Klack" ) what color is the car.

[DieselSpider]

Is it hard to push into gear or do you get any grinding noises when you try to put it into gear? It could be bad clutch adjustment caused by the cable stretching or possibly that the pilot bearing needs to be cleaned out and have new grease put in it.

When you put a standard transmission into gear with the car stopped the input shaft which was spinning with the engine is stopped so the clutch disc is no longer spinning until after you let the clutch out and the car starts moving however the engine with the pilot bearing in the center of the crankshaft is spinning around the nose of the transmissions input shaft with the clutch disc sitting still between the rotating flywheel and pressure plate.

If the throw out bearing was the problem the engine would usually stall whenever you put your foot on the clutch even if you did not put it into gear.

[jlw35]

This is my bottom line diagnosis, after much aggravation and troubleshooting.

I let the engine warm up to operating temp (the fan will have cycled on/off 2 times).
The engine does not die as if I had turned off the key, it's more like it sputters and dies. I can keep it running if I'm quick with the gas pedal, but it runs rough when I do that, as if it's missing.
I found that I do not have to push on the clutch to simulate the problem, all I need to do is push the shift lever as if I'm going to put it into gear without using the clutch, so just the act of pushing the shift lever so that it barely makes contact will cause it to die.

When I do use the clutch, it is not difficult to put into gear (no grinding or difficulty).
Pushing on the clutch pedal itself and not putting it into gear does not cause a problem, only the act of putting it into gear.

"If the throw out bearing was the problem the engine would usually stall whenever you put your foot on the clutch even if you did not put it into gear."
Just to be clear, the engine continues to operate fine even if I depress the clutch pedal. Just the act of pushing on the shifter is causing the problem.

Over on the other Fiat website, the diagnosis is the release bearing (a binding issue). I'm not disagreeing with the help and advice offered there, I'm just hoping beyond hope that I don't have to pull the transmission.

Finally, the color is Green!

Thanks for looking, always appreciate any advice.
Jeff

[18Fiatsandcounting]

It sounds to me like your clutch is not releasing properly, and there are a number of possible causes: warped clutch plates, bad throwout bearing, improper adjustment, etc. as mentioned above. If this is the case, with the clutch fully depressed, your engine will stall or falter if you try to put it into any gear, as the idling engine is now trying to move the car with very little power, especially if the brakes are on (handbrake or foot brake).

Try this: Do as you did before, but rev the engine up to around 1500 or 2000 rpm as you slowly try to put it into gear with the clutch fully depressed. If the car starts moving forward slowly (or backward if you're trying reverse), the problem is almost certainly a bad clutch or bearing or adjustment issue. Try this test with the brakes off, and of course make sure the car won't bump into anything if it does start moving.

One other check: Make sure the carpeting or rubber mats or any other obstacles aren't preventing the clutch pedal from going all the way to near the floor. From what I recall, the clutch pedal should be able to get within 0.5 to 1 inch of the floor if everything is set up right.

-Bryan

[jlw35]

Thank you Bryan, I'll try that tomorrow. Certainly appreciate any input.
Jeff

[SteinOnkel]

It sounds eerily like an electrical issue. I would hook up a multimeter to the coil positive and ground and measure voltage. If it starts to drop off significantly, that would explain the stumble. I believe the smog cars have switches in them on the clutch pedals to alleviate an overly rich mixture on cruising and some systems will also cut ignition briefly. I would remove all of this malarky in your case, but make sure your car actually is equipped with this first.

Also, a video would be very helpful.

Cheers
Steiny

[jlw35]

I do have a switch on the clutch pedal Steiny. I've removed the fast idle assy., but will also disable the clutch pedal switch as well.
Easy enough to test at the coil, I'll try that tomorrow and report the result.

Could a weak coil be the culprit as well?

Jeff

[SteinOnkel]

Hi Jeff,

a weak spark could be your issue as well, but I would think that unlikely. Try grounding/shorting out the switch first.

[jlw35]

Success! I disconnected the switch located at the clutch pedal Steiny! That was the final part of the smog assy?, I guess (I've removed all of it and will save it for the next owner).
In any case, the car is finally street worthy.
It seems that after warms up a bit and the idle stabilizes, the problem mostly disappears. It stills shows up intermittently on a drive.
I can tell that it isn't correct when I accelerate, still has a stumble or missing a bit (not as if the clutch is slipping). At other times, no problem at all, runs and accelerates smoothly, so some intermittent issue is still there, but I'm not afraid to drive it anywhere.

Maybe it will correct itself at some point or remain the same, either way I'm mostly happy and certainly appreciate all of the help offered here!

Thanks again
Jeff

[SteinOnkel]

That is excellent news.

What is the general condition of your ignition system? It sounds like your coil is still getting its supply voltage cut intermittently or the coil itself is on its way out. You should find out why and remedy it, otherwise you will be stuck on the side of the road in no time.

Cheers
Steiny

[18Fiatsandcounting]

Jeff, I'm glad you got the problem straightened out. I've been following the story on this forum and the other forum, but I still am a little perplexed. There is a switch on the clutch as you found, and one on the transmission when it is in 3rd or 4th gear, so that when the clutch is depressed and the transmission is in 3rd or 4th gear, the idle is at around 1500 rather than the usual 850 rpm. This is for emission purposes, and is referred to as the high idle circuit. If you had an air leak in this circuit's control valve or associated plumbing, then yes, the idle would be goofy if you depressed the clutch and then put the transmission into 3rd or 4th gear, since air is leaking into the intake manifold. When you disconnected the clutch switch, the control valve cannot open, so no leak and problem apparently solved.

The part I am missing is that this high idle circuit only operates on 3rd and 4th gears, at least on my early Fiats, and you seemed to be having the problem no matter which gear you tried. Perhaps your model year has a different setup?

Does my reasoning above sound consistent, or am I missing something? Not a burning question, but just curious in case I run across this again.

-Bryan