Technical 77 1800 stalls

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Technical 77 1800 stalls

DSwetnam

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Ok, just bought the car, so don't have much history. Purchased the car yesterday. Was running great during the 4 hour drive home, until I stopped for the first time after a long stretch on the interstate. Now it stalls each time I stop. ALWAYS starts right back up. As I'm driving, as long as I'm moving along, it runs good. No other indication of an issue. I'm going to do some troubleshooting today, but if anyone can steer me in the right direction, it would be much appreciated. Thx
 
Does the engine idle when warmed up to normal operating temperature?

Al.
 
Thanks for the reply...
No, it was not idling and any circumstance, but....

It's running great now! I think I found it. Suspected it might be the idle stop valve so I took it out wiped it down and put it back in. Started right up and doesn't die at the stop sign.:)

I figure it's going bad and will need to be replaced all together, but it's running good now.

I'm sure I'll be back with another question soon.

Next...get the wipers working again.

David
 
Sorry I've been away for a while. Had her running pretty good, so I was taking advantage of the warm weather.

Unfortunately that only lasted so long. I am back to having a stalling issue. Let me outline the history and see if anyone has any ideas...

1. Bought car and drove it home (4 1/2 hours) without issue.
2. Once at home, car began to stall when stopped at a light/stop sign.
3. Solved #2 by replacing the idle stop valve. :)
4. Car drove well for a couple weeks. Did notice a couple flat spots when at cruising speed.
5. Drove to work and when I went to go to lunch the car would not start. (turn but no fire)
6. In process of diagnosing the no start, I checked coil, fuel pump, spark..finally discovering that ignition mode relay was bad.
7. After replacing the relay, car will now start but only runs for a minute or so.
8. Suspect that it is the running points, so I have converted to single points.
9. Also replaced spark plugs and condenser as well as all relays. (although the ignition relay is now by-passed)
10. Will now start and run for a couple minutes before stalling (improvement?)
11. I now suspect that, in my tinkering, I have messed something up with point gap, dwell or timing. That will be the next thing for me to check on.

My question is this: Am I missing something? Is there anything else that you can suggest to track this thing down. I've been off the road for several days and the weather has been great! It's getting very frustrating.

Thanks for all the help!
David
 
Good idea to set points gap to 16 thou. and ignition timing to 10 degrees before top dead centre. Setting the points gap also sets the dwell angle.
You might have to retard the ign. timing to say 5 degrees BTDC if the engine 'pings' on acceleration but try 10 degrees first as imo Fiat T/cams start better/easier.(European models always used 10 degrees)

Need more info re the way the engine cuts out e.g. does it cut suddenly (likely = ignition) or does it stumble/falter then cut out (likely = fuel), does the idle speed drop first before cutting out, can the engine be kept running if you open the throttle slightly, can the engine be restarted straight away?
anything else you've noticed?

I'd be suspecting a fuel supply problem, any blocked filters? fuel pump faulty or its power feed, (I'm assuming your car has an electric fuel pump) incl. any controlling relay etc.

Next time it starts then cuts out, assuming it won't restart, I'd check for a spark first, then check if fuel is reaching the carb by carefully removing the feed pipe at the carb. Best to do this testing at home outdoors and have a fire extinguisher handy just in case!
Let's know how you get on,

Al.
 
Another thought - Are you sure there's no anti-theft or alarm system fitted, perhaps the remains of a long removed/redundant/bypassed system??

Al.
 
Thanks for the speedy reply Al.

Haven't had the time to do the tuning yet, maybe tomorrow...

After it starts it runs ok for a couple minutes, maybe a little rough, but then just cuts out. If I give it throttle it will keep running, but if I rev it a couple times it will die out almost like there is some opposing pressure that keeps it from continuing (timing?). It will restart immediately each time. Did I mention that I converted to single points? I've verified that there is spark on each plug although it seems weak (could this be caused by incorrect gap?). Fuel pump is still a question...yes it is electronic...doesn't run when key is in accessory position, but kicks on just before start...I haven't verified if it keeps running. I felt that it wouldn't have keep running for 2 minutes if the pump wasn't running. Bought a new fuel filter but haven't installed it yet.

I think that answers most of your questions. I'll let you know what happens after the tune up. Thank you again for the feedback.

David
 
Ok, did some tuning this afternoon and there is definitely some improvement but still stalls. I did notice as I was adjusting the timing that there was a distinct puff puff noise coming from the rear part of the engine on the carb side (I think). As I was trying to track that down I noticed a small white plastic part hooked to the vacuum lines mounted to back of the engine bay near the hood latch. It had a vacuum line on one side and nothing on the other (should there be?) and sucks air when the engine shuts off.

More later...

DS
 
Hi Dave,
Sorry can't help you with emissions equipment, European/Irish models were not so equipped. On the few models on which I worked having been imported from the US, we generally had to remove all the smog gear and fit a European spec carb to get the car to run/idle properly!!
Maybe try blanking off the open pipe and see what happens?
IIRC the idle jet (or jets?) are accessible on the outside of the carb, no need to strip the carb, these are (I think but not certain) fitted along with the solenoid idle valve., you might have a slight blockage.
Another thought, if there is much blowby from the crankcase, this is drawn into the airfilter housing and then into the carb, can affect idle. To rule this out, remove the top cover on the airfilter housing(canister) and see if much smoke/vapour is entering the filter from the c.3/4 in hose which attaches under the filter housing.
I assume your using the choke when starting from cold not the hand throttle (easily confused if not familiar with these cars)?
If idle is ok with a small amount of choke but cuts out when choke is fully off, you could try increasing the idle speed, some carbs have an idle speed screw, others use a volume screw(larger of the two screws side -by-side near carb base.
There is also a small mesh filter on the fuel suction pipe in the fuel tank, reached by withdrawing the fuel sender unit from top of tank (ring of 6? small nuts, 7mm?) and a mesh filter in the carb beside where(under?) the fuel pipe attaches (brass 19/21 mm? plug).
Re. the possibly weak spark, one check is to hold the end of the coil HT lead (king lead?) (detach from distributor cap) about 1/4in. from cyl. head and use a screwdriver to flick open the contact breaker points when they're closed with the ignition switched on. You should get a nice blue spark.
A large points gap reduces the dwell angle and potentially reduces the spark strength but if everything is ok (and I note you've already changed the common problem parts!) 16thou. points gap is fine IMHO. and prevents possible arcing of the contact points if they're set to e.g. 12thou (In my experience as a Fiat trained mechanic in the 1970's).
I don't want to waste your time/money checking/changing things but as you can appreciate it's difficult to diagnose a problem like this from a distance, I'm just giving you ideas of where you might find the solution to your problem. Obviously you drove it for 4+hours after purchase and it ran fine, so there can't be much wrong!!!! There's probably something very small causing your problem (cutting out on idle) and no doubt when when you find it you'll wonder why you didn't find it straight away but that's half the fun of old cars IMO.

Regards,
Al.
 
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I'm new to the Fiat Forum, and I'm finding it a great source of information. I'm really impressed with the help offered by F123C who seems to be named Al. Many people have probably benefitted from the original question and the answers given in these posts.


I too offer my thanks to Al! You're very knowledgeable and extremely generous with your time Al. Thanks a million from Georgia!
 
Problem is with the carb. It needs cleaning out. A quick fix is to take the idle valve jet out and rev engine and put cloth over carb so it stalls at high revs. Do this couple of times. Should clear idle circuit for a short time. The bowl of the carb needs cleaning. I would take carb off and strip it down. Whilst off, check the jet holes. If slightly oval, replace.

Andy.
 
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