Carbureted 190 keeps Stalling

[insanibasha]

I've been daily driving my 1987 W201 190 for quite a while now but yesterday she's developed a new problem. I usually warm the car up until it reaches just under 80C before driving off, and yesterday the engine decides to shut off after only about 30 seconds. Tried turning it on again, gave it some revs and then it shuts off again. Third time I tried it the revs dropped a bit and then it shuts off. I went to bed thinking it could be because of the weather at night that the carbs aren't working right but when I tried it in the morning, the same thing happens.

What are some possible causes for this problem? could it be that the carb setting is too lean? bad fuel pump? Don't be afraid to get too technical as I'm trynna learn as much as I can about the car so that I can make it run as reliably as possible. Thanks?

 

[neilrr]

I usually warm the car up until it reaches just under 80C before driving off...

Why?

 

[ALFAitalia]

I guess he wants to put extra wear on the rings and bores.... Tick over for 30 seconds max then drive it gently....it will warm up faster and you will get much less fuel washing the oil off the bores.

BOT....it certainly sounds like a carburation issue.....possible air intake air leak somewhere?

 

[vijilants]

If it is fuel starvation to the carb (and it does sound like it counld possibly be the issue) I would suggest that you should be looking at the fuel filter and pump. If both of these prove to be OK, then look at the carb.

 

[ALFAitalia]

Wrong thread!

 

[insanibasha]

I guess he wants to put extra wear on the rings and bores.... Tick over for 30 seconds max then drive it gently....it will warm up faster and you will get much less fuel washing the oil off the bores.

BOT....it certainly sounds like a carburation issue.....possible air intake air leak somewhere?

Damn, this is one of those habits where you just pick up as a kid and find out later in life that it's actually a bad one. I'm learning something new every time I open the forum, love it.

I'll definitely check for leaks from air intake, thanks!

 

[insanibasha]

If it is fuel starvation to the carb (and it does sound like it counld possibly be the issue) I would suggest that you should be looking at the fuel filter and pump. If both of these prove to be OK, then look at the carb.

Thanks for your response!

 

[insanibasha]

Wrong thread!

Where should I have posted this?

 

[ALFAitalia]

Where should I have posted this?

LOL.....no I meant that I posted something in this thread that I meant to post in another.....and since on this forum you cant delete posts I had to put something!!!

 

[grober]

The carburettor cars have a thermostatically operated flap that diverts inflowing air from a hot intake just above the exhaust or from the normal cooler air inlet-it's hidden within the air cleaner assembly- it's possible something is wrong with it. More likely is condensation within the distributor body base which volatalises into the distributor cap as the engine warms up. And shorts out the high tension ignition. Try drying out the distributor body and cap with a hair drier to see if that improves things?

 

[Bellow]

What are some possible causes for this problem? could it be that the carb setting is too lean? bad fuel pump? Don't be afraid to get too technical as I'm trynna learn as much as I can about the car so that I can make it run as reliably as possible. Thanks?

Confirm it is lean by pulling a spark plug and checking it is dry. If it is wet/sooted, that points to overfuelling or failing spark.
A neon spark checker will let you see if the ignition system is still delivering as it dies.

neon spark tester - Google Shopping

www.google.com

Diagnostics first - loading the parts cannon can wait.

 

[merc85]

I had a 1989 190, the idle was always really low, one day i experienced something similar to yours

Turned out the diaphragm in the carb had split, i repaired this with a =bit of rubber glove and vulcanizing fluid until replacement.

Problem solved ran like a dream after

 

[SW18]

More likely is condensation within the distributor body base which volatalises into the distributor cap as the engine warms up. And shorts out the high tension ignition. Try drying out the distributor body and cap with a hair drier to see if that improves things?

My old Haines manual back in the day said that cut-out issues were much more likely to be ignition issues than fuelling issues. Which was indeed the case with an old Volvo I had, often misfiring or cutting out when warm, and always damp in the distributor cap. Luckily it's an easy fix.

 

[insanibasha]

Confirm it is lean by pulling a spark plug and checking it is dry. If it is wet/sooted, that points to overfuelling or failing spark.
A neon spark checker will let you see if the ignition system is still delivering as it dies.

neon spark tester - Google Shopping

www.google.com

Diagnostics first - loading the parts cannon can wait.

Alright, let me get this straight. If the spark plugs are wet, then there is an overfuelling issue which then requires me to play with the carb to get a leaner setting. If they are sooted, then all I need to do is replace the spark plugs after I check that the ignition system is still running properly. Is this correct?

As for the ignition system, what would I need to do if it stops delivering as it dies? further diagnostics? get a replacement ignition coil?

Sorry if i'm asking stupid questions, it's my first time working on a car. And thanks a lot for the response!

 

[insanibasha]

I had a 1989 190, the idle was always really low, one day i experienced something similar to yours

Turned out the diaphragm in the carb had split, i repaired this with a =bit of rubber glove and vulcanizing fluid until replacement.

Problem solved ran like a dream after

This is reassuring to hear, thanks!

Did you find any other problems that relates to the issue before you fixed the diaphragm; such as, plugged up cat converter, bad fuel pump, etc?

 

[insanibasha]

The carburettor cars have a thermostatically operated flap that diverts inflowing air from a hot intake just above the exhaust or from the normal cooler air inlet-it's hidden within the air cleaner assembly- it's possible something is wrong with it. More likely is condensation within the distributor body base which volatalises into the distributor cap as the engine warms up. And shorts out the high tension ignition. Try drying out the distributor body and cap with a hair drier to see if that improves things?

I'm actually planning on taking a look at the ignition side of things before I mess around with the carb and fuel delivery system. As per @Bellow 's recommendation I'm gonna check whether the spark plugs have gone bad, and then I'm gonna use an ignition spark tester to see if the ignition system is still working properly.

Would a consistent spark in the ignition spark tester eliminate the possibility of a condensation in the distribution body being the root of the problem? and please correct me if i'm wrong, but the distribution body is the assembly I circled in the picture right?

 

[insanibasha]

My old Haines manual back in the day said that cut-out issues were much more likely to be ignition issues than fuelling issues. Which was indeed the case with an old Volvo I had, often misfiring or cutting out when warm, and always damp in the distributor cap. Luckily it's an easy fix.

Great to hear! I really wish this is an easy fix. My days are just way better when I drive my 190 to and from work.

 

[Bellow]

Alright, let me get this straight. If the spark plugs are wet, then there is an overfuelling issue

Wet is not firing - either overfuelled or undersparked.
Sooted is firing but overfuelled.

which then requires me to play with the carb to get a leaner setting. If they are sooted, then all I need to do is replace the spark plugs after I check that the ignition system is still running properly. Is this correct?

No, the plugs aren't the problem - they are just telling the story of what's happening inside the cylinder.

As for the ignition system, what would I need to do if it stops delivering as it dies? further diagnostics? get a replacement ignition coil?

Do as Grober advises - that particular engine is renowned for that problem. If that doesn't fix it, proceed to plug checks and unless sooted, be prepared to use a neon tester. If it shows ignition failure, then a number of steps ensue.

Sorry if i'm asking stupid questions, it's my first time working on a car. And thanks a lot for the response!

We all started somewhere....