Engine dying....

[JamesL]

Car is running great, starts well and all is well.

Except when the engine is warm and pulling away from a stop - so sitting in traffic is not fun. The engine dies. I accelerate as normal and the car splutters and bit and rather than spark into life, the revs drop and stalls/nearly stalls.

If I engage neutral and keep the revs up a little before engaging gear (auto), the revs drop a little but not enough to stall.

If I am chugging along at 30mph and take my foot off the throttle and depress it again, a similar splutter happens but it's almost as if the momentum of the car/engine prevents the stall.

Any thoughts please?

[mdsalemi]

James,

You'll get a lot of the obvious here with distributor, spark, timing, fuel, etc.

Here is the easiest to check and the not so obvious which befuddled me for years.

Check the integrity of the entire electrical circuit to the fuel pump in the rear.  Check it any all harness points, and pay particular attention to any connections, terminals and splices.  Check connections at the pump, too.  Do not overlook anything in this circuit.  Look for mechanical faults (bad connections, splices, etc.) and voltage too.  Suspect ANY kind of splice or harness repair.

This is actually considerably easier to do than many other tests.

[JamesL]

thanks Michael

I am running a crane ignition so have my doubts that it's that end of things (yes, I know they are not above faults)

[JimVillers]

James .... Do not overly trust your Crane units; I have had two fail on me.  Try cleaning the sensor and verify that when the vacuum advance moves that nothing is obstructed.  A quick check would be to change your ignition timing by five degrees and see if it affects your dying issue.  If it does, then you know your problem is in the distributor.

[mdsalemi]

James,

If you have the Crane, take off your distributor cap, get a flashlight (torch?) and carefully examine the internal wiring.  On mine (since replaced with Pertronix) I had the optical shutter wheel contact the wiring; when it does,  I had stalling and engine dying.

Only after I closely examined it all did I see that the insulation on the internal wiring (that which comes into the distributor and then goes around to the optical pickup) was slightly abraded indicating contact.

That's even easier to check than the fuel pump.  I had both issues... :'(

[Naj ✝︎]

James,

Also do a 'Blacklick stethescope' test on the small air filter on the inj pump to ensure that the air supply is completely shutting off after the engine has warmed up.
An air leak here would lean out the mixture and cause such problems. Also check the rubber connector pipe for cracks/air leaks.

happy fixing. perfect day for it!!!

naj

[JamesL]

OK

An update

I didn't get out to fix (long story) and the problem continued

And then today, on my way back from a LONG drive (another long story), it suddenly started to misfire at/above 3500 revs. So I pulled in the gas station for gas and a pie, and set off again. Engine warm so I needed to keep the revs up on pulling away, and once up and running, ran like a dream, all the way to my mechanic - where I nearly got killed as it died as I crossed the median...

Upshot was, they couldn't get it to run long enough to get it on the lift. I did that and they changed the fuel filter. They thought it was running lean but adjusted the airflow (removed the screw) and the car didn't stall. Suggesting the opposite to lean.... They stuck a meter on the exhaust and was running at about 5 on idle, but 11 when revved up. Car still stalling in gear but idling happily in neutral

Upshot is, they have let me borrow a w201 (2.6 auto - lovely car) for the weekend and will get their whizz on it on Monday. Hopefully we'll find out more, BUT the cold start valve was mentioned as possibly not shutting off



The long drive was to a bodyshop as I need work done. Seemingly - and why is this always the case? - more than I thought was needed Going to be an expensive winter....

[ja17]

Hello Tosh,

Linkage should be checked, timing should be checked, fuel pressure and volume should be checked. Ignition componants must be working properly as mentioned. Having a rich idle condition and a lean acceleration condition is rare but possible. Linkage or fuel pressue can be the problem.

"Read" the spark plugs. Don't be afraid to install a fresh set of spark plugs even if the ones in the engine are fairly new. Lots of fiddleing  around can cause problems with spark plugs. Originals can be saved for use later if good. A fresh set off plugs can often be all it needs and a cheap fix! Try a set of non-resistor NGKs.

[JamesL]

Thanks all

I had a feeling it was going to be one of those "tough to find, easy to fix" type problems. As I said to the chap in the shop, the advantage of a modern car is you just plug it into the computer to find the fault. The disadvantage is that there's so much more that can be wrong"

[JamesL]

Just a little update...

Chap looked at all the usual suspects and found nothing wrong

Finally, he ran a current through the rotor arm and found the resistance way too high. Swapped out the rotor arm and all ran well. So, one new rotor arm later.....

More costly to find the fault than to fix, but the suggestion was that the inside of the arm may have been breaking up, making it less efficient, thus the engine died...