Intermittent sputter and die

[mtiger_dds]

Hi all-

I have a 1973 Bavaria 4-speed. Original Zeniths. I replaced the mechanical fuel pump (Pierburg) a little over a year ago.

Last night, I drove on an errand about 10 miles/15 minutes, it sat for maybe 15 minutes, and then stalled a mile after taking off. I limped it to a parking lot.

Full tank of gas, new battery reading 14+ volts at the cigarette lighter.

It sounds like its running on less than 6 cylinders before dying. It’ll still turn over but die quickly.

I let it sit for a few minutes, started it back up, and then revved it a couple of times to keep it over 2k rpm, then drove it home just fine. This has happened twice in the last month. I can usually drive the car and it's fine to run similar errands, etc.

I have a new inline fuel filter that I'm going to swap today.

Air temp in NE Ohio last night was mid-60s.

Ideas?

 

[Stevehose]

What kind of ignition system - points or electronic etc do you have. How old is the coil and other ignition components - cap, rotor, plug wires, wires at coil, ballast resistor (if used) etc. All fuel hoses in good condition and tight? Fuel hose at gas tank sender tight? Gas cap correct and not holding vacuum? Other suspect can be intermitttent ignition switch.

 

[mtiger_dds]

What kind of ignition system - points or electronic etc do you have. How old is the coil and other ignition components - cap, rotor, plug wires, wires at coil, ballast resistor (if used) etc. All fuel hoses in good condition and tight? Fuel hose at gas tank sender tight? Gas cap correct and not holding vacuum? Other suspect can be intermitttent ignition switch.

Points. All ignition components mentioned are of unknown age (I've had the car since 2017) aside from the plug wires that were replaced 4 years ago. I have ordered a new cap, rotor, condenser, coil, and points for preventative replacement.

The only fuel line I have not replaced is the one from the tank to the back deck of the trunk. Gas cap is correct and not holding vacuum.

 

[Stevehose]

that's a good start!

 

[mtiger_dds]

Fuel hose in the trunk and fuel filter replaced. A quick trip around the block was uneventful.

 

[boonies]

Good to hear your brief run was un-eventful. Keep your old condenser as a spare, the new ones are notorious for being poorly made.

 

[mtiger_dds]

New Pierburg fuel pump and Bosch coil arrived today. I'm still waiting on Pelican to ship the points and rotor I ordered. My son was eager to lend a hand to swap out the fuel pump. Another 6 mile trip was without incident.

 

[Baikallackierung]

I would take a look in the fuel tank. Sometimes stirring up rust will temporarily clog things up (like your filter) and then clear up when everything settles.

 

[mtiger_dds]

Back to the drawing board.

I've driven it several times with no issue in the last week after replacing the above mentioned parts. That includes a mechanical fuel pump, fuel filter, fuel hose in the trunk, battery, coil, distributor cap, rotor, and now points. I have not replaced the condenser yet, but I have a new one.

After a roughly 18-mile trip this morning, we pulled into the car show venue and it died without warning. Wouldn't start back up, so we pushed it into its place and tried to enjoy the day.

I tried several times throughout the day to restart it with no success. We checked the points, gap was good. I had it towed home. I replaced the points when I got home, and it didn't help.

It cranks but won't turn over to fire up.

 

[sfdon]

Three things you need for a car to start and run.
compression
spark
fuel

Time to get that spare spark plug out of the toolbox in your trunk put it in the number four spark plug wire put the plug on the valve cover and crank the engine over.


question - do you have spark?

 

[bluecoupe30!]

Back to the drawing board.

I've driven it several times with no issue in the last week after replacing the above mentioned parts. That includes a mechanical fuel pump, fuel filter, fuel hose in the trunk, battery, coil, distributor cap, rotor, and now points. I have not replaced the condenser yet, but I have a new one.

After a roughly 18-mile trip this morning, we pulled into the car show venue and it died without warning. Wouldn't start back up, so we pushed it into its place and tried to enjoy the day.

I tried several times throughout the day to restart it with no success. We checked the points, gap was good. I had it towed home. I replaced the points when I got home, and it didn't help.

It cranks but won't turn over to fire up.

As sad as this feels, this is an important step in really tearing into this weakness. You are now on the road to recovery. Your next moves, especially with the expert assistance of this Group, will help you on your way to identifying and rectifying what is really going on. Hang in there, and keep reporting what responses you get from each adjustment.
There is no where else you can get such informed advice from owners/drivers who have been there, and sorted similar troubles out of their E9. Good luck, Dr.Dentist.

 

[Dick Steinkamp]

after replacing the above mentioned parts. That includes a mechanical fuel pump, fuel filter, fuel hose in the trunk, battery, coil, distributor cap, rotor, and now points

Firing the "parts canon" at a problem rarely results in success. The odds aren't good, AND you might introduce another problem which then makes troubleshooting tough.

question - do you have spark?

It's probably a good thing that the problem has gone from intermittent to always there. Hopefully there is still only one problem and no more have been introduced by the application of the parts canon. Think of diagnosing the problem as a decision tree. The result of Don's first suggested test will lead logically to another test, then another, etc. until the problem is found.

 

[Bearmw]

Suck Squeeze Bang Blow. The keys to the universe .

 

[JFENG]

question - do you have spark?

Next time the second thing you check in a “cranks but doesn’t start” situation is the spark. Almost always can be done on site with a screwdriver (or that spare spark plug in your the tool tray). My guess is on a bad condensor.

From another website:

There are a number of condenser problems that can cause you varying amounts of grief.

(1) It can fail "open" at which time the car may or may not run, but if it runs at all, it will run quite poorly and it won't run long.

(2) It can fail "short" at which time the car will not run/start/etc.

(3) It can fail intermittently (usually temperature provoked) at which time, the car behaves similar to # 1

 

[mtiger_dds]

Three things you need for a car to start and run.
compression
spark
fuel

Time to get that spare spark plug out of the toolbox in your trunk put it in the number four spark plug wire put the plug on the valve cover and crank the engine over.


question - do you have spark?

I'm going to check after work today and will report back.

 

[mtiger_dds]

Firing the "parts canon" at a problem rarely results in success. The odds aren't good, AND you might introduce another problem which then makes troubleshooting tough.


It's probably a good thing that the problem has gone from intermittent to always there. Hopefully there is still only one problem and no more have been introduced by the application of the parts canon. Think of diagnosing the problem as a decision tree. The result of Don's first suggested test will lead logically to another test, then another, etc. until the problem is found.

I've saved everything I've removed. I can revert back to original and start from scratch if necessary.

 

[bavbob]

So why are we not saying. "Get thee to a Petronix Unit" which will be a plus regardless of what is eventually found to be the problem?

 

[mtiger_dds]

So why are we not saying. "Get thee to a Petronix Unit" which will be a plus regardless of what is eventually found to be the problem?

I have a 123 on the shelf that I've been hesitant to install. The process seems to be above my pay grade.

 

[Ohmess]

So, you appear to be somewhat new around here. I tell all the rookies one important thing. sfdon makes a living working on our cars and donates his time here to help our little community. He has been massively helpful to dozens and dozens of us here in one way or another. If you post that you have a problem, and he jumps in, do what he tells you. And make this a priority over all the other replies.

Do the spark test he suggests and post the results.

And don't be shy about coming back and asking more questions. We've all been there.

 

[mtiger_dds]

So, you appear to be somewhat new around here. I tell all the rookies one important thing. sfdon makes a living working on our cars and donates his time here to help our little community. He has been massively helpful to dozens and dozens of us here in one way or another. If you post that you have a problem, and he jumps in, do what he tells you. And make this a priority over all the other replies.

Do the spark test he suggests and post the results.

And don't be shy about coming back and asking more questions. We've all been there.

Long time owner/lurker, seldom post but I'm extremely appreciative of the advice so far.

No spark.