Stalling out when decelerating. HELP!

[tisalover]

I feel your pain.   It has to be spark or gas. The symptoms strongly suggest a fuel delivery problem / intermittent absence.

Common things happen commonly. The 15 minute time/Waiting for it to cool down prior to restart suggests a heat component, i.e. vapor lock or unwanted effect of heat on electronics. The deceleration symptom may be a red herring.

 

I had similar problems with a object rolling around in my gas tank intermittently obstructing the inlet of the Tisa.  Years ago I also had similar problems with a 1602 hot rod where the old tired fuel pump could not pump enough fuel under high throttle going up hills and the car would starve itself. If I were you the first thing would try is rebuiling/replacing the fuel pump. Relatively cheap and very doable. Or you could run an electronic fuel pump.

I hope that your problem is not related to spark, as I desperately want the 123 ignitions to be dependable, as I am getting ready to install mine. My fear of too much technology increases in these modern days. (I hope no one on the board has relatives in an English hospital now) I used to just set my points with a match pack cover if the car started to run bad in the old days.

Nowadays I worry that I would be at the mercy of hidden microelectronics and intermittent electrical gremlins. (123/faulty pertronix etc.)

Let us know how it turns out, please.

Best regards, Peter

[avoirdupois]

 

Several things occur to me.  Yes, often the devil is in the details.

 

Chris is absolutely correct regarding the ballast resistor and the blue coil.  Although there were Blue coils that were not internally equipped with a ballast resistor, the majority of them are/were so equipped.  By using the pictured setup, your coil's output is probably limited and, at best, marginal.  Since your aftermarket ignition evidently requires very limited voltage to function adequately, you probably don't notice any reduced voltage issues.  Nevertheless, unless there are manufaturer's instructions to the contrary, consider bypassing the resistor or replacing the coil.  (The fact that the Blue coil was marketed as "super" never answered the question: "compared to what?")

 

I may have misunderstood your narrative.  I read about shutting down when decelerating.  Is this only on terrain that is unlevel?  (Uphill or downhill?)  As has been noted, Improperly adjusted floats might naturally be affected by an incline or decline.  So would a fuel pickup that is poorly positioned in the fuel tank and that might even include an in-tank mechanical pump located in an area prone to cavitation.    

 

Consider any not-so-obvious loose wires.  There have been numerous threads about engines that cut out during heavy braking or turning in a particular direction.  In some of those instances, the culprit can be a live wire with compromised insulation that barely brushes against a ground and briefly shorts out the system.  That might even be a wire traced to the ignition switch or under the fuse panel.  Often that sort of problem is difficult to detect even though it hiding in plain sight.  Sometimes shaking or prodding with compressed air or even watering can duplicate and isolate the problem.  (Looking at the fuse bus and examining the connections for obvious corrosion is never a bad idea.  Your car might seem like it is brand new, but who knows what is going on under the fuse buss?  If I recall correctly, two fasteners is all it takes to carefully lift and examine.

 

Finally, I turn to your aftermarket ignition system.  A subject that I know little about, other than it may be close to perfect, but that does not mean it is impervious to everything, including kryptonite found on the road.  Just as with any loose wiring, there could be a micro-short on a board or chip, affected by certain vibration or thermal condition.  From what I have read, the distributor body typically provides a needed ground, but your specific installation obviously is unknown.  Here is a troubleshooting guide borrowed from another source.  Although it does not mention kyptonite, maybe it will trigger some assistance.

 

Quote

Trouble Shooting tips for 123 from 123ignitionusa.com

2. Most cars have had multiple owners. Trace all wires and make sure the positive ignition wire is on the positive side of the coil and the negative is on the negative side of the coil. A 123ignition will light up but not fire if this condition exists.

3. The casing for the 123 serves as a ground for the unit. make sure as with any ground you have good contact. This would include your chassis ground to the motor and battery.

4. Put in a new coil. Coils can go bad slowly and old coils cannot be trusted. Even new coils can be bad.

5. Do not use Low resistance coils (Dry Coils) they can damage the 123Ignition causing the feed wires to come unsoldered. In particular the black wire. Which renders the unit inoperable. Remember, coils should not be less than 1ohm resistance. Most Dry Coils are around .5 resistance.

6. Now make sure we have power and green light not only when connected to the coil but when cranking the engine to start.

7. Some Volvos have a sort of safety anti theft feature I read about on the forum that interferes with the 123 voltage supply. To see if this is the case with you take the red wire that is supposedly connected to a switched 12v power supply and connect it to a constant unswitched 12v power supply. In other words it will be hot all the time. Not a problem as the 123 draws less power than a clock.

8. From time to time the contact on the cap does not always make contact with the rotor or the button falls out of the cap.

9. The rotor has not always been seated properly on the 123 post. Needs a firm push - consequently if not seated timing will be obscure or non existent.

10. Make sure the +ve ignition switch wire is indeed on the +ve side of the coil and not the negative side. This may sound silly but the 123 will not run if this happens, whereas a point set will, as in the old distributor.

11. If you have a ballast resister on the coil try taking it out of the equation.



Wiring the 123 in Series to work with Smith Tachometers.

May or May not work on your Tachometer

You will need to wire the unit in series to make the Smith Tachometer compatible. Here is how to do it:

1.)The White wire goes to the + terminal on the coil in the original configuration and should stay that way.

2.)In order to put the tach in series with the 123 all you will need to do now is connect the red wire from the 123 to the fuse block where the white wires connect.

3.)Now the black from the 123 will go to the -ve post on the coil.
http://www.mgexp.com/phorum/read.php?1,2882085

 

Edited May 14, 2017 by avoirdupois

[gordon415]

18 hours ago, HBChris said:

You shouldn't use a ballast resistor with a blue coil, it reduces your spark, but that isn't the problem unless coil is old and it overheats.

Thanks! I had no idea. It was like that when I bought the car a year and half ago. I removed the ballast resistor and jumped the green wires this morning. 

The coil is old (made in Germany instead of Brazil). I had it checked at it does what it's supposed to do, but I do not know if it's overheating. I may consider replacing it anyway if there's any chance it could be part of the problem.

 

 

13 hours ago, jgerock said:

What bulbs are in the H4 headlights?  Does the car stall when the lights are on? No matter what the responses are, I highly recommend adding relays to the high and low beam circuits.  Susquehanna Motorsports sells a wiring harness kit that works well and you don't have to modify the stock harness.

I went through Daniel Stern to do the upgrade. Great guy. The harness I bought from him is from Susquehanna. I'm hopeful that replacing the voltage regulator will prevent further burned out bulbs. 

[gordon415]

10 hours ago, tisalover said:

I hope that your problem is not related to spark, as I desperately want the 123 ignitions to be dependable, as I am getting ready to install mine.

The stalling problem occurred even before I installed the 123Ignition, although it's happening even more now than it did beforehand. That makes me hopeful that it's not the spark. Everyone I know who has installed a 123Ignition has been super happy with the increased performance. I hope you are, too! 

 

I'm going to replace the fuel pump like you recommend. Thanks!

 

 

 

6 hours ago, avoirdupois said:

I may have misunderstood your narrative.  I read about shutting down when decelerating.  Is this only on terrain that is unlevel?  (Uphill or downhill?)  As has been noted, Improperly adjusted floats might naturally be affected by an incline or decline.  So would a fuel pickup that is poorly positioned in the fuel tank and that might even include an in-tank mechanical pump located in an area prone to cavitation.

In terms of stalling, it happens downhill or on flat terrain. It's often associated with hard braking, which tends to occur more often when coming to a stop going downhill. I'm going to replace the mechanical fuel pump to rule out whether that's it or not. I'm not sure the last time it was replaced so might as well.

 

Thank you for all the ideas on where to look. I hoping to not have to inspect the wires so closely, but will do so if nothing else works. I looked under the fuse box as you suggested and all looks okay there. One weird thing my mechanic found there was a red wire that someone had fitted with an inline fuse. The wire powers the the hazard switch. Doesn't make sense to have an inline fuse going to the fuse box (and it's definitely not on the wiring diagram that way), so they replaced it with a permanent jumper. And soon I'll have a working hazard switch again! I took the ballast resistor off this morning, too. 

 

 

 

 

['76mintgrün'02]

1 hour ago, gordon415 said:

I'm going to replace the fuel pump

Be sure to buy the long necked version and not the stubby one that won't clear the coolant line running underneath it.

 

Tall

Short

[gordon415]

1 hour ago, '76mintgrun'02 said:

Be sure to buy the long necked version and not the stubby one that won't clear the coolant line running underneath it.

 

Thanks, and uh oh. I just ordered one that looks a lot like the short one in your second picture. It appears the tall one (133112616229) NLA. Blunt's website says it's superceded by 13311257784, which appears to be the short one in the pictures you posted. 

 

I just emailed Dave at Blunttech. Thanks for letting me know about this! You saved me from a lot of frustration.

[avoirdupois]

I must apologize for not reading the thread more closely and the fact that you are still using a mechanical fuel pump.  A weak pump (or even a strong pump that draws air into the system) could have something to do with your symptoms, but I have my doubts.  If there is enough pressure and volume to feed the carb reservoir at cruise, rapid deceleration would point more toward the float setting or something electrical.  Of course, you can't accurately set a float with a pin hole leak that is half full of fuel.    Also, when I mentioned a loose wire, I would look close to distributor/coil wiring near the firewall.  Bear in mind that the engine moves around on its mounts and that also means some of the wiring necessarily moves too. 

 

It is easy enough to swap out a mechanical pump.  But it is probably just as easy to test the pump with a simple (inexpensive) vacuum gauge.  (There are other means of testing the pump for pressure and volume, even without a gauge.  But - it is something I would not ordinarily recommend except for those who like to tempt fate and have a fire extinguisher handy..)   If you are wondering, since the pressure is only a few pounds, your finger can be a diagnostic tool. 

 

.

[John76]

Just one more thing to check....are your red ignition wires solid copper core, or resistance wires?

If solid copper core, the EMI could be interfering with the 123 distributor/Pertronix ignition module, causing strange /intermittent  behavior.

[gordon415]

I drove it around the block and attempted to replicate the problem. I stopped suddenly, while out of gear, and the engine cut out again. This time, though, I was able to restart the engine immediately and back into my driveway. I took off the gas cap immediately and there was no pressure.

 

Before the drive, I let the car warm up in the driveway and popped the hood and looked around. I brushed against the braided vacuum hose from the brake unit and heard an air leak. The engine began to sound different when I pressed against the hose. Not sure if this is related, but figure I need to replace this hose if tightening the clamps doesn't work (didn't try that yet). 

 

Additionally, I watched the amount of gas passing through the fuel filter. Very little. I sat behind the wheel and gave a little gas, got back out and checked again, and still not much there at all. The filter was replaced in March, and there's already a lot of gunk in it again. Perhaps a dirty/rusty gas tank is the culprit? I know it's never supposed to be full of fuel, but this seems significantly less than I've seen in the past. Could the fuel sender be blocked up with gunk, too? and the fuel lines? Not sure this would explain why the stalling happens when coming to a stop, though. Just adding projects to the never-ending list.

 

2 hours ago, John76 said:

Just one more thing to check....are your red ignition wires solid copper core, or resistance wires?

If solid copper core, the EMI could be interfering with the 123 distributor/Pertronix ignition module, causing strange /intermittent  behavior.

It looks like stranded copper wires to me. The label on the wires says "Autopart International Silicone Copper." Not sure of this brand....perhaps it's worth replacing them?

 

4 hours ago, avoirdupois said:

Also, when I mentioned a loose wire, I would look close to distributor/coil wiring near the firewall.  Bear in mind that the engine moves around on its mounts and that also means some of the wiring necessarily moves too. 

I checked them out and all is good. I tightened the connectors just in case. The mechanic said my front Bilsteins are a bit stiff and the car rocks a bit more than it would otherwise, so loose wires are definitely a possibility. 

I may pick up one of those vacuum gauges....the guy I bought my 02 from gave me boxes of parts that he got from the owner before him, including some used fuel pumps. I have no idea if they work.

 

So if the carb is the culprit, would the problem be happening more consistently? While the frequency of the stalling has increased as of lately, it does not happen all the time.

[Mike Self]

9 hours ago, gordon415 said:

I brushed against the braided vacuum hose from the brake unit and heard an air leak. The engine began to sound different when I pressed against the hose.

While those brake booster vacuum hoses are very strong (and have internal wire reinforcement) they do die of old age--especially the short section between the check valve and manifold.  That piece is under constant tension from being bent under the air cleaner, and will eventually crack/split.  You can't see the break due to the cloth covering (same with the old fuel lines, which you should replace if they're still there).  

 

If you find the booster hose's short section has the leak, order the E-21 part as it has a curve moulded into the hose so it won't crack.  That massive a vacuum leak can definitely cause stalling.

 

mike

[avoirdupois]

9 hours ago, gordon415 said:

I drove it around the block and attempted to replicate the problem. I stopped suddenly, while out of gear, and the engine cut out again. This time, though, I was able to restart the engine immediately and back into my driveway. I took off the gas cap immediately and there was no pressure.

 

Before the drive, I let the car warm up in the driveway and popped the hood and looked around. I brushed against the braided vacuum hose from the brake unit and heard an air leak. The engine began to sound different when I pressed against the hose. Not sure if this is related, but figure I need to replace this hose if tightening the clamps doesn't work (didn't try that yet). 

 

Additionally, I watched the amount of gas passing through the fuel filter. Very little. I sat behind the wheel and gave a little gas, got back out and checked again, and still not much there at all. The filter was replaced in March, and there's already a lot of gunk in it again. Perhaps a dirty/rusty gas tank is the culprit? I know it's never supposed to be full of fuel, but this seems significantly less than I've seen in the past. Could the fuel sender be blocked up with gunk, too? and the fuel lines? Not sure this would explain why the stalling happens when coming to a stop, though. Just adding projects to the never-ending list.

 

It looks like stranded copper wires to me. The label on the wires says "Autopart International Silicone Copper." Not sure of this brand....perhaps it's worth replacing them?

 

I checked them out and all is good. I tightened the connectors just in case. The mechanic said my front Bilsteins are a bit stiff and the car rocks a bit more than it would otherwise, so loose wires are definitely a possibility. 

I may pick up one of those vacuum gauges....the guy I bought my 02 from gave me boxes of parts that he got from the owner before him, including some used fuel pumps. I have no idea if they work.

 

So if the carb is the culprit, would the problem be happening more consistently? While the frequency of the stalling has increased as of lately, it does not happen all the time.

 

Silicone Copper wire, in all likelihood, indicates solid core wire.  So, you could have an interference issue.  I don't know enough about your aftermarket ignition to offer an opinion on that.  However, if the wires were a problem, I would expect many more engine operation issues to have occurred, e.g., misfiring or random cutting out versus just when heavy braking.

 

You mentioned something about a vacuum hose leaking when inadvertently flexed.  MIkeS may be on to something since you said the problem seems somehow connected with rapid deceleration, i.e., with heavy braking.  If you have a leaky brake booster vacuum hose, you might be reminded of that every time you brake.

 

I also thought about this issue with your fuel feed line, but your picture evidences hose that is not original and seems to be in pretty good shape.  As MikeS will tell you, the original braided fuel host had a tendency when old to develop some unwanted porosity.  It could swell and weep.  It could also draw air into the fuel system.  Most of the time the engine (and fuel pump) would manage fine with this situation, despite the fact that it was potentially dangerous.  Maybe, somewhere in your fuel delivery lines,  you have a pinhole or two that is hampering an otherwise decent fuel pump?  In other words, only occasionally, given the right circumstances of flexing and ambient temperature, your carb is starved for fuel.  This might even account for your occasional inability to restart immediately since the pump is drawing some air along with fuel. 

 

Another thing, you mention a dirty tank.  Maybe you ought to look into this.  If your fuel pickup screen is dirty, that pump is going to have a harder time overcoming that restriction.  The same is true with any inline filters.  You could take something like a mityvac and determine if the fuel lines are restricted by simply sucking on the line (with the mityvac, or some other means of applying vacuum.)  Or avoid the entire vacuum exercise and disconnect the line and blow them out with compressed air.

 

 

 

 

 

 

 

Edited May 15, 2017 by avoirdupois

[arminyack]

Single barrel or dual barrel solex? 

 

I had a grounding problem with my 123 that gave me a very similar problem. Someone posted above that the 123 is grounded via the body of the dizzy....not true on mine! I have a ground wire, and the connector I crimped for that ground wire came a little loose...so it was intermittently loosing ground. It wasn't very loose either. I crimped on a new connector just out of covering all the bases....I really didn't think this was it.....but then it solved the problem permanently . I almost lost my mind tracking this one down!

 

Another thing that gave me grief like this from a couple of years back....it was the thermostatic box that connects the air cleaner to the snorkel Do you still have this on? Something was going on with mine that would cause the car to die...then be a bitch to restart, or it would fire right back up again. I noticed that the times it refused to restart, if I popped off the cover of the air cleaner, it fired right back up. Air starvation. I took off the box, problem gone for good.

[Birdie]

I have a friend with a very similar problem that I have set out to help fix. It just seems like a fun challenge. We are also in the Bay Area so stalling on deceleration might henceforth be known as Bay Area Stall on Deceleration (BASD). I plan to go over there today and have some ideas of what to check but I am definitely taking input on all avenues - especially ideas on tests to run. 

 

Context:

When he drives it, if he go over maybe 3.5k rpms and then decelerates, it dies. He can start it fairly quickly - certainly not the 5-15 minutes mentioned earlier in this thread - maybe 60s max. Big puff of smoke comes out at restart (don't know color yet).

 

- This is a new rebuild - 1yr

- he's been driving it happily / reliably for one year

- the car runs great right up until he decelerates and it stalls

- weber 32/36 electric choke

- no solenoid cut off

- no fuel return line

- no fuel return valve

- no fuel return check valve

- vacuum advance disconnected

- no smog equipment at all

- battery is in trunk - this is one of the more spacious engine bays you'll ever see. 

- he recently had the master cylinder (this might be very important)

 

I bumped into him at a Cars and Coffee (he was in a different car) and we discussed his issue. I offered to come by and have a look. To be honest, I was ill prepared but figured I would run some tests and then come back to the gang at 2002aq for input.  Here is the interesting tests we ran.

 

His car was in the garage so he started it up and backed it into the driveway. We then easily reproduced his problem by having him sit in the driver's seat and rev it up 4k+. When he released the accelerator pedal - the car died. He then shows me a forum posting he made at an inferior forum 🙂 where someone suggested he clean his carb idle jets. Agin, I am just there to get the lay of the land so sure, we clean/verify his idle jets. We then start the car and a large plume of smoke comes from the exhaust. Unfortunately, I didn't see it because I had my head in the engine bay but my daughter notified us of it's occurrence. I therefore, can't verify the color of the smoke. Ok, so with engine running for the second time, jets clean, I use the throttle linkage in the engine bay to reproduce the problem No one is in the car (again, I think this might be relevant). I rev the hell out of it and drop that throttle with vigor. No stall. Tested over and over again with crazier and crazier rpm levels. No stall.

 

Now I thought there was almost no chance we had actually fixed this problem but everyone cautiously high fived. I'm no old timer but nothing has ever been fixed that easy on my car so... Later that day when he texted to let me know it was still dying when driving around I was not surprised. I was even a little excited that we had an actual mystery on our hands. 

 

I am heading over there today to run some tests. First, I plan to check and see if he has brake fluid in his booster. He did have the MC replaced recently and while his brake fluid level is okay - the fluid maybe have been in the booster prior to the change and not have been removed.  It could also just some sort of booster vacuum leak.  I am leaning towards the brake booster because he used the brakes to move the car out of the garage and he was likely pressing the brakes during the first test.  Then when I performed my tests, no one had been or was pressing the brakes. We could no longer stall the car parked in the driveway. However, he goes driving and I assume used the brakes... repeat stalls.

 

So, my question to folks is:

a) might I be on to something (I am no real mechanic so you won't hurt my feelings if I am way off)

b) if I am on to something what should I do to verify fluid in the booster: just pull the hose and it will be obvious? / pull hose and look inside the booster (possible?) / pull hose and put something long and skinny into the booster to check for fluid, etc.?

c) how to best verify a vacuum leak in the booster (no fluid)

d) what else should I check? 

e) should he connect his vacuum advance?

 

as always, thanks.

 

['76mintgrün'02]

9 minutes ago, Birdie said:

e) should he connect his vacuum advance?

 

He could try it, but I think he should buy an Innova 5568 first, so he can see how the distributor is behaving.

 

Here's a good thread on that topic.  (Unfortunately, it stalled out).

 

https://www.bmw2002faq.com/forums/topic/335822-weber-3236-vacuum-advance-question/

 

Tom

 

['76mintgrün'02]

Googling suggested that excessive fuel pressure can cause stalling on deceleration, as fuel is forced past the float needle, flooding the engine.  Do you have a gauge you could T into the line?