Hesitation & stalling when hot (was: camping...)

[TomWesty]

[Randy in Maine]

You have to love the cheap fix. I always keep a spare TSII in my toolbox.

[PEI Jonny]

Well, I went out this evening to take a look at the temp sensor, pulled the lead wire and it fell out of the connector to the EFI wiring harness. I thought it can't be this easy, right? RIGHT! that's all it was! I reluctantly took it for a spin expecting to stall out and die at the first stop sign, but she ran great! So I went a little further smiling ear to ear while I did! Hated to come back to the shop!
Thanks Robbie and Randy, that's what makes this site so valuable! I'm going to order a new temp sensor just to have in case.

Cheers!

Jon
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'70 vert
'72 super
'73 std beetle( not running)
74 std beetle ( not running)

[Randy in Maine]

Yes a defective TSII will make that exact symptom. The FI actually thinks the engine is cold and gives it too rich of a fuel:air mixture and thus the blackened plugs.

Make sure the TS II is snugly connected to the head, but don't reef on it as it has pretty fine 10mmx1.0mm threads.

Also inspect the electrical connection to make sure it is 100%. You can also ground out the crimp connection that goes to the engine wiring harness to a known good ground to get you home if needed.

[PEI Jonny]

Hey Robbie, huge fan! You've got an amazing knowledge of this stuff!
I do have a multi meter, not half as nice as the one your showing. I have read on a couple of other threads that the temp sensor could be the culprit. I will definately check that and get back to you. I'll definately be the first one to tell you I'm not a mechanic, but a decent hobby mechanic?! Thesamba has saved my butt more than a few times.
Thanks again, I'll check that out and getback to you. If the temp sensor was bad, would it be causing this problem?

Jon
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'70 vert
'72 super
'73 std beetle( not running)
74 std beetle ( not running)

[airschooled]

Hi there,

Do you own, and know how to use, a multi-meter? If so, I would recommend using the component checking chart on p. 40 of the fuel injection training and troubleshooting manual.

https://www.thesamba.com/vw/archives/manuals/afc_f...Manual.pdf

Pay special attention to "pins 13 and ground" as this is your head temp sensor, or warm up sensor. It is called TS2 by most people.

(The last four tests on the page are useless in your case; ignore them. You may not have "3 and 18" function either, no problem here.)

If you don't have a multi-meter, I recommend this one, as it does everything you need and nothing more.

https://www.amazon.com/gp/product/B000R8NL8I/ref=a...d7e9fbda83

Familiarize yourself with where the TS2 is located, because my crystal ball tells me you'll be looking around there soon.

I think this is WastedTYouth's photo; either way it's great:

Let us know if you have more questions; it's hard to tell someone's mechanical aptitude in one post.
Robbie
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One-on-one tech help for your vintage Volkswagen:

www.airschooled.com

https://www.patreon.com/airschooled

[PEI Jonny]

Hi folks, I figured I'd post here rather than start a new thread. I'm having the same issues once engine is warmed up I can hardly get out of first gear from the hesitation, bucking and stalling, luckily I live downhill so I can coast home!
Driving a 78 westy, fuel injected, GE engine, my distributor doesn't have the vacume advance, thinking it's a 009
So far I've checked and replaced the fuel filter , cut that open and had nothing in it, was rather clean actually.
Then I checked for vacume leaks, found a few, fixed those and tried driving again, still the same hesitation/bucking, to the point that the bus stalls.
Tonight I replaced the plugs, which were fouled black badly. So then I thought I had fixed the problem. But to no avail. Let the bus warm up in the driveway, took it for a spin around the block, once getting about .5 mile away from home, same thing started happening. I notice this time that it took longer for this to happen so I'm sure replacing the plugs helped a little, but still bucking, stalling, to the point where I barely made it home and couldn't get out of first gear
It seems to me that I'm not getting fuel? Maybe dirty injectors? Bad fuel pump? I plan to order a new pump just in case. Checked the plug wires and rotor, points, all seem fine, but will look closer at that as well. bought this bus last October, drove it for a few weeks then stored it. It ran fine before parking in the heated garage for the winter. Any info would help! I'm new to this FI stuff so I'm slowly learning as I go!
Thanks in advance!!
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'70 vert
'72 super
'73 std beetle( not running)
74 std beetle ( not running)

[WhirledTraveller]

Just to chime in that I had the same bucking symptoms that slowly worsened over time, and it too was a worn out AFM wiper track. Every time I fixed something else I thought it was running better but it always came back. But now at least I know my ignition and fuel system are in tip top shape!

It only seemed to do it warm. Which is odd when you think about it. I suppose because the worn out AFM causes lean running and when cold, the TSII makes everything rich and masks the symptoms.
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1977 Westy, Automatic. Big Valve heads, CS Cam.

[ol36er]

I hope this is the cure AB! I'm having the same problem and I'm gonna try a different AFM tomorrow. Fingers crossed
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WTB - Green Middle Seat Snowflake Kickpanel
WTB - Wingnut air cleaner

[AB westy nut]

I'd like to give what I hope is the final update on my intermittent miss/hesitation issue. About a month ago I replaced the AFM with a good spare and so far, after about 400 miles of driving, the issue hasn't returned. Crossing my fingers that this is the end of the ordeal!
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1963 Ruby Red 356 Cabriolet
1976 Sage Green Westfalia Deluxe

[AB westy nut]

I totally agree with your thinking that it's a cracked or corroded wire somewhere in the system. I replaced the negative battery strap with a brand new one a few weeks ago but clearly wasn't the culprit. I also purchased a new Wolfsburg West positive cable but it was way too short (anyone else run into this?) so I think I'll have to make my own as I can't seem to find one the right length.
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1963 Ruby Red 356 Cabriolet
1976 Sage Green Westfalia Deluxe

[aopisa]

I don't want to sound like a broken record either, but I had the EXACT symptoms that you have. It would go underground for long periods of time only to resurface and repeat the sequence with no predictive pattern. Sometimes it was a minor hesitation for a only a second then it would behave perfectly for several weeks. Every time I thought I had solved the problem(coil, TS II, etc.), it would return, as if the bus had malicious intent. It finally got so bad last summer that I could no longer drive it. I began to hate my bus.

I think I tried to get help both here and a multi page thread on the IAC site.

http://www.itinerant-air-cooled.com/viewtopic.php?f=3&t=11517

I will hazard a guess and say that this problem will not fix itself.

I have also come to realize after reading countless threads that nearly every one of these bucking issues seems to have its own unique cause and solution.

On a dark night of hair pulling and cursing in my driveway a friend discovered my problem and it has been smooth sailing ever since.

To refresh your memory it was the all too simple negative battery cable making a very poor (paint and sand) connection with the chassis.

I am sure you have checked and rechecked everything that you can think of. I am still betting that there is some bad or weak electrical connection somewhere that is giving the FI system fits. I hope you can track it down soon.
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1977 Westy 2.0L FI

Leap into the boundless and make it your home! ---Chuang-Tzu

Please let me know if you do not receive this message...

[AB westy nut]

Mid-summer update: I've been putting on about 100 miles every weekend so far this summer. Conditions are usually the same when I set out; sunny and dry and about 22C. Not once had it hesitated or bucked up until this past Sunday, when about 15 minutes down the highway it stumbled slightly for about 10 seconds. Then all was fine again for the rest of the trip. Sorry if this is sounding like a broken record but I'm just wanting to keep the thread going until I find a solution. I'm going to install and adjust the spare AFM this weekend to see if that cures it. The problem is, the stumble is so infrequent and random that if it's not the AFM it may be weeks before the issue reappears. Sure makes for a tough diagnosis. Whatever it is, it seems the combination of all the little things I've tested/checked/tightened/adjusted/replaced has lessened the severity of the issue. If you recall, last summer there were times when it was nearly un-drivable and it would hesitate & buck nearly every time I took it out. Stay tuned...
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1963 Ruby Red 356 Cabriolet
1976 Sage Green Westfalia Deluxe

[AB westy nut]

Interesting. I just picked up a spare AFM which I'll try if and when the hesitations kick up again.
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1963 Ruby Red 356 Cabriolet
1976 Sage Green Westfalia Deluxe

[sylvanacres]

Hi there
I had the same problems on my 77 westfalia
I did the same tests to chase the same problem
Turned out to be the air flow meter
I had one from an 82 Vanagon that I put in and it has worked fine since
FYI

[erikgundy98]

When my bus was hiccupping bucking and hesitating, I checked my spark. I thought it was fine. But, in checking my bug spark, I noticed that I couldn't check for spark without getting the shiz shocked out of me- and realized I had really weak spark on the bus. SO- in the end, my problem was my coil/ condenser. I replaced both, and spark was immediately MUCH stronger. I haven't had any problems this spring.

I did check my spark back when I was having all my issues, but thought I had "good spark", as it was "blue" not yellow or orange, but I figured it out when I saw a "good" spark on my bug. I forgot how strong it was.

Just my 2 cents.
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'90 Multivan Westfalia

[jdedini]

[AB westy nut]

Hey guys, I thought I'd fire this thread up again as I don't want to leave it open ended. I recently woke the bus up from it's winter hibernation and, surprisingly, it has yet to repeat the bucking/hesitation problems from last year. I took it out one day last week and did a lot of city driving with no issues. Yesterday we did a little 75 mile trip into the foothills and it ran flawlessly. There are still a host of tests that I'd like to perform so I'll keep updating this thread as I go. It would be nice to think that the winter storage somehow miraculously cured the issue, but I have my doubts...
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1963 Ruby Red 356 Cabriolet
1976 Sage Green Westfalia Deluxe

[crushie]

[AB westy nut]

Thanks Crushie, but are you sure the key should be in the 'start' position and not just the 'on' position? My bus starts just fine.

Also, you're more than welcome to come by and give me a hand, since you love the cold so much.
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1963 Ruby Red 356 Cabriolet
1976 Sage Green Westfalia Deluxe