Very strange "no power" phenomenon with '89 2.1 (SOLVED)

[ourv12]

It starts in the morning and drives absolutely fine.....then park it for about 30 minutes while shopping or whatever. I get back in and it starts just fine but when I go to drive it has no power whatsoever...it just will not accelerate past idle speed....so I pull over and stop...kill the engine..wait about 15-20 seconds..then start it and it drives just fine again all the way home.....no problems. It does this same exact thing every day for the past week. It never did anything like this before. Ive never even heard of anything like this before lol. If I had to guess its fuel related since it will always start and idle during the symptom...so I know its not ignition related. Any ideas as to what I should check? Thanks for any help!

[Phaedrus]

How's your oxygen sensor connection? Wire good? Connector good?

Temp II sensor good? Connection good?

Good, clean grounds throughout the engine bay?

What's the AFM needle doing while this symptom is occurring? Open the AFM cover and watch while you try to rev off of idle while experiencing this symptom. Try to see what it's doing both while working normally and while symptomatic. Any difference?

Reads to me as electrical issue causing a fuel issue. Do your basic checks beyond what I've outlined above: everything connected? nothing leaking? nothing loose? etc.
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1986 WBX (Tin Top Camper)

[the joker]

cat's clogged

[VicVan]

[MarkWard]

[the joker]

I once drove a 150 miles out of NH with the clogged cat, stopping every few miles, till I figured out what was happening, then punched a few holes in in, and drove the rest of the way on back roads made it without the flat bed being called , that was in a 81 aircoooooler, almost smoked the engine but it was real tired by the and

[ourv12]

Well I am completely stumped
I have replaced everything related to the fuel injection and nothing has solved the issue. First I swapped the AFM with a known good working one, same results. Then I swapped the ECU with a known working one, same results. I then replaced the temp 2 sensor (even though it checked out fine with the ohm meter) and still the same results. I then replaced the O2 sensor, and still the same results. I checked all connections and they are good and clean. All the ground wires are clean with good contact at the firewall.
What gets me is that this ONLY happens after its been driven and then parked for about 30 min and the issue happens when I try to drive it after its been parked 30 min. So it has something to do with the fact that it gets to operating temps and then cools off a bit. It NEVER has this issue upon FIRST morning or cold start up and driving, ONLY after driving and parking for awhile AND THEN driving again, which tells me its about it getting to normal temps then cooling a bit before driving again. IM STUMPED!
I dont know what else to check relating to the FI system. I think Ive swapped or replaced everything I can think of that would tell the ECU information.
I highly doubt its the Hall sender??? Or the coil??? or the fuel pump??? because if it were one of those items then the issue would happen all the time which is my thinking. I also looked inside the CAT and its absolutely fine with no breaking up or pieces causing it to plug up.
Any ideas out there? Im stumped and need some help here.

[DigiMatrix]

Have you tried unplugging the O2 sensor and driving like that to see if the problem is still there. The reason I ask this is because a bad O2 signal to the ECU can mess up the fueling. I had an O2 gauge tapped into the O2 signal on another Digifant car I owed that ran fine for years. Then I started having issues on restart. The car would stumble and often die on warm to hot re-start. Often a second re-start would correct it I chased this problem for longer than I care to admit. One day I came home fed up and ripped out the O2 gauge. Problem was solved. Lesson to self - don't mess with low voltage signals.

If you have a bad connected between your sensors and the ECU, it doesn't matter how new sensors are.

Also, have you used the Pro training manual and gone through the steps it outlines to check voltages at the ECU connections? Just changing parts won't necessarily get you anywhere if the proper signal isn't making it back to the ECU. O2 voltage AFM signal and temp II sensor are critical for fueling and or timing.

[VicVan]

Hi

I'm going to throw ideas out there, not sure if they're relevant, but since you're stuck:
Fuel supply: is the fuel tank vented well enough? After a non-power episode, shut off the engine and open the gas cap. Is there a "pschiit" sound of air rushing in?
Fuel pump, coil, hall sensor: the issue is intermittent, so don't rule these out. Check them, both electrically and visually. Check, clean and lube (dielectrical grease) every connection.
Ignition: Check distrib cap, rotor, wires (check resistance as per Bentley), spark plugs (wire brush, dielectrial grease on plug end)
Vacuum lines (especially to the fuel pressure regulator): in good shape, well fitted?

Also, keep a detailed journal of your diagnostics, results and changes. It will help.

Good luck, keep us posted
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'90 Little Blue Truck, 2WD auto, FAS GenV 2.0 NA (AVH)

[kamzcab86]

The only thing I can suggest, since it's an '89, is to read this https://www.thesamba.com/vw/forum/viewtopic.php?t=724983 to its conclusion.

Updated Digifant ProTraining manual: http://oldbluesblog.com/files/DigifantProTrainingManual_SingleSided.pdf
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~Kamz
1986 Cabriolet: www.Cabby-Info.com
1990 Vanagon Westfalia: Old Blue's Blog
2016 Golf GTI S
"Real knowledge is to know the extent of one's ignorance." - 孔子

[Mark Lewalski]

So this is just something more to check.

I have also had running issues on my 89 and swapped everything over from my 87 to no avail: AFM, ECU, throttle body, idle stabilizer, etc.

History of the 89 was that it was bought not running after having been stored for multiple years. I found a problem with the Hall sender, which I replaced, and at which time the van would start.

Had unusual idling issues - loss of idle, surge of idle, loss of idle until the engine would die.

I know I need to clean up the grounds and am in the process of doing that.

But... I also found one day that my fuel pump was no longer priming the FI system when ignition was turned on prior to starter engaging.

I found a huge voltage drop across a connector to the fuel pump. I fixed this.

The pump still wasn't working so I ordered a new one. When I went to remove and replace, I found that NO fuel was coming out of line from the gas tank! I mean NOTHING.

The tank had so much gunk built up in there that I don't think I was EVER getting good fuel flow.

I'm currently waiting on a new tank (and associated items) so I can replace and then find out if that was my problem all along.

Anyway... just don't know the history of your ride but since we've both replaced most ignition or electrical components with no resolution, I thought I'd pass on what I found in case you've got something similar.

If you determine your issue and find a remedy, please update us.

Thanks,
Mark
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'89 Vanagon GL Wolfsburg "Bluestar" (given to and owned by my son now)
'87 Vanagon Weekender
'74 Thing

[DanHoug]

replace your ignition coil. it is heat soaking after the engine is off and mis-firing. well, i shouldn't sound so definitive from afar but if it were ME, i'd replace the coil.
_________________
-dan
60% of what you find on the internet is wrong, including this post.

'87 Westy & '89 Westy both 2.1 4spd

Past projects can be found at--
www.thefixitworkshop.com

[bettingonvans]

I agree with DanHoug, you should try replacing your coil. It would not be a bad idea for you to carry a spare anyway.

I had a very similar problem a couple years ago on a very long trip. Started great every morning. Problems would start when we'd sit in traffic for a bit or stop for a short while (not long enough to cool off, maybe 5-10 minutes) before restarting.

It got worse and worse until I showed up at Art's Import Workshop in Hailey, ID where he took a couple looks and decided the coil was too hot. We replaced it with the spare I was carrying and it has run well since.

Mostly well, anyway.
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1990 Westfalia, GW2.2, Peloquins TBD

[davlance01]

I say do not replace one single part!!!!!!!!!!!

Do not spend any money on any part based on anyone's opinion on a internet forum you will go broke in a hurry with these vans.

Do not buy a coil, fuel pump, AFM, temp II sensor or anything else until you know what is actually broken.

Spend your money on diagnostic tools and not parts and quit looking for parts to replace and start looking for what is wrong.

The best investment I have made has been a cheap hantek 1008c oscilloscope and a few accessories for it and I haven't purchased a part that wasn't actually broke since.

I've been there dude and take it from me that scope will pay for itself 100 times over in knowing what part is broken and more important what isn't.

If it is a bad coil it will show up in the secondary ignition test in 2 seconds flat!
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Life is short and the road is long so if you want to see it all you have to drive fast!

[ourv12]

Well so far i have replaced every FI part with my other running '91 van and nothing has helped the issue. the only thing I replaced with a "new" part was the temp 2 sensor and the oxy sensor.... everything else came from my running '91 van. I replaced the AFM, the ECU, the fuel pump, fuel injectors, cap, rotor, cleaned all grounds, ohmed the plug wires, replaced the fuel filter, new oxy sensor, checked the throttle body switch, checked idle control valve, checked every single wire from the ECU connector to each individual component in the system with my meter, I checked the Hall sender, everything checks out fine. I checked the CAT to see if its plugged or lose broken pcs and its fine. The only thing i havent checked or replaced is the coil. But I thought it should be ok since the van ALWAYS starts and idles just fine. My initial issue is when its driven and gets to normal operating temp and then is parked for 20 -30 min I can start it just fine and it idles just fine but when I go to drive it there is no power....it wont rev either......but will only idle even pushing on the pedal. this is why I thought the coil should be ok since it starts and idles its getting a spark. Then if I shut it off and wait about 15 seconds it starts and drives normally again. This is driving me mad that i cant figure out whats wrong. What else is there in the system? Ive replaced everything! lol

[bettingonvans]

Strictly speaking, davlance01's advice is the best. I think that some of us get used to having a full regimen of spares handy, as is good practice on very long trips. Think the coil is bad? Pop in your spare.

But, other than getting in there and analyzing your ignition system with a multimeter or oscilloscope - most anything else is sort of guesswork with this weird intermittent stuff. Someone told me to replace my fuel filter when I had similar problems to what you described. Turned out to be something else! But at the time, I had all that stuff packed with great efficiency under my bench seat.

Since you are not on a trip and have time to debug, and you can reproduce this issue it would be very interesting to learn what you can find in your signal analysis!
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1990 Westfalia, GW2.2, Peloquins TBD

[ourv12]

Well thanks for all who gave their advice, thoughts and ideas! I never would have guessed it. My engine always started, so I assumed there was nothing wrong with my coil. Thank you suggesting that it could be my coil. It turns out that it was my coil. I swapped my coil with another one and it hasnt had any issues since. I never knew that a coil could have intermittent issues even if the engine starts and runs fine most of the time. Lesson learned! Intermittent ignition issues?.....check your coil!
Thanks again guys!

[Steve M.]

Good news. Now get the thread title edited to add "Solved"
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[Vanagon Nut]

[ourv12]