Solved: 1990 Vanagon Hot Start and Running Issues

[NWRangefinder]

Hi all,

Halfway through my trip from Port Townsend to Portland yesterday, my van started to intermittently hesitate upon acceleration. I eventually started losing power and pulled over, at which point the van would crank but not start. After 30mins of waiting for AAA, I cranked the engine and she started right up like usual. We decided to risk it and rolled down the highway for another 45mins without issue. As we got off the highway for gas, I noticed some hesitation and sputtering had returned. After gassing up, she would crank but not start again. We grabbed dinner and after 45mins, she started right up and we were on our way again. After another 0mins or so, she started losing power on an incline, so we pulled over for the third time, at which point I had her towed home.

The van has a 2.2L GoWesty with 6,000 miles on it. We just had a tune up and new injectors. Does anyone have thoughts on where to begin troubleshooting? I'm new to Vanagons, but based on experiences with old Volvos, my first thought was the fuel pump. Forum searches here have me wondering about the temp2 sensor.

Thanks in advance!

[DigiMatrix]

Based on the symptoms described, I am inclined to think it is either the temp2 sensor or wiring to ECU between the temp2 sensor and the ECU, or possibly a coil that is on its way out.

Use the Digifant Pro Training Manual found here for the
https://oldbluesblog.com/files/DigifantProTrainingManual_DoubleSided.pdf
Page 17 for the temp2 sensor checks
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'91 Syncro Westfalia
soon to be 2.5 liter stroker WBX 10:1 comp
Digifant ECU with knock sensor and custom
cylinder selective knock control by me

[Vanagon Nut]

[NWRangefinder]

[Vanagon Nut]

[E1]

If you are safe to do so, and nobody’s around, and you’re going dead straight(!), and you’re 100% comfortable doing it, and can do it over just a couple seconds…

(I’m over-warning because you sure don’t want to lock the ignition!)

… next time it stalls and you’re going over 50 or so, study for safety and immediately dump the clutch, barely turn off the ignition and immediately turn key back to run position, let out clutch a second later.

This is a good test to suspect or discount an ignition switch, a bad idle stabilizer (early Digijet vans only), far less likely the ecu, or at least a pretty solid indicator of electrical fault and not fuel.

If it sputters back to life when letting the clutch out, it’s probably fuel.

If it fires easily and runs instantly normal again, it’s probably electrical.


I’d also dump in a load of red HEET, the hard-start after stalling could well be watered gas… that’s down on my list in this case, but only because the issue continued after a fuel fill… but your comment of having just done injectors would have me checking plugs.

Also, if I doubted the age of the fuel filter, I’d swap it and only use the metal canister type.

Check and clean grounds, especially the fuel pump ground and wiring, and all coil connections. Also see if the fuel pump is really hot when it stalls, and better yet, learn the normal fuel pump temp in advance, before it does stall.

It could be several other things beyond all suggestions so far, but all good possibilities. When the likely stuff is also the easy and cheap stuff, all the better.
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1984 Westfailure/2.1 Digijet/5.43 Ring & Pinion/Peloquin/D-rated BFG KO2s
AI has spoken to further illiteracy, to steal, to cheat, and to replace humans

"Adding power makes you faster on the straights.
Subtracting weight makes you faster everywhere." — Colin Chapman

[sanchius]

[MarkWard]

You don’t need to install a known good spare temp sensor to test when the problem occurs. Granted it’s hot, but unplug the installed sensor and plug in your spare. A tie rap or tape will secure it enough to drive the van. While not ideal mixture, it will get you to your next stop. You can then let the engine fully cool and swap in the good one.

Intermittent problems are the hardest to diagnose and repair. When you set about diagnosing, a connected timing light and fuel pressure gauge can help narrow in on spark and fuel when it happens.

[NWRangefinder]

Thanks all, I really appreciate your thoughts/advice. I have an ignition coil and temp 2 sensor on order while I troubleshoot. I figure that these relatively inexpensive parts will be good to have as spares, should the issue turn out to be something else.

I will definitely update this thread as I work through the problem. Thanks again.

[MarkWard]

Might be worth searching for a spare ECU to carry. If you search my username and MSD, I posted a temporary fix for a digifant van, that during a day of driving, the engine got harder to start after each fill up until it wouldn’t start. The owner would swap in a coil and all would be fine for another day. It was actually killing coils over a long day. Even with a chassis Dyno could not replicate the failure, but tested the 3 coils that had died. All 3 ohm’d out, but would not run the engine.

As a test installed an MSD ignition box and a Blaster coil. The van has traveled multiple cross country trips without a problem. If I had to guess the coil driver in the ECU was the culprit. By adding the MSD, instead of the ECU having the load of firing the coil, it only had to send a trigger signal to the MSD. The MSD took over the load firing the coil.

The owner did not want to remove the MSD. Some purist members rolled their eyes at this method, but a happy owner is a happy owner.

[NWRangefinder]

My mechanic thinks it’s the ECU and let me borrow one to check. His advice was to drive the van until the problem recurred and keep my eye on the tach when trying to restart: no tach movement will mean that it’s not getting primary ignition. Will report back

[NWRangefinder]

Update:

I started her up the other day and noticed that the idle felt slightly rough, even with the cold engine, and there was a hint of hesitation when giving gas. I switched out the ECU and there was no discernible change.

Today I replaced the ignition coil with a brand new one (dealing with those bolts was a bear of a job). She started up and idled smoothly right off the bat. I drove around to get her up to temp and she ran smoothly throughout. I won’t call the problem solved at this point, but I’m cautiously optimistic. I’ll go for a longer drive this weekend (with the spare fuel pump, filter, temp sensor, ECU, tools, and AAA card just in case) and report back.

Thanks to you all for the help

[E1]

I’d suggest not pitching the coil just yet.

We carry a new spare, and a used one. I removed and replaced the used one when a stalling issue suggested coil.

When the issue came back and was something else, I reverted to the used one as a weeks-long test, it was fine, and is a second spare again.

We’ve saved much anguish carrying “too many parts,” before learning we actually don’t. Several are “dealbreakers” that’ll leave one stranded without: alternator with pulley mounted, fuel pumps, ignition switches, relays, belts, caps, rotors, and wire, wire terminals, coolant tanks with caps and sensors, hoses, fan switch, throttle cable, oil and fuel filters, valve cover gaskets, the lot).
_________________
1984 Westfailure/2.1 Digijet/5.43 Ring & Pinion/Peloquin/D-rated BFG KO2s
AI has spoken to further illiteracy, to steal, to cheat, and to replace humans

"Adding power makes you faster on the straights.
Subtracting weight makes you faster everywhere." — Colin Chapman

[NWRangefinder]

Thanks, E1. That’s good advice

[NWRangefinder]

I’m going to call this solved (for now). I drove for a few hours today on freeways and city streets, up hills, and in bumper to bumper traffic, all in 90 degree heat. She ran like a champ with no sign of previous issue. Only change was a new ignition coil.

Many thanks to the folks who chimed in to help. I hope this post helps someone in the future and I will circle back here if the issue returns