Has Spark, Has Fuel, Won't Start... Help!

[Andross]

Hi everyone, have been reading a ton of posts over the last 24hrs but still haven't figured out my issue.

Van is an 87. Has been running great for months, but yesterday after merrily cruising along for 1/2 an hour it misfired.

Drove for a few more minutes and misfires continued sporadically, eventually it stalled and I pulled over to the side. I quickly checked for spark by shorting the coil to ground with a screw driver, and seeing none, called a friend for a tow.

Back in the garage, I set up a jumper to the starter solenoid, so I could crank the engine and do some diagnostics solo.

I found that there was spark at the plugs when cranked via the jumper. But oddly not when cranked from the key. After cleaning engine grounds, and tightening and cleaning as many connections as I could in the engine bay I found that I now have reliable spark at all the plugs when cranking from the key.

Still no start.

There is fuel, there is fuel pressure, the fuel pump and relay are fine, the injectors are spraying in a cone shaped pattern, the hall sender is functioning as it should: triggering injectors and spark. I thought maybe the fuel was contaminated with water so I drained the remainder and filled up with fresh fuel.

Still cranking, but not firing at all.

Air filter is clean.

Flow from the exhaust pipe seemed almost non existent so I removed the catalytic converter as apparently they can plug solid. There is exhaust leaving the system.

I did all my spark diagnostic cranking with the injectors unplugged to avoid flooding, but was concerned. So I removed all the plugs, and injectors. Cranked it a bunch and left it for an hour.

Reassembled it all, and still no start.

Marked the position of the distributor, then loosened and started to adjust timing incrementally. After turning around 5 deg counter clockwise it fired very roughly a few times for the first time today. I turned it back to previous position and tightened down. Cant imagine the timing getting out of whack.

Not sure what else I can try.... I have had many, many.... many breakdowns over the years but all have been pretty obvious either fuel or spark.

Can AFM, temp sensors, oxy sensor, cause no firing at all?
Can I rule out the ECU based on having good spark and injection?
Can the idle control unit cause no firing?

I will start off tomorrow with a compression test after visiting my flaps.

Lastly, I cleaned the engine bay a few days before the mishap. I used that GUNK brand degreaser and rinsed with a hose. I started it no problem and ran it without issue for 20 minutes and blow dried with a leaf blower. Started up no problem the next day.

Many thanks![/list]

[djkeev]

Spark plug condition?

Compression?

It may now be flooded, pull the plugs, let it air out, install new plugs.

Get a new ignition switch electrical portion.

Remove the distributor cap, check it and the rotor.

Washing it my have introduced moisture to iffy ignition components. Dry the cap, unplug the wires and dry terminals, spray it all with a drying agent.

The engine wash is very suspect.

Dave
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[Wildthings]

Water in fuel because of leaks in the top of the expansion tanks?

[Andross]

thanks for the quick response as usual!

I thought water in the fuel may be possible so I disconnected the fuel return line and pumped about 15 L into a pail. Refilled with 20 L fresh fuel.

Plugs look great, no soot or corrosion and only a year old.

Will test for compression tomorrow if I can get to the flaps for a tester.

I was concerned about flooding so I pulled plugs and injectors and cranked it for a bit then lit sit for an hour... plugs were not wet, but maybe still could be an issue was around 0 degrees C so wont dry out very fast.

Distributor is one of the DANSK brand aftermarket ones, it is about a year old. Rotor and Cap look decent and spark is good.

[Andross]

oh the electrical part of the ignition is also new + I hot wired to bypass just to be sure. No Change.

[Steve M.]

https://www.thesamba.com/vw/forum/viewtopic.php?t=349429

take a look at this link.
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[Andross]

Great tool, I'll have to build one!

[Abscate]

Give it a sniff of ether, three second blast, to separate ignition from fuel on the diagnostic tree.

Put the distributor back to TDC for this.
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.ssS!

[markswagen]

Check for voltage when cranking, I found an engine that would not start, everything appeard good, lots of parts were replaced, in the end it was found that the imi high torque starter motor was at fault, taking too much current, with a change of starter, the van was back up and running again.
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619 201 0310

[Andross]

Never used starting fluid before, I assume this is used with injectors unplugged? I'll try this tomorrow

Will the van start and run (theoretically) when cranked from a solenoid jumper when the ignition is in on? This is the easiest way for me to crank the engine while working solo.

I will check the voltage from the alternator post to ground while cranking, but kind of reading am I looking for? The starter is a year old, one of the high torque gear reduction ones from GW.

I have had issues with my battery going dead if I don't drive the van for a week or so, though I have had a 6amp smart charger connected for all of my trouble shooting and the van cranks well. Battery is under warranty at Ctire so I'll go grab a new one to rule that out. I'll pick up new plugs too, should have an extra set anyway...

Also why do any of the component issues matter if there is fuel and spark?Shouldn't it start and run rough at the very least? Or maybe my spark is too weak because of other faulty ignition components? Just thinking out loud...

[Abscate]

[Andross]

roger that. I'll add starting fluid to my shopping list of: compression tester, warranty battery, and spare plugs

[Phaedrus]

Yeah, I'd want a compression test and go from there.
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1986 WBX (Tin Top Camper)

[dabaron]

swap the fuel and ecu relays, does the fuel pump still work?
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[Toolcan]

No expert.

But this Tool will help.

https://www.thesamba.com/vw/forum/viewtopic.php?t=349429
And a Remote starter.


If you have spark it sounds like you have Gotten after Grounds under Relay Box / Coil and the one off Halls to block?

Slight warning If your cycling for start a great deal with your injectors in
Your just dumping mass fuel in your case/oil.
Foul plugs
Watery fuel Oil

Pin test ECU for Power and Ground yet?


Annd remember only you can prevent Van Fires!
(For $50-$75 bucks)

Making certain you have fresh fuel lines and all your factory undersized load wires
from Starter Alternator AC are a bigger better Guage.
Do ad grounding Starter to frame.
Put a fuse inline on power steering wire.
Hose clamps on vacuum line from fuel presure regulator
(Though the they typically don't fail)

I either had load wires melt and make fire?
There was a older 2 battery isolator in that load wire mix
Or fuel pressure regulator diaphragm fail and turn into a flame thrower via little vacuum
Line off the end?

We still have a Van do to 5lb extinguisher up front.
($65 Metal Unit not plastic head)

Best to you....

[Andross]

Did a cold compression test for whatever its worth:
120psi on 1,2,4
105psi on 3

Took the battery to be tested, passed with 730 CA

Measured coil resistance: terminal 1-15: 0.7 ohms, 15-4: 3.6 K ohms (which is .1 K Ohms over spec)

AFM Checks all passed locally

ECU connector tests all passed. Thought my signal stabilizer harness was bunk until I read the caveat: no continuity between pin #2 when installed.

Swapped fuel and ECU Relays, pump works in both instances.

Tried starting fluid, no change

Measured voltage across battery terminals while cranking. Started at 12.9, went down to 10.9 after 5 seconds or so of cranking, then back up to 12.9 after stopping cranking.

Resting Fuel Pressure is 42 psi, is it possible that the injectors are flooding the engine instantly?

[VicVan]

I see that OP is banned. What's up with that?
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'90 Little Blue Truck, 2WD auto, FAS GenV 2.0 NA (AVH)

[Andross]

[jberger]

I've read several times where it says you have fuel and spark. This is tested at the spark plugs and the injector tips? You have verified TDC for #1, rotor points at #1 wire? All the wires went back in the right place? 1432..

J

[Andross]

Success! Van is running again!!!!

I got a suggestion from Dan via PM to try a jumper between the Alternator post to the post inside the connection box on the drivers side of the firewall.

Hooked up a 10 gauge wire with ring terminals between the two, pulled the plugs and injectors and let it all dry out again for a couple hours. Then boom started up no problem!

I also switched to new plugs after letting everything dry out, but I am quite confident that the jumper is part of the equation. I will change the oil and give it a good run later this week then pull the jumper off to see what happens.

Thanks for everyone's ideas. Has anyone had experience with this solution?