Sudden Engine No Start Issue [solved]

[-Derek-]

Hi All,

My van suddenly won't start. It cranks, but won't light off. Prior to this it always caught immediately, so this is very out of the norm. I've been troubleshooting for the last 5 hrs and I'm running out of things to check.

Symptom: Engine cranks but no start. No hint of a start. Occasionally the starter sounds like it is bogging down: WaWaWaWaaaaaaWaWaWa. Every once and a while I'll hear a short hiss - but not at an regular interval.

Background: 1983 1.9 L with auto transmission. I took the van on a camping trip Friday as a test run before a longer upcoming road trip to make sure that there weren't any surprises. Van recently had new suspension/bushings installed, and I've been doing miscellaneous tasks (a lot of camper improvements, but also new ground straps and re-terminating most of the grounds that attach to the engine block). Round trip was about 40 miles. On the last part of the drive it sounded to me like the engine was down a cylinder during acceleration (dugadugadugaduga engine sound, more reluctant to get up to speed). After parking in the driveway at home I started pulling spark plug leads from the distributor cap one at a time. I didn't hear much of an RPM drop when I pulled one lead (can't remember now if it was #2 or #3). Just as I grabbed lead #4 to pull it the engine died. That was 24 hrs ago. I haven't been able to get the van to start since.

What I have checked:

Spark: I've grounded each spark plug to the block and visually verified there is spark. Tried bypassing the idle stabilizer, no change. I pulled the hall sender connector from the distributor - pins look a little green - but if there was an issue there I'd get no spark, right? I also tried pulling the black wires on the coil (there are two, tried each individually) - as I read on another thread about the one that goes to the instrument cluster causing start problems - still no start.

Fuel: fuel pump runs key ON and I hear it running momentarily when the engine stops cranking. I rented a fuel pressure gauge and measured 34 psi key ON or cranking at the test port, and it holds for ~10 minutes after key is OFF. I also pumped about a pint of fluid into a container just to verify that the pump can produce flow and fuel looks clean. I pulled the injectors for 3 & 4 and verified that they are spraying (haven't done 1 & 2 because they're hard to get at and the whole process is scary). I measured the injector resistance at the ECU connector and cylinder #2 was open circuit - aha I thought! I removed #2 injector connector and one of the terminals had come out of the connector. I re-bent the retaining tab and re-inserted it. All injectors now measure 16-18 ohms at the ECU connector, but still no start.

Compression: tested compression on all four cylinders. #4 was about 100 psi, the others 110-120. These numbers are consistent with past measurements.

Miscellaneous: Measured 3260 ohms at the ECU connector for the coolant temp sensor, seems normal for the ambient temp (and cold engine). Air flow potentiometer resistance was in the normal range per the troubleshooting manual (don't remember the number). New coil, distributor cap, rotor, spark plugs, spark plug wires within the last 1000 miles/year.

Appreciate any suggestions you have. Thanks,

Derek
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'83 Vanagon
'72 914

[DanHoug]

nice job troubleshooting. you've verified spark at the plugs, fuel spraying at the injectors (well, 2 of 4 but it should pop), and compression.

the only other variable is timing, otherwise the engine can't help but run. a timing light MIGHT give you enough flash at cranking speed to see the timing marks. otherwise you can make a simple tool to verify timing with power off and just rotating the crank thru with a wrench:
https://www.thesamba.com/vw/forum/viewtopic.php?t=701391&highlight=

this will verify that the reluctor window is indeed passing at the appropriate timing mark (not sure what that is on a 1.9). or you can get pretty close just looking at the rotor position with the dist cap off.
_________________
-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

[Ahwahnee]

Isn't it possible for an ignition switch to fail in a manner that you get spark when cranking but then none when released to the run position?

[DanHoug]

[-Derek-]

Timing was the problem! I don't know anything about adjusting timing and my first instinct after removing the cap was to remove the rotor. When I did I saw a bit of broken plastic - the indexing tooth on the rotor was broken. Swapped it out for a new rotor and it fires right up! I must have jostled the cap enough when pulling/installing the plug wires to cause the rotor to strike the housing and shear the tooth.

Thanks for the help!

_________________
'83 Vanagon
'72 914