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Weird no-start '79 B21F KJet lamda

Bricktothefuture

Bricktothefuture

Well-known member
Joined
Aug 11, 2015
Location
Central NH
Trying to start this car after installing my cleaned up '76 wiring harness - updated it to '79 style injection with the green relay. Non CIS car. I got it to fire up for just a moment the other day but turned the car off after 10 seconds or so as I wanted to double check any potential fuel leaks, etc. Haven't run this since August and was extra paranoid. Two weird things going on -

1 - The starter doesn't sound like it's engaging the flywheel all the time- I hear more of an even whirring sound than the chug-chug of the compression pushing back. What's odd is that the belts are spinning as I can see the fan moving when I try to start the car. Verified fuel and spark, checked the timing belt marks and have spun the distributor a few times to see if ignition timing was the culprit. Which leads me to the second oddity...

2 - When I either move the distributor to the extreme left or right the frequency valve kicks in for a moment. I thought there was maybe a bad ground or a pinched wire somewhere but haven't found the culprit. I can also get the frequency valve to buzz by either disconnecting the ignition module connector or disconnecting/reconnecting the blue wire that supplies 12V to the module.

I've gone over my wiring diagrams a dozen times and checked out @dbarton's site and everything seems to be where it should be. Anyone ever come across this before?
 
I also just found a thread suggesting the blue coils have an internal resistor and don't need the stock ballast resistor - I have a blue Bosch coil and brought over the resistor from the '76 harness. Might try bypassing it, will report back.
 
The symptom of rotating the disti and hearing the frequency valve may be normal? I'm thinking that if the rotation triggers a spark, that the fuel pump relay may see that spark and turn on, which then energizes the freq valve briefly.
 
Bricktothefuture said:
... I hear more of an even whirring sound than the chug-chug of the compression pushing back. What's odd is that the belts are spinning as I can see the fan moving when I try to start the car. ...
Click to expand...
Huh? Sounds like timing belt if I'm reading you right... Forgive me otherwise, I'm listening to the senate deliberate the budget bill.
 
Yup - The car is wired up for Lamda with an O2 sensor and has an aux air valve, so no CIS brain or constant idle speed motor. Want to add that the fuel pump relay is working properly and I hear the pump running for the 1-2 seconds after I stop turning the key. I've also bypassed the relay to run the pumps and test things out with no luck. Definitely seems like a spark issue.
 
Check the plugs. Are they wet with fuel? Make sure you haven't fouled the plugs. If they are good with spark at the plug and the plugs are wet. It could be clogged or poor spray pattern on the injectors.
 
Swapped the plugs - they were indeed fouled with fuel. No change with new plugs. Tried moving the distributor back and forth while my wife cranked to see if I could find a sweet spot, but nothing. Never even hits the point where it feels like it's starting to catch. Went through the fault tracing flowchart and everything seems ok - voltage at the coil is good, all values within spec.
 
Back on your comment of "I hear more of an even whirring sound than the chug-chug of the compression"
make sure you don't have a sheared cam gear pin - peer through the oil cap when cranking to verify that you see the cam rotating, and that both #1 lobes are upwards, or both are downwards, when at TDC.
 
PCH said:
I believe in the reference to the idle speed that would be only the VW's term for having a timing adjustment module instead of the air throttle bypass idle control (constant idle speed).
Click to expand...
VW, Audi, Porsche, etc, called K-Jet "CIS", short for Continuous Injection System. They also started using KE-Jetronic in the mid-1980s, which has the control pressure operated via an electronic module on the side of the fuel distributor, instead of the separate CPR or WUR used on K-Jet. Volvo calls K-Jet either K-Jet, or CI System. In 1981, Volvo started referring to the Constant Idle (Speed) System as "CIS", when they introduced it for the California B21F-5 (Bosch ignition), the B21F-9 (B21F-MPG), the B21FT, and the B28F engines.
 
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So after changing the plugs and trying again. Look at the plugs again. Are they wet? If they are wet you are getting fuel. With kjet you need to verify the spray patter if the fuel is getting into the chamber. If the injectors have a poor spray pattern. They just wet down the plugs and foul out the spark.
 
The weather is going to cooperate for the first time in like two weeks starting tomorrow. I’m putting on a new Volvo timing belt, my continental one started to walk with a known good tensioner. I’m also going to pick up a good strong battery. I needed a new battery and thought I would try the NLP 20, at this point I’m wondering if it just doesn’t have enough power to get a good spark for Kjet… I’ll post an update as soon as I can!
 
It was the battery! New full size battery and she fired up. Ignition timing dialed in and idling pretty well for six month old gas in the tank. First immediate issue is that she won’t stop running until I remove the key. Turning to “off” does nothing. Still feels good to have her going!
 
It’s a brand, new engine wiring harness, and all of the wiring from the firewall in has been tested and is in good shape. I’m wondering if maybe I goofed with something hooking the fuse panel back up.
 
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