Rough starting, cold

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Mulcheese
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Rough starting, cold

Post by Mulcheese » Fri Mar 25, 2016 12:04 pm

I originally thought I had, only, a CSV issue but after posting it I have been made aware that I have something greater.posting.php?f=50&mode=reply&t=12969

When the van is warm it starts right up on first compression. If it sits for a day it will take a few compressions. If it sits a week, which is most of the time, then it takes many, many revs. The battery will drain down if it is cold out. Sometimes it takes a good 30+ seconds. This is all w/out a CSV.

Timing is 7.5° and advances to >28°. Dist is a SVDA.

What should I look at first?
"attending to things in the moment with curiosity and acceptance."
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82 Vanagon Westy - aka: Honey Badger - "cause she just dont give a ...."

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asiab3
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Re: Rough starting, cold

Post by asiab3 » Fri Mar 25, 2016 12:54 pm

Ok, so continuing from the last thread:

Your timing checks out, and as long as your dwell is in the ballpark this should not be an issue.

When it takes 30+ seconds, does it eventually start? Or does the battery just give up?

I read somewhere that L-Jet needs a certain minimum threshold voltage to fire the injectors successfully. (I do not remember if it was a credible source.) There is a possibility that your battery is just below this. The number in my head is 10-10.3 volts minimum during cranking. Try a trickle charge over night before starting it next time you let it sit a week and report back.

-

Once you have eliminated the battery as a potential issue, we'll try some tests to greatly increase and decrease the fuel mixture. after removing the air cleaner, hold the AFM flap open a bit with a wooden dowel or something else long, skinny, and safe. This will trick the ECU into thinking extra air is flowing, and the ECU will then attempt to inject extra fuel. If it starts much easier, you know the engine wants more fuel. If the engine still won't start, smell the exhaust for raw gas. Report back.

Robbie
1969 bus, "Buddy."
100k miles with me.
279k miles on Earth.

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energyturtle
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Re: Rough starting, cold

Post by energyturtle » Fri Mar 25, 2016 12:59 pm

Have you checked vacuum? Valves adjusted properly? Compression check?

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energyturtle
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Re: Rough starting, cold

Post by energyturtle » Fri Mar 25, 2016 1:10 pm

asiab3 wrote:Ok, so continuing from the last thread:

Your timing checks out, and as long as your dwell is in the ballpark this should not be an issue.

When it takes 30+ seconds, does it eventually start? Or does the battery just give up?

I read somewhere that L-Jet needs a certain minimum threshold voltage to fire the injectors successfully. (I do not remember if it was a credible source.) There is a possibility that your battery is just below this. The number in my head is 10-10.3 volts minimum during cranking. Try a trickle charge over night before starting it next time you let it sit a week and report back.

Robbie
.....and everything Robbie said! While my engine was breaking in, it would kill a weak battery in 10-15 seconds. When the engine turns slowly, its hard to start. It seems to throw things out of "balance" by slow cranking? Just keep it simple, I feel it's something trivial that is your potential issue. I read your original thread again. Go through the motions. Go get ya a new set points, adjust valves, BASIC tune up protocol. And go from there. All the information you've received is great advice. Always start small. The FI is very robust.
Scottie

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Mulcheese
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Re: Rough starting, cold

Post by Mulcheese » Fri Mar 25, 2016 2:24 pm

More things to add.

AFM has been adjusted as per Colins write up. Runs great with head Temps 390-410.

No points, Crane Cams electronic ign.

Last time compression tested, years ago, 120-130psi. Along with the valves adjusted. I'm confident this hasn't changed much since.

I've searched for vacuum leaks many times and have yet to find any. Not to say that there aren't any but I couldn't find any.

The AAR has been adjusted and open further. As a result is does idle higher at warmup.

Yes if the battery is weak it just cranks until the battery caps out but I have a good battery now so it does eventually start. I'm not worried about it starting it just takes to long.

I think when I take it out next weekend I will try the AFM stci trick to see what that will do.
"attending to things in the moment with curiosity and acceptance."
____________________
82 Vanagon Westy - aka: Honey Badger - "cause she just dont give a ...."

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asiab3
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Re: Rough starting, cold

Post by asiab3 » Fri Mar 25, 2016 2:47 pm

Mulcheese wrote: Last time compression tested, years ago, 120-130psi. Along with the valves adjusted. I'm confident this hasn't changed much since.
Do not pass go, do not collect two hundred dollars. Adjust your valves and report back please. :pirate:

If nothing else, you should do this for the forensic aspect. If your lifters are hydraulic, carefully note how many turns it takes to get to "0 lash" before going back your preferred 1.5 or 2 turns in. If your lifters are solid, you should see what the clearance is with other feeler gauges before setting them to .006". Any major adjustments should be treated with suspicion and monitored.
1969 bus, "Buddy."
100k miles with me.
279k miles on Earth.

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Randy in Maine
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Re: Rough starting, cold

Post by Randy in Maine » Fri Mar 25, 2016 6:23 pm

Does the Thermotime switch really deliver voltage to the CSV when the engine is cold?
79 VW Bus

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Amskeptic
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Re: Rough starting, cold

Post by Amskeptic » Sat Mar 26, 2016 5:12 am

Randy in Maine wrote:Does the Thermotime switch really deliver voltage to the CSV when the engine is cold?

The cold start valve is energized with 12 volts directly from the starter via 86 off the double relay. Every time the starter is actuated, the cold start valve has 12 volts.

The cold start valve, thus being offered the opportunity to spray only during starting, is unable to spray without a ground path. It is the thermo-time switch that grounds the cold start valve. The thermo-time switch provides only a momentary ground. It has its own electrical supply just to run the SooperQuik heater that breaks the ground path for the cold start valve in:

1/2 second at 60*
2-3 seconds at 32*
11 seconds at 0*

Remember that this is all predicated on starter operation. If your car happens to fire up in 2 seconds at 10* below, and you release the starter, the entire cold start valve circuit is de-energized.
Colin
BobD - 1978 Bus . . . . . . . . . . .111,130 miles
Chloe - 1970 bus . . . . . . . . . . . 206,787 miles
Naranja - 1977 Westfalia . . . . . 94,615 miles
Pluck - 1973 Squareback . . . . . 55,510 miles
Alexus - 1991 Lexus LS400 . . . 72,990 miles

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Randy in Maine
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Re: Rough starting, cold

Post by Randy in Maine » Sat Mar 26, 2016 6:01 am

Whatever....before you go deep into this moneywise make sure that the electrical connection actually exists and allows current to wake up the CSV when it is supposed to.
79 VW Bus

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Amskeptic
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Re: Rough starting, cold

Post by Amskeptic » Sat Mar 26, 2016 6:24 am

Randy in Maine wrote:Whatever....before you go deep into this moneywise make sure that the electrical connection actually exists and allows current to wake up the CSV when it is supposed to.
The most typical failure of the csv circuit is
tts not plugged in (look for broken or missing spring clips) or cleanly grounded to bracket,
red white wire not cleanly plugged into starter solenoid spade terminal
red/white wire not cleanly plugged into double relay

I personally have not run into a clogged cold start injector. Even this Naranja fuel tank/filter crap saga has not affected injectors or whatever . . .
Colin :cyclopsani:
BobD - 1978 Bus . . . . . . . . . . .111,130 miles
Chloe - 1970 bus . . . . . . . . . . . 206,787 miles
Naranja - 1977 Westfalia . . . . . 94,615 miles
Pluck - 1973 Squareback . . . . . 55,510 miles
Alexus - 1991 Lexus LS400 . . . 72,990 miles

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Mulcheese
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Re: Rough starting, cold

Post by Mulcheese » Sat Apr 16, 2016 4:55 am

My analysis would have to say that the combination of a non-working CSV and a low battery is what lends to this condition. I now have another CSV installed and I have placed a trickle charger on the battery. With these improvments the van fires up 2nd or 3rd compression everytime.

The van usually sits all week long and only is driven on the weekends. In that time the battery, which is fairly new and strong, drains down just enough to cause issues.
"attending to things in the moment with curiosity and acceptance."
____________________
82 Vanagon Westy - aka: Honey Badger - "cause she just dont give a ...."

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Amskeptic
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Re: Rough starting, cold

Post by Amskeptic » Sat Apr 16, 2016 6:22 pm

Mulcheese wrote:My analysis would have to say that the combination of a non-working CSV and a low battery is what lends to this condition. I now have another CSV installed and I have placed a trickle charger on the battery. With these improvments the van fires up 2nd or 3rd compression everytime.

The van usually sits all week long and only is driven on the weekends. In that time the battery, which is fairly new and strong, drains down just enough to cause issues.
Install a ground interrupter switch in your negative battery cable, or disconnect before the Long Sit. Vanagons are a little tricky with long cable to the starter, and that mess behind the dashboard. If you have what you would deem A Battery Drain somewhere in the system, we have a diagnostic path to take.
Colin
BobD - 1978 Bus . . . . . . . . . . .111,130 miles
Chloe - 1970 bus . . . . . . . . . . . 206,787 miles
Naranja - 1977 Westfalia . . . . . 94,615 miles
Pluck - 1973 Squareback . . . . . 55,510 miles
Alexus - 1991 Lexus LS400 . . . 72,990 miles

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