Cold start and cold idle woes

type11969 · Posted: Mon Jul 15, 2013 7:18 pm Post subject: Cold start and cold idle woes

Been chasing this problem for a while, recently it has become worse, and I can't figure it out.

Background:
76 Westy
Camper special engine kit (2.0L) - installed about 8k miles/4 years ago

Symptoms:
Engine is "cold" - the below happens even in 90 deg humid NJ weather
Engine will sputter once when cranking - will not start
Engine will start if you hold the throttle down
Engine won't idle until warm without holding the throttle down a bit
Once warm, the engine runs great
LM1 read AF checks out on the highway, at idle I have enough reversion in the exhaust that I can't get a good reading

What I've checked/replaced:
FPR is new, fuel pressure readings are good
Fuel injectors have less than 3k on a rebuild
Fuel injector seals are new
Pulled the AFR last weekend, sealed the seams, now holds a strong vacuum and closes in ~one minute
Pulled the plenum, vac/pressure/bubble tested it, plugged some minor leaks around the CSV screw threads, now holds a good vacuum
Pulled the rockers, pressure/bubbled tested the manifolds, no leaks at the heads or the injectors
Pulled the S-boot, pressure/vacuum/bubble tested it, no leaks
Checked TSII at the sensor and at the ECU - in spec
Checked all other readings at the ECU - in spec (although I do need to clean my grounds)
Brake boost holds a vacuum
Decel, vac advance, EEC all hold vacuum
Running the engine with all vac lines disconnected from the plenum (holes plugged) makes no difference

The only wildcard I can currently think of is the throttle body. I definitely have leaks around the throttle shaft - throttle body on the plenum and the assembly can't hold a vacuum, pressure test shows lots o bubbles around the shaft (although the seal is biased to hold vacuum). Is this enough to create the issues I am seeing? Of course I will fix it, but I'd be interested to hear if you think this is the likely culprit. I thought for sure that the leaks I was finding around the AFR were the issue, but nope. I guess I am having a hard time believing that the throttle body warms up enough to close up those leaks . . .

Of course, last question, where can I get a new throttle shaft seal? Quick search turned up that they are NLA - anyone have a source?

Sorry for the length - and any help would be greatly appreciated. Been spending a lot of time trying to chase this down and I am stumped . . .

-Chris
_________________
1969 VW Beetle - t4ed indeed
1971 Porsche 914 - jackstanded
1976 Westy - DD

AB westy nut · Posted: Mon Jul 15, 2013 7:50 pm Post subject:

Thanks for the thorough write up. Looks like you've done your homework. It sounds like you've checked the AAR (you called it AFR, I think?) and confirmed that it closes in about a minute. But the issue might be that it's not open enough to begin with. There is a small adjustment nut on the AAR body that allows you to widen the static position of the aperture. With the adjustment nut loose, set the aperture all the way open with a small screwdriver, then tighten the nut. Reinstall and report back!
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1963 Ruby Red 356 Cabriolet
1976 Sage Green Westfalia Deluxe

busdaddy · Posted: Mon Jul 15, 2013 8:11 pm Post subject: Re: Cold start and cold idle woes

Wildthings · Samba Member Joined: March 13, 2005 Posts: 50353

The cold start valve should still be functioning even at 90°, it just will not be open for very long.

Does your fuel pump come on at your first turn the key to start?

It sounds like you may still have vacuum leaks so fixing the shaft seal on the throttle body would be a good place to start. Someone somewhere must have the seals, have you tried a European source like JustKampers?

type11969 · Posted: Tue Jul 16, 2013 6:32 pm Post subject:

Sorry, should have mentioned that the CSV valve is working, not dripping, and is on for a few seconds at startup (what causes the initial catch at startup).

The fuel pump turns on too with the key, and I've tried priming the system by running the pump independently before startup just in case (even though the fuel pressure regulator is new/working)

The AAR (sorry for the typo) is open all the way when "cold".

It takes a good 5+ minutes of pedal pressure (enough to maintain "elevated" idle speed) before the engine can sustain itself - even then it is a low/crappy idle. Good idle will come after another couple of minutes of driving.

Yeah, I've been beating my head against a wall on this one. I think I found another throttle body I have in my stash with a newish seal that I replaced a long time ago - but never used. I think it is a 1.7 throttle body though, not sure if they are smaller than the 1.8 that I am currently using. It will be interesting to see how it works.

Any other ideas I'm willing to give em a shot, thanks for the ideas so far!

-Chris
_________________
1969 VW Beetle - t4ed indeed
1971 Porsche 914 - jackstanded
1976 Westy - DD

busdaddy · Posted: Tue Jul 16, 2013 6:40 pm Post subject:

What happens if you unplug the TS2?
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larrydeville · Posted: Tue Jul 16, 2013 9:10 pm Post subject: cild start

I had the same problem after fresh fuel pump, AFM and injectors which after 35 or so years they needed to be freshened up with the engine any way. I have a 77 camper. I hooked a test light to the plug that goes to the start injector , pulled one of the wires to the coil to disable it and had my wife crank the cold motor. The test light went bright for a moment and then slowly dimmed and went out. I removed the injector from the plenum and duct taped the hole over. The fuel and the plug were hooked up. My wife cranked the motor and the injector did not squirt. Replaced the cold start injector and its all good......warm or cold start. I think there is two offerings on the thermal time switch and the later offering is supposed to be better for cold start. Good luck.....Larry

ivwshane · Posted: Tue Jul 16, 2013 10:23 pm Post subject:

I had a similar issue and to verify it was the AAR I put it in the freezer for about 20 minutes and then immediately installed it in my bus. The problem was gone. I thoroughly cleaned the AAR and adjusted it to be open more and my problem is gone.

I don't know if vacuum leaks would cause the issue but I had some and after they were fixed the issue persisted.
_________________
77 westy 2.0 FI
69 ghia coup 1600dp
70 single cab

Stuartzickefoose · Posted: Wed Jul 17, 2013 12:35 am Post subject:

someone have alink on how to "open" the AAR properly? Thanks!
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2011 Jetta Sportwagen TDi 6 speed manual

206-841-7324
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ivwshane · Posted: Wed Jul 17, 2013 12:48 am Post subject:

Whitley · Posted: Wed Jul 17, 2013 8:53 am Post subject:

I had a similar issue on my 76. Have you checked the seal between the throttle body and the pleneum? Also, the vacuum diaphragm on the air cleaner? I replaced the AAR, found a new AFM, and also found that my dwell was a little out of spec. Although I had tested the AAR and it appeared to be in spec, I think that was the main problem because I was getting a real high idle when restarting it hot.

Now she starts and idles like a dream hot or cold.
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Kismet2013 · Posted: Wed Jul 17, 2013 9:08 am Post subject:

I had the same problem last year. After days of frustration I ended up cleaning the connections for the FI Double Relay (both plugs) and moving it's ground to a new location and Bam...problem solved. Good luck

When solved could you post remedy for future reference

type11969 · Posted: Wed Jul 17, 2013 6:08 pm Post subject:

Thanks guys - got some ideas to try this weekend, I will definitely report back
_________________
1969 VW Beetle - t4ed indeed
1971 Porsche 914 - jackstanded
1976 Westy - DD

thewalrus · Posted: Mon Jul 22, 2013 11:41 am Post subject:

I'm having a similar issue. Any updates?
_________________
'73 Transporter 1.7L Dual Carb

type11969 · Posted: Mon Jul 22, 2013 6:54 pm Post subject:

Next weekend - hopefully . . .
_________________
1969 VW Beetle - t4ed indeed
1971 Porsche 914 - jackstanded
1976 Westy - DD

Stuartzickefoose · Posted: Sat Jul 27, 2013 7:46 pm Post subject:

i have a 77 automatic with FI (all stock) that it starts after a few cranks (suspect CSV not fully working) and then it idles a bit low and will die sometimes, and if i put it into drive it dies. if i hold the revs for about 30 seconds to a minute it runs beautiful otherwise. i suspect its running a bit rich due to an AFM adjustment being needed...would this cause my problem? i would love to dig into this tonight if i can...
_________________
Stuart Zickefoose

2011 Jetta Sportwagen TDi 6 speed manual

206-841-7324
[email protected]

AB westy nut · Posted: Sat Jul 27, 2013 7:50 pm Post subject:

How does it start when the engine is warm? I would check the AAR first.
_________________
1963 Ruby Red 356 Cabriolet
1976 Sage Green Westfalia Deluxe

Stuartzickefoose · Posted: Sat Jul 27, 2013 9:47 pm Post subject:

i opened the AAR up as best i could (loosen nut, push plate open with a screwdriver as far as i could, tighten nut) and it seemed to go away. i also cleaned a VERY oily breather box...doubt thats related though.

now i have noticed a random mis at idle, where it stutters just a bit. it can happen in drive or neutral, and is noticeable in drive the most as it jolts the whole bus a bit. it also seems to do it in motion too....i just didnt notice it until tonight.

any ideas that may be related? im thinking AFM at this point....all the ignitions been replaced recently...
_________________
Stuart Zickefoose

2011 Jetta Sportwagen TDi 6 speed manual

206-841-7324
[email protected]

ivwshane · Posted: Sat Jul 27, 2013 9:55 pm Post subject:

Stuartzickefoose · Posted: Sat Jul 27, 2013 10:01 pm Post subject:


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