Vanagon Driveablity problems....

[mrlimbo]

Hi Gang,

My 87 vanagon is experiencing some driveablity issues. Like thats a surprise.

Symptoms: Hi idle cold... 2500-3000 after warm up the idle is fine.

Runs poor cold. It acts like the choke is stuck on while cold. But of course its not carbureted. No power, skipping. During this time, I have to feather the throttle in order it get and keep the van moving.

But as soon as the O2 sensor warms up and kicks in it smooths out and runs decent enough. I know its the O2 sensor thats working because I unplugged it and it ran poorly and never got better until I plugged it back in. But it still isn't perfect. The engine has no power on the low end. But as soon as it hits 22-2400 RPMs the power smooths out and the van runs just fine. I could drive all day at highway speed without any problems.

Taking off at lights and climbing hills are as real PIA. I have to get the RPMS up and slip the clutch a bit to take off and climbo hills. Not good. for the clutch.

I've done a tune up. Plugs, cap, rotor, wires, air filter. I haven't done a fuel filter yet, but its on the list. Though I don't think its a fuel delivery problem. It has plenty of power in the upper RPM range.

I replaced the fuel pressure regulator thinking there was too much pressure it was fooding out at low end. No change.

I've replaced the coolant temp sensor. Twice. No change.

I've replaced the idle stabilizer because of the hi idle. No effect.

I don't have a spare AFM. So I haven't had a chance to check to see if thats the problem. I suppose I should get the book and my multimeter out and check it out.

I've got to read up on the double idle relay.

I've also checked out the green O2 sensor wire too. It checked out. I replaced the end just in case.

I did double check all the grounds and electrical connections at the various plugs for corrosion and poor connections. They all checked out fine. I cleaned a couple just to be sure.

I'm wondering what to do next. Or if anyone had any thoughts. Thanks.

I don't want to give up on the Fuel injection. For the most part, I've had years of trouble free service from all the vanagons I've owned. Its just got me stumped.
_________________
-Jim DiGennaro, Samba lurker, Disc Jockey and LiMBO freak www.LiMBObus.org
'67 Kombi- April, its not original and I don't care.
'87 Vanagon GL (daily driver)
'01 Jetta Honey's car
Looking for a Vanagon weekender or Escorial green camper.

[insyncro]

I would check the:

idle control valve, needs to buzzzzz
idle control unit, behind pass tail light, check for condensation in the plastic case.
throttle postiion switch, proper alignment

A DigiTool would help debug this issue in about 10 minutes.

dylan

[mrlimbo]

[Dogpilot]

Cleaning the idle vale is a good measure to start with. I would see how your van runs without the Idle Control Computer hooked up. The easy way is to disconnect the RPM signal to it, leaves it powered up, but in a neutral state. This way you can see what you bottom end of your idle is, without a stabilizing system. There is a wire with a single inline spade connector that runs along the forward side of the firewall. You disconnect it and it cuts that signal. Adjust your idle, so you have a bottom end with the big screw on the Throttle Body.

You may want to get your DVM and check the values against the ProTraining or Bentley Values on the table, Especially the Temp I (in your AFM) and see what you get at the ECU plug.
_________________
Geology with a Syncro rocks!
86 Syncro Westy AKA "The Bughunter"
98 Disco I
08 Range Rover SC
08 VW Rabbit S
1951 O-1G

[insyncro]

I hope it isn't, but I have seen many wiring harnesses go bad over the last year or so on vans.
I would check everything, including all wires associated with the temp sensor.
On the 2wd vans the temp sensor has a ground wire, trace it and check it.

I'm over in Hudson NY.
I have three vans that will be parted in the next 60 days.
All have good running drivelines so I will offer up a good harness
if needed.

dylan

[Silence262]

I would check for vacuum leaks first. Easy and cheap.

Silence
"Knowledge, sir, should be free to all." - Harry Mudd
'87 Vanagon GL 7-seater "Pokey"

[Silence262]

I would check for vacuum leaks first. Easy and cheap.

Silence
"Knowledge, sir, should be free to all." - Harry Mudd
'87 Vanagon GL 7-seater "Pokey"

[CessnaJon]

Remove the injectors and have a friend turn the engine over to verify fuel is discharging correctly-it should be a cone shape.Also -check the torque of the intake manifold bolts.They work loose with time,creating an air leak.Good luck.
_________________
1973 Westy (shared birthday)
1990 Westy Multivan
2015 Passat TDI 6sp
2015 Sportwagon TDI 6sp
LR-JET, Gulfstream 159

[mrlimbo]

[[email protected]]

Might want to check the base of your intake manifolds down by the injectors, mine had developed some rust holes, the result was a high idle tough cold starts.. purred after replacement..

[mrlimbo]

[BillM]

Jim,
I got a 88 Westy that is smashed up in the front. Don't know if I am going to fix or part yet. If you want to borrow the afm,ecu,ect.. to trouble shoot with just let me know. I can get it to you by priority mail. Let me know.

Bill M
Mystic,ct

[tencentlife]

Don't just check the grounds (how? an ohmmeter won't tell you a thing; with no current passing the ohms will be zero), renew them all. Clean connections, remove paint at the bolting points on the body, stainless star washers and dielectric grease at all the bolted connections. That's job one for unknown FI complaints on these.

The first thing you have to establish with almost any FI system in use is fuel pressure, because the whole thing is calibrated to the assumption that pressure is right. With a new one it should be good but I would test it to be sure.

There is no double idle relay. The Idle Speed Control system could be involved in your high cold idle but with your other symptoms I would say probably not, and it simply can't be responsible for the revving and running difficulties you're having.

Check the AFM S-boot for cracks and make sure it is securely clamped onto both TB and AFM.

What you've described and what you've done so far points pretty strongly to the AFM. The reason is, the only thing that changes when you add the O2 signal to a warmed-up system is that the AFM signal gets back-burnered regarding mixture. The lambda system takes over and dictates mixture via the O2 line. At that point the AFM signal on a Digifant influences spark timing but has little to no influence on mixture, that is until the O2 signal disappears in which case the ECU looks again at the AFM.

Swapping in another AFM is a hit or miss prospect at best since it won't be adjusted to your engine. So before messing with that, you should first rule out dead spots on the one you have by doing a signal test, I demonstrate it here:

http://www.thesamba.com/vw/forum/viewtopic.php?t=369815

The AFM checks in Bentley will merely confuse without telling you what you need to know. The test I showed does. Use an analog meter if you want to be able to trust your results.

Rule that out, then check your ignition timing and adjust as needed. Once again, ignore the confusing procedure in Bentley and adjust for total advance as explained in this thread:

http://www.thesamba.com/vw/forum/viewtopic.php?t=252560&postdays=0&postorder=asc&start=0

Read the whole thing because it gets into what to do and an explanation of the theory. You can also see the mistake some people end up making because they try to combine the two procedures. This is far simpler and more trustworthy a way to get where you need to go with timing.

Why should you check the AFM before checking timing? Because on Digifant it's the AFM signal that tells the ECU the engine load, and the typical dead spots on AFM's are right at and above idle, which is where the load signal will be when you rev the engine with no load. Bad signal, bad timing. So do the checks in that order.

Once you have all that stuff nailed down, the last thing to do is to try some adjustments of the AFM air bypass screw (CO screw). First establish where it is adjusted now by turning the screw CW and count the number of turns by quarter-turns until it bottoms out (gently). If you knw the number of turns you can always get the screw back to that starting point if you don't get positive results. It sounds like if all else was well that yours is on the rich side, so try moving the screw CCW a half-turn at a time and road-test each adjustment.
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Experience is death to doctrine.

[xoo00oox]

Jim, I didn't re-build that whole engine, when I worked on it, it had a low mileage factory rebuild and it came in with a dead cylinder. I replaced both head gaskets and 2 pistons and cylinders on one side if I remember right, the bottom was left alone. If you need to try a air flow sensor, I have one here you are welcome to use. Make sure the engine and trans are grounded to the body good first. Andrew

[Destructo]

It must be spring, all the New Englanders are starting to post more!

Jim wish I could help you, but if things start running better we may just cross paths truckin around in the Berkshires.
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1985 Wolfsburg Edition Westfalia Camper Bostig conversion

Dude, where's your van?