78 SuperBeetle FI Phantom

[got_the_bug]

At the risk of offending the folks over at TS that have been helping me, I'm moving my questions here as I'm stuck and circling around the same issues with no clear path ahead of me on what to do next. I need some additional perspective as I think I'm heading towards an adjustment of my AFM and that worries me a bit.

This place looks pretty experienced with the AFM among other things. So before I step into the AFM adjustments I want to be darn sure thats the next most logical choice to fix my problems because I suspect I can really screw things up if that isn't the primary issue.

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PRIMARY SYMPTOMS
The car is a 78 Super that would not start when I purchased it. I know nothing of the history other than it was running but had recently started losing power when it was put in storage. When it came out of storage it wouldn't start.

My problem is it only starts every once in awhile after I've fiddled with it. It usually sputters and fails to start or starts briefly and runs for 2-3 seconds then dies.

Every once in awhile it does start but runs very poorly, will only just barely idle and produces black poisonous smelling smoke. If it let it run for 5 minutes the apron metal over the exhaust muffler gets hot enough to blister the paint. But the oil dipstick is just warm to the touch. When I pull the plugs they come out totally black and dry.

This is not a California car and does not appear to have a CAT converter. Only has the large single muffler the full width of the rear apron.

Here's the results of testing so far

New bosch blue coil: old one had a weak spark
New rotor
New cap
New bosch points
New plugs: .028 gap
New spark plug wires
Valves adjusted to .006
Dwell angle 46
Valve covers did not leak oil and cork seals had normal shape
New Head Temp Sensor
Compression test 140 at all 4.

Fuel pressure rail is 38 PSI when I crank the engine. Fuel pump runs fine at engine start and with the AFM flap open and turns off when the flap is closed.

Battery charged is monitored and is 12.4V
All air hoses replaced and clamped due to leaks.
All dizzy vaccum lines replaced due to leaks.
S-boot inspected - looks good
Injectors spray tested - nice round spray pattern
New fuel line segments added to injectors.
Injector seals replaced.
Oil filler cap fits tightly.

CSV Tested - does not leak but also does not spray fuel. Assume this is ok for now as external temperature is 70 F and I'll not be driving it in cold weather.

AAR Tested - observed the valve opening and closing when voltage is applied. Closes completely after about 2 minutes with the key on and AFM flap open. At 70 degrees the opening is about the size of a match head.

Double Relay - tested every connector with mult-meter. No issues.

ECU - swapped with another known working ECU, no change.

Voltage tested at each injector was fine.

Attempts to adjust the idle using the bypass screw on the throttle body have no effect.

Timing - can't get this perfect due to idling and running issues, have it static timed at 5 ATDC.

When I did have it running vacuum at idle was 5 in HG at 800 RPM's at 17 in HG at 3500 RPM's.

I did not replace the fuel filter.
There is a hole in the EGR filter under the apron by the muffler.
There is no vacuum hose on the small end of the decel valve

****************

So what do you think - is it air fuel mixture adjustment time or do I need to consider something else before I start?

[midatlanticys]

Hi Bug, Welcome!
I'm (kinda) new to VW's and definitely no f/i experience to offer, but in general your "black poisonous smelling smoke" would point to unburnt fuel; together with exhaust temps that blister paint I'd say the ol' girl isn't able to breath. Is she able to get full air? I'm sorry if this response is overly simplistic.

Have you read through the first page or so of Troll's thread on AFM adjustment vs. doing a full/complete set of diagnostics? http://www.thesamba.com/vw/forum/viewtopic.php?t=363625

Could you point us to your TS thread for this glitch?

[got_the_bug]

Hi Bug, Welcome!
Is she able to get full air? I'm sorry if this response is overly simplistic.

I would say at full throttle air isn't the problem as the throttle valve is wide open and the AFM flap is wide open at 3500 and it's still blowing black smoke. It could be the problem at idle.

[midatlanticys]

I would say at full throttle air isn't the problem as the throttle valve is wide open and the AFM flap is wide open at 3500 and it's still blowing black smoke. It could be the problem at idle.

OK, I'll buy that, but black smoke is still unburnt fuel - does your dizzy gearing, rotor/cap/wires orientation etc all check out 100%, no, 1000%.

black smoke can also mean too much fuel; so, incomplete burn, no? like the injectors are staying open too long and dumping too much fuel in the cylinders?

Is 5º ATDC the *only* way to time a reluctant/non-running engine?

[vwlover77]

You've noted that you replaced the head Temp Sensor. Have you verified that the wiring between the sensor and the ECU is good? A disconnected or broken wire makes the ECU think the outside temp is extremely cold and it will make the mixture way too rich. Your description seems to indicate an overly rich mixture....maybe!

You definitely should replace the fuel filter - and cut the old one open to see what kind of gunk might be in there.

A hole in the EGR filter will result in additional unwanted air being drawn into the engine. I'd either replace it or block off the pipe to the intake manifold.

Please give more detail of which connection on the decel valve has no hose. There are three. Two relatively large and one very small. Which one is disconnected? I'd want to know what's going on at what would be the other end of the missing hose.

Don't touch the AFM adjustments until you know everything else is OK!!! But, can you verify that the air flap in the AFM moves smoothly?

[got_the_bug]

Ok I checked out a club members 78 Super and verified where the decel hoses are supposed to go and matched mine up like his. My 2 big hoses are fine. 1 went to the S-Boot and the other to the opening down by the AAR valve.

The small hose is going to the EGR valve first with a 3 way connector and then continues on down to connect to the manifold and the line going to the fuel regulator with another 3 way. Mine now matches that with all new vacuum lines. So basically the decel valve, EGR valve and fuel regulator lines are all connected to the manifold.

Today the car decided to grace me and started. It idles at 225 RPM just barely.

Heres a picture of my AFM at rest. It started to rain so I may be done for the day. The AFM flap operates smoothly.


[/img]

[got_the_bug]

Picture of the engine compartment (used to have A/C so that big hoses on the top left is just a leftover still hanging there)



I pulled off the air cleaner and turned the AFM over so I could look at it.

[got_the_bug]

You've noted that you replaced the head Temp Sensor. Have you verified that the wiring between the sensor and the ECU is good? A disconnected or broken wire makes the ECU think the outside temp is extremely cold and it will make the mixture way too rich. Your description seems to indicate an overly rich mixture....maybe!

I tested the Temp Sensor wire earlier but not since I replaced the sensor. I'll check it again...

[Amskeptic]

You've noted that you replaced the head Temp Sensor. Have you verified that the wiring between the sensor and the ECU is good? A disconnected or broken wire makes the ECU think the outside temp is extremely cold and it will make the mixture way too rich. Your description seems to indicate an overly rich mixture....maybe!

I tested the Temp Sensor wire earlier but not since I replaced the sensor. I'll check it again...

Advance the timing a total of 12 degrees. That will fix it. You cannot statically time to a specification that requires the engine to be running with vacuum to the retard diaphragm (5* ATDC). Statically, you need to time it to 7.5* BTDC, then WHEN IT RUNS OK, you can time to 28* at 3,200 rpm with the hoses off.

If it still runs poorly, lean it out a bit with the mixture screw on the AFM, and report back. WAIT! I just looked at the photograph of the AFM. Please screw that poor mixture screw in all the way to the bottom, and count 4 1/2 turns back out (leaner). Then, ONCE YOU GET IT RUNNING NICELY, you may need to loosen the screw in the black plastic wiper and move it CLOCKWISE in relation to the screw you just loosened. Go only one tooth of the wiper, and check. They are little teeth. Make a note of precisely where the wiper is before you loosen anything.
Colin

[Robert Berglund]

Maybe the lighting or my computer screen but the potentiometer seems to be somewhat worn.
Are you sure your getting good contact ??

[got_the_bug]

Advance the timing a total of 12 degrees. That will fix it. You cannot statically time to a specification that requires the engine to be running with vacuum to the retard diaphragm (5* ATDC). Statically, you need to time it to 7.5* BTDC, then WHEN IT RUNS OK, you can time to 28* at 3,200 rpm with the hoses off.

If it still runs poorly, lean it out a bit with the mixture screw on the AFM, and report back. WAIT! I just looked at the photograph of the AFM. Please screw that poor mixture screw in all the way to the bottom, and count 4 1/2 turns back out (leaner). Then, ONCE YOU GET IT RUNNING NICELY, you may need to loosen the screw in the black plastic wiper and move it CLOCKWISE in relation to the screw you just loosened. Go only one tooth of the wiper, and check. They are little teeth. Make a note of precisely where the wiper is before you loosen anything.
Colin

Set the mixture screw to 4 1/2 turns out from the bottom. Advanced timing to 7.5 BTDC this helped the idle a little but not much. Still idles real slow.

It's definately not running nicely. Still looks rich, lots of soot coming out the tail pipe seems like even more than before.

Not reseting the wiper yet but did loosen the screw to see how to set it. Not sure what those teeth are for, they don't contact anything. Also rotating the wiper to the right only 1 tooth CW (towards the minus side) really pushes the copper ground lever over and the wiper almost comes off the magnetic strip. Is that right or am I mixed up on how to do that adjustment. Based on it's current setting there's really no room left to rotate it.

Just started it up again and it is definately more rich than before with the new timing and mixture screw setting. I backed it out another full 1 1/2 turns and it didn't help any.

[Randy in Maine]

If it where me, I would back up and start checking things again.

I would pull out the injectors and replace all of the injector seals for < $10 and the fuel fuel lines if that has not been done already. I would just send all of the injectors up to www.cruzinperformance.com and have Rich in MI clean them up so that I knew they were 100% for < $100.

Make 100% sure that the valves are adjusted correctly. The notch on the pulley should = 5º ATDC. Incorrect valve adjustment could be a possible.

Make 100% sure that the firing order is indeed correct and that the distributor cap is on correctly. This thing should not be able to idle at below about 600 RPMs, but you keep mentioning 200 RPMs. Make sure your dwell tachometer is actually correct. I don't think it is.

I like a big ass vacuum leak with those low vacuum readings and the fact that the idles speed screw on the throttle body doesn't do anything. Injector seals or throttlebody seal or intake seals at the heads. Something in there is bunko.

[got_the_bug]

Incorrect valve adjustment could be a possible.

Make 100% sure that the firing order is indeed correct and that the distributor cap is on correctly. This thing should not be able to idle at below about 600 RPMs, but you keep mentioning 200 RPMs. Make sure your dwell tachometer is actually correct. I don't think it is.

I like a big ass vacuum leak with those low vacuum readings and the fact that the idles speed screw on the throttle body doesn't do anything. Injector seals or throttlebody seal or intake seals at the heads. Something in there is bunko.

Ah, I wrote that RPM down wrong, it should be 400 RPM's for the idle. It's the barely idling. The injector seals are already new..

Wouldn't a "big ass vacuum leak" result in a lean burn since this would be unmetered, the ECU would not be compensating with more fuel. That doesn't add up for me.

I intend to crawl under and recheck the valves this week to see if something came loose after the last adjustment. On my pulley TDC is a dimple. I use a straw in the piston method to verify it.

If the firing order is the standard 1-4-3-2 then I'm good.

I agree, something is definately "bunko". I'm either missing something or the AFM is way off.

[got_the_bug]

Make 100% sure that the firing order is indeed correct and that the distributor cap is on correctly

How the heck can the cap be on wrong?
And what should the vacuum readings be? I haven't found any useful info on what's normal for idle and at high RPM.

[Randy in Maine]

The cap really only fits well one way. Make sure yours is on correctly and the the rotor is good.

The L-tronic FI system is very dependant on having no vacuum leaks and correct engine vacuum. If you have a vacuum leak, the sytem thinks that you are stepping on the gas and will give you all of the fuel it can. You should be seeing around 12-15" of manifold vacuum.

Put a golf T in the vacuum line aht goes to the air cleaner EEC valve if you have one. See if that helps any.

This thing should be idling at 800-950 RPMs.

I of course have never had a FI beetle, but there should be some sort of gaskets at the intake to head mounting, and also between the throttle body and the air plenum. Make sure yours are indeed good.

Here is how ours are set up on a bus if that helps any......