1977 fuel injected bay window fuel pump and timing issues

[SGKent]

turning the screw out lets air bypass the flap so you are correct, you are now leaner.

The real issue is that you do not know what was done to it before. I gave a weight that two NOS flaps just started to open at, so contrary to other's opinions I am confident it is a good place to start adjusting a flap spring. I would check it the next time it is out but don't waste your time unless it is out. I would not change anything without really thinking why. The numbers I posted were solely to help someone find a starting point when their AFM had been tampered with. Yours has passed so you have to be in the window close or it would not have passed.

One thing I would recommend - if the fuel pressure regulator is old, consider a new one before they become totally obsolete. If yours allows a little higher pressure then you will run a tad richer. Other things that can vary the mixture is if the injectors are tired and dirty. They can stick open longer, spray in a pattern that is larger droplets than a fine mist - making it harder to burn it all - which can throw the mixture off. So a new FPR and having the injectors cleaned if you haven't already are two good places to go next if you are looking to improve things.

A LM1 or equal will let you do a lot. The down side is that once you are happy with the performance it is really rock solid and rarely changes, so other than an occasional check you won't use it much.
_________________
Canned Water - the new California approved parts cleaner (except in a drought in which case rub it with sand).

George Carlin:
"Most people don't know what they're doing, and a lot of them are really good at it."

Skills@EuroCarsPlus:
"never time to do it right but always time to do it twice"

[guanella74]

This seems like another case of there being no one left working at any mechanic shops who REALLY know these old beasts. I didn't have confidence in their tuning it when I left, and I don't have the confidence to take it back to them that they really know how to fine-tune it. I had the Itinerant Air Cooled article with me, and at one point when the mech didn't know what to do about it not leaning out enough when at the max of the range, I took out the article and we used it to get the rest of the way...

Anyhow, I passed, and am now looking into getting my own LM1 and doing it right. Glad to be registerd and legally driving the bus now!

That reminds me, I need to update my build thread...
_________________
- Travis

1974 Westy CampMobile - the OG!
1979 Transporter
1979 Transporter
1977 Transporter
1974 Transporter
1973 Transporter
1971 Westy

[Randy in Maine]

After you pass, take it back to them and have them adjust it back to where it runs the best.

Take notes on the changes so that you can put it back yourself when needed.

[guanella74]

OK, I took the bus in today to Verner's VW in Boulder since they've always treated me right. With a warm engine, they put the sniffer in the exhaust and let it idle, and to get down to <1.5 on the CO, we had to a)adjust the idle bypass almost all the way out, and b)turn the tensioned spring in the AFM 6 clicks CW. We ended up at ~1.3 on the CO at idle, with all tuning parameters in spec. I'll go to get emissions tomorrow, but...

It seems like everything I've read to this point means that with our adjustments, the bus would now be running WAY lean. We're at the far end of the range on the idle bypass screw and not 1, not 2, but 6 clicks CW on the tensioner spring. Should I be concerned about baking my heads and being too lean, or am I just being paranoid?
_________________
- Travis

1974 Westy CampMobile - the OG!
1979 Transporter
1979 Transporter
1977 Transporter
1974 Transporter
1973 Transporter
1971 Westy

[SGKent]

[guanella74]

Yes - that's what I was referring to, and thus far I had it adjusted as per the smog recommendations by Colin in that link (which is great, btw).

The middle, from what I understand, is ~3.5 turns, but I already have it at 4.

I may just have to bring it somewhere; I don't want to just shoot from the hip either for passing emissions or daily driving. It's always a bummer though having to educate the mechanic at the shop as to what to do as most these days haven't looked at this FI system and don't know about the fine adjustments...
_________________
- Travis

1974 Westy CampMobile - the OG!
1979 Transporter
1979 Transporter
1977 Transporter
1974 Transporter
1973 Transporter
1971 Westy

[Randy in Maine]

When you say "mixture screw" are you referring to the idle by-pass screw on the left side of the AFM unit? that is how the idle gets adjusted for CO. Put that bad boy in the middle of the range.

Been here?

http://www.itinerant-air-cooled.com/viewtopic.php?f=50&t=7834

If it were meI would take this to a shop that has a exhaust gas sniffer before I went back to the test place. If they did some work on a VW bus before that would be a plus.

[guanella74]

Thank you both for your help thus far.

I've also replaced the temp sensor with a new unit, and I'll follow your advice and clamp down/double check all vacuum connections.

Is there a consensus on NGK vs OEM Bosch plugs? I've got new, gapped Bosch units in there. I haven't looked into the aux air regulator; any directions on what to do there, and are those units fairly robust or do they go out often? They look like they're hard to come by and expensive!

Also, I've got my mixture screw turned 'out' 4 turns at this point; it was out 2.75 turns when I started. If everything else checks out, should I just keep leaning out on the mixture screw until it starts to miss, turn it back a bit, then go for a hard drive on the way to the emissions station?
_________________
- Travis

1974 Westy CampMobile - the OG!
1979 Transporter
1979 Transporter
1977 Transporter
1974 Transporter
1973 Transporter
1971 Westy

[SGKent]

[Randy in Maine]

If it were me, I would go back and check everything I had done so far since that is free to do......

I would start first with the plugs to make sure they are the good NGKs gapped correctly with no anitsneeze on the tips. Personally I like the triplegrounds ones. Inspect the wires and use yoru ohm meter on them to confirm that they are 100%. Confirm the dwell and timing is to spec.

Clean out the aux air regulator to make sure it is opening and closing correctly.

Looks for vacuum leaks. Sometimes you have to use a wrap of electrical tape or a zip tie to make those connections 100%. Are the injector seals good? How about the S boot? Temp sender II ohming out correctly?

Report back you results of the investigations.

[Wasted youth]

I did not have any problems with mine. And, I am not knowledgeable about working through failed smog checks on these, so I cannot really help. Mine passed the very first time, but I am sure I was lucky. Anyway, here is my smog check sheet. This was based on all stock set-up, tuned normally. Only difference is it had an Accufire electronic ignition in a new distributor and a new exhaust system, including an Emico CARB 2 compliant catalytic converter.

Don't know if this really helps, but maybe you can use some of the info to help you figure it out.

[guanella74]

Yes indeed - thanks for asking. There was a hose that has backfired off at some point creating a huge vacuum leak.

Now my only problem is passing emissions - took 2 tests already, and failed both with high CO. First test it was at something like 4.5, then I leaned it out according to general recs in Amskeptic's post on the Itinerant forum, and second time it measured at 2.5, but still not in spec at 1.5. At this point I guess I'll keep leaning it out and see if that does the trick. Any recommendations?

Thanks,
_________________
- Travis

1974 Westy CampMobile - the OG!
1979 Transporter
1979 Transporter
1977 Transporter
1974 Transporter
1973 Transporter
1971 Westy

[Wasted youth]

Confirming that your idle problem is resolved?

[guanella74]

Oops - forgot that my meter is for 8 cylinder engines so I have to double the number! Puts me in spec
_________________
- Travis

1974 Westy CampMobile - the OG!
1979 Transporter
1979 Transporter
1977 Transporter
1974 Transporter
1973 Transporter
1971 Westy

[Randy in Maine]

You want the dwell angle to be about 47º +/- 3º

[guanella74]

Wasted, no worries either way on the post - and thanks for the help.

I do still have the sticker; I've also set all the typical items to spec - dwell @23 or 24 degrees, timing at 28 max advance with dist hose off, 7.5 idle, etc, and have replaced the following with new Bosch:

double relay
dist. cap
rotor
condenser
coil
plugs
plug wires checked - as new
fuel tank (as-new)
fuel pump
fuel filter
injectors rebuilt
all hoses

I don't seem to have vacuum leaks and I have yet to check the fuel pressure, but the engine starts right up even in 10 degree weather without having to touch the pedal, and seems to run out alright.

I just failed the emissions test for too high of CO, and I'm guessing it's rich, but I'm flying blind to adjust it without an analyzer it seems.
_________________
- Travis

1974 Westy CampMobile - the OG!
1979 Transporter
1979 Transporter
1977 Transporter
1974 Transporter
1973 Transporter
1971 Westy

[Wasted youth]

I just pulled my previous post, because on afterthought, I did not think those pics were relevant to your problem. I can repost if you like.

I am not entirely sure you need an analyzer, but it would certainly put you into a higher league than most folks. I found that if I took the time to bring each component into factory spec, tuned it with a timing light to the emissions label and eliminated all weak spots (old vacuum lines, questionable wiring connectors, aged gaskets or seals) I had a great running bus.

Because my bus was sitting for twenty-odd years, it took a few good road trips for the Samba community to help me work out all the bugs, but in the end it was a pleasure to drive.

Do you still have your emissions decal

[guanella74]

These are excellent!! Thank you for sharing (and inciting a bit of envy with the cleanliness of your engine compartment...). Nice work and great for reference.

I'm now trying to find the best and most cost-effective source for an LM-1 or similar analyzer so I can fine tune things and not cook my engine accidentally. Anyone have any beta on which one to get/what has worked for them?
_________________
- Travis

1974 Westy CampMobile - the OG!
1979 Transporter
1979 Transporter
1977 Transporter
1974 Transporter
1973 Transporter
1971 Westy

[guanella74]

Guys, thanks for the help. I still need to fine tune the system, but I got it idling just fine now. I noticed that my Intake elbow to aux. air regulator hose was leaking at the S boot junction. The hose is a bit loose at the ends; ideally I'd get a replacement, but in the meantime I'll clamp it on both ends and hope that does the trick.

Thanks again guys!!
_________________
- Travis

1974 Westy CampMobile - the OG!
1979 Transporter
1979 Transporter
1977 Transporter
1974 Transporter
1973 Transporter
1971 Westy

[SGKent]

since it is an FI bus it needs fuel pressure which comes from a circuit that is controlled by the AFM flap. If the points aren't adjusted right inside the AFM they may not be closing until you move it a little further than normal. Try cleaning them and making sure they are open until the AFM flap moves just a small amount. Your fuel pump should come on at idle. You may be moving the flap just a little further which makes it come on.

The other possibility is that your idle mixture is too lean.
_________________
Canned Water - the new California approved parts cleaner (except in a drought in which case rub it with sand).

George Carlin:
"Most people don't know what they're doing, and a lot of them are really good at it."

Skills@EuroCarsPlus:
"never time to do it right but always time to do it twice"