76 FI Harness in a 78 bus question plus bonus info- Fixed!!

[ac78]

I have been searching threads for hours and can't see to find what I'm looking for...

Tonight, I decided to run continuity on the injector wires and found I am running a 76 harness(022 906 239) with a 78 control unit(022 906 021 AG) Finally my issue. The harness plug does not quite match Bentley. I tried cross-referencing the site below with Bentley and at least the FI connectors call for the same wire number on the plug: http://manuals.type4.org/ljet/introduction/ljet21.html
Using Bentley(top of plug to the right) and above site(diagram seems upside down) as my guide:

Plug laying like Bentley shows, Right to Left-
It appears that pin 4 top tow- wire 33(#3), pin 4 bottom row- wire 15(#4) and pin 5 top row- wire 32(#2) are correct. It appears pin 5 bottom row should be wire 14 (#1), but it's blank. The #14 wire has continuity on top row pin 6. Is that correct?

Edited- I just saw Randy's post from a couple weeks ago that it doesn't matter where the connectors are plugged in as long as they are all firing. I missed that tidbit in all my time here and hours with my Bentley. I am still curious about the plug though...

Bonus info- Since my overhaul, I am having a slight miss(Not the bucking thing) through the gears that is most noticeable at cruising speed, highway or city. I have adjusted my valves 3 times at 0, 1.5 and 2 with no noticable difference. Fuel Pressure 40 off, 32 on. I have new cap, wires, spark plugs and set my timing 3 or 4 times a piece to make sure I had it right, at idle 7.5 btdc on and 3500 rpm 28 btdc off. My vac settles in at a solid 17" after a drive around the block. Temp II is about 2000ohms @75f ish and amost nil hot. Pertronix ignition. Using Actron-CP7677, Hot coil-shows 3.5 ohms primary and 9500 ohms secondary. Pretty good power getting up to speed, but a slight miss and poor hill climbing ability. My last 120 miles I got 17 mpg, so I have to be getting close to solving this. I am leaning toward electrical, but any help with this would be great.

Thanks
_________________
78 Westy 2.0l hydr. FI

VW Campmobile
For people who believe a family's
car should be it's castle !

[Randy in Maine]

Suggestion...

Could you remove the top of the AFM unit and take us a nice picture of the little metal strip the copper gizmo slides over? What I am thinking is that there may be a "bald spot" on that strip.....or that you may be running little bit lean as you request the engine give you max power.

In your picture, make sure you include the white dot on the cog wheel.

Also on top of the AFM is that little screw that determines how much by passed air the AFM doesn't count. It is used to fine tune the idle emissions. Count how may 1/2 turns it takes to get it all of the way tight and note it. Then see how many turns it takes to get it all of the way out and try to be in about the center of that range. You may have to go back to where you started which is why you noted it.

Then go for a ride and see if that changes anything.

[ac78]

Sorry for the link, I still don't have the resizing thing down yet.
http://78vwwesty.shutterfly.com/pictures/40
The tracks look very good, even under the copper arm blocking the view. I turned the screw 7- 1/2 turns to get to closed and it's a little tough to tell where open is, but seems to be 26-30 1/2 turns. My first time up was 30 out and it only took me 24 to close. Right now I settled on 13- 1/2 turns from closed to see what happens.

I did not have a white dot, so I made one by each arm.

Thanks.
_________________
78 Westy 2.0l hydr. FI

VW Campmobile
For people who believe a family's
car should be it's castle !

[Randy in Maine]

Well it is a nice day with not much going on, lets play. I am putting the carpet back in my DD after having had the floorpans replaced. It is a Jeep so nothing fits like it should.

Using 2 small screwdrivers, move that white dot on the cog wheel about 2 notches counter clockwise and see if that changes anything. You need to lift up the silver "prong" with one of them and then move the cog wheels with the other one.

We want to be able to go back to where we started if we need to.

Go for a ride and report back.

[rockerarm]

You mentioned a couple of things that perked me up. I was a dealer tech back when you bay was new and was on salary pay(in leiu of commision) to assist the service dept with these performance issues.
1- you mentioned cyl head temp senser measured "nil" when warm. Even though specs were "less than 400 ohms" we would obtain resistors at values of 100, 200, 300, and 400 ohms and wire them in to improve driveability. In fact VW eventually came out with a short extension that moved this senser away from the head about 1".
2- you mentioned lack of power up hills. We have found that even though we had correct fuel pressure, a restricted filter or malfuntioning pump, or even the early rubber non leaded restrictor would break and block fuel flow. So, we always measured fuel capacity for 30 seconds to assure the motor had sufficient volume of gas.

Question, did your bus have the high speed (full throttle) enrichment switch on the throttle housing or was that a later version?

What spark plug types and model # are you using and have you considered swapping back to a standard point ignition to see if there would be a change?

Hope this helps, Bill.

[ac78]

Just wanted to clear up/add a couple items.

Temp II- Just got back from a drive and it is reading 102 ohms.

Fuel Pressure- I have replaced the filter. My new filter after hooking everything back up was replaced after about 30-45 mins of run time. I cut it open and found 4-5 small grubs smashed against the filter in the hole, no particles, just the grubs. I had my line exposed for a couple weeks after draining. Although the pressure is correct now, I mentioned in another post a couple weeks back that I forgot to take my clamp off the return line and my previous 30-45 minutes of run time was with fuel pressure pegged on a 100psi guage. The only other thing I wanted to mention is that when I touch the fuel line there is a noticable vibration on the hose. It's been a long time since I've had this running, but I don't remember it being like that. I also believe there is an audible hum from the fuel going through the lines. Maybe I'm crazy on that one...

Spark Plugs- I started with 2 sets Bosch supers, foueld them, could only get champions local and fouled those until I found a bad injector connector. Ran those for about 150 miles(20mpg) and then got a set of E3 from Oreillys(Hotter spark, better fuel economy my rear end!) When I took the champions out, they actually looked a lot better, since I was firing all injectors and pressure was good. After another 150 miles(17mpg) I just got back from getting a set up Bosch supers. My slight miss has been present with the last 2 sets of plugs. I am changing them again back to bosch supers to rule out running plugs I'm not suppose too.

Throttle switch- 78 doesn't have it. Mine did, but was disconnected. I completely removed it prior to installation. I put the screw back in the hole to block it.

Distributor- I have thought about putting the points in or just putting my old distributor back in(with points) but when I checked myPertronix box, I didn't see a gapper, just new points. Bought it already installed into a new SVDA distributor from aircooled.net. Not sure if I can get it back in properly just yet if I take it out.

I will be changing the plugs and rotating the cog 2 clicks counter-clockwise and will report back.
_________________
78 Westy 2.0l hydr. FI

VW Campmobile
For people who believe a family's
car should be it's castle !

[ac78]

I did change the plugs, found that 2,3 and 4 looked pretty good, but #1 was fouled again. This is also where the new FI connector was butt-spliced on. After changing the plugs, I remade the FI connector connection and went down the road, no change in miss. I put a couple pics of the plugs below.

http://78vwwesty.shutterfly.com/pictures/44#47

Althought I am positive I connected the right wires to the plug, if I would have reversed the wires, wouldn't I have blown something up, control unit, etc.? Or is is that I am getting plenty of fuel and no spark? We'll see...

Did not move the cog until I fix the above issue.
_________________
78 Westy 2.0l hydr. FI

VW Campmobile
For people who believe a family's
car should be it's castle !

[Randy in Maine]

There is no polarity to the FI plugs you speak of.

I read what rockerarm wrote and if you have a new TSII, lets try it.

[ac78]

I don't have a new Temp II, just my old one that acts the same. I'll have to get one on order tomorrow.

I am going to put my pressure guage back on in a few to make sure it's still doing what it's suppose to do. Previously, it was going down too fast when I turn off the key. I confirm both of those in a bit.

I do have good spark at the plug and I do have voltage at the connector. I didn't have a test light and used my meter, it was reading .36v, but would bounce to .37-.38, .34 and back to .36 for most f the time. It was I am still curious about reversing the wires though. Bentley says the connector on the injector side should have continuity by itself, so I wouldn't think it should make a difference.

I was thinking about pulling the injector to look at spray pattern and if its leaking more than 2-3 drops per minute as per Bentley. What do you guys think?


Thanks!
_________________
78 Westy 2.0l hydr. FI

VW Campmobile
For people who believe a family's
car should be it's castle !

[ac78]

Fuel pressure 32 on (bounces a bit to 33) and 40 off.
Fuel injector definately firing, appears to be fine mist. Used a clear baggie to test. Why is only this plug starting to foul?
I will have the key off leak down shortly. Seems to be losing pressure too fast and with the audible noise/vibration on the hoses, something may be up with the fuel pump...
_________________
78 Westy 2.0l hydr. FI

VW Campmobile
For people who believe a family's
car should be it's castle !

[rockerarm]

You stated #1 plug was fouled? Gas fouled? Well the computer fires all the injectors at the same time so if one plug is fouling AND it won't hold residual fuel pressure after pump is off, that may be a problem. Once the pump is off, you can use needle nose vice grips on both sides of the fuel rail to determine if its injectors/cold start valve and/or pump or regulator.
Since you said one plug is fouled, that needs your attention, but consider adding the 100-300 ohm resistors to improve the driceability if we later determine we are lean on the other cyl's.
You've ruled out any egr valve leaking, power brake hose leaking, etc.

[ac78]

I can't really say why the plug is fouling or if it is completely fouling. It's dry black and doesn't really smell like anything. The best I can do is the pics I had a couple post ago. All the plugs were like that a couple weeks ago and once I replaced the injector connector, they all started to burn some of the crap off. Then I went to new plugs and all but #1 look "normal."

As for the running 32 psi fuel pressure once I turn off the key:
28psi after 30 sec
26- 1min
24- 1 1/2 min
22- 2 min
20- 2 1/2 min
18- 4 1/2 min
16- 5 1/2 min
14- 8 min
12- 15 min
Then I got distracted. I need to find the link to the post key-off tests and try those. I think I have it on my other laptop.

Edited-- I checked the link and I do not have any problem staring when warm. Hot or cold, it starts right away. Just wanted to add that.

The only thing I can link #1 to so far it that it's the last stop before returning to the tank. I do have my old pressure regulator which had the same results as my new one. I could put that on to rule it out...

Not sure what you mean about adding 100-300 ohm resistors. Where?How?

EGR is blocked off and I feel pretty good that the brake booster is good. After I have a good drive, the vac is solid 17. When I am reving in the driveway for a few mins it's 14.
_________________
78 Westy 2.0l hydr. FI

VW Campmobile
For people who believe a family's
car should be it's castle !

[rockerarm]

Well, back again. I will say you are good with collecting and posting data. Nice work.
If your fuel pressure is dropping because of an injector or cold start valve we have to fix this because it controls fuel into the motor. But if fuel pressure is dropping because of the pump or regulator, I would not worry. Do you know if a Bosch Service Center is around to bench test your injectors?
Since all the injectors fire at the same time would you consider swapping the electrical plug and see if the problen repeats itself on the same cyl? Then if the same cly fouls swap injectors with the cyl alongside it. Trying to diagnose without just replacing parts.

Regarding the resistors, see my post at 10am this morning. This won't fix one cylinder fouling but a lean surge it may improve the driveability.

Also, in my factory was a procedure for misfires where the factory suggested driving bus w/out alt belt. If miss goes away,replace volt reg and reinstall belt and road test. If miss still exists repl alternator. Hummmm!

[ac78]

As part of my overhaul, I bought 4 reman fuel injectors from bus depot. So I have to say, I am disappointed with your suggection about finding a service center for testing. That said, I do like the idea about switching the injector connetor and/or injector to #2 to see if it follows it. I will run with #1 and #2 switched for a 100 miles or so on my new plugs to see what happens.

I am assuming I shouldn't drive to long without the belt, since I loose my cooling ability... Based on my previous tests, I will know within a mile round trip.

Thanks!
_________________
78 Westy 2.0l hydr. FI

VW Campmobile
For people who believe a family's
car should be it's castle !

[rockerarm]

Why would you be disappointed! Do you own bus depot? I don't either. And I don't think bus depot does the remanufacturing in house. As a VW tech, you learn to suspect more stuff as it unfolds. Kinda like a detective mechanic, he he. Really, things happen even with rebuilt items. Just gotta keep an open mind.

Don't worry, the fan is bolted to the end of the crank. The v-belt turns the alternator only. HEY your already being open minded. IE: think outa da box! Bill
Gotta be late there at home. Gotta big day on monday, so rockerarm out here.

[busdaddy]

[rockerarm]

Busdaddy, and what theory is that?

[ac78]

I am encouraged to find a single injector to trouble shoot. The miss may or may not be related.

Good point on the fan guys! I will have to wait until the morning to test. I'll let you know I soon as I can.

Thanks again!
_________________
78 Westy 2.0l hydr. FI

VW Campmobile
For people who believe a family's
car should be it's castle !

[Randy in Maine]

When I was having a similar problem a few years ago, others helped me write a little "Residual Fuel Pressure Test".

http://www.itinerant-air-cooled.com/viewtopic.php?f=42&t=213

[ac78]

Didn't have too much time today, but here's where I'm at. I switched the #1 and #2 injector connector and it is definately running worse. Still very driveable, but worse none the less. For fun, I reset my valves to zero last night and cruised around today(only about 6 miles worth.) Tonight, I set a watch and did the valves to 1.5 turns in under 21 minutes. Could have been faster, but #2 exhaust locknut is pretty chewed up, gotta put that on my list. May go back to 2 turns, but wanted to try it for a day or so.

After I took it out of the garage, I parked it and took a listen.
My fuel pump seems to be getting louder, it is up to a pretty good hum. I held my phone by the back tire and made a quick video. It's dark so there's nothing to see, but I was wondering if any of you can make out the pump?? I'm thinking that should be first on my list before troubleshooting anymore. In 13 years, I've never heard the sound it's making.

http://78vwwesty.shutterfly.com/pictures/50

Thanks!
_________________
78 Westy 2.0l hydr. FI

VW Campmobile
For people who believe a family's
car should be it's castle !