Going back to FI

[dingo]

3 and 18 go to throttle valve-switch (if you have one i.e. 75, 76)

[vdubyah73]

I went back to the junk bus and scoured it for the lid off of the AFM. I found it jammed up in the air filter bracket. The part # didn't correspond to anything in my Bentley. I googled it and came up with this on the type 2 list
http://www.type2.com/library/fuel/fuelibo.htm
Fuel Injection (Bosch Parts Interchange)

My AFM comes up as a '78-'79 non California. I Have a good '78 ECU.

The question of the day is, will any year FI harness work with this ECU and AFM or do I need to find a harness for a '78 - '79. I'm concerned about the full load/throttle enrichment circuit.


Bill

[KYLE]

The best thing that I can tell you is that all of the L-Jet FI harnesses are basically the same (excluding the 75 with the 6 pin AFM and electrical EGR valve). I don't know how in depth you want me to go so I will explain a bit and if you have more questions, please ask.

The Full Throttle Switch is connected to leads 3 and 18. It seems that the odd 75 model year had a FTS that also controlled the EGR. In 76 the FTS remained (as far as I know, but I haven't actually had the harness to verify), but was deleted by late 76 or 77. As far as I know it did not return until the Vanagon in 80 and remained thru 83 when the 2.0L was replaced with the 1.9L water-cooled. I have tryed to figure out why there always seems to be more pins than needed, but the information is limited and vague.

I have seen a few harnesses that had two wires branching out with the #1 wire for the IGN coil, but they were not for the FTS. I can't find my notes right now, but I think they were connected to pins 9 and 12, and one of them was tied to another wire in the Double Relay. The best theory that I have is that they are for an Automatic Trans. decel valve, but I have heard a few other ideas thrown around in the forums.

If all the information that I have seen is correct, then the 78 ECU does not use a FTS. I have been making all of my harnesses the same and recommending that customers just leave the FTS leads loose. Everybody has given me nothing but positive feedback and I have even heard reports of a more responsive engine and some improvement in mileage. I make no such claims, but it doesn't surprise me since the original harnesses are around 30 years old. Be careful since a harness may work well before being disturbed, but the wires are brittle and the insulation is prone to cracking.

I hope that this helped.

KYLE

[Amskeptic]

The Full Throttle Switch is connected to leads 3 and 18. It seems that the odd 75 model year had a FTS that also controlled the EGR. In 76 the FTS remained (as far as I know, but I haven't actually had the harness to verify), but was deleted by late 76 or 77.

The EGR portion of the switch was for only partial throttle. Its continuity test would show 0 only just off idle and would re-open before full throttle.
Colin

[vdubyah73]

Thanks everybody, thanks Kyle for the prompt reply to my message. I think I've got my answer now. 7 pin connector for AFM with a 7 pin harness and the '77 or later ECU should work. Maybe I made much ado about nothing, can't help myself, when I delve into a new project, that I don't really know anything about. It won't take long for me to be proficient with FI, I have a voracious appetite for finding out everything I can with new challenges. I find it to be a pressure relief valve for my every day BS.

Wait until I decide it's time to go turbo EFI on my Buggy. It's estimated at 150 rear wheel horsepower. I'm gonna be looking for 250 or more when I make that jump.

Bill

[tristessa]

If it'd help at all, I've got the CPU+AFM+Harness combo from an '80 California-spec Vanagon out in the garage. I'm not using it, just taking up space.

The CA system has the injector resistance built into the CPU and makes use of a Wide-Open-Throttle switch, but is otherwise mostly the same. Let me know if you could use it.

[vdubyah73]

Well it's done! I now have electronic FI. Engine went in and gas lines plumbed yesterday. Today, hook up all the wires to the Bus and turn the key RRRR RRRR RRRR RRRR nothing. Takes a long time to fill all those new fuel lines. Turn key on and nudge the wiper, I can hear the fuel filling the system. Actually heard the air bubbling in the tank as the return line finally filled. Try again, starts right up in about 2 revolutions.. Idles high at first, but drops in a few seconds or so after releasing key. Guess the cold start valve and thermo time switch work. Gawd those flat lifters make a racket, had the engine down to long block while out. Stopping some weepy case nuts and checking around, took out lifters and checked wear pattern.After running for a bit the idle continued coming down slowly till it settled. Guess the auxiliary air valve works too. No idea what idle RPM is, didn't really check anything. Ran real smooth and the lifters finally pumped up after about 15 min. of running. Tomorrow I finish the tin, install seal, tune it a little. Once I put it back on the road I will get it really warmed up and dial it in. All the parts were free, out of a rusty hightop. Cost a little over $100 in shop supplies and sundry items, like fuel line. If I save a couple gallons of gas a week it will pay for itself in a little over 2 months. Thanks to this site, TS and Ratwell I got a crash course in FI. I have a local guy that helped out a lot too. thanks everybody.

Bill

[vwlover77]

Congratulations!

[Amskeptic]

Well it's done! I now have electronic FI.

Congratulations! Yer #2 on the list, after our Pioneer FI Return Voyager, Velokid1.
Let us know how the mpg and driveability are.
Colin

[vdubyah73]

OK, I put the bus back on the road all legal like and everything. Did quite a few out and backs yesterday. Out and back is when you hop on the highway and go a couple....several exits and come back to the shop Some out and backs all highway some highway and secondary roads. With no adjustments done by me, my warmed up idle is rite at 950 RPM. Engine runs smooooth, and wow is fuel injection a lot quieter than the barking of carbs!
Is it possible that a well tuned FI system from one engine will be a well tuned bolt on for another engine? I don't think I have to adjust anything! Idle goes down when moving wiper in either direction. Goes down with a smidge less movement CW. 2500-3000 RPM, I can move about a quarter inch CCW before RPM drop and a bit less than a quarter inch CW before the same. More out and backs today, and a refill on the tank with some Techron in there too. I'll let you know my MPG, but I don't expect much improvement with this tankful. I've been driving it like I stole it, with hard accelerations and anywhere from 60 to 80 MPH on the highway.

Bill

[vdubyah73]

I got 14 MPG driving 100 miles like I stole it. Every acceleration was hard and I went anywhere from 60 to 80 MPH on the highway. With the carbs I would have gotten 12 MPG. Driving gently and sedately on this tank of gas I will report back with MPG. This is a pretty fair comparison for a seat of the pants type of data logging. The dual ICT's were damn close to a perfect tune. they ran smooooth when warmed up drivability was good. Transition from cold to warm was fairly smooth, once it ran for a few minutes you drive away. It would only cold bog from a stop a couple times and clear up. Th FI is smooooooooth almost immediately, no bog. How many times can I say how quiet it is compared to dual carbs. I do miss the instantaneous throttle response of the carbs though. If you moved the gas pedal you got instant response whether giving it gas or letting off, Instant feedback. With the FI you can tell that there is a lag as the AFM opens or closes and the ECU decides what to do with the signal. You also have a decel valve, that you can see with your eyes, the throttle has closed yet the engine takes it sweet time coming back down. The feel of this when driving is kinda spooky, with dual carbs you let off the gas and you immediately feel it slow the bus down. FI no such sensation.

Bill