Q: Tuning Air/Fuel Mixture on 1977 Bus with Fuel Injection

[equinox]

Ok, I really need your help and will try to be as through as possible.

i have a 1977 VWBus. It has a 2L engine in it that has been rebuilt and has hydraulic lifters, electronic ignition, and fuel injection in it.

When I first got it a couple years ago, it was getting 19.4MPG.

Recently over the winter I fudged up. I cranked the crap out of it trying to get to idle and backfired even. I had it towed to a local VW mechanic and Bosch Service Center and to be brief, it had some vacuum leaks, a hose of some sort blew off, and they said the backfire blew out some plug on the Air Flow Meter. They alledgedly repaired all leaks and plugged the hole. they said the EGR wasn't working so used some sort of spring to hold it open or what not and I got it back from them.

It works, but went on a cruise over the weekend and it's been a couple weeks now so went through about 4 tanks of fuel. I keep track of everything and am getting about 13.27MPG (really bad).

I contacted them and although I figured it was fully ready (why else would they call me to say it was and pick it up), they are saying I should get an AFR gauge and put it on and monitor it and adjust it myself or pay someone to do it.

Let me tell you, after them having it for 5 weeks this time and paying $2700 this time and $2000 last year, the LAST thing I want is for them to get in there and sodomize me anymore. Did I mention there was a slapping when I picked it up. I found the problem myself and the upper shock bolt was about 3/4" out!! They didn't discover that on their test drive(s)?? Great goin Munks, NOT!

I'm looking for my fellow bus owners to help out a brother and need and let me know what I should do and I'd like to taclke this on my own now that the bus is running. Any advice would be greatly appreciated, especially after the scare tactics of these characters and suggesting, oh, it's probably critically lean and had you not had hydraulic lifters, you probably would have burnt up your valves, if you haven't yet! Can you say something worse than "jerk?"

Anyway, any help is greatly appreciated. Thanks in advance. Maybe this is even tackled already in a thread.

[SGKent]

You immediately like tonight need to PM Amskeptic (Colin) and hire him to look it over. The cost is less than a regular shop but it will be good work. http://www.thesamba.com/vw/classifieds/detail.php?id=1248631

He is in NY right now but will be in Livonia MI Jun 1. Once the passes you by he heads to the West Coast and won't normally be back until next year. That is the best solution. He has the proper air to fuel meter you will need. He can also look over the other work they did.

http://www.thesamba.com/vw/forum/profile.php?mode=viewprofile&u=2768
_________________
“Most people don’t know what they’re doing, and a lot of them are really good at it.” - George Carlin

[equinox]

Sounds very interesting except I would need to know expense up front. I've spent enough and have extensive automotive knowledge worked at a dealership for 2 years, literally worked on hundreds of engines, but not VW, and worked the last 21 years in automotive engineering here in Detroit as a Tech, Engineer, Project Manager, and Global Program Manager!

I just need time and direction. If I need an AFR gauge to monitor fuel/air, just let me know what to get, how to hook up, and how to adject fuel air. i have the repair manual, maybe it's in there also.

I would LOVE a second set of eyes on it also and from an expert which leads me to the other issue...out of town 6/1 thru 6/7 on business, so doesn't sound like I'll be around.

Any advice on how to measure and adjust would greatly appreciated.

[kevin77westy]

Are you positive its the mixture? Have you checked your timing? A few degrees out it'll run great but MPH goes south.

[equinox]

good call. no, i am not n a friend suggssted may be retarded also!

the shop had to do a few things n u would think they would have done all this, but quite frankly, i don't trust it and them n why i've always worked on my own vehicles.

i'll check the timing also.

as theynhad to repair the mass air flow unit n repair the plug, is there any further adjustment to that needed or woukd they have set that on a scope or what not?

the geometry was off on the engine and evidentaly when they rebuilt the engine, they cut the block, heads, and/or intake n had Harris Racing checkmit out locally n the rods were 6mm longer than they should been so cut a set to the correct length.. you woukd think after getting geometry right, gettung MAF fixed, they would have set the timing n air/fuel mixture. i'm pretty funking pissdc tk tell younthe truth. they lost a newer seckndary battery n upper shock bolt was 3/4" out when i picked it up!! between cost n quality of workmanship, i can honestly say somemof the worst ever!

[aeromech]

Okay mister smarty pants😉. Go buy one of these.

http://www.innovatemotorsports.com/products/lm2.php
_________________
Lead Mechanic: San Diego Air and Space Museum
Licensed Airframe and Powerplant Mechanic
Licensed Pilot (Single engine Land)
Boeing 727,737-200-300-400,757,767
Airbus A319,320,321
DC9/MD80
BAe146
Fokker F28/F100
VW type 1 1962,63,65,69,72
VW Type 2 1971 (3 ea.) 1978, 1969
VW Jetta
VW Passat
Capable of leaping tall buildings in a single bound

[Wildthings]

So you delivered it to them with a shock bolt that was falling out and didn't tell them to fix it and now you are upset??? Would you want them to do a $2000 repair on the front end without telling you because of the steering was sloppy? Maybe (or maybe not) you got hosed on what work you did have done, but you can't expect them to take it upon themselves to fix every part of your ancient vehicle just because you brought it to their door.

[BellePlaine]

While an LM2 would be sweet to have, it's a bit spendy. While you're saving your pennies, here's a good rap on adjusting an AFM.

http://www.itinerant-air-cooled.com/viewtopic.php?f=50&t=7761
_________________
'75 Riviera

Whether you are a novice or know your way around an ACVW, a day with Amskeptic is money well spent. My mechanical ability/knowledge/bus is always better after Colin visits.
http://www.thesamba.com/vw/forum/memberlist.php

[equinox]

Wildthings - I think you missed the point, entirely!

They did some other work like replacing the engine seal and what not. Not sure what they did in the aggregate as I wasn't the one doing it and wasn't there, but my POINT is that there was no slapping and loose shock bolt. They did work on it, TEST DRIVE IT (you dolt), and called for me to pick it up and it was this way and did not even pick up on this (I had to find this out). This, the extravagent price for the amount of work done, the air/fuel is funked up, but said ok to pick up, and did I mention they lost a brand new battery I had in it and at best want to give me a "credit", but are an hour away EACH WAY from my place! Yeah, you are damn right I'm pissed as ANY reasonable person would be. This has been a horrible experience. They know their sh*t, the rest is crap!

BellePlaine - Thanks for the link. I will review it as well as Service Manual I have, but would appreciate any direction anyone could give that would be beneficial.

Oh, I forgot above to mention I work for Bosch currently also!

[Greg in GA]

[Randy in Maine]

A day with Colin would be the best money you could possibly spend if you intend to keep this bus. He teaches YOU how to fix your bus.

[SGKent]

[equinox]

Greg in GA - Wildthings DID miss the point and I'll tell you how...he suggested the bolt that was backed out was unrelated to the work or me just wondering why they didn't repair...whatever. The backing out of the bolt happened with them over 5 week. It was instantly noticable by me, but yet they did not hear it on their test drive! That's ludicris. I go for a ride with mechanic friends all of the time and they hear sh*t I didn't even hear and will say, did you check your wheel bearing on my truck or whatever. No, it's poor workmanship and quality to call up the customer and say come a f*cking hour drive and pick it up, it's ready, I test drove it.

Again with the Colin. I get it. I appreciate it. Did you get my response, I'm out of town 6/1 thru 6/7 in Mexico and Florida and this won't work? I'm looking for a resolution now.

In regard to the link...VERY nice link (http://www.itinerant-air-cooled.com/viewtopic.php?f=50&t=7761) and illustrated and well understood. Thanks. I'll read trough it thoroughly as well as the service manual. Yes, I'm thinking at this point, it is NOT going to go into their hands again and definitely can do it myself.

[SGKent]

[equinox]

thanks.

the shop (Munks) already did a smoke test and all leaks should currently be solved, so the only thing outstanding is adjusting the air/fuel mixture.

the timing they set also at i believe 32 deg at 3200 rpm with 009 distribuutor and 8-12 deg static. i can recheck that, but if still ok, as well as valves, air/fuel shoild be all thatis left to do n why i wanted feedback how to do it n what equipment to use.

they recommended a wide band airflow meter like PLX AFR meter. the LM-2 suggested seemed pretty cool with data logger.

being my MPG is crap suggests it is rich, not lean, which is probablyis a good thing so engine or valves do not over heat.

now, what to do? the like privided about adjusting AFM seemed pretty cool. ill have to read through it in its entirety as well as the service manual. ill have to get a meter to monitor this though n figure out which one to get

[SGKent]

I'd start with setting the timing the preferred way here. For passing smog my bus is at 7 1/2 degrees BTDC which is 32 BTDC at 3500. For longevity of the engine it is at 29 BTDC at 3500 RPM, and idle falls where it falls.

Your mixture can be rich because of

1) prior owner tampering with AFM
2) bad TSII
3) Leaky CSV
4) Bad FPR
5) Injectors wrong model, bad, or need professional service

Check 2-5 if you haven't already. Some are very prone to causing the condition you have.

Also wrong dash cluster, replaced transmission with a different ratio, or wrong size tires can all cause mileage to be off. GPS is not always accurate either as to actual miles driven.
_________________
“Most people don’t know what they’re doing, and a lot of them are really good at it.” - George Carlin

[kevin77westy]

You have bashed the shop pretty good (and it sounds like for good reason! $2700 for the work described = you got hosed) but you still trust everything they told you ? Check the easy (and cheap) things first yourself before just ruling things out because the shop said so. Adjust your valves, look for vac leaks (buy a cheap vac gauge if you need), set timing as described above. Check for spark at all plugs. I think you will find the problem is not the mix but you gotta get the basics covered first no matter what so get to it! If you do end up monkeying with the mix you have to make sure you have NO exhaust leaks before you measure your exhaust or the readings are not good. LM2 is a kick ass tool (I love mine - logging the data is nice feature!) but you might not even need it. Just sayin.

[equinox]

thanks for heads up on timing. remember thou i was getting 19.4mpg before it went to the garage, so had nothing to do with tires or transmission or anything.. in fact it would have been running with a lean condition, not rich condition! they messed with the timing n air/fuel and AFM, so i'm certain adjusting this is the ticket. ill start with the timing, then measure and monitor with meter, then make adjustments to air/fuel. i will look at the other items for giggles. they may have said it was all jacked up before, but it ran smooth n got excellent mpg, now it runs very low idle n poor gas milage! i guess that's what u pay experts for! lol

[airschooled]

[equinox]

I think you hit some things on the head asiab3 and I'm very wary. I think again some folks are misreading some thing. I agreed on the expense and there was quite a few things done. I didn't like the amount, but paid it, IF the bus was fixed. What those folks are missing, is it is NOT right, yet, they failed to realize the upper shock was freakin almost backout out entirely and slapping around (but test drove), and they lost a new battery!

They wanted to weasel out of the battery and asked for the reciept, then suggested maybe the warranty wouldn't cover it since the battery alledgedly leaked (how can anyone verify, they lost it). They asked about removing the A/C since the compressor wasn't there, removed the cruise (but I never said to do that), there is some hoses removed and hose open in the bay and I think they said was a breather!...which you indicated above if I read you right and something about not finding the vacuum leak (thou they alledgedly did the smoke test)! There's a lot of red flags and I have a right to be downrigh f*cking pissed. A LOT of folks recommend them. I see them as experts, but shisters and all you need is one things done, but will scare you into a laundry list of things, then when those are done, suggest a laundry list of other things of which advise to do or else catasrophic valve or engine melt down! I would not recommend them to anyone and in fact would deter anyone from using them. Now, I finally got them to just say, hey, we lost the battery and write a check for it. They've quoted something like $350 for a wide band metering system or them to install it and work with them to get the air/fuel right. At this point, I'm just ready to take them up on the check and cut my losses.

Soo again, I just needed to know how to adust this. I think with the link and manual, I have what I need. I want to get a meter with data logger. Not sure which one yet. the one you guys suggested I'm all for purchasing, but I like to research and shop around. I'm more than happy to let you guys know how I fair out. I think I may post a few pictures of the engine bay also and get some feedback of the photos also, so stay tuned for them and thanks for your help!