TheSamba.com :: View topic - 78 Westy FI 2.0 / Won't start....Electrical woes!

Fri Aug 08, 2008 7:41 pm

1978 Westy Camper
2.0 FI Engine
Trying to get it on the road!!!

Bear with me...I am new to the site, VW's and posting!!! Trying to start the engine, will fire up initially but will not stay running . Replaced all ignition parts, went to electronic, new plugs, new wires, had new combo relay I put in just to rule that out. Fuel pump not getting power. jumped it to make sure it would work and it did. Pump is good. Did the loop with a test light to see if we were getting power to the pump and we were not. Checked pressure and all the readings seemed to be good. Also did a pressure check by squeezing the fuel line near the regulator to make sure the regulator was working properly. The constant presure went from the constant mid 30s to bethween 55-60 and when released, it went back to the constant 36ish (I believe this was the Collins test, or something similar). Good fire everywhere. Coil is sending constant to the brain box. However, the test light indicated only the bottom connection was getting power. The coil was sending it in, but nothing was coming out. Checked both plugs on the combo relay and only the ones with power from the switch in front were hot. Also, getting no power to the airflow meter. Getting no power to the cold start (5th injectior). We tried to run power directly into the brain box with a jumper wire and still nothing coming out. I was under the assumption these did not go out easily, but it looks like that may be the problem???? Just don't know. Any thoughts?

" I might have been born yesterday,
but I've been up all night long!"

Fri Aug 08, 2008 8:17 pm

One of the other guys might jump in here but I think I have read that it may be the AFM. There is a switch inside the AFM that triggers the fuel pump. There is a small adjustment to the switch that might do the trick. I think there is a FI troubleshooting guide somewhere here. I will take a look.

Fri Aug 08, 2008 8:20 pm

First thing to try is a pencil down the throat of the AFM, it may be stuck shut from a backfire. If it does move does the fuel pump come on when the key is on and you depress the flap?

Sat Aug 09, 2008 4:21 am

Thanks...bot of you. We did have a few backfires in the initial revival phase. I'll check that. However, we are still not getting power to either lead on the fuel pump. Battery strong, power checks out at the coli, checks out back to the brain box, but no power to the fuel pump, air flow meter, or the combo relay (other than the couple of contacts that run off the switch power.
Thanks,
John

Sat Aug 09, 2008 5:35 am

I would make sure the contacts in the AFM touch (the two little ones all the way on the right) when the flap is moved. This contact I believe powers half the double relay which then powers the fuel pump. Test is to turn ignition on, take cover off AFM and move the little arm/flapper, you should hear the relay pull in and hear the fuel pump start.
my .02

Sat Aug 09, 2008 5:35 am

You may want to check all the grounds also. Battery, body and trany. Can't hurt.

Sat Aug 09, 2008 9:28 am

I had this trouble once after reinstalling my engine. I had forgotten to attach a wire to the coil. Make sure all you connections there are good.

Does your wiring to your coil look like this?

I had left off that black wire at the very top.

Tue Aug 12, 2008 5:36 am

Thanks everone. Found a few bare spots in the wiring. Have a harness on the way. We have done all the checks with the AFM to no avail. Seems to be some type of electrical. We are going through the entire eiring to verify eveything is grounded, all wires are good and the correct current is going where it needs to go. I'll be back.

Fri Aug 22, 2008 10:09 am

New wire harness installed. Gone through all diagonistics on double relay. Everything seems fine. Did manual test of moving air flow module to see if fuel pump kicked on. It did. It turns over well. It wants to run, but it just will not stay cranked. THANKS Ifbwax for the photo. That was one of the problems. That black wire was hidden in the corner. I had two wires, but it was because I added a Pertronix. Testing the cold start valve today. Still working through the diagnostics from the Bentley book. Any suggestions where to look next. One questions. I have two wires gong to terminal 50 on the starter. they are a red/white striped smaller wire and a bigger red wire with a small black stripe. They are going directly to the terminal 50 with a spade connector. Everything else is going directly to a screw terminal on the starter. I don't think that is the problem, but I just wanted to verify that was right. I think electrical is good. We have checked fuel pressure, AFM, good gas, fuel pump working, and a few more things. It just does no seem like it wants to run for any length of time. That is why we are going to the cold start valve. Just let me know any other options you may have.

Fri Aug 22, 2008 10:20 am

Humor me....

Stick your 12 volt test light into any of the FI wiring harness slots attached to the injector. Polarity doesn't matter.

Have someone turn over the starter and see if the test light flickers.

Fri Aug 22, 2008 1:20 pm

Did you set the timing?

Fri Aug 22, 2008 5:53 pm

Thank you both for the reply. I'm fighting this thing. I did stick the test light into the FI harness and it did flicker. I was thinking it is something with the injectors or the cold start valve. What are your thoughts on the injectors themselves. Odds are all of them would not go unless they were not getting the feed from the harness. We also did all of the checks (via the Bentley book) last night on the double relay. All of those checked out as they should. I just finished the check for a leaky cold start valve and checked it to make sure it was working properly. Both came out OK. The timing is very close. I will go back and double check to make sure. Thanks again for your input. Bear with me...I'm still learning. If some of these things seem remedial, they are probably new to me.

Fri Aug 22, 2008 6:40 pm

Temperature Sensor II? What's your resistance measurement?

Seems to me that you have checked everything per Bentley. If it's not your Temp Sensor II, maybe you do have a problem with the ECM. They do go bad sometimes.

Pull the connector off of the ECM and check the wiring from the ECM connector to its final destination. Just to double check things and make sure you have not made any mistakes in previous diagnosis.

It really is a very simple system. This is a good lesson.

Sat Aug 23, 2008 5:14 am

Thank you for your help. I received a different "Brain Box" on Thursday. The gentleman had checked it out the morning he sent it to me. He marked it so we would be sure it was the right one. I will check the resistance on the temp sensor II. This has been a good lesson. I joke with my "upright" friends that I am the only person to be ostrosized from the VW community before I got in good. Not a ton of love for the FI pancake where I am. I am also changing / checking all vaccum lines, even the ones not directly related to the engine (i.e. break booster). Maybe on of these will give us a winner.
Thanks again for your input.

Mon Aug 25, 2008 5:48 pm

Running....Yah hooooooo! We finally got the bus running today. We have worked through a few vaccum leaks, and a slight leak at the cold start valve (thanks to my less than stellar handi work). The bus runs good. Everything sounds great mechanically! Getting fuel, power, etc! The only problem...we have to manually hold the AFM open about 2/3 of the way over. The first thing we thought was vaccum leak or air coming in somewhere. We went back through everything. No leaks. Could it be a faulty AFM or a couple of faulty connections on in the AFM? Thoughts. Thanks again for everyones help. Almost there!

Mon Aug 25, 2008 6:45 pm

Check the little resistive surface inside the AFM...does it look worn through in some places? That may explain why you have to hold it open. It's possible I think, to undo the screws inside and shift the thing around a little to get a fresh contact on the surface for the needle to run on.

Tue Aug 26, 2008 4:37 am

Thanks for the info. We tried to move it around a little with no luck. You can see a little grove where it has been sliding over the years. We will work on it some more and hopefully have better luck. I may try another one that has been tested or even new.
Thanks,

Tue Aug 26, 2008 5:51 am

I have been following your dilemma, and I am glad you got it running. That is a sweet sound after you have chased the ghosts in the machine.

If this bus has sat undriven for many ice cream seasons there may be a vacuum issue. Think about this... the AFM is working at least partially, the fact that it'll only run with the AFM flap cracked open 2/3 of the way may indicate the need for increased fuel to overcome a lean condition caused by the enemy, unmetered air.

I suggest buying any seal, o-ring and rubber elbow and hose available. Replace the injector o-rings and gaskets as well as the intake runner hoses. There may be a seal of sorts where the throttle valve attaches to the intake air distributor and other sundry cracked/dried out things made of rubber that are allowing alien air into the system the AFM can't compensate for. Even if hoses are not cracked, they harden and loose thier grip and the enemy slips in on the wrong side of the AFM. Will it start on its own, or must you prime it? If it requires a prime, the system is leaned out and the 5th injector is overwhelmed with air, it is designed to operate with only what enters the filter side of the AFM. Any air coming into the system after that will defeat the ability of the components in place to work together.

I know little about the intricacies of the AFC injection systems, but if the engine runs smooth at a higher rate of RPMs then stalls when the AFM flap returns to closing would indicate to me that general fuel delivery is being achieved, and timing is close to where it needs to be. Do the tedious now so you can enjoy later. Perhaps Scott at German Supply could be of assistance as far as the soft parts that seal out unmetered air?

Hang in there, and keep on hackin' away. Keep in touch!

Tue Aug 26, 2008 6:08 am

Thanks for the reply. To not know a ton about FI (as you say) you might have just nailed it. This morning I have pulled numbers from about three or four specific hoses/lines that show possible cracking/leaks. I am also ordering the four hoses to the manifold (and clamps!!!). If you ever decide you want to come over and wrench, I definately have a paying gig for you!!! Thanks again for your kind words. Just FYI...and to cover all the bases, have you ever heard of a "Retel" valve. My son said that could be the problem. However, knowing him he may just be sending me on a wild goose chase!!!!

Tue Aug 26, 2008 6:19 am

... sounds like you are in my area, j whale. Are you a big guy?

I don't enjoy wrenching on the suitcase engines much, but economic times are tough and I will consider your kind offer on one condition... I adhere to a don't ask, don't tell policy if 72> bus engine repairs and my name are mentioned in the same sentence.

My son, now grown and a dad himself, once had a girlfriend he called rettle, or possibly grettle... he could have just made the whole thing up?

If your young son mentions a rettle seal or hose, you may have an aspiring independent air cooled Volkswagen technician in your home.

Jeff