77 Fuel injection trouble shooting

[jmarshall024]

Hi all- I know there are a ton of threads on FI issues. I read through a bunch of them, but could use a little simple step by step help.

I'm working on a friend's 77 bus with FI. When he bought it the previous owner told him it ran but very poorly and then died. Looking at the old fuel filter my guess is they ran this thing until it just clogged up and died.

So far I've done the following:
1. Drained the tank and washed some fresh fuel through it. I still think it will need a tank out cleaning.

2. Replaced the fuel filter.

3. Changed the fuel pump. I determined the previous pump was bad by putting the key to on and hitting the lever in the air flow meter. I can hear the new pump working/circulating fuel now.

I noticed no change after doing the above. The engine just cranks with no sign of starting.

I tried putting some fuel down the S boot today. No change.

Until today I thought this had to be a fuel delivery issue (given condition of the old filter, fuel pump and drained gas), but putting fuel in the S boot did nothing.

Now I'm thinking it could be lack of spark. I did confirm power at the coil and cleaned the grounds under the plenum. The vacuum lines aren't in great shape but I went around and made sure all the connections are a secure as possible.

I think a lot of work will be needed on the vacuum system and fuel injection components before this can be driven regularly, but I'd like to at least get it to fire before just having my friend buy parts on a hunch.

Any thoughts/ideas to at least get some signs of life?

[aerosurfer]

Did you test for spark at the plugs? Running points or pertronix? What's the timing tentatively set at for now?
_________________
Rebuild your own FI Harness..My Harness

77 Westy 2.0L Rockin and Rolling Resto!

72 Sportsmobile (sold)
79 Tran$porter... Parts car money machine (gone)

[KentABQ]

Have you seen this manual yet?...

https://www.thesamba.com/vw/archives/manuals/afc_f...Manual.pdf
_________________
-Kent-
1976 Riviera, 1.8l FI chrome yellow VAN - "Chloe"

"I must say, how can you be in a bad mood driving this vehicle full of vibrant color.
Cars of today are so bland in comparison. It's like driving a celebration!" ---WildIdea

Bus ownership via emoticons:
---williamM

[Wildthings]

Test for spark by setting the distributor end of the coil wire 1/4" from a good ground, if you have spark there then remove each plug wire in turn and use a spare plug to check for spark.

Your points could well be corroded up or just not opening.

[jmarshall024]

thanks guys. I only get over to the bus on weekends so I'll attack spark next weekend.

I have been using the AFC manual here and there. The bus is running points.

The points, cap and rotor all looked ok, but agree on testing for spark the way described and probably replacing the points just in case.

I didn't get even a pop putting gas down the S boot so definitely think spark next. I'll report back in a week or so. thanks

[rottenkid]

You can buy a spark plug tester from Harbor Freight.

I have four of these testers. They really put on some light display.

[rottenkid]

I have had those testers for years. I see that you can get them at Amazon. They do make troubleshooting easier.

https://www.amazon.ca/Spark-Plug-Tester-Ignition-C...ug+testers

[Wildthings]

[sjbartnik]

Sorting out the ignition system is step 1 before you start dicking around with the FI.

Also this system hates vacuum leaks.
_________________
1965 Volkswagen 1500 Variant S
2000 Kawasaki W650

[Randy in Maine]

If I might offer just a bit of a suggestion....

While it is nice that you are trying to get it to start in its present condition, that is likely not sustainable long term. Drawing fuel directly from a gas can will sometimes allow you to get adequate fuel pressure in the system even with a rusty fuel tank. A dwell meter and timing light will confirm that you have decent spark.

I would just plan on removing the engine/transmission as a unit and getting it on an engine stand. Once that happens you will be able to remove the injectors for servicing, the fuel tank for proper cleaning, the fuel lines for replacing, and will be able to clean up the tinwork to whatever your budget allows.

Make sure you own a dwell meter, a volt ohm meter, and a fuel pressure gauge.

If you need to borrow some stuff (like an engine stand) or something like that, let us know. There are lot of us bus guys in the area and we may have some of that stuff to let you borrow. Sometimes we even help out when we can.

[SGKent]

[Randy in Maine]

Only if you have never sinned or had impure thoughts does that work.

In short it has never worked for me.

I am about 2 hours north of the original poster by the way.

[SGKent]

[Wasted youth]

[SGKent]

[Wildthings]

[jmarshall024]

Thanks for the continued replies. I have tools and equipment needed to test the ignition system. Just didn’t have them with me yesterday. ( I was secretly hoping to get some response from the gas in the s boot).

As suggested I do think pulling the engine and tank will be necessary. Even if I got it running I wouldn’t trust driving it and I’m sure bad injectors and vacuum leaks will keep it from running well.

But while I have everything intact I can’t help trying some basic stuff. At least that way I won’t reinstall a cleaned up junk part.

[Wasted youth]

[alman72]

pulling the motor and tin may give you the win in the mouse nest thread as well

[alman72]

pulling the motor and tin may give you the win in the mouse nest thread as well