1978 FI Hot Start Relay Install Questions (with Diagrams)

[clicknathan]

Hi again!

So I'm installing the hot start relay I got from Bus Depot. https://www.busdepot.com/WR1

I'm doing this because after 2 hours of driving or so, when things are hot, I can't start the old girl.

While doing research, I came across this page on Ratwell: http://www.ratwell.com/technical/EssentialUpgrades.html#hotstart
The picture on the right there, I've got one of those, and a ton of wires going to my solenoid. Mine doesn't look exactly like the one in the picture, but the metal & plastic part at the top is similar. The wires coming out are much simpler and older.

Here's a photo of what I'm assuming is an old hot start relay. Kind of crappy, but it does look quite similar to the pic in Ratwell's site above. Mine says "made in Spain" but I couldn't find a part number, though I didn't take it out yet.

Now, here's what I'm dealing with:

My questions are, from this little diagram:

1. Is that device above an old hot start relay, and can I safely remove it and every wire involved in it?

2. Looking at where I have two wires near the top labeled IRWt (Ignition Red & White Wire thin) and IR (ignition red), am I correct that these are going to the ignition?

3. The instructions that came with the hot start relay (see below) state that the RED wire from the new hot start relay should go to "Spade Terminal on Solenoid". I've only got two (my old one had three). I'm thinking if I remove the old hot start relay (see question 1 above), then I'll have a free spade and can hook it up there.

4. Are my + & - markings correct on the solenoid in the picture (left of the starter). That is, the starter connects via the thick flat cable to the solenoid's negative screw on terminal, right?

5. Would the BROWN wire (which the instructions read should connect to "Starter Solenoid Red/Black Wire Ignition Switch") go to the + on the solenoid as shown in my diagram?

6. Which would be the same place the YELLOW goes to?

7. And the BLUE would go to the - terminal on the solenoid??? The instructions just say "Ground".


Here are the instructions:

More info on the current setup:

A. The wires currently listed as to + / Also to Bat+ in my photo all connect to the bolt I have labeled + on the solenoid (except the one marked "to 2" which connects to the spade at the top), as does the IR wire near the top of the pic.

B. Nothing but the starter connects to the place I have marked as - on the solenoid at the moment.

If this is correct, should the BLUE wire NOT connect to the terminal I have marked - on the solenoid?


Thanks in advance, just want to try and get this right as "testing" will probably take a good solid day's drive or possibly weeks because the no start when hot problem doesn't always happen, only when I'm in a really inconvenient and trafficky place where plenty of other motorists are trying to get home from work and not be bothered by some jerk in his 40 year old Bus.

[clicknathan]

Also, these are the connectors that came with the kit.

So given that only the big yellow one could fit on my solenoid round / bolt connectors and that there's a flat connector, I'm even a bit more confused.

[telford dorr]

This is the way the harness came???

Looks like the red and yellow wires are much heavier than the blue and (unshown) brown. Thus, these must be the starter solenoid wires. The two lighter ones must be control wires for the relay.

If it were me, I'd rework the whole thing, doing this (note my wire colors and terminal designations differ from the official instructions):

- crimp a 1/4" female terminal to one end of all four wires. These terminals will connect to the relay somewhere.

- crimp a big ring terminal (that fits the battery stud on the starter) to the yellow wire. The other end of the yellow wire should go to relay terminal 30.

- crimp a female 1/4" blade terminal to the red wire. This wire connects relay terminal 87 to the solenoid terminal where the red/black harness wire was connected.

- crimp a 1/4" male terminal to the blue wire. This wire connects the free end of the red/black harness wire above to relay terminal 86. Be sure to insulate this free-floating junction!

- crimp the small ring terminal to the brown wire. This wire connects relay terminal 85 to a body ground somewhere (probably using the screw which mounts this new relay to the body).

-----

No idea what the device in the first picture is. Kinda looks like a voltage regulator or something. Unless it's wired up to the starter solenoid, it's not a "hot start" relay.

On your schematic above, the harness labeled "to ignition?" goes to the FI. The red wire is power to the FI; the red/white is the start signal to kick-start the fuel pump.

The harness labeled "also to bat+" comes from the front of the bus, and thus should contain the red/black wire from the ignition switch: probably the one going to "to 2". This is the wire which will drive the hot start relay coil. It should also contain a heavy red/white wire. This sends battery power to the fuse block.

-----

Here's the standard method of connecting to a Bosch relay (IGNORE wire colors; pay attention to the terminal numbers and their standard connection type):

In this case, "+12 volt coil drive" is from the ignition switch; "load" is the starter solenoid coil.
_________________
'71 panel, now with FI
'Experience' is the ability to recognize a mistake when you're making it again - Franklin P. Jones
In theory, theory works in practice; in practice, it doesn't - William T. Harbaugh
When you're dead, you don't know you're dead. The pain is only felt by others.
Same thing happens when you're stupid. - Philippe Geluck
More VW electrical at http://telforddorr.com/ (available 9am to 9pm PST)

[aerosurfer]

That looks like your voltage regulator in the first picture. Leave it alone.

Here is a thread that has good details on the hot start wiring. Most of the way down on the first page are schematics.

https://www.thesamba.com/vw/forum/viewtopic.php?t=404521&highlight=hot+start

But please make sure you use good wiring ends on your connections. Take a picture of the starter wiring before you start so you can always put it back on the way it was if you get lost.

I'll try and post a pic of mine later for you.
_________________
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)

[furgo]

[aerosurfer]

The wiring is simple really...

From underneath the bus

Remove the black striped red wire from the starter and attach it to the blue wire going to the relay.

Replace the black wire from the relay onto the open spade from step one.

Put the red wire with the ring terminal onto the lug of the starter where all other wiring is.

Take the yellow wire and ground it to the bus somewhere. Mine goes to the same ground as my battery ground near the FI computer

You can see all 3 wires at the starter in the first picture. The ring terminal with the yellow jacket, the fat black wire in the center and the blurry blue connection in the foreground. Thats it!

If you can as i have mine mounted, use a firewall screw to mount it high and dry in the engine bay. It helps keep the elements off it, ad well as easy access to it should i need to ever troubleshoot the relay or change the fuse.

As others have said, you should be solving one problem by actually covering up another. I would add to the list of maintenance items a starter and solenoid clean and lubriction. The starter gets heat soaked and if the solenoid is not greased you are just fighting heat expansion.

Followed by checking as much wiring as you can find. You already know there are hacks within the system, make sure nothing funny is going on under the dash near the ignition switch. The HSR alleviates the voltage travel on the system, but doesnt fix anything else.
_________________
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)

[aerosurfer]

Just re-read your instructions..... your wiring colors are associated differently than mine. You will have to use the relay numbers. I made mine from the diagram in the thread i linked up above. Specifically from this.....

Just dont want to confuse you and have you fry your wiring.
_________________
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)

[Abscate]

It is much cheaper to ...

Run a new wire from B+ to fuse box, putting in a quick disconnect switch on the way.

Run a new wire from Terminal 50 ignition switch to starter solenoid.

Two pieces of wire keep your wiring stock and simple, and protect you from fire too.

If you do worry about your ig switch contacts, you can wire in a push button starter bypass at the dash to handle this without rolling underneath.
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.ssS!

[clicknathan]

[GARRICK.CLARK]

Why is the blue a ground wire.
I always thought the brown wire was a ground colour.
I think the description of the blue and the brown wire is the wrong way round

[SGKent]

[GARRICK.CLARK]

Yes I no.
I'm gunna fit 1 tomorrow and was searching for info and found this. Doesn't matter how old it is really does it

[SGKent]

[GARRICK.CLARK]

I'll do that. The relay is just the 1st and cheapest option. It probably will be a rebuild of the starter that's needed.

[Wildthings]

[GARRICK.CLARK]

Well. I must have a bad relay.
Its wired as per diagram, engine starts on the key, but the starter keeps going. And keeps going with key turned off. Gotta get under it and pull a wire off the starter
Its wired
Yellow to starter/battery terminal
I've put 86 blue to ground
85 brown is the problem wire
87 red goes to the red and black wire on the solenoid
And as I said it turns and starts engine but keeps turning.

[SGKent]

[telford dorr]

[Wildthings]

[SGKent]

for the record I accidentally dropped a box end wrench once while working on a friend's car. It bounced between the starter hot and a metal fuel line. A small 1/2" wide fire started under the car where the oily debris the wrench knocked loose landed. I thought it was a grease fire and hit it with a rag. The rag instantly ignited into a larger flame. A nearby fire bottle put it all out. Unfortunately the spark had arced a pinhole in the metal fuel line where the fuel was dripping down and that is what had been burning, so the car had to be moved outside all night. I wrapped the pinhole as best I could to slow the leak but it took a trip to a wrecking yard the next day because the line that wrapped around the engine was NLA, and several hours of work to replace it once I found one on an engine at the wrecking yard. Since then I pretty much always remove one of the battery cables when working on something that requires a wrench or metal tool.
_________________
“Most people don’t know what they’re doing, and a lot of them are really good at it.” - George Carlin