Which Sterter Solenoid?, Looking to remedy the infamous hot-start issue Options

[JDW914]

Hi all! I recently took my first long road trip in my 914 (700 mi round trip out to Peoria, IL to finally pick up a replacement windshield) and while the car performed beautifully, I had my first encounter with what I've learned is the "infamous hot-start issue." Happily I was caravanning and, when unable to find a clear reason as to the car's failing to start after a pit stop for lunch, we tried jumping it, assuming the battery had gone bad, which resulted in enough current to pop the solenoid and start it up. This was necessary a few times during the trip. While it has never caused me trouble before (I've been driving the car pretty regularly for 2 years since its restoration has been "finished") I'd prefer to remove the issue so that it doesn't come back to bite me, especially now that the car has proven itself as such a good road-tripper.

Now in my research since encountering the issue, I've found much documentation of the issue and its solutions, in particular a Ford starter solenoid or a Bosch hot start relay kit. I'd like to go about it with the replacement starter solenoid as this seems a simple and straight-forward enough change-out, however, I've not been able to determine what solenoid it is in particular that will fit into an old VW starter motor. Is there a particular part number or set of models/years that use it, or does Ford have enough standardisation that any old solenoid will work?

Thanks for any enlightenment you can provide!

[stugray]

Are you talking about replacing the solenoid on the starter with a different model?

Or are you talking about the modification where you ADD a relay back at the starter to carry the starter solenoid current instead of the ignition switch (key)?

My current setup is:
Ignition switch (key) provides current to a high current standard 12v Relay.
This relay connects the Starter +12V (Big Red wire to starter from battery) directly to the Solenoid input.
I also use the high torque starter you can get on ebay.

You can see the setup (when still messy) here:
(IMG:http://www.914world.com/bbs2/uploads_offsite/i366.photobucket.com-10819-1435900142.1.jpg)

[markb]

This is what I had on my 72 for years & never had another issue. Simple & effective.

Are you talking about replacing the solenoid on the starter with a different model?

Or are you talking about the modification where you ADD a relay back at the starter to carry the starter solenoid current instead of the ignition switch (key)?

My current setup is:
Ignition switch (key) provides current to a high current standard 12v Relay.
This relay connects the Starter +12V (Big Red wire to starter from battery) directly to the Solenoid input.
I also use the high torque starter you can get on ebay.

You can see the setup (when still messy) here:
(IMG:http://www.914world.com/bbs2/uploads_offsite/i366.photobucket.com-10819-1435900142.1.jpg)

[john77]

I had the same problem 12 months ago. I bought a high torque starter and a hot start relay off pelican, but never ended up wiring up the relay. Haven't had a problem since.

[Mark Henry]

The Ford solenoid is the on the fender type they used for years in both 6V and 12V versions, either one will do.
If you are careful you can bend and dremel the bracket to fit the bottom starter bolt hole.
I have one on all my aircooled cars and I've never cut a single wire or drilled a hole in any of my cars.

I've used them since the 80's, never have replaced a single ignition switch, never cut/replaced any wires anywhere, I just don't have these issues.

(note: I have cleaned grounds, terminals and fixed a hell of a lot of DAPO owner ignition wire hacks, etc. Also I don't have any use for the bosch relay, in fact I have a brand new one sitting on my scrap wire pile)

[worn]

I had the same problem 12 months ago. I bought a high torque starter and a hot start relay off pelican, but never ended up wiring up the relay. Haven't had a problem since.

That is interesting. I bought a tractor part from ebay that I believe is the same thing. Only mine was activated by grounding the control connector. No go for the ignition switch. Except it was easy to switch it around because they are simple as can possibly be inside. Be careful though about whether you get a minus or plus terminal. Many have both, which is fine.

I was wondering about actually using mine though, figuring a new starter and all. This thread makes me think I should.

[type47]

There are lots of relays out there that can be used. One thing I haven't noticed mentioned is the relay needs to be able to handle about 30 amps. That said, I have an American car, maybe it's a Ford, relay in my circuit.


thanks to Mark Henry for the schematic!

[Mark Henry]

There are lots of relays out there that can be used. One thing I haven't noticed mentioned is the relay needs to be able to handle about 30 amps.

I've never found any of those relays to be as good as the Ford unit and just about everyone that knocks the the Ford solenoid solution were using a small bosch horn type relay.

The bottom wiring diagram is mine that I posted way back when this site started in 2002, thanks for the credit. (IMG:style_emoticons/default/laugh.gif)

[Tom_T]

You may have one or more of a few things going on there.

1. The infamous hot start problem due to fuel vapor lock problem on 70-74 914s - if your fuel pump is in the engine bay, then it gets so hot that vapor bubbles form in the lines whenever you stop & it gets no fuel. The best solution which Porsche did a service bulletin for, has the fuel pump relocated to up behind the steering rack below the fuel tank (in 75-76 models they move the fuel pump up front for that reason).

It's not a running problem in hot weather as long as you don't shut down, since the fuel running thru the pump cools it enough to prevent vapor forming (as soon as you shut down the hot fuel pump forms the vapor), so you could leave it running for a quick pee stop with someone else in the car.

A temporary fix is one of those heat blankets that some of the Porsche supply houses sell for it, but the fuel lines can still bubble up & cause the pump to cavitate.

So you really want a fuel pump relocation kit like AA & maybe others sell - or make up your own looking at the kit - then move the pump.

The "in the field" solution is to let it sit & go have a milkshake or something, until the fuel cools down enough for the bubble to turn back to liquid, & you could take water up under there to pour on the pump to cool it down, but I wouldn't on these rust prone cars - plus it's very tight & a very hot engine, tins, etc.

.

2. The ole "flat spot" on the starter's rotor problem - the Bosch starters on all air cooled & some water cooled VW's & Porsches get hot & develop a bad contact area or "flat spot" on them & when you stop for food/lav breaks, then they can refuse to start/turn at all.

The solution is a new starter - OEM Bosch or upgrade to a hi-torque aftermarket one (several out there).

The old school "in the field" solution is to reach or get under there with a ball peen hammer or wrench or something & tap the starter casing hard-ish (NOT the solenoid) while someone else in the car turns the key to start it. It may take 2-4+ tries, but that usually breaks it loose to get the starter to turn. It only works if someone else is turning the key to start.

.

3. Related to the above, is the solenoid sticking due to the heat expanding the mechanism, so it cannot push the starter gear into the engine's ring? gear (spacing on the gear name now) to start it - as discussed by others above.

The fixes are the high torque starter, hot start relay kit &/or running a new set of direct wiring lines to the battery with a protective relay yourself - since the old wiring as it ages has more resistance & gets less "juice" to the starter (my mechanic recently did the latter on our `88 Westy waterboxer for tough hot starts on it). I've never heard of the Ford solenoid thing, but maybe that works too??

The old school "in the field" solution is to try the starter tapping above &/or a LIGHT tap with a screwdriver on the solenoid if the other doesn't work.

.

So I guess that's my contribution to the annual run of spring/summer hot start problem posts on here! (IMG:style_emoticons/default/biggrin.gif)

PS - Thanx Mark - I haven't come across that Ford relay / solenoid solution before!

Happy 4th & Thanx to those who served! (IMG:style_emoticons/default/flag.gif)
Tom
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[SLITS]

I use the "Ford Starter Solenoid Relay" on all my 914s just to lessen the load on the ignition switch, since replacements are KRAP.

[Mark Henry]

You may have one or more of a few things going on there.

1. The infamous hot start problem due to fuel vapor lock problem on 70-74 914s - if your fuel pump is in the engine bay, then it gets so hot that vapor bubbles form in the lines whenever you stop & it gets no fuel.....


2. The ole "flat spot" on the starter's rotor problem....

.

3. Related to the above, is the solenoid sticking due to the heat expanding the mechanism, so it cannot push the starter gear into the engine's ring? gear (spacing on the gear name now) to start it - as discussed by others above.

The fixes are the high torque starter, hot start relay kit &/or running a new set of direct wiring lines to the battery with a protective relay yourself - since the old wiring as it ages has more resistance & gets less "juice" to the starter (my mechanic recently did the latter on our `88 Westy waterboxer for tough hot starts on it). I've never heard of the Ford solenoid thing, but maybe that works too??
....

#1 To me vapour lock and hot start are two different things, vapour lock it still cranks, hot start it at best gives one click and that's it.

#2 the solenoid fix doesn't work for a bad starter, ignition switch or grounds, but it can help narrow the search for the issue.

#3 This is not what is happening, but then you start to get onto the real issue which is resistance.
A bosch starter needs a full 9V to kick the solenoid, all the old wiring, the switch, the length of the run, etc. by the time it gets to the solenoid you just are not getting enough juice.
Not to mention the incredible load you are putting on the tiny contacts within the switch.

The Ford solenoid only needs about 3 volts (6V ford solenoid needs even less volts) to kick it and then if you wire like in my diagram you get a full 12V direct from the battery to the starter solenoid.

I use the "Ford Starter Solenoid Relay" on all my 914s just to lessen the load on the ignition switch, since replacements are KRAP.

(IMG:style_emoticons/default/agree.gif) The best reason to have one, even if you swear you don't have a problem. (IMG:style_emoticons/default/shades.gif)

[jeffdon]

I run a ford solenoid mounted on the starter. Interestingly enough, I have burned through two new ones from FLAPS. My dad gave me a few from his stash that are probably as old as the 914, and I am still on the first one years later. Guess they do not make them like they used to.

[Tom_T]

[quote name='Mark Henry' date='Jul 3 2015, 11:03 AM' post='2205665']
[quote name='Tom_T' post='2205625' date='Jul 3 2015, 12:28 PM']
#1 To me vapour lock and hot start are two different things, vapour lock it still cranks, hot start it at best gives one click and that's it.

I agree, but it's that time of year when it happens, so I threw it in, since he didn't say whether it cranked at all AFAIK.

#3 This is not what is happening, but then you start to get onto the real issue which is resistance.

I did say that Mark: "since the old wiring as it ages has more resistance & gets less "juice" to the starter" - as you explain further below...

A bosch starter needs a full 9V to kick the solenoid, all the old wiring, the switch, the length of the run, etc. by the time it gets to the solenoid you just are not getting enough juice.
Not to mention the incredible load you are putting on the tiny contacts within the switch.

The Ford solenoid only needs about 3 volts (6V ford solenoid needs even less volts) to kick it and then if you wire like in my diagram you get a full 12V direct from the battery to the starter solenoid.

^--- Interesting details, thanx for explaining further Mark! ---v

[quote name='SLITS' post='2205631' date='Jul 3 2015, 12:38 PM']
I use the "Ford Starter Solenoid Relay" on all my 914s just to lessen the load on the ignition switch, since replacements are KRAP.
[/quote]
(IMG:style_emoticons/default/agree.gif) The best reason to have one, even if you swear you don't have a problem. (IMG:style_emoticons/default/shades.gif)
[/quote]

Cheers! (IMG:style_emoticons/default/beerchug.gif)
Tom
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[JDW914]

To be clear, my car's problem is that at high running temperature (several hours of ~3000rpm in hot weather) the solenoid on the starter motor does not deploy when the key is pressed to the start position; I get a quiet, rapid ticking from the starter and nothing else. This is a brand new Bosch starter and a direct replacement for the original.

I *had* been under the impression that the Ford solenoid fix was a replacement of the solenoid on the starter, but apparently that is not the case? What does the relay circuit do that improves current flow to the starter

[Kansas 914]

I *had* been under the impression that the Ford solenoid fix was a replacement of the solenoid on the starter, but apparently that is not the case? What does the relay circuit do that improves current flow to the starter

It reduces the amount of wire (therefore resistance) in the circuit. Like SLITS said there is no high current running through the keyswitch. The keyswitch simply pulls in the coil of the relay and then the contacts of the relay take the load.

[Mark Henry]

To be clear, my car's problem is that at high running temperature (several hours of ~3000rpm in hot weather) the solenoid on the starter motor does not deploy when the key is pressed to the start position; I get a quiet, rapid ticking from the starter and nothing else. This is a brand new Bosch starter and a direct replacement for the original.

I *had* been under the impression that the Ford solenoid fix was a replacement of the solenoid on the starter, but apparently that is not the case? What does the relay circuit do that improves current flow to the starter

Read Post #11

[ThePaintedMan]

I've often heard them used synonymously, so correct me if I'm wrong. But you guys are talking about a Ford solenoid relay, correct? A solenoid is an mechanical lever that is electronically activated (i.e. the trunk "pop" solenoid"). The relay is an electrical component that helps deliver high power to a given component by way of battery power and a low-power signal, correct?

[Kansas 914]

I've often heard them used synonymously, so correct me if I'm wrong. But you guys are talking about a Ford solenoid relay, correct? A solenoid is an mechanical lever that is electronically activated (i.e. the trunk "pop" solenoid"). The relay is an electrical component that helps deliver high power to a given component by way of battery power and a low-power signal, correct?

George,

You are right. Relay is the more accurate term.

Ford relay in line to switch current to the starter solenoid which in turn engages the starter.

[JDW914]

I've often heard them used synonymously, so correct me if I'm wrong. But you guys are talking about a Ford solenoid relay, correct? A solenoid is an mechanical lever that is electronically activated (i.e. the trunk "pop" solenoid"). The relay is an electrical component that helps deliver high power to a given component by way of battery power and a low-power signal, correct?

George,

You are right. Relay is the more accurate term.

Ford relay in line to switch current to the starter solenoid which in turn engages the starter.

Well, I had been talking about the mechanical solenoid on the starter, but I was apparently misguided in doing so.

It reduces the amount of wire (therefore resistance) in the circuit. Like SLITS said there is no high current running through the keyswitch. The keyswitch simply pulls in the coil of the relay and then the contacts of the relay take the load.

I get it now; thanks. Sounds like a relatively simple fix that I ought to be able to manage.

[Mark Henry]

I've often heard them used synonymously, so correct me if I'm wrong. But you guys are talking about a Ford solenoid relay, correct? A solenoid is an mechanical lever that is electronically activated (i.e. the trunk "pop" solenoid"). The relay is an electrical component that helps deliver high power to a given component by way of battery power and a low-power signal, correct?

The Ford solenoid is a true solenoid, it may not seem to be pulling on anything, but the rod is closing the contacts. So it is pulling the contacts.
https://en.wikipedia.org/wiki/Solenoid

A relay may be doing a similar job as this solenoid, but it is mechanically different from a solenoid.
https://en.wikipedia.org/wiki/Relay


It is the bendix that engages the drive gear, so it is in fact not the solenoid, it is a separate part that is merely connected to the solenoid.
A solenoid is a solenoid, rod, cable, valve, bendix, contact, etc. it doesn't matter what it is pull/pushing.