Hot start relay - anyone mounted one in engine bay vs at the starter

[oh snap]

Going to see if a hot start relay will solve my intermittent starting problem. I've searched but seems almost everyone installs the relay at the starter. This looks pretty straight forward but I thought it would be nice to put it in the electric panel on the left side of the engine bay. It will make it easier to get to if I need to troubleshoot/replace the relay, and it will give more protection from water and dirt.

Has anyone here done this? Is there a good place to get the 12v power from on the electrical panel? Better to run wire up from the starter? From the alternator? In which case where do you put the fuse?

Would running longer wire up from the starter to the relay and then back down to the starter again somewhat defeat the purpose of the relay?

Any other potential hang up's or considerations?

Appreciate any advice you all can offer

[Tremelune]

Standard automotive relay should last decades...I would put it wherever is convenient (which sounds like the starter).

Hot start relay seems like a band-aid on a larger issue...There should be no trouble getting 12V to the starter solenoid...Maybe clean the contacts and ensure your battery voltage is holding...

what does the hot-start relay do?

I had intermittent start problems related to getting enough current to the starter in my 944, and I found is was because the terminals corroded every single winter...I cleaned them thoroughly and coated them in Liquid Electrical Tape (though Fluid Film would probably due) and the problem went away.

[GH85Carrera]

If you are having a problem with the starter only when it is hot, and heat soaked, a relay does not help much if any at all. BTDT.

My Bosch starter would just lock up when hot, I tried a relay and it did nothing to solve the issue. The only true fix was to go to the high torque starter sold her on Pelican. It 100% solved the problem and has been flawless for many years.

Few things are more fun than stopping for lunch while on a road trip on a HOT day, and parking for 40 minutes while we eat and discovering the starter is refusing to budge. Then trying to push the car fast enough for my wife to pop the clutch and start the car is not really an option. I really love my high torque starter. It does take a little while to get used to the different sound, but the sound of the starter spinning when you hit the key is a wonderful sound and even sweeter when the engine springs to life.

[oh snap]

Thanks for your help. It is a Band-Aid solution but seems many people have solved their starter problems with it, and when the wiring gets old enough it might be the best option unless you are ready to take apart the dash and replace wires.

I've replaceled the battery, the starter twice (first bosch, now the high torque one) and I had the engine out and cleaned and dialectic greased every contact I could see. The problem remains. I guess next step is to order a new ignition switch but I think it's still not a bad idea to cut that length of old wire out of the path either way

I guess since it's easy to make one Nd install it at te starter I'll do it there and see how it goes. Thanks again for your replies

[proporsche]

did you clean your appropriate grounds??also make a video of your starting problem.

Ivan

[thetorch]

Related question: does a relay protect the ignition for an earlier (1969) 911 with a 3.2 starter? My car came with a relay between the ignition and the solenoid and I thought it was to protect the switch. I have a new hi-torque starter and am wondering if the relay is a good idea (as some have said) or just another point of possible failure?
Thx

[oh snap]

Originally Posted by thetorch

Related question: does a relay protect the ignition for an earlier (1969) 911 with a 3.2 starter? My car came with a relay between the ignition and the solenoid and I thought it was to protect the switch. I have a new hi-torque starter and am wondering if the relay is a good idea (as some have said) or just another point of possible failure?
Thx

As I understand it with no relay the ignition switch is part of the circuit so the current needs to travel to the dash and then back down to the starter solenoid to start the car. Using a relay "removes" a few feet of wire from the circuit and with less wire there is less resistance, especially if the wiring is old or corroded. So more current ends up at the starter. You could think of that as protecting the switch because it doesn't need to carry as much load to do its job which should make it last longer. More likely I think is that a previous owner had trouble starting and installed the relay for that reason.

As mentioned, some people say it's a Band-Aid solution because something is corroded or worn out for it to not start and you wouldn't want to add a relay to solve a problem with a dirty ground wire or battery terminal clamps that aren't tight enough, or something like that. The circuit should work without a relay and that's how the engineers at porsche saw fit to design it. On the other hand porsche sent full voltage to the highbeam switch making them prone to failure, thus adding a headlight relay is a popular mod that some people say should have been installed at the factory. I'd say its worth checking the grounds and testing some components before installing one, but if you have done that and still face starter problems it's probably worth a try before you pull apart the dash and all its wiring lol.



As for the specifics of my car, it's hard to test because it's intermittent, but last time I had a no start I checked the voltage at the battery and it was 12.8v. I think it was around 14v when it's idling, I don't remember the number but I checked at the time and it was in the normal range. Usually the no start is after a drive and it happens more often in the summer, but it's happened in the winter too. Sometimes it will start up after I wait a 5 to 10 minutes. Have had to push start it a couple times, usually when I was in a rush. I've had the problem once or twice when the car sat for a couple weeks without the battery tender connected. It's sometimes refused to start after the first couple of key turns, only to start normally on the 3rd or 4th. When I replaced the starter the mechanic extended the ignition line so it would reach the starter solenoid. I thought that was possibly a weak connection so I redid that extension wire again very carefully but the problem remains. I'll probably replace my ignition switch next time I have some parts to order but figured I'd install a relay now since I have them handy and a few winter vacation days coming up.

Other suggestions are welcome. I've read a dying voltage regulator can cause starter problems so maybe I'll figure out how to test that as well, but after a fair amount of reading porsche and vw forums I've more or less decided that in my case the relay is worth a try and I was just hoping someone had a clean, factory looking engine bay install I could copy lol


Edit: just went in the garage and I got 12.42v at the battery so I think I have some loss somewhere, but still the car started easily. Got 14.25 volts at idle.

[GH85Carrera]

Double check every single ground. Especially the transmission to body ground strap. If that is old, and beat up, replace it. Clean the surfaces that the ground strap touches, and double check the ground strap from the battery.

I would bet (just a guess) 75 to 80 percent of all electrical problems are just bad grounds. They are a vital part of the system, and it is impossible to have too good of a ground. When it doubt, check the grounds!

[thetorch]

FWIW I have had no starter problems with the relay, neither with the original bosch 3.2 starter nor a new hi-torque starter. My reading of the wiring is that the starter solenoid is indeed unfused and as you say travels through my ignition switch like the headlights were originally, which seems like a bad idea. Perhaps I am missing some protection that exists in the circuit, but I think not. Happy to be corrected if I am mistaken.

I'll keep my engine-bay-mounted starter relay unless someone has further insight. It works without issue: I use 12 gauge wire for the relay, and a 15 amp fuse on the 30 terminal, which I am pulling off a new 40 amp fused 8-gauge main to my engine bay that is run off the main starter power feed.

This seems safest to me, it works, and the fuses and relay are mounted on the side engine electrical panel so they are accessible. Mounting at the starter made them a lot less accessible, which is how the car came to me.

Just my experience. YMMV

[Tremelune]

It looks like the solenoid alone can draw 10A...That's a lot higher than I had thought, and now I'm leaning towards having the relay to avoid that current going through a Very Expensive switch...

If it were me, I'd stick the relay right next to starter, tap the starter for power, and use the existing switched starter wire for the relay...Standard automotive relays do fail, but not often.

[proporsche]

as suggested by me and Glen start with the basics...Grounds to be checked , also the one behind the fuel filter...

Ivan

[87maniac]

might wanna check those grounds...

[oh snap]

Sorry I didn’t mention this in the original post (although I did mention it in the subsequent post...) The grounds have been checked, cleaned and protected with dialectic grease. I still had the same problem which was quite disappointing. Ive done every contact and ground you can find when you take the the engine out, I replaced the transmission strap and been reasonably deep into the front trunk as well. Any grounds I haven’t gotten to I’m not going to get to until the interior comes apart which I’m not interested in doing if a simple relay will solve the issue. Maybe someday when I take the glass out to paint the car, redo the carpets and replace the headliner.

All the same I appreciate the advice. I had already more or decided to install a relay so I didn’t include the stuff I’d already done but next time I will make it clear from the start the steps I’ve already taken.

If anyone has an engine bay install I’d love to see what you did but seems like it’s fine to install at the starter. I’ll pick up some terminal connectors and a fuse at lunch today and update if it solves my problem. Thanks again

[proporsche]

ok we are clear on the grounds....now this one..
quote...
____ Got 14.25 volts at idle.------------on idle it seems a lot of V..How many V when you go let`s say 3000 rpm??
1.Also do you have in your car immobilizer-alarm?
2.the engine turns over just no start?
3.how about the cylinder head temp. sensor,have you ever replace it?

Let us know

Ivan