another hot start problem

[odie]

First... I did search "hot start" and got lots of ideas. But it's best to get other opinions 'cause everyone's hot start problem is a little different, but all related in some way.

The car starts great when cold...but often has no starter engagment when hot. Not even a click. The fuel pump runs and all other electrical indications seem normal. Car has no "relay" kit.

1. At first I pulled the wiring harness from the ignition switch and used a jumper wire between two of the big wires (red and yellow I think). This would case the starter to turn over. I would then plug the wiring harness back into the back of the ignition switch and the car would start.

2. So I replaced the ignition switch. The new switch did not help (old switch works better???). Really strange was sometimes the ignition switch would not work with the key but if I removed the switch from the steering column and turned it with a screw driver the car would start. But now that trick does not seem to work too well. The jumper wire trick also does not work so well anymore.

3. Checked battery connections. Cables seem tight but old and some surface corosion. I cleaned the connections. No improvement.

4. Jumped the two big terminals on the starter solenoid with a screwdriver. Starter spins but does not engage the flywheel.

5. Hit the starter and solenoid a few times with a hammer and jumped the terminals again. Starter still spins but no engagement.

6. Car cools down for about an hour and starts.

7. Car ALWAYS starts with push start.

8. Sometimes when hot, car still starts...sometimes.

9. Car ALWAYS starts when cold.

Please offer all ideas...there are lots of possible culprits...I just want to avoid starting in the wrong direction.

[pbanders]

My car had the same symptoms as yours for 20+ years. I finally wised up and bought a rebuilt Bosch starter. It took about 30 minutes to install. Problem solved.

[odie]

But was it the starter or the solenoid that was bad. They are sold as a unit but are really two separate items.

I think my starter is fairly new. I bought one a few years ago (maybe 20k miles ago) but am not sure for which 914 I bought it. I'll have to check my receipts to be sure.

I'm thinking it's just a bad solenoid that is getting "stuck/frozen" when hot. If so, installing a remote solenoid would probably be best.

[BenI]

I've had problems stem from "dead spots" in the starter. Age can cause this areas of high resistance where the brushes contact the coil contacts. Resistance incrases with temperature so the hotter the starter the more pronounced the problem. I agree with the above post-try another starter. If your engine turns over fine with a stock starter, do not go to a hi-torque starter. I've seen varying quality in these starters and have even ruined a flywheel because of it. Buy a stock rebuilt or used starter. I've seen good and bad used starters, but i've seen good and bad rebuilt ones too. I'd buy a rebuilt starter from a place that I could return it to, or exchange it if your problem persists.

[odie]

I'll check my starter reciept when I get home. If the new starter is on my car, its only got 20,000 miles max on it. If it went on my ex-914, then it's gone and I've got one old worn-out starter on my current 914...

[jc9]

i had the same problem. i thought i would be smart and get a vw ign switch from the local vw guy. after the third new switch, made in some third world country,i went up to high performance house in redwood city. he showed me the german one i tryed it and no more problem since. he has new and used parts for all 914. jc

[odie]

I replaced the ignition switch last month with a new one from Paragon (here in Corpus) but that did absolutley no good so I'm sure that was not the problem. It must be some where else.

[philinjax]

odie,
You need a hot start relay, simple to do, inexpensive and allows you to start when the engine is hot. I do it on all of my (four) 914s.
The hot start problem with the 914 is a design defect. With some exceptions, it effects all 914 cars. Send me your fax number and I will send you a
diagram and bill of materials. It is quite simple to install and wire.
Phil

[pbanders]

Originally posted by philinjax
odie,
You need a hot start relay, simple to do, inexpensive and allows you to start when the engine is hot. I do it on all of my (four) 914s.
The hot start problem with the 914 is a design defect. With some exceptions, it effects all 914 cars. Send me your fax number and I will send you a
diagram and bill of materials. It is quite simple to install and wire.
Phil

I basically agree with what you say here. The problem here is that the current path for the starter solenoid is extremely long in the 914 - it goes from the battery, up to the ignition switch, then back to the solenoid. Along the way, there are several junctions and contacts, all which introduce resistance in addition to the resistance of the long copper runs.

When everything in the system is "right", it all goes fine. There's still sufficient pull-in voltage for the solenoid when you turn the key. But if things are even a bit "wrong" (e.g. old starter switch, sticky solenoid, corroded contacts, etc.), then there's insufficient voltage and solenoid won't pull in.

I'm personally of the belief that 99% of the hot start problem is due to the solenoid. Why? Because that's what gets "hot". Perhaps the clearances and design of the solenoid cause it to bind when hot. This is also supported by the finding of myself and others that you can usually get a hot car to start by having one person turn the key while another (usually, you) whacks the solenoid with the jack handle. The rap frees the stuck solenoid and the car starts.

Regardless, the hot start relay isn't such a bad idea. It eliminates the long current path by bypassing it with a relay near the solenoid, reducing the voltage drop to a very low value. There's also a secondary benefit in that you no longer have the high current path through the starter switch, increasing its reliability and lifetime.

[Bruce Allert]

Originally posted by odie


4. Jumped the two big terminals on the starter solenoid with a screwdriver. Starter spins but does not engage the flywheel.

To engage the solenoid I found I had to jump the big terminal on the left with the small terminal above the 2 large ones. Jumping the 2 big ones only spun the starter w/o engaging the solenoid.
I also replaced my starter with a '68 911 starter that I picked up at the local German auto wrecker for $25. Cured my hot start probs.
bruce

[odie]

Looked at my old receipt...it WAS for my old 914...and I'm sure I didn't swap it onto my "new" 914 before I sold it...damn...some one got a new starter and it ain't me...

Anyway...I pulled the battery and cleaned up the posts, cables, battery ground, trans ground strap, solenoid posts and cables. I'll see what happens next time I run the car for a while and try a hot restart.

But I am guessing that I will still be needing that hot start relay set-up.

pbanders...my fax number here at work is 361-516-6926

or you can email me at "tom.v.ormrod@nrs.navy.mil"

My old 914 already had the relay set-up...I should've swapped it over...damn...

Thanks,
Tom

[jsb]

Well, for what it's worth, here is my two cent's. I had a hot start problem with my 2.0 when I bought it. It already had a "hot start" kit on it, and the p.o. installed a second battery with a selector switch so you could "jump start" yourself. This was not a selling point in my mind for the simple fact you shouldn't need it. My solution was quite simple, checked the ground strap on the trans, replaced it with a new 4 gauge wire and copper lugs, removed the hot start relay , removed the starter and cleaned the mounting faces, installed the starter and wrapped it with header tape to act as a heat shield. I currently don't have a hot start relay, I don't have hot start problems, and have never needed a jump since I have done this.

Heat and age take their toll on anything electrical. The trick with the header tape is one learned from my friends 69'Mustang 429ci Mach 1. He would drive it for and hour park and wait a half hour to start it again, the starter is close to the headers on his car, I mean really close. The starter just soaked up all this heat, we wrapped the headers and the starter with the insulating wrap, and he hasn't had the problem since. Just my two cent's worth.


73' 2.0 914
74' 1.8 914
88' BMW 735i

[Bruce Allert]

I was having the problem with the hot fuel pump thing (vapor lock?).
While in my local Ace hardware store I noticed a heat barrier sheet measuring 9"x8". It was to keep an area safe from being burnt while using a torch. For $12 I purchased it and put it between my fuel pump and the heat exchanger. I haven't had a problem since.
bruce