somewhat unique hot starting difficulty...

PorscheDV · 10-01-2001, 12:39 AM

ok guys,

ive searched my topic for old threads, and actually turned up a few, so i know im revisiting an old topic, but none of the threads had my particular hot start problem...so here's my situation..

this board has been a huge help, and gave ALOT of advise, but i was mistaken, certain circumstances led me to believe i had a bad charging system, i know believe my alternator/battery are fine..im having hot start difficulty with me 912E, but selectively!?

anyway, not all the time (but frequently) after the cars run for some time it wont start...not turn over at all! as if the starters bad, but its not consistent...

its (thus far) always started when completely completely cold...but at times i'll let the car sit for up to 3-4 hours (after being driven for a few hours) and it still would not start...i would write that off as 'hot start' problems, but at times i'll take the car literally up the street (not even giving the engine a chance to get warm) and it wont start, but its ALWAYS push-started...

so its not exactly when the motor gets 'hot' its almost random! (but at least 'warm' seems to be the common denominator) what could it be...the starter? if it is, its throwing my off that, when it does turn over it turns over fine, all my previous-vehicle starter problems have showed signs of fatigue and hints it was going (regardless of eng. temp)

i'm planning on checking all the grounds/connections (frequently blamed for 'hot starting' problems) or can anyone tell me, its the starter for sure? someone mentioned Air flow meter? is that possible?

thanks again everyone!

CamB · CamB's Garage

Hmmmm, I have an interesting problem which is similar.

My car occasionally does the same thing, especially if I stall it. I think the reason is related to the way in which the twin batteries have been converted to one (at first look it appears to involve a lot of electrical tape)... this problem cut all of the power to the car. If figure the grounds are crappy as well. I "fix" this problem by reaching under the hood and wiggling the battery and ground wires. I really ought to fix that.

Another option is (showing lack of Porsche knowledge - I guess they have one) the starter solenoid (is there a click but no starting action)? Or the starter motor not engaging (put car in gear, roll forward two feet, then try starting).

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Cameron Baudinet
1975 911S (in bits)
1969 911T

stlrj · 10-01-2001, 06:34 AM

I had the same problem that was driving me crazy for two years, but was so intermittent that I never took the time to fix it.

When it finally gave out and would not start at all, it took me another month to trace the problem to a bad solenoid, even after removing the starter and having it tested, only to find out that there was nothing wrong with it on the bench test!

$75 later and a new solenoid on the old starter, problem solved.

Joe

86 Carrera

RoninLB · 10-01-2001, 06:51 AM

Bosch starter sol. are heat sensitive. They are,IMHO, a problem waiting to happen. You may be able to jump it by going under there with a screwdriver and jumping it. If ignition switch has built up pitting on contacts you may be delivering lower vol/amps to sol.

Early_S_Man · 10-01-2001, 06:52 AM

There are a couple of things you can do:

1. Run a ground wire directly to the lower starter retaining stud made of #4 ga welding cable. Use a soldered lug rather than crimped ends on the cable.

2. Remove, disassemble, clean and lubricate the starter, bendix mechanism, and solenoid linkage with Swepco 101 or other high-quality moly grease.

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Warren Hall
1973 911S Targa
1992 Dodge Dakota 5.2 4X4 parts hauler

john walker's workshop · 10-01-2001, 06:55 AM

just replace the starter/solenoid unit with a SR17X bosch rebuilt. easy. it's just a vw starter in a 912E so it's cheap.

Kurt B · 10-01-2001, 08:43 AM

I had a similar problem with 914 which (warning) was never solved.
Tried replacing starter, failed.
Tried a starter relay, failed.
Tried new ground strap, failed.
I noticed eventually, that it had a charge leak problem that I have never tracked down.

I've had the car setting now without being driven for more than a year. It always cranks now because I disconnect the battery.
This is proof it's a slow leak. Where? I have no idea.
It isn't the alternator because it'll run with a disconnected batter (no F.I. only carbs).

Your mention of "fatigue" leads me to believe they might be related.

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84 Cab

[This message has been edited by Kurt B (edited 10-01-2001).]

PorscheDV · 10-01-2001, 11:42 AM

Mr. Baudinet, i didnt think it was sthe solenoid because there was no clicking...but i'll give it a try...

ok, looks like the majority believes its the starter/solenoid, i'll start with that whole unit, i'll replace it with the SR17X bosch unit...mr. walker, will that bolt/plug right up w/o any modifications? all plugs will plug? bolt holes line up? will the pinion engage with the 912e flywheel? this looks to be my safest bet right now...i'll keep you guys posted...

thanks again...

Early_S_Man · 10-01-2001, 12:00 PM

Your starter IS a Bosch SR-17! The 'X' version just designates an exchange rebuilt unit. All early 911s and 912s used that same starter that was common on air-cooled VWs with automatic and semi-automatic Saxomat transaxles.

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Warren Hall
1973 911S Targa
1992 Dodge Dakota 5.2 4X4 parts hauler

PorscheDV · 10-01-2001, 02:04 PM

AH! thanks warren! i'm also going to try your 2 previous suggestions...