Engine not turning over intermittently

[Stephenjk]

Three times now in last few weeks ive been to restart the car from warm and ive just had a click when turning ignition. Both times ive tried again and engine turned over fine and started.

Do you think starter motor is on its way out?

I've looked on rennlist and seems to be many suggestions, but just looking for what you think is probably and where to start looking.

One other question if anyone has a thought, my battery sometimes runs down after a week. I replaced battery to rule that out but still happened. I plugged in multimeter in series at weekend and current draw was tiny 0.04 ma. How long do you need to check for draw? Is few mins enough ? If it isnt current draw only other thing i can think of is it isnt properly shutting off sometime so to watch for the doulble flash when i lock it. Any other thoughts?
Thanks
Stephen

 

[bernard tester]

Starter motor is quite likely the fault for non starting! I have often found under bonnet light can stay on and drain battry you can just unplug the wire and give it a try.

 

[Stephenjk]

Thanks on starter motor. under bonnet light is already disconnected. It also wasnt showing on current drain test so had discounted that as the potential cause.

 

[russmw]

A friend with a 993 had the same symptoms and it turned out to be a corroded earth cable (maybe engine to chassis but I'm not 100%). Maybe explain it if the starter isn't getting clean power to it.

Good luck

 

[Stephenjk]

Thanks that is a good point to check (san cheap!)

 

[Old and Slow]

On mine it was the starter solenoid, a well-known problem as discussed on other forums. I dismantled mine and cleaned the contacts, which were blackened, since then no problems. Hope this helps.

 

[Old and Slow]

I should add, mine's a 911C and it isn't too difficult to drop the starter/solenoid assembly with the car on ramps; I took photographs of what I did, so could send them to you. Don't know if it is as easy on yours though.

 

[mcgc0]

I naturally bow to Bernard's expertise and experience re suggesting the starter motor route - Bernard's probably forgotten more than I know Just to throw in a couple of suggestions (in terms of easiest/cheapest to eliminate);

Have you swapped out the fuel/DME relay #41? Like one or two other relays (oil cooler being one I believe), it's always live and will draw current when tucked up in the garage. They can play up and draw more than they should. A friend used his infrared camera when he suspected the relay was playing up, and boy, was that thing glowing overtime.

The 964 coil pack (after 25 years service) often comes up as a culprit. Many replace these with the more robust 993 coils. However, one of the occasional signs is sometimes the instruments start to light up ('christmas tree' effect).

Only last thing to add is I occasionally get a similar issue - unable to start ignition at all when engine is max working temp (in my case hours of hard driving - single dash to Le Mans, spirited North Coast 500 etc). 8-10 mins of cooling and it starts. I have a feeling it's the aftermarket immobiliser a previous owner installed.

Good luck and keep us informed with any progress.

 

[Dekker]

I would look for the simple and cheapest things first before assuming it's more expensive items like the starter motor.
If you’ve had any work done recently, recheck the areas and make sure no plugs have been dislodged
Earth from battery to chassis also from the starter motor end are a must to check. If they are OK the 12v line comes from the ignition switch which will sometimes go intermittent before failing completely though the fact that you’re hearing the clicking sound does suggest that circuit is OK. I understand that there’s a braided connection within the starter motor which can corrode so if all else fails and your left with the starter motor as the culprit, open it up, especially the solenoid and check the condition of the cable feeds before sending it away for replacement.
If you’re getting a battery drain which is higher than normal an easy check is to get a blown fuse and solder connections to either end so that you can connect your multimeter across it to measure the amperage drawn through each fuse.
The CCU is often a culprit as the fan you hear when getting out your car runs for several minutes and these units are prone to not disconnect the little fan at the back of the unit. This circuit is permanently live.

 

[colin129]

First thought was DME, always carry a spare [8|]

 

[Stephenjk]

I have a dme from type911 arriving today so if i can get it to go wrong for a while i can try that. In the meantime i have quite a few suggestions.

On the ccu fan could that also be intermittent when i turn off as nothing was drawing current the few times i checked sunday? An intermittent fault would explain what im seeing or not seeing

 

[Dekker]

I thought about the DME but from memory that controls the fuel pump, nothing to do with the starter circuit.

Also the Alarm circuit that controls the fuel pump and ignition circuit but not the starter.

 

[Ray]

I have always found that chasing a problem with bit part surgery is quite expensive.
I have an off road 4X4 with an erratic tick over problem and I have thrown a lot of money at it trying to resolve the issue. Finally I have bitten the bullet and taken it into a garage and do you know what he is having problems and he runs a Paris Dakar outfit.

Ray

 

[Dekker]

Marcus, I like the infrared camera trick, never heard that before, good one.

 

[Dekker]

I have always found that chasing a problem with bit part surgery is quite expensive.
I have an off road 4X4 with an erratic tick over problem and I have thrown a lot of money at it trying to resolve the issue. Finally I have bitten the bullet and taken it into a garage and do you know what he is having problems and he runs a Paris Dakar outfit.

Ray

I'm amazed at the bungling attempts made by some garages trying to sort out electrical problems. Just change a whole bunch of items and to hell with the cost to the client who'll end up paying for a whole bunch of new stuff they didn't need. You need to prove your hypothesis is correct by bridging contacts or applying 12v to see if you are correct.

 

[Ray]

I don't know about the 964 but the 22 year old 4X4 I have is a plug and play motor. Trouble is you need the correct plug and software to be able to interrogate and diagnose problems, is this the same issue on the 964?

Ray

 

[mcgc0]

Marcus, I like the infrared camera trick, never heard that before, good one.

Quite revealing David. You can really see what relays are working hard - good idea to baseline an image when no ignition from cold (what relays are live) then again after a 30 min run. It was a mobile phone imaging camera attachment (android and iOS). Thing is though a decent one is @ £350!

 

[Stephenjk]

This problem seems to be getting worse where I get into the car cold and turn the ignition and car clicks but wont turn over. if it turn ignition off and then on again a couple of times the car does eventually turn the engine over and then starts as normal.

The car is on trickle charger so the battery is fine. I've replaced both earth leads in frunk and the one on the starter. Any ideas what to look at next?

 

[vitesse]

Just because the battery is on a trickle charge ,doesn't necessarily mean that it is producing the necessary starting voltage.
Presume you've checked it with a meter-also the starter motor could have a lazy solenoid coil,poor live connection/slightly loose connection,etc.

 

[Ray]

Spot on. I was going to mention this. As soon as the key is turned, the voltage could drop off with not enough remaining to crank the engine.