csmab

Ok experts. I am experiencing an issue starting my car after it is fully warmed up. This has happened 4 times over the past several weeks. If I try to restart the car after it is warm/hot the engine will turn but not start. It will eventually start but it takes a couple of attempts. This usually happens after the car sits for 10 minutes after it is fully warmed up. I have no problems with cold starts. It springs to life immediately on cold starts. Take a look at the video below. I filmed this today so the experts could chime in. The video was taken after the car had sat for 10 minutes after a 25 minute drive that fully warmed up the engine and oil. There are 2 start attempts in the video. The first attempt you will hear the engine turn but not catch. The second attempt (immediately following) you can hear the engine catch and you hear a loud clack noise right after it starts. Turn up your speakers to hear it. It is a metal on metal clack noise at 38 seconds. I will confess that I accidentally started the car in gear without depressing the clutch 4 weeks ago. The Dealer left the car in gear after my State Inspection and I started it without realizing it was in gear. The car leaped forward. I always leave it in neutral. When I tried to restart it the engine took 2 attempts to start. I don’t remember a clack noise during this incident. Not sure if this has something to do with this issue or if I damaged the starter. I normally drive the car once every 2 weeks without any stops. Once the car is parked in the garage it isn’t restarted for a couple of weeks. Searching the site has turned up several possibilities from CHT sensor, starter, or vacuum issues. The car has 73k miles. I thought the video might help with a diagnosis.

goofballdeluxe

Bad starter is what it sounds like to me, in fact I'm pretty sure that's what it is.

Garth S

Sure sounds like the starter's bendix drive is pouched -- if the engine runs OK after starting, here's the second nod for a starter R&R.

The Bendix/sprague clutch deal is the most likely area of starter failure IMHO .... and engaging the starter while in gear dramatically increases the load on this component.

KMASS993

I have this same issue! Been wondering what it is. Will have to pick up a new starter.

pcarrera993

I always press clutch before starting, old habit. Yeah sounds like starter. Btw car sounds pretty awesome.

swmic

+3 for bad starter.

e9stibi

I had starter issues and finally diagnosed it correctly: in my case it was the starter but I could rule out a lot by just making proper measurements:

http://forums.rennlist.com/rennforum...oot-cause.html

Just for the benefit of the great forum I want to add some details to the trouble shooting:

0. Swap DME relay with the spare I had in the glove box. Car did not give a single sound while starting -> rule out DME relay issue at the moment
1. Battery voltage 12.8 V and I switched it with the one from my second (starting) 993. Still no cranking or klicking from the solenoid -> battery ok
2. All connection at battery tight and mass band in trunk "looks like new" -> ruled out issues here at the moment
3. Switched Starter relay (R61) with a similar relay that knowingly works (e.g. horn that is easy to test). car still "dead while starting -> starter relay R61 ok
4. Pull starter relay R 61 and do the following measurements:
4.a Check pin 86 for 12V. This is the 12V from the immobilizer to the starter relay coil that acts as an interlock to start the car. In my case I got the 12 V when I opened the car properly and turned the ignition on within the required time. -> immobilizer ruled out as an issue
4.b. Check pin 85 for proper mass signal (resistance measurement against mass). MJ 97 and later have a clutch switch that provides the mass to the starter coil switch. I measured "0 Ohm" with depressed clutch -> ruled out clutch switch

The previous measurements confirmed that the starter relay coil gets the proper supply. No to the power side of R61

4.c. Check pin 30 for 12V with the ignition switch turned to position 3 (start position to crank). I measured 12 V. -> ruled out ignition switch issue

The previous measurement confirmed that the power side of the R61 gets the proper signal too (12V). This all ruled out any relay related issues "in the trunk". I than moved to the starter and its connections as I assumed that an issue with the cable that provides the switched 12 V from starter relay power side to the starter solenoid is not likely.

5. Checked starter for tight and clean connections. Need to include the mass connection at the chassis side -> everthing was thight and clean like new -> IT MUST BE THE STARTER

6. Replaced starter -> car starts as it is suppsed to start!

Bottomline is as Steve already said: Root causes can be multiple and proper and "cheap" diagnosis before replacing expensive parts like Immobilizer unit can safe both time and money.

Here is the list of potential issues again that can lead to a car not starting "from the electrical side" and I am sure there is more when you include general "cable issues" between working components.

1. DME relay
2. Battery
3. Battery connections
4. Starter Relay R61
5. Immobilizer Unit / maybe key fob if you are lucky
6. Clutch switch (for MJ 97 and 98)
7. Ignition switch
8. Connections to starter
9. starter itself

Good Luck!

csmab

Thanks for all of the feedback. I was leaning towards a starter issue after hearing the clack noise. I will do some additionally trouble shooting to confirm. Does anyone know the book time to replace a starter? I will most likely have my shop perform this task.

bojali

on my 1998 C2S, my starter was replaced back in 2008 and I was billed 2.75 hrs. I remember them saying that the nut/bolts were a PITA to loosen!

goofballdeluxe

My starter motor was replaced at my mechanic in early 2011 at a cost of $700, including all parts and labor.

SC2993

A mechanical click for sure, PM sent!

IXLR8

Remove the DME relay so that you can turn over the engine without starting it.

This way you can repeat the clack phase repeatedly and also confirm that is has nothing to do with anything else engine related (ignition or fuel).

shamrock

Failing to start from hot typically points to starter motor , I've also had this , did a bit of leg work myself by getting the starter motor shipped and then sending back the 'core' afterwards. Labo(u)r was about €300.
The tech who did the work on mine reckons its a weak point on our 993's , that we'll all need a new starter at some stage , due to its position. It sits right in the line of the hot air being blown by the fan thru the cylinder heads. And electrics don't like this type of heat!
I also reckon its more likely the motor will fail if the car has spent a lot of its life sitting in traffic getting heat soak .. But then , that's just a personal hick opinion.

goldcountryboy

Please explain. If the engine is hot and the starter turns the engine over...if the engine does not start, how can this be a starter problem?
What am I missing?

Garth S

Here's a light hearted primer on starter operation ....
That a starter motor turns over when the key is twisted to 'start' is not an assurance that the engine is turned over fast enough to start - or even turned over at all: the sprague clutch drive must move into the ring gear - and have its 'one-way' function mechanically sound to adequately transfer enough torque to spin the engine without slippage.
As the drive wears, the one way slippage becomes two way = loss of starting torque + unpleasant noises .... generally first noticed when the drive gear is heat soaked.
This wear is often progressive, and is evidenced (obviously) by repeated attempts to start a hot engine and unpleasant noises: let the car cool down, and it will start like new. The starter is dying, and was kind enough to give notice.

At least, in my book, that's how a starter may 'apparently' turn an engine over and fail to start.