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Turbo S won't Start !

chrisg

Member
Dear All,

Here's a conundrum if ever I was presented with one !

Trackday 7th March -can ran fine and didn't miss a beat.

Several trips to work and back w/c 8th of March. Then put away in garage for ~ 8 days as running low on fuel and budgets tight.

Went to start the car on Saturday, no response - turned over but wouldn't fire. Thought to myself, ahh running a bit a low on juice I'll put ~ 10L of Tesco 99 in it.

Tried again Sat PM, no response. Thought, wonder if the DME relay has gone down ?

Changed this over, car started immediately then ran for ~ 15secs before dying wouldn't start again.

Looked through Clarks and found the DME relay jumper instructions, tried this, car ran again for ~ 15secs then died again.


Eventually, (much to my embarassment/ annoyance) called the RAC. Possibly the most helpful RAC patrolman ever (particularly on a rainy Saturday eve.) tried a number of things but found:

Fuel at the rail but no pulse to the injectors
No spark at the plugs

So, where do i go from here ?

Could it be:

Hall sensors/ rpm/position sensors that have gone off or moved ?

Fault with the DME unit which has fried itself/ disintegrated ?

Intermittment issues/ problems with the immobiliser ?

Your thoughts, comments and experience very gratefully received ?[:mad:]
 
I have had this before after a lay up on one my turbos that sounds just like this,car started then would die,i basically kept revving the engine trying my best to keep it going,then i filled it to the brim with fresh fuel,i had a loose theory in my head about crud at the bottom of the tank,or fuel that had gone off....?...something like that fuel related??,whatever it was it did go away with use in my case,but deffo a little irritating.Someone will pipe up in a minute about using the car more but on this occasion it was a lay up after a major amount of bodywork that took a while.A brimfull of fresh fuel and use it a bit perhaps is my suggestion...
 
I'll take a few stabs in the dark!

I recall reading someone with a similar problem and filling up with a fresh tank helped to sort it.... I think something was mentioned of the fuel filter and the filter thats inside the tank or something like that? I can't remember so it might be miles off!

I THINK the plugs only fire when a certain RPM is reached by the engine so that might explain why theres no spark - it needs to spin longer?

Maybe the fuel pump? Thats why there is fuel there but not enough pressure? Theres a way of testing this if you have the correct fittings.

Or electical wizardry gone wrong? Someone with far more knowledge than myself should be a long shortly, we don't have anything better to do [:D]
 
I would have thought Clarks Garage is the place to start

suggests dizzy/coil, sensors, DME in that order. I still have a spare (early) DME if you need one for testing - it's 24-pin I think so probably won't work with your chips, but would be enough to start the engine.

Only 2 months to get it ready for the 'ring [;)]
 
Ed

thanks for the offer. I'm going to have a go tonight and see if fiddling with/ adjusting the two hall sensors make any difference or will start the car.

Failing that the car will be RAC transported down to Mark's for full work up. A loan of your DME unit would be very helpful !

thanks

Chris
 
Don't know if we have any courier service this week - I will be in London Mon / Tues so could come home via yours on the Tues pm

 
Well.... bugger me, just been out for fiddle around the hall sensors and guess what ?

The engine started straight away !

It's obvious that both the flywheel position sensor and the Speed sensors have to provide a signal to the DME before it will provide either a spark or signal at the injectors !

So if the DME relay is working fine check both the hall sensors at the back of the engine !
 
ORIGINAL: chrisg

Well.... bugger me, just been out for fiddle around the hall sensors and guess what ?

The engine started straight away !

It's obvious that both the flywheel position sensor and the Speed sensors have to provide a signal to the DME before it will provide either a spark or signal at the injectors !

So if the DME relay is working fine check both the hall sensors at the back of the engine !

I might be wrong but could this have been that the new fuel you put in has had time to disburse the blockage that formed from running it too low? I just can't see sensors failing suddenly when running fine then sat for 8 days?

Like I said probably wrong but maybe?
 
I think its the fuel aswell,when i had this problem it was really random until i put the new fuel in and it had cleared its way through.
 
I thought it would if it's intermittent - which is usually the case for an electrical fault. The usual failure is the plug into the wiring harness - gets brittle & falls apart.

I believe one sensor is required for starting, the other to keep the car running

 
Based on what I found last night, I would suggest that the issue was clearly an electrical glitch most probably down to one or both of the flywheel/ringgear sensors.

The 'new' fuel was getting to the injector rail on Saturday as there was 45psi pressure at the rail. The issue was that there was no spark at the plugs or pulse at the injectors.

My best guess is that there was/ is an intermittment fault with either or both of these sensors and the DME wasn't receiving a suitable signal from them, and not firing either spark or fuel.

At least now I know where to start !
 
I had this problem with my car twice last year. Both times it happened when I'd run my tank dry the previous night and it failed to start the next day. At the time I didn't make any connection and simply put some petrol in the tank.

The first time it took me 4 months to find the fault. I searched every mention on the net and every article I could find.
I checked and double checked everything .used fuel pressure and flow rate guages, multimeter noid lights etc nothing

I finally got the car started and i'm convinced it was caused by water and crud in the bottom of the tank getting into the fuel system. Simply that.

The only fault s I found were dirty contacts and sticky injectors .
 
Chatting to my brother tonight he is at a similar state with my race car, obviously the fuel tank was empty for many months but was thoroughly cleaned out. Car cranks over fine, spins really fast but doesn't start. It only has about a gallon in it now, my suggestion was a flywheel sensor, but it could be loads of things. He reckons he only heard the pump for a few seconds which is odd. If its anything odd I will report back as he will be working through all the usual things in the morning.

Bit frustrating really as everything else works perfectly which is a huge relief given its the first time power has been applied to that loom in nearly a year and of course in its been installed in another body shell.
 
Neil the petrol pump will only pump until full pressure is achieved so thats normal. If the car had just been switched off and then back on you probably wouldn't hear the pump at all as the pressure in the fuel system would still be there.

If you haven't flushed the fuel pipes and cleaned the injectors I would recommend it. Any detergents and laquer pumped up from the empty tank might still be clogging the pipework and injectors.

I put a single gallon in mine and it still wouldn't start . The solenoids in the injectors had become clogged and sticky.

I would first check the pump's flow rate by attaching a piece of garden hose to the fuel rail and removing the DME relay and replacing with a 3x way jumper. You don't need the ignition on because terminal 30 on the DME is always live. Stick the hose into a large 2lt clear pop bottle and see what you get in 15 seconds. Multiply by 4x to get lts per minute .'

Next check you have 12v+ to the injectors with the ignition on ( DME relay back in) You might find there is 12v+ to both terminals on the injectors .

Next test you have a pulse supply to injectors when cranking the engine .Connect a Noid light to all the injector connectors( about £5.00 from ebay Halfords etc) Make sure the engine is cranking fast, the ECU needs to see about 200rpm min or it will switch off the fuel pump and injector supply (safety feature to prevent a fire in the event of an accident)

If you have a nice healthy spark when cranking and it still won't start I would clean the injectors next with a 9v DC PP3 battery.

Connect a pair of wires to the PP3 battery with bare ends. Stroke the leads over the injector terminals quickly to simulate a normal pulsed supply which should cause your injectors solenoids to click loudly as they strike both ends of the injector hopfully squirting some fuel into your inlet.
I would repeat this at least 10x with each injector (including the cold start injector if fitted) If you cannot then hear the injectors clicking sharply and loudly then you'll need to remove them and get them professionally cleaned and checked .

This got my S2 started after 3 months off the road. Hope its some help.
 
Thanks Peanut, great advice, pretty much what we where talking about last night. He said he was going to get another gallon and we discussed disconnecting the fuel line from the rail and just pumping it through, also talked about checking power to the injectors and coil.
 

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