Flywheel impulse sender ???

[Ant7]

Hi All,

Well, I guess after nearly 14 years of ownership, it was always on the cards that the day would come when the old girl would refuse to start, tracked the fault down to no spark, have power at the coil, so I guess the most obvious suspect to start with would be the flywheel impulse sender, unless of course any of you here can suggest anything else that I may be overlooking, I have already changed the DME relay as first port of call, made no difference.

All input welcome, also a price and availability on said item would be great.

Ant.

[Nige]

https://type911shop.co.uk/epages/de867ca1-377e-432e-84fd-bdccf2206766.mobile/en_GB/?ObjectPath=/Shops/de867ca1-377e-432e-84fd-bdccf2206766/Products/3455

Price is decent and easy enough to DIY.  Though it may still not solve your problem, but finger crossed.

Bad earthing, coil, or ECU could also be playing a part.

Have you checked/replace the dissy cap and rotor?

 

 

[sopor]

Pretty sure you should repalce both, not just one.

[Nige]

Might as well whilst you are in there.  The effort is pretty much the same.

 

You can also test the resistance, without removing stuff.

 

 

[Ant7]

Cheers for the suggestions guys, I have checked as much of the simple stuff as possible i.e.; I have checked whether there is spark directly from the coil lead to engine, thus eliminating the rotor arm and cap, changed the coil lead etc, there is voltage to earth on both coil terminals, so I am assuming that the coil gets grounded through the ECU being pulsed from the flywheel impulse sender, I will do the resistance checks on the sensors when I get chance before going any further.

Ant.

[Nige]

Just be careful when you remove the old senders from the ali bracket.  It can be quite brittle and spendy to replace if you break it.  Just drill the old senders out they're only plastic, rather than press/hammer.

 

https://type911shop.co.uk/epages/de867ca1-377e-432e-84fd-bdccf2206766.mobile/?ObjectPath=/Shops/de867ca1-377e-432e-84fd-bdccf2206766/Products/2410&ClassicView=1

[Ant7]

1 hour ago, Nige said:

Just be careful when you remove the old senders from the ali bracket.  It can be quite brittle and spendy to replace if you break it.  Just drill the old senders out they're only plastic, rather than press/hammer.

 

https://type911shop.co.uk/epages/de867ca1-377e-432e-84fd-bdccf2206766.mobile/?ObjectPath=/Shops/de867ca1-377e-432e-84fd-bdccf2206766/Products/2410&ClassicView=1

Understood, Cheers Nige!

[Ant7]

Well, just did a few more checks, both flywheel senders measure around 950 ohms, which I believe to be correct, checked both the DME Relays I have, and re-soldered them completely, checked both relays inside are operating in each etc. Checked ignition Coil for resistance, and also powered it up from a 12v supply, with original coil lead and spark plug attached, and observe a decent spark while interrupting the 12v supply etc. Not sure where to go from here, Do I suspect the ECU/DME unit next ? or a possible voltage failure at the DME Relay itself ? Anyway; enough for today, again all input welcomed.

Ant.

 

[Nige]

Do you have fuel?  Can you hear the pump prime up when the ignition is on?

[Ant7]

Don't hear any pump noise with just ignition on, only when cranked do I hear the pump running.

Cheers.

Ant.

[Chris T]

Going back to your Monday post;

On 10/06/2024 at 15:45, Ant7 said:

I have checked whether there is spark directly from the coil lead to engine

I was warned by Wayne Schofield to never ever crank the engine with the coil centre lead not attached. It can apparently allow a high voltage back into the ECU and destroy it's coil driving circuit. Not sure how that can happen but I took my warning. Not sure where or how you later saw a decent spark, I hope this isn't your problem but worth mentioning to all owners (same applies to SC's CDI box, told this time by Jonny Hart).

[Ant7]

5 minutes ago, Chris T said:

Going back to your Monday post;

I was warned by Wayne Schofield to never ever crank the engine with the coil centre lead not attached. It can apparently allow a high voltage back into the ECU and destroy it's coil driving circuit. Not sure how that can happen but I took my warning. Not sure where or how you later saw a decent spark, I hope this isn't your problem but worth mentioning to all owners (same applies to SC's CDI box, told this time by Jonny Hart).

Hi Chris,

You may be onto something there, first of all; I checked the coil for spark separately from the ECU/DME wiring etc, however;  because my car hadn't run for a while, I did initially disconnect the main coil lead so the car wouldn't start while I cranked it to get oil pressure, so maybe my ignorance has cost me an ECU.

[Chris T]

I really hope it isn't the case, but perhaps once you have checked everything else, borrow an ECU or send yours to be checked out. I highly recommend Wayne at Superchips but he is a very busy man! 

Also, as a P.S. those sensors have been known to measure correctly but in fact fail when warm. Yeah, I know yours is cold but maybe still an issue. They are both the same so you could buy/replace one at a time? While you are there, check there is no metal debris stuck to a sensor, they are magnetic. 

 

[Type911]

As Chris says, replace the sensors, if they are OK now, they wont be for long

[Ant7]

Cheers,

The more I think about it, the more I am leaning towards a DME issue, considering the last time the car was used it was fine, and the only thing I can think of that might have changed that is the coil disconnect issue, unless anything else obvious shows up like missing voltage on the DME Relay etc, then I think I am going to remove the DME and do some internal checks on some of the main components i.e.; transistors caps resistors etc, If turns out to be damaged, then I can imagine the same thing happening if a coil lead goes bad, or a rotor arm goes open circuit, hence nowhere for the spark to go!

Ant.

[sopor]

If you hear hoofbeats don’t look for zebras…

The senders are common failure items on a 3.2. They’re relatively cheap and relatively easy to fit. I’m guessing that in your 14 year ownership they’ve never been changed? And there’s nothing in any previous paperwork to show they’ve been changed?

You only disconnected the coil because the car wouldn’t start, right? So probability is very high indeed that there’s an issue other than a yet-to-be-proven ECU fault.

 

[Ant7]

3 hours ago, sopor said:

If you hear hoofbeats don’t look for zebras…

The senders are common failure items on a 3.2. They’re relatively cheap and relatively easy to fit. I’m guessing that in your 14 year ownership they’ve never been changed? And there’s nothing in any previous paperwork to show they’ve been changed?

You only disconnected the coil because the car wouldn’t start, right? So probability is very high indeed that there’s an issue other than a yet-to-be-proven ECU fault.

 

"Part of an earlier post"

"because my car hadn't run for a while, I did initially disconnect the main coil lead so the car wouldn't start while I cranked it to get oil pressure"

[sopor]

Ah, forgot/overlooked that statement in your original post. Thank you for the reminder. 👍

That said I still feel you're on borrowed time with your original sensors.

Whereabouts are you located; you might be able to try someone else's ECU? I think I have one that came with my car (now on Motec) but have no way of confirming that it still works so trying it may not be conclusive.

[Phill]

5 hours ago, sopor said:

If you hear hoofbeats don’t look for zebras…

 

Unless on safari in Africa 

[Ant7]

4 hours ago, sopor said:

Ah, forgot/overlooked that statement in your original post. Thank you for the reminder. 👍

That said I still feel you're on borrowed time with your original sensors.

Whereabouts are you located; you might be able to try someone else's ECU? I think I have one that came with my car (now on Motec) but have no way of confirming that it still works so trying it may not be conclusive.

No worries, easily done when your following threads etc, 

I am in Mid Glamorgan near Caerphilly, To be able to try another unit before condemning my own would be great!

Ant

[Type911]

5 hours ago, Phill said:

Unless on safari in Africa 

You're not helping are you.................

[sopor]

3 hours ago, Ant7 said:

No worries, easily done when your following threads etc, 

I am in Mid Glamorgan near Caerphilly, To be able to try another unit before condemning my own would be great!

Ant

calling @Busybee…

[Phill]

11 hours ago, Type911 said:

You're not helping are you.................

I’m sorry, you are right, I should be less flippant and make more rounded, full suggestions.

Could also have been Wildebeest or Water Buffalo 

[Ant7]

1 hour ago, Phill said:

I’m sorry, you are right, I should be less flippant and make more rounded, full suggestions.

Could also have been Wildebeest or Water Buffalo 

12 hours ago, sopor said:

calling @Busybee…

Sorry, not sure, You'll have to educate me on this...

[Phill]

7 minutes ago, Ant7 said:

Sorry, not sure, You'll have to educate me on this...

@Busybee Haith is near you and has a fleet of Porsches.