944 ignition coil question

[Rapsey0909]

Hi all, sure someone can answer this very easy.
I think I need a new coil and looking around the bosch coil is discontinued so I can see that design 911 sells an aftermarket one but its over £100 plus delivery.
Most coils I look at are 12v and the bosch coil is 14v (if that matters) but if I look at MSD or Pertronix the voltage is not stated.
Pertronix looks to be the best value for money but does not state a volt amount just that it will work in the vast majority of applications. So will this work just fine or will I have issues (do I need anything to go with it) or can someone suggest a coil that works goes great, goes straight in and that will not cost an arm and a leg.
Cheers all

Porsche 944 1986 2.5 NA

 

[944Turbo]

There is a fairly tight range detailed somewhere in the workshop manual for resistance across the coils it is how I proved mine was duff some years ago (faltering at high revs) if you want to double check before ordering (multimeter required).

part number is I think 944 602 11500 and seems to be used in a few models of 911 and 928.

https://wooliesworkshop.com/products/porsche-924-944-coil-94460211500-b2-3 have second hand ones but they will be as old as your one - cheaper as a quick check to confirm though.

https://teile.com/en/porsche-parts-shop/model-911-964/3/Lighting-electrical-parts/901-Ignition-control-units/54/901-00-Ignition/Ignition-coil/17961 want 200Euros for one so design 911 looks cheap!

in the alternate parts fitment thread in the faqs it says it may be shared volvo v6 and pug 604 (referencing bosch coil catalog)

https://www.deancent.com/porsche-944-parts-without-the-premium-price-tag/ lists the Bosch part number, but I guess you have that 0 221 118 322

MSD red 8202 is listed as 944 suitable here http://www.autoatlanta.com/Porsche-944-Ignition-Coil-srch.html#:~:text=Msd%20red%200.7%20ohm%20blaster%202%20ignition%20coil.
and is available from amazon for £70 delivered.

https://www.amazon.co.uk/MSD-8202-Blaster-Hi-Performance-Coil/dp/B000182BDK

I don't know much about the pertronix but did see that there are different resistance ranges available - I vaguely remember something about 0.6 but double check!

Is it definitely the coil? does happen but more often its an old immobiliser or a faulty crank position sensor.

good luck electrical issues can be a nightmare!
Tony

 

[944Turbo]

Just scrolled down the auto atlanta page and they list pertronix 40001 for all 944s
Tony

 

[944Turbo]

Oh and to add to the list of other more common culprits - DME relay
Tony

 

[Rapsey0909]

Sometimes it fires and sometimes not, so am looking at changing a few things at once and this was one of them. As it fires sometimes I think that rules out the DME but was thinking of going to a SSR when funds are available anyway.
I will be doing new fuel pump, filter and injector seal kit as I have already treated her to a new dizzy and plugs but thought if price was right could go for a new coil as well.
The flamethrower looked good value (and adds a bit of bling) but sometimes they use resistors so just checking if there was something I am missing.

 

[Eldavo]

I think I may have a good used coil in a box somewhere - bought it from Euros, used it for a couple of hundred miles max and then rebuilt engine and switched to a wasted spark setup.

 

[944Turbo]

DME relays can be intermittent. Also another issue that pops up is broken injector wires - pull them in turn or wiggle just above plugs.

The workshop manual (section 28) - used to be available to download from various places on the web ignition system testing (2.5 na).

Says to check earths by reference sensors for cleanliness / firm contact.
If you have access to an oscilloscope there are various checks to try for speed and ref sensors.
Check dizzy cap for damage / burnt spots / dirt and proper installation.
Rotor has a 1k ohm resistance.

coil resistance
primary term 1 to 15 = 0.4 to 0.6 ohms
secondary term 1 to 4 = 5 to 7.2 Kohms
check for damage or burnt spots

plug caps and leads resistance 3k - ohms (on caps I think)

Ignition timing 5 to 15 degree before TDC (at 800 + 50rpm)

airflow sensor - push back sleeve leaving connector attached across term 9 and 6 = more than 8v
then remove air cleaner and between term 7 and ground 105 to 250mV
push airflow plate to full throttle slowly voltage should rise to 8V when sensor plate fully open.

Manual then goes on to fuel system testing injectors with a scope.

Tony

 

[Rapsey0909]

OK so update is they can't find a fault as its been starting fine since it went down the garage, the guy said the coil is reading fine and although I like the idea of a new one he said there is really no piont so he is going to clean up the grounds just on case. I have gone for a new injector service kit plus a few other bits but funny thing is I got a new fuel filter and pump to change out as I thought it would be a good time to change the filter and seen as he was in there a new pump couldn't hurt but he said he could not fit the pump I had as the non threaded nozzle was too big but after looking there only seems to be one size.
I have looked at vids on YouTube plus other sights and nothing indicates to a size difference on the inlet.
Any ideas.