No spark on 3b engine :(

[Welleh]

Hi guys,
just recently ive bought a 91 s2(3B) coupe as a non runner (no spark) it was cheap enough so i got it and got it trailered home!
anyway now its at home its been sitting in the garden for a few weeks whilst ive been pondering what could be wrong with it. first off i used an l.e.d and a jumper wire to pull the codes off, unfortunatly it just showed up a constant red light. took it to a garage and they said the ecu was ******ed, although i have 2 reciepts here saying the ECU is fine (tested just 3 months ago - car hasnt been running for a year!), so i took it as there were no faults found will have another go when i get some time off work!, then i replaced the coil (the one on it was off an audi 100 so!) still no luck. then after reading that sometimes the dizzy drive gear can snap i took the dizzy cap off gave the rotor arm a wobble, no play what so ever! so now ive kind of narrowed it down to the 'hall effect sensor' as i heard these can sometimes go. ive had a poke with me multimeter and from ecu pin one (+ ecu pin 10 (gnd)) theres no reading so its not a dodgy wire to the coil(ig module), also from ecu pin 8(hall effect sender input) (+ ecu pin 10 gnd) it's giving weird readings e.g: ignition off - the'll be some resistance there, ignition on - no reading what so ever, then cranking - no reading again then after cranking with ignition on there will be resistance there. its confused the hell out of me and somehow gives me an idea that the h.e.s is ******ed. someone also said the crankshaft position sensor pin can also break at time's and it wont show up a fault, however with the multimeter once again had a poke, conclusion - ill get later as the battery died LOL. can anyone shed any light on this?
also after its trip to the garage the heater blower motor and aircon has stopped working for unknown reasons to mankind (bloody cowboys ) anyone have any ideas on this?

cheers guys
Stevo

[Jas11n]

welcome Steve,
these guys will sort you out

oh, and yes, IIRC that 7A dizzy on ebay that martin gave the link to, will fit the 3B.

Jas

[Welleh]

cheers mate

[WabTheKing]

timming could be 180' out, i had this problem with a 7a engine, took months to figure it out!

[Chris M]

Make sure the rotor arm turns when the engine is been turned over. Here's a link to another simular thread LINK

HTH,

Chris

[martinjs]

Hi Steve, forgot to say that dizzy will work ok but the rotor arm will need changing for a 3b item (narrower tip), that price for a complete new dizzy isn't that bad mind.
I'd definately check the timing first though before changing the dizzy, the previous owner might have cocked it up. Check all the spark plug leads are in the correct places (easy mistake to make).

martin

[Welleh]

timming could be 180' out, i had this problem with a 7a engine, took months to figure it out!

if its 180deg out wouldnt it just fire the coil at the wrong time? or does the TDC sensor determine that aswell? thought they were vac controlled? this is one thing i was unsure about i'm assuming its vac righto?!

Make sure the rotor arm turns when the engine is been turned over. Here's a link to another simular thread LINK

HTH,

Chris

The arm turns when the engine is being turned over, dosnt stop when you try to stop it either! (silly me cut finger trying LOL), also the tools he mentioned, how do i make those!

Hi Steve, forgot to say that dizzy will work ok but the rotor arm will need changing for a 3b item (narrower tip), that price for a complete new dizzy isn't that bad mind.
I'd definately check the timing first though before changing the dizzy, the previous owner might have cocked it up. Check all the spark plug leads are in the correct places (easy mistake to make).

martin

all ht leads are correctly fitted to the dizzy cap and there firmly on there, i forgot to mention i checked that first! , problem is, its before the coil as the coil isnt actually fireing at all! if you put a very very small current to the middle pin of the coil the coil will fire (be carefull if you try it, firstly because it fires several times, and if you have any small form of heart condition and the spark catches you it can trigger it off! high tension sparks are not good for the body either and in some cases can leave entry and exit scars in weird places!), the lead on the middle pin is ecu pin 1, when i turned the engine, nothing what so ever comes thru that but theres resistance in the whole wire so it's defo not broken!

Cheers once again guys
Stevo

[PeterS]

Steve:

Check out http://www.sjmautotechnik.com/troubl.../20vboost.html, Scott Mockry has lots of tips for the 3B.

it's very likely that the dizzy is either mis aligned ( firing order is 1, 2, 4, 5, 3) - the hash mark for the #1 TDC should be near the 8 o'clock position.: http://www.sjmautotechnik.com/troubl...g/eng.html#tim

Ensure that the dot on the cam gear is within the "V" on the valve cover ( will have to loosen the Timing Belt top cover to see) and that the timing mark on the flywheel is also at "0" - scroll further down the web page.

Bottom line, I think you have no spark because either the the hall sensor in the dist is bad, or the dist is misaligned - which tells the ECU not to fire the coil....

Hope this helps!

[Welleh]

ahh so just being mis aligned it will not fire! now iC what WabTheKing means, although i doubt its 180 deg out!
i will have a deep look into that site abit later, start getting used to german engineering as it looks like the way forward!, still its so complex against the french engineering im used to tinkering with!
cheers guys, hopefully ill come back with some resaults this time! then its time to get it remapped!
Stevo -

[Robatron]

I had a firing problem a few years back on a mini (stop boo-ing!!) and it turned out to be exactly what Wab had told you. The funny thing is, the dizzy turned 180 degrees on itself and the engine just cut dead when I was doing about 30mph. After standing by the road side checking all the usual places, I got my mate to try and turn the car over whilst I twisted the dizzy round.

Once I got home I adjusted the timing and the car ran fine again. I hope this is a similar problem that can be solved easily without spending too much money!

[Welleh]

thing is i thought if the timing was out by so much (180deg) it would just revert the firing cycle oppisite to the compression cycle and fire at the end of the exhaust cycle instead if you get my drift!
and yes hopefully it will be quite a cheap fix! starting to run out of money!!

[PeterS]

Stevo :

From my understanding, you only have a window of 3 degrees in setting the distributor to top dead center of #1 cylinder....you could set the cam and crank timing, eyeball the distributor position, and move it very slightly until it starts.

Another thing about distributor positioning that Mihnea taught me is that eventhough it may be "good enough" to start the car....if you get mysterious reductions in boost between 3800-4800 rpm, you may have to "fine tune" the distributor position further.

[Welleh]

iC so if the tdc mark on the fly isnt withing 3deg of the dizzy the ecu wont fire to prevent kickback incase its out quite a bit. (kickback meaning - firing on wrong part of cycle sometimes resulting in bent/broken rods/crankshaft).
i assumed these would be boost controlled for some reason (yes laugh at me please ) as on some older boosted(mainly carbed) lump's it relied on vac/boost to retard/advance the ignition. then i just remembered the vac pipe going to the ecu is to control boost! LOL!
right im with it now, still cant believe i diddnt think of that earlier!, ill fiddle with the timing a bit tomorrow i thinks!, thing is do i have to remove the inlet plenium? - if so do i need to unbolt numerous amounts of things to do so? as the bottom bolts holding the plenium on are in the most divine places!, and do i have to make a super dooper long allen key to get thru the plenium? looks like the only way to get them off!

Cheers once again doods!
Stevo

[PeterS]

Stevo...
you DONT have to remove the intake plenum....
Worst case you can work a open ended wrench in from the firewall to loosen the dist mounting bolt - perhaps you might have to remove the ISV to give yourself a bit more room. To check the Cam timing, you could try using a short L shaped allen key to to loosen the TB cover behind the aux radiator - just enough to pull it back and look for the dot....

[Welleh]

cool cheers peter will crack on today!