Mi16 Won't Fire

[arwel 43 2 Cars]

As some of you may have seen my rally car thread, my rotor arm let go big time last weekend. I have fitted a new rotor arm and dizzy cap but it still wont start. We have fuel and we have spark going from the coil to the dizzy but it doesnt seem to be going any further. Any ideas or is it a dodgy cap or dodgy rotor arm?

[omri617 18]

Co sensor connected?

[welshpug 1,626]

Any ideas or is it a dodgy cap or dodgy rotor arm?

 

 

got to be that if there's spark on the king lead.

[ORB 227 1 Cars]

What WP said. If its coming from the coil and the king lead is kicking its got to be cap/rotor and there after.

[arwel 43 2 Cars]

Cheers people. . New one of each it is then.

[arwel 43 2 Cars]

Update on this.. or lack of update really. Another new rotor arm and brand new dizzy cap fitted and still no joy with it. I have one idea. The rotor arm on the MI16 is held on with 3 little allen key bolts. When the original one let go one of these little bolts sheered of and left the remains inside the mount for the rotor arm so now only 2 out of the 3 hold the rotor arm on to the end of the cam. As there is only 2 bolts holding it on, would that leave a tiny tiny gap where the 3rd one should be that is allowing the spark to disapear through it instead of doing what it should be doing??

Edited July 2, 2013 by arwel

[Tom Fenton 1,526]

1 of them missing won't make a difference to it running or not, I once used the screws out of my sunvisor to bodge holding the rotor on when the bolts came loose on my 405 Mi16 on the M1 many years ago to get me home.

However I would recommend drilling out the bust one to fix it properly, as you've discovered they can sometimes fail if they are not 100% right.

[arwel 43 2 Cars]

Cheers Tom. It will be drilled out asap but I just wanted the damn thing to start so I can move it. Im totally stumped now. When the rotor arm let go, could it have somehow back fed and killed something else? We've tried a different ignition module and that didnt do anything either.

[Tom Fenton 1,526]

Are you getting a spark at the plug now? Are the leads in good order? Are the plug holes dry, the Mi's collect water here which makes them not run or run rough? Have you tried another cool, again I've previously had one pack in without warning? Are the injectors firing, this will tell you if the crank sensor is good or not? A few things to try anyway.

[arwel 43 2 Cars]

Spark is the same, from the coil to the dizzy, Leads all seem good, plug holes were dry as well. Have't tried another coil yet as its giving spark out I presume that is fine. Injectors are firing as the stentch of fuel gets worse the more you turn it over. I just find it odd that it wont start now after the rotor arm let go when it ran spot on before then.

[S@m 156]

I have run mine with only two out of three of the screws for quite some time now, so that shouldnt be it - to tell you the truth the third one got loose and smashed its way out of the cap - and it still ran! What brand dizzy cap are you using? I had a brand new intermotor one once that didnt work out the box because the sprung part in the centre where it contacts the rotor arm was decidedly unsprung - although since you have tried two its unlikely.

[arwel 43 2 Cars]

A few people are suggesting the distributer itself. Is there something hidden behind the rocker cover that can be removed like the old 8v motor? ?

[Tom Fenton 1,526]

There is nothing more. All that is there is the cap and arm. Ignition timing is decided by the crank sensor and ECU.

[arwel 43 2 Cars]

Thanks Tom.. its got to be going to earth then for some reason. More investigation needed.

[arwel 43 2 Cars]

Got it started at last. Swapped the coil over and it fired straight up. Appears even though it had spark at the main lead it clearly wasn't giving a strong enough one.

[2052NV 24]

I was about to say get another coil and module. Both can half work and make a spark happen that just isnt strong enough to get it running. Have experianced this my self. I carry a spare module in the car at all times

[DrSarty 90 1 Cars]

Glad you've got it sorted...but I'm surprised no-one mentioned if the plug leads were on in the correct firing order!

 

Was it obviously a weak spark at the dizzy cap then?

 

I'm guessing it wasn't (just) the strength of the spark, but just a crap coil that wasn't performing correctly, i.e. charging and discharging at the appropriate speed to deliver enough spark rate to the cap.

 

Anyone else had a weak spark?

[arwel 43 2 Cars]

I wouldn't say it was obviously weak really. Like you said, the strength wasn't there. I guess when the rotor arm disintegrated it must have back fed down the lead and toasted the coil.