Johnny G Pipe

In times of trouble, who else to turn to but good old Rennlist (makes a change from arguing about prices!)

After a great spirited backroad drive to work today - touched 125 a couple of times (err.. in the isle of man)- suddenly the car started to miss and pink ( or something similar) under load after 3k rpm. Otherwise she is fine at cruising speed or taking off from a standstill.

Seemed to happen relatively suddenly - so I immediately thought dual dist. belt failure. Can someone remind me of the test procedure - I know its in the archive, but I was never sure which was the primary lead - left or right?

Anyone got any other suggestions meantime?

Thanks in advance

John Boggiano

Sorry to hear this, Johnny.
I bet it's something simple, such as your suggestion.

I think if you take off a dizzy cap, you can see the belt. Or not, as the case may be.

johnfm

Primary dist is on the right, with shaft that connects into the motor. The secondary hangs to the side and it driven by belt.
Simple test without removing dist caps - pull the central wire from the lh distributor. If car still running, this coil & distributor is OK. Then reconnect. Do same with RH dist.

If car is running odd only over 3k, this may not be the problem.

TO check coil, swap the leads and repaet the test.

Johnny G Pipe

Thanks for rapid reply John B..its a problem shared already!

Last time I opened up the dist. caps - with the intention of checking the belt I got as far as the caps and arms but couldnt see anything resembling a belt..beyond that it looked a bit foolhardy to dismantle on limited knowledge, so I left it at the time, with the intention of getting it checked next service. Is it relatively safe to dig deeper?

I was hoping to do the 'pull the primary lead' check this lunchtime in the hospital car park!

Edit: Thanks John FM (all the Johns are here..)- you must have posted whilst I was typing..I'm off to the car park!

John Boggiano

Be sure to let us know the result...

GaryN

Hi Johnny,

The way my OPC showed me how to check was:
1. Start engine, get it idling.
2. Open engine lid, standing behind car facing farward, on the left side against the body work in the engine compartment you will see 2 black electrical plugs. Remove one of them while the engine is at idle revs. They have a metal clip in place to hold them in place, this just lifts up and you will be able to remove the rubberized plug.

At this stage if the revs stay exactly the same ( no change in the sound of the idle) there could be a problem!! Further investigation required.

What should happen on a good distributor belt is the idle sound should get rough (sounds almost like a car that is missing). As it is now running on only one distrib.

You would need to do this with both plugs to make sure you have included the primary. So put removed plug back on and secure metal clip. Then remove the plug next to the one just removed and check for the above.

Don't know if this helps but it is a very quick way of checking the belt without the use of screw-drivers and getting technical. It should take about 5 minute max to check.

Cheers
Gary '91 C2

Johnny G Pipe

OK, I'm back.

Gary, thanks for the reply - I was out pulling leads..lucky I have an understanding boss..

Ok, this is good news, I think, i.e immediate diagnosis:Pulled right (primary lead) - wouldnt start...( and then pulled left hand (2ndry)lead - starts up no bother.)
This confirms broken dist belt, no?
Otherwise, secondary would drive primary even if primary disconnected..(sorry I need these things broken down nice and simple!)
Does each dist have its own coil, meaning it could be a coil down rather than the belt?

So -Two Big Questions, sorry Three Big Questions..(spanish inquisition)

1.Is it safe to drive home?
(and should I disconnect the secondary to make sure I'm not firing on a closed cylinder?)
2.I would replace the whole unit rather than the belt alone - is this a DIY job (otherwise got to drive the car an hour away)
3.Is there any way I can check if I have done any damage so far?

Thanks again guys!

johnfm

Johhny

there are two sep coils. You 'could' have a coil problem. Swap coil to dist leads & re-test. If same problem occurs, coils are OK.

Re: belt repair, there is a DIY on 964 site, but I think it is a bit tricky from memory. My specialist swapped my dist assembly. They keep a re-cond unit in & swap for £130 - they do this as a swap over is quick, a rebuild takes longer. THey still cost the same, but you get your back a day earlier!


I would check your rotors (take caps off) I have someone crank the starter. It will confirm your diagnosis (one rotor will turn, the other won't!).
You need to make sure the secondary isn't stopped right on a contact - otherwise it will be always firing & this can damage the motor.

John Boggiano

Presumably, Johhny could remove the rotor arm on the secondary distributor and then drive home/to workshop gently?

Edit: ...or just left its lead disconnected, of course.

Johnny G Pipe

Coil to dist lead is central lead, right? Duhhh..

John Boggiano

Yes.


Edit: Paula just looked at this thread and said, 'Distributor... is that the thing that looks like an udder and has leads that attach like milking machines?'

Which, I suppose, is all true!

johnfm

Yes

remove central lead from secondary - then if rotor is stuck on a cylinder you won't damage it much!

Don't know what this will do to the coil, if anything??

Johnny G Pipe

Ok, I'm going home on 6 plugs - I can't see it damaging the secondary coil. I guess it should drive smoother with the secondary dist. out of the picture?

Will pull the caps at home to double check, and post a separate thread on whether I can replace the unit myself.

John B:how long has Paula had the cow fetish?

BS911

Hi Johnny,

If you do fully confirm your dist belt as broken, there is a DIY for replacing the belt that I wrote up and is on my site listed in my signature below. Unless you have serious problems like I and just have to get into more trouble than is necessary, I wouldn't touch this DIY. In fact, for the day and a half I spent on this annoying little bugger, the effort isn't worth the relatively very little amount of money you would spend to have someone - Steve Weiner - rebuild it for you. Replacing the entire distributor body is very easy though and a definite DIY. Line up on Z1 for plug #1, remove just one bolt, pop the dist caps out of the way and then you are out and ready to ship off for rebuild.

Also, for statistical tracking, I drove my 964 and 993 both for some time while diagnosing the broken belt with no damage. I would agree though to disconnect the power going in to that secondary coil to prevent misfiring to the engine to be on the safe side. While many times there is no damage because of this, the possibility of a severe misfire is there which could cause damage.

Johnny G Pipe

OK, I made it home..jeez its hard to drive that car slowly!

Car drove smoothly but not her usual self. Opening the engine to check the coils (yes, secondary coil powers up on primary distributor just fine) there was a very unpleasant smell of burning, plus a whiff of smoke drifting about - which I REALLY HOPE is the fragments of belt within the distributor

Brian - yes, I have read a couple of reports on replacing the belt - there's one on John Miles' running reports too. I have already decided that it looks like a major PITB to do!!

Hearing that swapping out the whole unit is a breeze is music to my ears - I just don't understand the .
Can you translate?
(Today has already been a real day at school!)

Many thanks