1976/7 924 with points distributor

[vitesse]

Well at long last had a good day today with my friends 924.

After rebuilding the original Bosch fuel distributor & getting the car to start & run having checked everything else as well,including cam timing out by 75mm on the marks,therefore distributor out by 180 degs,I came to fit a new fuel filter only to find black particles in the fuel & these must have then blocked the fuel distributor.

Replaced this with the next generation having steel fuel lines from a later car my friend also had,but couldn't get the car the stabilise-so then discovered I needed the later 40 cc fuel accumulator to match the fuel distributor.
Obtained one from a Golf GTI S/H plus had a new fuel pipe made up having looked underneath & found that the existing 2 x 20 cc ones seemed knackered anyway with one blocked off-this was after having the fuel tank drained & flushed-a huge mound of grot was found on top of the fuel outlet plate that bolts to the tank.

Fitted the 40cc unit plus the new pipe a few weeks ago-friend then went to their house in Cypress until 2 weeks ago so today checked the connections with the fuel pump relay bypass in place-tightened up the fittings-no leaks-so rechecked ignition timing again-adjusted as retarded somewhat &asked friend to turn the key.

Bingo!!-engine started -coughed-spluttered-stopped-this repeated 3/4 times -next time I twisted the throttle arm & got the engine to rev a little,then it settled down to a slightly rough idle & as it warmed up a little it would then rev quite well.

As it is still in his double garage in the house ,we stopped it then but massive progress.

My impression is that it seems still retarded-so must check that -or some part of the cold start system isn't quite working properly.Next steps are to fully check all the engine cooling system/hoses -check all MOT aspects & then get an MOT so that a few good warm up road runs will see it knocked into useable shape.

 

[924nutter]

This is good news. If everything else has been fiddles about with and bearing in mind that I realise you are no idiot. (I thought I was the only person to have ever rebuild a metering unit) just check that the metering plate is central in the plenum chamber when it is at rest using I think a 0.1mm feeler gauge. If you splice a switched earth into the cold start injector you can enrich the mixture by about 25 % to maybe get it warmed up if you think the control pressure regulator is at fault. if you remove the banjo bolt on the regulator from the pipe that does NOT come from the centre of the metering unit and put the end of the pipe in a glass jar you should get some fuel if the regulator is working properly because when the inlet manifold is cold the bi metal strip inside the regulator bend open and bleeds some of the control pressure away to allow the plate to deflect further for a given airflow and it closes progressively as the regulator warms up. No flow could indicate that the rubber sealing piece is stuck to both the pipes internally

 

[vitesse]

John ,
Thanks for the message of support-as I started in the engine bay,& the car wouldn't start,all the initial work was done on it static in his garage & not easy to put outside as his driveway has a slope on it coupled with his inability to really put too much physical effort into anything(result of the brain tumour).

I stripped the cold start fuel regulator early on after checking all the more simple items with a test lamp/meter after I had rebuilt the Bosch fuel distributor.
It was only when I came to fit the new fuel filter that I found all the "tea leaves" in the fuel which is when I got him to arrange to have the car towed away to have the tank emptied & thoroughly swilled out.

All the cold start items may well be working now & with having only run the engine yesterday for 2/3 minutes it could be just a bit of ignition advance,starting from cold not having run for years ,really, etc ,etc ,but all your very helpful comments are noted & I will try them out if my next session leaves me with problems.I had also checked the centering of the lift plate .
Since I started with this,I have been fortunate to borrow & copy a Bosch Fuel Injection manual so have both Jetronic & Motronic content to assist.

Of course I have no ability to check fuel pressure yet as don't have the necessary kit,but current thoughts are -as it now starts & idles & will rev & probably better when warmer & out of cold start conditions,if it ain't broke why fix it.

I'm hoping that the fitting of the 40 cc accumulator now maintains the fuel pressure/volume to feed throttle openings compared to the deficient 20 cc units which may have been /were the problem before, once I had got the engine to start & run.

Can you tell me whether this engine prefers extra advance over the standard setting?

Oh for a car lift!

 

[924nutter]

Even with my modified cam in my own 924 I ran it bang on the money. In fairness it did have the breaker-less ignition. Did you set the cam up with the flywheel marker? I don't know if the very early cars had 7.5 and 10deg marks on the flywheel. Mine was an 84. if you have the requisite marks you can connect a lamp fitting thus. pos to centre blob, body to the contact breaker terminal. You then set your timing mark up where you want it, turn the distributor in the advance direction LESS THAN 90deg until the light comes on, ensuring that the heel of the breaker is on the leading edge of the lobe then turn the distributor retarded until the light goes out. That is the exact point that the breaker opens.

 

[scm924s]

It will take a while to get the fuel system fully flushed of old fuel if the car has been standing. My Martini had been stored for about 15 years and took about a twelve month to be sorted fully. Be prepared to change the main fuel filter regularly, if your car is original, it should have a small filter between tank and pump, this will pick up rubbish from the tank and blocks easily, it is NLA and can be cleared easily with an airline and need frequent attention until sorted. Check that the fuel distributor lift pin is free to fall easily under it's own weight, it gums up readily with old fuel. Check the injectors have a good spray pattern and the injector seals are good. Vacuum leaks throw up loads of issues on these cars and need to be eradicated.

The points distributor system works fine, but check the auto advance is working and the vac advance also with no leaks in the vac advance line.

 

[vitesse]

Thanks again,John & Stan--It does have the 3 timing marks on the flywheel & I used those when I discovered the cam marks were out by 75mm-I also used a strobe with them until the contaminated fuel stopped the engine running reliably-so now I have got it running last Sunday ( & only 3 mins or so) I will strobe time it again once it has really warmed up- last Sunday I just used the bulb method as you describe ,John,which I must say has always stood me in good stead from sidevalve Ford Pops,through A 30,105E Anglia,Cortina,Viva HB,Hillman Minx Super 1725,Avenger,Mini 850,MGB GT's etc.

As you say ,Stan,it needs to get out more & pass plenty of nice new clean fuel through it-hence the pressing need for a MOT which requires a good check over the critical affected other items.

 

[924nutter]

When I post I post in a sort of why keep all this stored knowledge to one's self you never know who else might find it useful.

 

[vitesse]

John,

I think we are of like minds one -can never have too much information-to which end,I have printed these last posts to add to my Haynes manual which literally bulges with such good stuff!