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Flat 6

'83 SC won't start, not fuel

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52 minutes ago, proporsche said:

nope this is 91SC  81SC from behind, you silly;-) Carrera does not have ..for example an airboot;-) and air decelerator and auxiliary air regulator...........should keep going;-DD

 

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Ivan, pump is fine. Fuel getting to filter in engine bay with strong pressure.

Issue seems to be with green wire between CDI & Dizzy?

A.

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On 6/24/2019 at 6:06 PM, Flat 6 said:

Hi Jonny,

Didn't take an accurate note I must admit but it climbed gradually the more I cranked and then settled at a max of let's say 3000-4000.

I've just tried again to take a proper note but it is now not climbing at all.  The tacho is not totally dead in that it is lifting maybe 2mm from rest but not getting beyond '0'.  

And I've just taken that resistance reading.  With my meter set at 200 I'm getting a reading of 0.7.  I take it this means the wire is broken?

If so, do I have to buy one of those looms that takes the replacement green wire Matt sells or if there an alternative just to replace the green wire all the way to the connector?

A.

 

Meter reading low res.jpg

Pin low res.jpg

In the second picture you are measuring across the coil which is about 1 ohm.  Remember that connector is the mirror image of the box. 

Move your meter to other end which will measure across the distributor pickup and also test the green wire.  It should be around 600 ohms.   Get you meter probes to stay connected and give the wire a good  flex.   If the reading changes then the green wire is the culprit.  

 

Edited by Jonny Hart

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16 hours ago, proporsche said:

nope this is 91SC from behind, you silly;-) Carrera does not have ..for example an airboot;-) and air decelerator and auxiliary air regulator...........should keep going;-DD

Sorry, was on a phone so just saw the crank hoses and thought they were from a 3.2................................wheres me coat?

 

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Hi,

OK, got back to the car to take another reading.

Looks like 579 ohms at the other end of the block - does that mean everything is OK?  No change on wiggling green wire.

Am I using my meter correctly? i.e. .579 on the 2k setting = 579?  Must do a course in basic car electrics before all the old skool lecturers who remember this type of wiring retire!!

If this is all OK then I will have to look elsewhere for the problem...

Al.

2nd Meter reading low res.jpg

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Yes, that’s ok.   So green wire good.  

If you are a absolutely sure that the tacho does not read the cranking RPM correctly, I would say the dizzy input circuit in the CDI has failed.     

I can bench test it for you.  

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Thanks Jonny,

I will check tacho again tomorrow. You're saying it should just read actual revs on cranking yes?

Cheers,

Al. 

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On 7/11/2019 at 11:37 AM, proporsche said:

ok 1st basics...did you try to see if the pump work by it self? Jump fuse number 6(from the windshield ) with no.3-4 where there is always power.If you can hear the pump --pump is not your problem.

2nd.once you eliminate this--saying pump is working..go to the engine and behind the air both is a safety roll over Bosh plug -on the pic .Disconnect it and put the key on --you should be able to hear the pump If yes this plug is kaput.You can drive like this ,just do not leave the key on(light on dash only) so the pump is not running .

 

 

try it and let me know

 

Ivan

Hi Ivan,

Just re-reading your helpful post.  The pump runs when the ignition is on. I can also get it to run by removing the relay and putting power direct to the pump via 30 (I think, haven't got my diagram here...). But it doesn't run when I bridge fuses 6 and 3 or 4. Is that a problem? 

Cheers,

Al.

Edited by Flat 6
Reword

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1 hour ago, Flat 6 said:

Thanks Jonny,

I will check tacho again tomorrow. You're saying it should just read actual revs on cranking yes?

Cheers,

Al. 

Correct. 

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if you bridge the fuse 6 and other under power the pump should run....with the ignition key off.

 

Ivan

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OK, everything is connected as it should be. On cranking I am getting no revs on the tacho. It lifts about 1mm and on one attempt jumped up to 1000 but only for a millisecond.

Is the conclusion therefore that CIS is faulty?

I have a CIS '73 2.4 in restoration. Could I swap over CDI or are these very different?

Also concerned that fuel pump doesn't run when following Ivan's test...

Al.

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Just did a further test of fuel pump setup by lifting airflow plate from inside air intake. With key at run position the pump runs when I lift airflow plate which presumably means all is well with fuel pump switching despite possible gremlin at fuse panel?

A.

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OK, thanks all for your help. The car is now running beautifully.

The problem? Nothing at all to do with fuel pump, CDI, or any of those things I have spent many hours fiddling with...

I had taken the air filter off to check fuel pump activation when lifting airflow plate. I was putting the filter back on again when I happened to notice that the airbox pop-off valve was sitting at an angle.  Gave it a wiggle and out it came. Whoever installed it many moons ago had used some sort of rubber sealant rather than epoxy and the seal was no longer intact.

Epoxied in and hey presto...away we go!

Salutory lesson there to look at the simplest culprits first. If I hadn't removed the air filter to check the airflow valve I would never have spotted the problem.

Still not sure why the tacho wasn't showing any revs on cranking but it is certainly showing a nice steady idle now. Anything I should be concerned about there?

Hopefully another learning saga that might help someone else avoid hours of unnecessary trouble shooting. On the upside, I have learned some new stuff during the process so all good.

Thanks again to all for your help.

Al.

 

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