1979, 504 Ti - Running rich

Alex Foss

Alex Foss

Member
Tadpole
Joined
Oct 19, 2021
Messages
54
Location
Norway
Hi everyone. I have read alot of old posts in this forum with great interest, and its obvious that a lot of you have both experience with and knowledge of the Kugelfischer injection.

I have a 504 Ti which i just recently rebuild the engine while a local shop tackled all rust and resprayed the car. My problem is that its running rich, the plugs get sooted, and it wont idle when it gets up to temperature. I have read all info i could find regarding the Kugelfischer, discussed it with a lot of people, and tried my best to adjust the enrichment lever, the throttle flap and the air bypass / enrichner stop screw, but now i am running out of ideas.

Some background;
Electronic ignition, new - OK
Spark plugs, new - OK
Coil, new - OK
Ignition leads, new - OK
Electrovalve, tested - OK
Air filter - OK
All vacuum hoses, new - OK
Diaphragms in the pump, new - OK
Injection valves, tested - OK

Do any of you have some tips for me? I would really appreciate it!
 

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I don't have any answers, but hopefully others will. What a great looking Ti. You've obviously spent a lot of time and effort on it .
 
My first thoughts on reading your post was the diaphragms in the pump , but then I see that they are new .
My second thought is , have the diaphragms been installed correctly , if the big screw adjustment is not set back in the exact position it was in , you are going to have weird issuses , running rich may be one of them .
I dont know of anyway to reset it correct tension , but there are some very knowledgeable people , I am sure someone will come alone
 
Firstly, check that the cold start solenoid (and hence injector) is not energised continuously.

Spent many months trying to tune my Ti because the inj. pump had been molested by the previous owner. Eventually bought and installed a wideband oxygen sensor meter - and voila! Got it running beautifully the next day. (Mind you, had to get another used pump and matched barometric sensor).

This was the unit -

 
To rule out electro-valve problems: disconnect the 12v. (The car will start without it however not as quickly).

Are all the manifold hoses reconnected in their correct locations?

Was the main pump tension nut set in the same setting as before overhaul? (Should still run if reasonably close).

Was the main pump large diaphragm damaged during replacement? (Easy to over rotate and rip whilst rebuilding). That plug has been running very rich. Does the engine note at end of the exhaust sound like a car with a big cam in it?

Did the engine run well before overhaul?

My money is on the main diaphragm being damaged. Though I have been wrong before.

Hope I am wrong.

Good luck.
 
The symptoms remind me of another case of (very) rich running discussed on AF - in that case (I believe it was a Fuego belonging to jo proffi) the problem was that the fuel return line had been pinched/trapped, causing much higher pressure in the injection system than normal, leading to over-fueling.
 
It looks ruined and cant be fixed. You should immediately put it in a container and send it to me in Australia where I can safely dispose of it ;)
 
Air leaks will make the 504 KF unit overcompensate and run very rich

If the problem is the cold start injector flooding it you can get a repair kit from L'Aventure Francaise, possibly also from Der Franzose. It involves a bit of machining / fitting. Presume that you'd need a functiing cold start system in Norway :)

For advice closer to home it is worth trying Koller u. Schwemmer in Nürnberg, who are the official agents and only official repository of bits ( Bosch bought out KF years ago, K u. S are a Bosch subsidiary )

hermann.sattelberger@de.bosch.com. He is a nice bloke who knows them inside out and who will give good advice

Best Wishes

Andrew Watkins
 
Rally said:
My first thoughts on reading your post was the diaphragms in the pump , but then I see that they are new .
My second thought is , have the diaphragms been installed correctly , if the big screw adjustment is not set back in the exact position it was in , you are going to have weird issuses , running rich may be one of them .
I dont know of anyway to reset it correct tension , but there are some very knowledgeable people , I am sure someone will come alone
Click to expand...
Yes, it was marked before dismantling, and replaced the exact same way. I have also tried a different pump head, same result. Could be that both of these have been tampered with before my time, but i believe it sits where it should be.
 

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pugrambo said:
What speed does it idle at ?
Click to expand...
It varies, but the last time i was adjusting it, i got it running at about 1100 cold, and close to 900 when it reached 70-75`C. But as it gets hotter, it drops further and eventually stops, while at the same time im trying to raise it with the air bypass screw almost all the way out.
 
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con said:
Firstly, check that the cold start solenoid (and hence injector) is not energised continuously.

Spent many months trying to tune my Ti because the inj. pump had been molested by the previous owner. Eventually bought and installed a wideband oxygen sensor meter - and voila! Got it running beautifully the next day. (Mind you, had to get another used pump and matched barometric sensor).

This was the unit -

[/URL]
Click to expand...
Thanks. The solenoid (i refered to it as the electrovalve) has been tested and operates as it should. I could mention i have also tried a different barometric sensor (i know they come as a "pair"), and it actually got a tiny bit better with it.
 
BIGRR said:
To rule out electro-valve problems: disconnect the 12v. (The car will start without it however not as quickly).

Are all the manifold hoses reconnected in their correct locations?

Was the main pump tension nut set in the same setting as before overhaul? (Should still run if reasonably close).

Was the main pump large diaphragm damaged during replacement? (Easy to over rotate and rip whilst rebuilding). That plug has been running very rich. Does the engine note at end of the exhaust sound like a car with a big cam in it?

Did the engine run well before overhaul?

My money is on the main diaphragm being damaged. Though I have been wrong before.

Hope I am wrong.

Good luck.
Click to expand...
The electro-valve or solenoid have been tested, it works as it should.
All hoses are new and correctly connected.
Yes, it was marked prior to dismantling, and replaced the same way. But i cant say that it was correct before, as it did not run well before the overhaul either. Thats why i initially changed the diaphragms, even tho it turned out that the old ones were still intact. Have also tried a second pump-head, same result.
 

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you may have checked it but the thermo operated enrichening valve which sits at rear of pump at about 45degree angle and has shaft down to mixture control shaft should have an air gap of about 6mm when engine hot, when cold piston in valve moves up and lifts enrichener to rich mix for cold start. when mixture is correct and engine hot 4mm Allen key in mixture adjuster is lifted and engine revs will rise slightly then drop, if revs don't rise then mix is out, requiring 4mm grub screw turned in or out as required to lean or enriched. been about 30years since i have done one so may stand corrected. ...jim
 
when engine hot make sure valve shaft is fully out with approx 6mm gap, can adjust gap by holding 17mm outer(do not rotate this) loosening 10mmlocknut then rotate 17mm for adjustment, lock, 10mm.rotating 17mm nut while locked may damage thermal section of valve... .jim
 
dacia4x4 said:
you may have checked it but the thermo operated enrichening valve which sits at rear of pump at about 45degree angle and has shaft down to mixture control shaft should have an air gap of about 6mm when engine hot, when cold piston in valve moves up and lifts enrichener to rich mix for cold start. when mixture is correct and engine hot 4mm Allen key in mixture adjuster is lifted and engine revs will rise slightly then drop, if revs don't rise then mix is out, requiring 4mm grub screw turned in or out as required to lean or enriched. been about 30years since i have done one so may stand corrected. ...jim
Click to expand...
Yes, i have done the adjustments, i have the right gap when the engine temp is about 80`C. But i have never got the engine revs to rise while lifting the arm, except last time i tried, it rised +/- 200rpm, but that was with the air bypass screw almost all the way out, the co screw all the way out, so nothing left to adjust, and after a few minutes with temp increasing the engine revs decreased and it stopped. If i screw the co / mixture adjuster in, the revs dont rise when i lift the arm, and regardless, the plugs get sooted.
 
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