300-24, spark plugs fouling with soot

[Drift202]

Hi, more issues with my trusy old wagon...bit of a story this, so please for anyone that can be bothered to read, bear with me. My car has been messed aorund with.it is a drift car that is used on track aswell as my daily. recently i have been trying to resolve some of the issues that have been caused from drifting. Quite a big part of this was replacing the existing fuel tank with a plastic race spec 12 us gallon sumped, foam filled fuel cell. The car has been a work in progress so has had the interior out of it a while now, and as i wanted to get to a drift day last minute, i strapped the new tank in the back pretty much above where the original was, connected the main fuel pump directly at the outlet and ran 8mm braided fuel line through the car ,same with the return. i did initially have some warm restart issues when i first did it,but strangely enough that was resolved by reconnecting the temperature sender for the guage. The car, like this has been working fine, faster than ever with no leather.starts, revs well to 7k, generally back to its awesome self. My issue was, i really wanted to put the trim back in. Its all been cleaned whilst out and has come up like new, its a sportline with mushroom leather, orthapedic drivers seat etc.I wasnt happy to do this with the fuel lines in the car and really didnt want a plastic fuel tank sat up behind the rear seat. I sent it to a garage owned by a friend that specialises in drift cars, but he does some good welding so i got him to cut a hole in the floor and weld a box in place for the tank to sit down in, ideally low enough so i can still put the floor panel back in and just refill the tank by lifting the rear panel. and run the fuel lines in the recess where the original ones where, but rivet a plate over to protect them. i was called on friday to collect the car as it was all done, and the work he has done was of a very good quality. only problem is the car doesnt run right now, so he still has it. his shop is about 40 miles away from me and mostly motorway. i cruised at 70, took it up to quite a bit over 70 aswell and it just felt fast. so i am not happy to take the car away now not working properly. i cant see anythiing wrong with anything he has done. So today i got some news, he tells me that he pulled the plugs out and they are black and sooty and fouled, he said he cleaned them up and tried the car and intially it was ok and pretty much staright away started to mess about and he pulled the plugs and they were the same again? the plugs are very new, fitted i think the day before the car went to him, and he is saying that they must be the wrong plugs, something to do with them being a higher resistance so a very weak spark? the plugs i fiitted are bosch r6 fr8dc, i got these from euro car parts, i gave them the bosch number the sticker on the car says, which is bosch f8dco. they said this is the modern equivilant? Anyway, if anyone is still with me after all that, any thoughts would be great, i am quite concerned why this has happened, and really hope its the plugs
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[grober]

Assuming your car is running KE-JETRONIC your warm restart issues may be because you removed the fuel Accumulator which is a spring loaded device to main system pressure for a time to assist restarts. The KE jetronic also modifies the mixture via the electrohydraulic pressure regulator controlled form the ECU-If the engine coolant sensor was disconnected the ecu may have thought the engine was cold and richened the mixture It sounds as if your engine is still running rich though. I suggest that by changing the position of the tank and altering the fuel lines [ is there still an inline filter?] you may have increased the supply pressure which is controlled by the main primary pressure regulator [ adjustable by a thread sleeve inside the outlet ] this produces what is known as the control pressure for the injection system. If this was too high the engine would run rich. You need to check the supply pressure with a gauge to see if its within limits. ---- that's my guess.

 

[carat 3.6]

You should be running non resister spark plugs, fit a set and report back.

 

[Drift202]

are the plugs i said i fitted resister plugs?

 

[carat 3.6]

are the plugs i said i fitted resister plugs?

Yes.

Try NGK BCP5ES or Bosch F8DC4.

 

[Drift202]

Yes.

Try NGK BCP5ES or Bosch F8DC4.

thanks, i will order some first thing in the morning. would this cause them to burn out so fast ,they are completly covered in like a charcoal?

 

[ray_hennig]

thanks, i will order some first thing in the morning. would this cause them to burn out so fast ,they are completly covered in like a charcoal?

I agree 100% with the non-resistor recommendation but I fear that resistance alone wont foul them up as you describe. I got misfires with r plugs but no such fouling.

I think there's something else.

Have you verified 50% duty cycle on fuel delivery. This is a must.

RayH

 

[Bellow]

would this cause them to burn out so fast ,they are completly covered in like a charcoal?

They aren't burning out - the opposite, they are running far too cool.
Rich mixtures are the cause of sooted plugs and as the fuel system has been modified you have to suspect the fault lies there. No point pursuing that without the correct plugs though - you'll only be chasing your own tail.

 

[Drift202]

well, i gave him a set of non resistor ngk plugs, and was expecting my car back today. he tells me that now only the rear three plugs are sooting up? i have to be honest i have lost confidence ,so think i will be going with my truck to collect my baby later no matter what. I am more than a little concerned over the state i am in now, bearing in mind it worked perfectly when i dropped it off, and had been fine, even with resistor plugs in it

 

[Drift202]

i have just been doing some reading, and it would seem if the fuel pressure is low, the piston doesnt open and it runs very rich? low fuel pressure, would make sense being whats beeen done to the car

 

[Bellow]

I have the Bosch KE Jetronic Technical Manual. It is a 42 page PDF - too large a file to attach here. If you think it could be of use, PM me an e-mail address and I'll forward it.

 

[carat 3.6]

Just so I'm clear on what you've done.

You've removed the underfloor tank and fitted a fuel cell in the rear of the car. Your still using both fuel pumps, fuel filter, and accumulator from the original setup. Car now runs rich.

Replaced plugs to correct non resistor copper core items, car now only runs rich on 3 cylinders but fine on the other 3.

If this was a fuel system problem I would expect it to run rich on all cylinders, so I think you have an ignition problem. If you've only swapped the tank for a fuel cell but kept the pumps, filter ect, it should not affect the system.

I would check the cap, rotor arm and ht leads next.

 

[grober]

I have the Bosch KE Jetronic Technical Manual. It is a 42 page PDF - too large a file to attach here. If you think it could be of use, PM me an e-mail address and I'll forward it.

http://www.berlinasportivo.com/Technical/lancia/Thema832/Bosch-KE-Jetronic-OCR.pdf

 

[grober]

Primary pressure should be around 5.3-5.5 bar if memory serves correct but don't take it as gospel?

 

[Drift202]

ok,i have taken the car back today.I have fitted a new distributer cap as it was suggested the old one was a problem, it hasnt made any difference. basically what seems to happen is, if you start with clean plugs it runs fine and revs up ok, but there is a lot of black smoke and as she sits ticking over the idle gets worse to the point it doesnt want to run at all as the plugs are fouled again, takes like a minute and a half lol. so it seems to me the car works ok except for that it is running extremely rich, what reasons can make a k jet run so rich all of a sudden?.

as far as whats on there, it is only the lift pump and the main pump, no filter,no accumulator.when i dropped it to him and it was working fine, it only had the main pump ,nothing else.

 

[Drift202]

he did also remove the cat and then put it back in as he thought it was the issue? what i am thinking, could it be the o2 sensor?

 

[Bellow]

No reason I can think of not to reinstate the accumulator - just in case its absence is having an effect. It may well be needed come summer.
Could be O2 sensor at fault - or given how suddenly this problem has arrived, the electrical connection to it.

 

[Drift202]

it is running rich on all cylinders, i am not sure the imformation i was getting back was that reliable

 

[Bellow]

Dirt in the fuel system after it being opened up interfering with the metering? Pressure regulator stuck open?

 

[grober]

You really need to check the primary pressure setting to eliminate it as the cause. If the plugs are fouling up after a mere couple of minutes something major is wrong with the fuelling. This is not the injection adjustment being "slightly out" . If there's that much fuel getting into the engine you also run the risk of diluting the oil.