Jump to content

Recommended Posts

Dear Tr6 experts,


Recently the engine of my PI is cp “dieseling.” when I swich off the car.
The car runs fine and nothing has changed recently.
The wrong ignition may be due to carbon residues, but where does the petrol come from when the Bosch pump is switched off.
At the moment I put the gear in 4 th and let the clutch slowly come in  to stop the engine. 

Please advice where to look to cure this problem

Thanks and Greetings from Ben

Edited by Bendirk
Link to post
Share on other sites

Alan,

Indeed, I assumed the pump is off . The feed to the relay of the pump is coming from  same source as the feed to the ignition.

But perhaps the relay is sometimes “ sticky.“

I will do some checking

 

Thanks 

Ben

Link to post
Share on other sites

Hi Ben,

I would also check if the ignition remains energized (with a voltmeter connected to the coil feed) at the moment of switching off.

Groetjes,
Waldi

Link to post
Share on other sites

I have had a similar issue when the electric fan continues to run after stopping and switching the ignition off.

Paul

Link to post
Share on other sites
47 minutes ago, Paul J said:

I have had a similar issue when the electric fan continues to run after stopping and switching the ignition off.

Paul

We have discussed this before I believe, fan generates enough current to ignite any unburnt fuel

Stuart.

Link to post
Share on other sites

I measured some things.

When  I turn off the key I immediately measure 0 (zero) volts on the ignition coil
the spark plugs therefore cannot spark.
No illegal current from the fan and wiper motor.

Fuel pump

also stops. Relay is burned in, it may stick sometimes.
Now testing  with a new one.
Thanks for the tips the story continues
Ben

Link to post
Share on other sites

Hi Ben,

You could try to push your gas pedal a bit when stopping the engine. This will lean the mixture.
Using petrol with a higher octane will also help.
Waldi

Link to post
Share on other sites

Hi,

 Two separate posts way above sound like alternator powering an additional ignition power relay. A diode bPut an end to that nuisance.

Sounds like running on as something is still igniting fuel.

Edited by SpitFireSIX
text
Link to post
Share on other sites

Hi Ben,

Can I suggest you have a look at the plug fouling topic that is currently going? I certainly learned from that (but do not have any issues at the moment.

Cheers,

Waldi

Link to post
Share on other sites

Hi,

it's me, the guy with the stupid questions and different opinion.

Sorry me for asking myself  (and you) something about a 6 PI without knowing anything about this engine.

"Dieseling" is a not controlled ignition? This is the case with the ignition switched off?

Yes.

But the still running fan produces voltage to suply the ignition?

Yes.

Then, with the ignition still suplied with voltage, and still working - why is there a NOT controlled ignition?

Ciao, Marco

 

 

 

Edited by Z320
Link to post
Share on other sites

Not a stupid question Marco.
let’s wait for the answer, from people who know. my car has an electric fan, but it stops immediately after switching off.

Guess the wiring diagram around the ignition barrel provides the answer.

Waldi

Link to post
Share on other sites

If the cooling fan is wired through the ignition switch, when the ignition is switched off when the fan is running, the momentum of the fan blades will keep the fan motor turning for a few seconds.

During this short period of time, the fan motor can act as a dynamo, providing current to the ignition circuit. This may be enough to produce sparks and keep the engine running.

However, the fan should quickly stop, then the current stops and with no more sparks, the engine should stop. I can't see how the cooling fan could supply enough current to run the ignition for more than a few seconds.

Wiring the fan via a relay is recommended, to reduce the load on the ignition switch. Wiring via a relay should also prevent the turning off the fan from energizing the ignition circuit.

Others with more electrical expertise will be able add to my basic explanation.

Nigel

Link to post
Share on other sites
4 hours ago, Z320 said:

Hi,

it's me, the guy with the stupid questions and different opinion.

Sorry me for asking myself  (and you) something about a 6 PI without knowing anything about this engine.

"Dieseling" is a not controlled ignition? This is the case with the ignition switched off?

Yes.

But the still running fan produces voltage to suply the ignition?

Yes.

Then, with the ignition still suplied with voltage, and still working - why is there a NOT controlled ignition?

Ciao, Marco

 

 

 

Hi,

If no additional relays have been added to the ignition circuit, a decelerating cooling fan can not supply the energy to fire the plugs.

So, I do not believe what you describe is possible.
Yes I have heard this myth before.

Link to post
Share on other sites
4 hours ago, Z320 said:

Hi,

it's me, the guy with the stupid questions and different opinion.

Sorry me for asking myself  (and you) something about a 6 PI without knowing anything about this engine.

"Dieseling" is a not controlled ignition? This is the case with the ignition switched off?

Yes.

But the still running fan produces voltage to suply the ignition?

Yes.

Then, with the ignition still suplied with voltage, and still working - why is there a NOT controlled ignition?

Ciao, Marco

I agree Marco. If the ignition system is supplied with a current, from whatever source, it still controls the engine firing. The engine running should be as normal. There should be no uncontrolled diesel "knock" as happens with preignition.

 

 

 

Link to post
Share on other sites

Why switch off the ignition on a PI?

There is no reservoir like the float chambers on carburetors?

I would test to switch off the fuel pump WITH the ignition ON.

This way I expect a controlled ignition until the engine stops because of no fuel.

BUT - as I told before - I know nothing about the PI, you PI guys  have to find out.

Wishing you much success 

Edited by Z320
Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Restore formatting

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Loading...
×
×
  • Create New...

Important Information

Please familiarise yourself with our Terms and Conditions. By using this site, you agree to the following: Terms of Use.