Fuel filter and slow running for 2 L dohc

[andrewjo]

Two things, I was going to replace the pre-pump filter in the Cabrio.
However the current filter has different inlet and exit pipe diameter.
Eurospares has something for huge cost any advice please for a new filter?

Also when warm the tick over is very irregular going from 800 rpm to almost stalling and back again until it,does stall!
Doesn't happen all the time, possibly on restarting the engine while still warm seems to provoke this wayward activity.
Any thoughts gratefully received.
Many thanks

[Harry]

Re: Fuel filter and slow running for 2 L dohc

Evening, on the subject of you're tick over problem, especially once the engine is warm, it could be you're ignition module starting to break down ( If you have electronic ignition fitted ) I've replaced a few that caused very similar problems, otherwise check the carbs over ?

[philcoyle]

Re: Fuel filter and slow running for 2 L dohc

You could try and reset your Throttle Position Sensor.
1. Turn ignition on, do not start engine.
2.Press throttle pedal up and down fully, about 10 times.
3. Switch off.
4. Wait a minute, now start engine.

Some times it works, if it doesn't you will have to look for other causes.
Phil

[andrewjo]

Re: Fuel filter and slow running for 2 L dohc

Hello and thanks to you both for your thoughts.
I should have mentioned that it is an EFI, thus has , as far as I understand, an electronic ignition system so the thought that it is the electronic ignition being faulty seems very relevant.
I have tried that throttle position therapy but sadly I did some speed reading and didn't notice you had to turn off the ignition I.e. Stage 3
This I will try next .........
Thanks again
Andrew

[philcoyle]

Re: Fuel filter and slow running for 2 L dohc

When you press the pedal up and down, try to do it quickly but make sure they are complete stokes, fully down and fully up.
But my guess is a future fuel pump failure.
Phil

[chris_cussen]

Re: Fuel filter and slow running for 2 L dohc

The ECU controls the tickover on an EFI engine by the Idle Control Valve. On the original Sierra it is located on the air filter assembly. It has 2 wires going to it and a 1/2 inch pipe connecting it to the inlet manifold. If it becomes defective or there is an air leak the tickover will become erratic. New ones can be got from Ebay for £20 to £30.

[andrewjo]

Re: Fuel filter and slow running for 2 L dohc

Thanks for the new info.
The idle control valve was replaced a year ago, however an air leak somewhere has been suspected and now you have given me a clue where to look.
Thanks both
Andrew

[Motormouse_67]

Re: Fuel filter and slow running for 2 L dohc

I would agree idle speed control valve or air leak the most probable cause.

[ggrum]

Re: Fuel filter and slow running for 2 L dohc

My 2 litre EFI would tick over fine when cold but increase when warm and become erratic. It also had a bit of a flat spot at lower revs. I suspected the idle control valve, took it off and cleaned it but no difference. I then replaced it and still no improvement. I then replaced the throttle position sensor and both problems disappeared. After checking for any air leaks might be worth thinking about.

[philcoyle]

Re: Fuel filter and slow running for 2 L dohc

This is an old post I have dug out it might give a bit more insight if you get out the Multimeter. You can "teach" the ECU to recognise the throttle position sensor settings,

Switch on ignition, do not start engine,
Press throttle pedal to the max and release at least 10 times quite quickly,
Turn off ignition, leave it for a few minutes, and then start engine.
This gives the ECU the values/voltage for idle and full throttle settings, and should reset itself accordingly.
Hope this helps.
For EEC-IV ecu voltage from ecu 5 volts. On EEC-111 it is 9 volts. ECU has three wires, 1. Supply voltage (depending on ecu).2 earth return, 3. REF signal return to ecu. Time to get out the multimeter!
The signal return wire should read for EEC-IV,
Closed throttle should be 0.5/0.6volts.v
Full throttle about 4.5/4.75volts, anything reading 5 volts or 0 volts TPS is faulty.

Ideally you will have about 12% of the voltage at tickover and 90% at full thottle.
Not all TPS are adjustable it depends on vehicle age ECU.

Ooops sorry forgot to mention EEC-111 readings 1.4v to 1.8v on tickover and 8.5v at full throttle. 9v or 0v faulty TPS. All readings taken on the Reference signal return wire.

[andrewjo]

Re: Fuel filter and slow running for 2 L dohc

Thank you all and thanks for sending the previous post Phil, I was about to look for it so saved me the trouble!
This will keep me busy for the next week.
Kind regards to all
Andrew