Fail 44 Where is the mistake

Hallo

After a short period of time and the engine speed drops when the vehicle is stationary, the engine control lamp comes on and when it is switched on again, fuel Fail 44 is in the speedometer

then I cleaned the butterfly, air flow meter and idle regulator. since then the idle speed has increased to 1200-1500rpm. Accelerating power is there.

Throttle valve butterfly on closed 0.55v (less does not work) ans adjust in 0.05mm

oxygen sensor: heater 5ohm voltage has 12v. measuring line in idle (warm)
while driving it goes down further and further until it reaches 0.1volt. it doesn’t commute either … but sinks more and more

the fuel pressure is at 2.8bar while accelerating it increases to 3.2bar. after switching off the pressure is kept at 2.8bar. Fuel pump and pressure is OK . injectors were expanded. are dense and atomize cleanly on two jets.

The engine control light comes on relatively early and is noticeable with a brief drop in engine speed when the vehicle is stationary or when moving off.
it drops to about 500 rpm on D.
the approach is then very delayed.
does not accept gas for a short time and then drives off at once.
then the engine control lamp comes on

then wanted to set the idle. but that is not possible because the regulating screw is already turned all the way in.

Speed ​​is at 1400-1500 rpm every now and then it fluctuates.

Air flow meter arrives 12v. between Pin1 and Pin 6 there is a resistance of 650ohm.

if I unplug the air flow meter, the error 44 remains and no new one is added.

so far everything has been dismantled … there is no air leakage to be found. either it is really the Oxysensor because it does not swing a curve but shows steadily decreasing milli volts (which I almost don’t think they actually never break) or the air flow meter because it does not show 1000 ohms as described in the literature …?

I bought the vehicle second-hand, because the speed was sometimes too low, I cleaned the butterfly, air flow meter and idle regulator. since then I have Fail 44

I’m slowly getting stuck.

the vehicle is from 03/1990 is a 4.0. why does he have no AIR / EGR system?

I hope WE find the bug, thanks for all the tips in advance.

Stojan …

Let’s troubleshoot the o2 sensor.

On a 3 wire sensor there is a single signal wire and two wires for the heater. The sensor is grounded via the body being screwed into the exhaust.

On a 4 wire sensor the fourth wire is used for a ground instead of the sensor body.

Pull back the rubber boot at the signal wire connector and check the voltage by putting one lead of a multimeter on the connector (do not disconnect it) and the other lead to ground. Do this with the car warmed up and running. The voltage should rapidly oscillate between 0 and 1 volt. Ideally it should average around .5 to .6v. If it’s closer to 0v the car is running too lean or if it’s 1v it’s too rich.

The ECU receives this information and adjusts the fuel injection pulses accordingly.

The car should idle around 650 rpm.

If the insulation sleeve is missing from the O2 sensor where the wires run into it, it could trigger the FF44 code.

Yep I’d be going for the o2 sensor, should definately be getting a swing in voltage once the engine is warm.

Joe …

Well-l-l I’m not sure I completely agree with that. As I understand the way the system works it’s the ground wire that shields the signal wire and prevents false readings. The insulating sleeve protects the wiring from overheating and actually melting (which of course would then cause major havoc :grinning:)

Hello

and thanks for all the answers !!!

So the Oxygen Sensor:
it is a 3 wire sensor,
the heating works and has 5ohm,
12volt also arrive.

on one sensor cable I have about 0.7v when cold, the warmer it gets, the lower the voltage, it goes down to 0.1v. but the tension does not vibrate/oscillate ,
whether cold or warm.

greetingss-l400

Dennis, years ago I wasn’t able to remove the o2 sensor so a mechanic did it and of course they didn’t reuse the sleeve. After that I kept getting the FF44 code. I made my own insulating sleeve and the code never popped up again.

can it also be the stepper motor / idle controller? if it is always open or too wide?

You’re talking about the idle speed control valve. According to my Haynes manual, it would trigger FF46, FF47, FF48 code(s).

Joe …

Well you can’t argue with success and I’m glad that worked for you. What material did you use for the sleeve?

Dennis, I used a metal tape and stuck some small foam pieces to it then rolled it around the sensor.

in the German forum that would be recommended to me. when cleaning I pushed it back by hand … could it be broken?

The idle control valve sits on top of the inlet manifold between cyl. 3-4. I don’t know how you can push in the pin by hand. You shouldn’t be able.

some strength was needed … but it worked. I’ll unplug it … then FF 46,47,48 would have to come …?

Luckily the same motor is fitted to several cars so it is easy and cheap to replace.
Most common replacement part is for a Renault Megane. I have one in my own car.
https://www.ebay.com/itm/Stepper-Motor-Idle-Air-Control-Valve-For-Renault-Megane-Scenic-1-6l-8V/301723962102?hash=item4640264af6:g:hT8AAOSwTapV3h85

Fixed the link - this one is in Lithuania so shipping should be cheap too

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funny, just looking for one, priceless at Jaguar, now one comes from France to the English … I can’t tell anyone. thank you very much

Hello.

yesterday had a little test with a multimeter on the oxygen sensor.

In the cold state, the sensor brings 0.4v,
which it has about 2 minutes until it is warm.

warm it then falls to 0.25v. and then slowly goes up to 0.1v.

but everything is constant and not swinging as usual for Oxygen Sensor

Stojan …

Here’s some good information on the operation of an o2 sensor …

I think the probe is defective.

Reference voltage of 0.4v is still ok when cold

but it should give a sine (commuting) signal when it is warm. that’s not the case with me. ,

the value is fixed for me

Update:
an inexpensive idle regulator for the Renault was installed today.
the head piece or valve cone did not fit, it was too small, but could be converted from the original without any problems.

Idle actuator works, idle is more stable.
however, the engine control lamp comes on after about 2-5 minutes if the engine is a little warm.
Fail Fuel 44.
oxygen sensor is stable at 0.17v and does not oscillate.

is it both defective ???

tomorrow comes the new oxygen sensor.

But what I also noticed is that the engine or the chain rattles when cold … that stops after about 5 minutes in the state and a few throttles.
Chain too long?
Oil too old?
or the chain tensioner?

can man somehow check the tensioner on the fast? Tips ???