Ford ka fuel trim

[paullap]

Hi I need some help please, I am working on a ford ka 2009 1.2 petrol. I have some problems with the engine and want to look at the fuel trims but they are different from anything I have seen before. I can see Lamda intergration, is this where i should be looking ?, and what do I look for, all the cars I have worked on before where short term and long term plus and minus 25%. But this car I am lost. I have no fault codes, it feels like it is a misfire about 2000 rpm. I scoped one of the injectors today and the pulse width is jumping all over the place.
Any help would be much appreciated.


Paul

[phill57]

Fuel Trims

What happens if you try generic OBD2? Maybe that will help.

[paullap]

Hi I did try that yesterday, but I cant remember what the pids where, nothing stood out but I will have another look tomorrow.


Thanks

[Crusty]

Yes, Lambda is similar information to the Short term and Long term fuel trims.

I havn't read this article but here's a link.

http://www.austincc.edu/wkibbe/lambda.htm

--------------------

GM used to use a short term fuel trim called "integrator", and a long term fuel trim as "block learn".

128 was the no change value. If either indicated more than 128 (the half way point) the ECM was trying to add fuel. If either said less than 128 the ECM was trying to take fuel away (from the base programming)

Same thing as Short Term and Long Term fuel trim, just different semantics.
Same thing with "lambda" readings.

(with the older GM, the maximum value that could possibly be displayed was 255. Zero to 255 is 256 digits. The half way point which equaled no change in program adjustment was 128. 8-bits to a byte, 8 bytes to a baud. 256 is divisible by 8. The more things change, the more they stay the same...)

[paullap]

Thanks for the help, I need to spend some quiet time reading up on this.

Why cant they use the same easy long term short term trims.


Paul

[Crusty]

Lambda 100 = no change to fuel programmed strategy
Lambda 101 = ECM is compensating and adding fuel
Lambda 99 = ECM is compensating and lessening the fuel delivered

[paullap]

KA fuel trim

Hi I have these readings at 3000 RPM.

In the normal data pids for car
Lamda Integrator down stream is at 1.00 constant
Landa intergrator upstream min 0.91 / 1.23


In OBD
Short term - 70%
Long term _ -99.0%

Pre cat 02 sensor switching nice between 0.2 and 0.9v

In OBD it looks like it is taking shed loads of fuel away


Am I correct?.

[Witsend]

In OBD it looks like it is taking shed loads of fuel away


Am I correct?.

Yep, things I would check is FRP fuelrail pressure and leak down , Fuel leaking past the fuel rail pulse damper diaphragm into the vacuum hose at the damper or FRP sensor. check the MAP Pressure sensor reading KOEO, check the BARO reading in HZ if it agrees with what it should be at your altitude , Clean the MAF sensor, check the air filter condition and air cleaner box for restrictions. Just basic checks

[paullap]

Hi Map and baro match so that is ok. changed the map from a good running car. I am struggling checking the fuel pressure as the fuel pressure kit I have does not have the correct connection for this car, It has a schrader valve thread on the inside of the valve and a air line type of connection on the outside. Would it be ok if I send you the snap on file of pid readings for you to have a look at for me please To see if anything jumps out. I will not give up on this car until I find the problem I am not in a rush to get an answer as I am way tomorrow until Tuesday night. you would have pm me your email address. I completely understand if you would rather not.

Regards


Paul

[paullap]

update

This Ka is still baffling me, I havent managed to test the fuel pressure yet as I dont have a fitting to get on the schrader valve on the pressure rail, I have just ordered a new fuel pressure testing kit, it has a shed load of fittings so I am hoping it has the correct one, It would help if I knew what was actually happening with this car.at 2000 and 3000 rpm it sits and splutters in the inlet manifold. The pids to me show the ECU is taking a lot of fuel way, overfueling big time, but the o2 sensor is still switching normal , even at 2000/3000 revs when the car is running like ****, the car will accelerate ok , and it is also definitely better when cold, probably in open loop.the other thing I noticed if i open the throttle up to about 2000 RPM and hold it the revs will drop right down without moving the pedal. this is what I have done so far.

compression tested 250 PSI on all 4 cylinders
scoped the crank sensor
scope the cam sensor
scope the throttle position sensor
scoped the throttle pedal sensor.
scope the secondary ignition ( does not look good) I cant send you the whole waveform as it is to big.
scoped the injectors, the pulse width is jumping all over the place, i would have expected this to increase as more fuel is demanded but it is jumping erratically.
changed the plugs ( they look a light brown when I took them out) that to me is normal.

I think that is about it.

I have the latest pid recording if anyone has the time to have a look for me, Just pm me an email address and I will send it.

Paul

[Cliffy]

Hi Paul,

I had the fuel trims on one of these give me the run around, mine would log a P0300 dtc when the trims hit +100%. Are you getting any dtc's?

This was with both O2 sensors operating as expected and 4 gas figures correct. ( this is when I stopped believing the trim pids )

A few questions, what brand spark plugs have you fitted?

Is the coil pack a genuine part?

What Map reading are you getting ?

Do you have a WPS500 or similar to carry out a cylinder pressure test on your scope?

Have you had a vacuum gauge on the engine?

[Witsend]

Does it have Exhaust Gas Re-circulation valve and Differential Pressure Feed Exhaust Gas Sensor with the 2 hoses you might be able to hook a vacuum pressure gauge to downstream hose briefly before heat damage it and see what the exhaust back pressure actually reads when you get it up to 3000rpm?
A lot of fords with returnless fuel systems you can see your fuel rail pressure from the FRP pid.
I am not sure an older Verus with XP supports the Team Viewer or remote diagnosis program , but I'm thinking if it did , you might be able to have someone remote in and see what's going on live and talk via Skype. Seen some guys remote in on my Maxi Cyst when it was messed up and any Joe Smoe can do it that knows what he's doing. But can you trust any Joe Smoe in your tool?

[paullap]

KA

Thanks for taking the time to help me, I wish there was a way I could post the pid list so you could see my results, I can email screen shots but it would be good if you could scroll through the pids.

A couple of things dont look correct.

At start up the ECU voltage drops to 8 volts for a short while and then returns to 12 volts.

at idle of 700 RPM the throttle position on the pid is showing 0 deg ?


I have done a pico sweep test on the throttle and looked fine

if I start the car and take the engine speed to about 2000 RPM the RPM will drop considerably without moving the pedal?.

The problem is worse as it warms up.

The strange thing with all this, it is not a happy engine but will not throw any codes.


Regards


Paul

[paullap]

Ka

Hi Cliffy, Thanks for the help mate.

I have tried the plugs from a good running car ( no difference )


Coil pack is genuine and I tried one from the good running car and leads (no difference)

Map reading 1017m/bar stationary and about 220 m/bar between 2000/3000 RPM
I did put a vacuum gauge on the engine, I used the small pipe that goes back to the top of the air filter, It seems a bit slow but it goes up to about 19", but at wide open throttle no change, and I thought it should go to Zero?. May be I should try to get the vacuum source from somewhere else.

I do have a WPS with my Pico, I am new to this pico so you have to take what I find with caution, all the cylinders looked ok at idle, Not sure when I increase the revs, I need to look in to a bit further, But manually check the compression I had 250 PSi on all 4 cylinders. on the pico it is showing about 4.8 bar at idle, That is if I have it on the correct setting. If I knew how to I would post all these tests, but that is a bit beyond my capability i am afraid.

I think that is enough information for now .


I will get to the bottom of this car if it is the last thing I do. It is only a small stupid engine.

Thanks for the help

[paullap]

secondary ignition expert please

Still on this KA, I need a secondary ignition expert to have a look at my secondary ignition waveforms. should the spark line change dramatically when RPM is increased?. mine is allover the place, nothing looks consistent. i am going to try to post some images.


Paul