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  #1  
Old 04-30-2019, 09:41 AM
paullap paullap is offline
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Default Ford ka fuel trim

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
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  #2  
Old 04-30-2019, 12:12 PM
phill57 phill57 is offline
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Default Fuel Trims

What happens if you try generic OBD2? Maybe that will help.
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  #3  
Old 04-30-2019, 12:21 PM
paullap paullap is offline
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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
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  #4  
Old 05-01-2019, 02:19 PM
Crusty Crusty is offline
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Default

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...)
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Old 05-02-2019, 10:50 PM
paullap paullap is offline
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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
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Old 05-03-2019, 03:50 AM
Crusty Crusty is offline
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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
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Old 05-06-2019, 11:29 AM
paullap paullap is offline
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Default 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?.
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  #8  
Old 05-07-2019, 05:53 AM
Witsend Witsend is offline
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Quote:
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
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  #9  
Old 05-08-2019, 12:03 AM
paullap paullap is offline
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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
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Old 05-10-2019, 11:01 PM
paullap paullap is offline
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Default 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
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