AEM Uego, but trouble!!!

[Chrismo]

Please help me with the following problem. I have an AEM Uego installed on my K11 1.3, and I'm not happy with the numbers! When I go WOT, the numbers should be around 12-13,5:1 (A/F). The strange thing is when I drive the 1, 2 or 3th gear and go WOT the AEM gives a reading between 12-14. This I think is ok, no problem. But now this: if I go to de 4th or 5th gear, WOT, At first the AEM keeps moving between 14-16, up and down. If I keep on WOT, in 4th or 5th gear, after a while the AEM gives the number 13,5-14.

What is wrong???? Is it the fuel-pump?

The following thing is what I did: I placed the AEM Uego as an extra safety for my engine. The standard lambda sensor was connected to the ECU. Now I got these weird numbers I thought my oem lambda sensor was bad, so I connected a new sensor fot this oem sensor........same problem! Now I connected the AEM on the ECU (The AEM has one setting to give the same signal as an original lambda sensor). Now it's a BIT better, but still not good!




Please help me with my problem, as in Holland no one can help me......only tell me the AEM is not working ok. The stupid thing is that in 1, 2 and 3th gear the AEM gives the good numbers when WOT.












gr Chrismo

Next to the fuel-pump I have a theorie the gasflow inside the exhaustpipe is to slow at low rpm's in the 4th and 5th gear.......but this is one thing I guess!





gr Chrismo

 

[jabran200]

Check for exhaust leaks pre lambda. They a/f at wot in most gears will be around 12.3-13:1 ( I think not 100%) around the top of the range.

Might be a small leak, Can you calibrate the AEM if so it may need calibrating. Try taking it to a place like dyno or rolling road to compare readings ideally.

 

[Chrismo]

You are right.....I need to take it on a dyno, but I was hoping there would be somebody having the same problem!







gr Chrismo

 

[jabran200]

To be honest very few people on here will have fitted a wideband to their cars.

You see the ecu goes to open loop after a certain condition are met and usually go as rich as 12-12.5 (Mine did this when I had my wideband) after about 4000rpm.

It could be you have some underlying condition causing your car to be lean??

 

[Ed]

There is nothing wrong with it. The OEM map of the K11 is closed loop through its entirety.

 

[Chrismo]

I get it, but the thing that makes no sence is (all Full Throttle) in the 1st 2nd and 3th gear I get numbers between 12-14, but in the 4th and 5th gear at first it turns between 14-16.
All this Full Throttle, and the same rpm's. The ECU can not see what gear I drive, so why this??



gr Chrismo

 

[Ed]

Full throttle you run in the acceleration part of the map. In 4-5 gear the acceleration is minor so it doesn't apply much fuel acceleration.

The ECU does not need to know gear, its only concerned by rate of acceleration, and also wheel speed has some affect.

This is one reason why I don't generally recommend wideband meters to people, as they can lead to believing there is a fault when in reality there is not.

 

[Chrismo]

Ok thanks man! Only if I go full throttle in 5th gear, as far as I know the a/f should be optimal, to avoid (as we call it in Holland) pingelen (self detonation). Because at this point the engine is giving it's full power.



gr Chrismo

 

[Ed]

K11s don't det unless fuel is VERY poor. Their compression ratio is too low, so you just get loss of power initially if ignition is too advanced.

AFR is more important due to combustion temps than det resistance and if you have to run overly rich to avoid det then thats just hiding other problems anyway.

Cheers,

Ed

 

[Chrismo]

Thanks again ;-)

Before I connected the AEM into the ECU, the original Lambda sensor was doing the job.The AEM was only for checking the A/F. When I was driving in 4th or 5th gear suddenly sometimes the power was GONE. I needed to shift back one gear and push the throttle to get power back. At this point (when feeling the loss of power) the AEM meter went OUT of it's reach, to the lean side. This problem even was here after testing the Lambda by using a NEW sensor (original lambda sensor)
This "power loss" problem was realy ####ty, but after connecting the AEM to the ECU this problem has been solved.......al least it's gone for about 1 month.

The MAIN reason I want to know all about this AEM issue, is that soon I put in another engine, rebuild with fastes cams an other pistons. And at that point I need to be 100% sure the a/f is ok.

Ed, one more question....in Holland there is another man I know with the same car as I have, same engine. He also has a wideband, no AEM, but Inovative. His readings are stationairy (low rpm, NO power) 12-13, and full throttle 13.5:1
I compare this with my AEM and it's totaly different. That is the main reason I don't have the idea my AEM is doing right OR my engine is not fine (fuel, ignition)



gr Chrismo

 

[Chrismo]

The only difference between our two cars is mine is from 2000, his from 1997. But I don't think there are any difference between the engine and it's ecu-control.





gr Chrismo

 

[Ed]

Yours is normal his is rich.

His lambda sensor may be defective.

Ed