ABY injectors on 3b

[Erikb]

Hi all,

Last week I fitted aby injectors on my standard 3b engine. Because the car really was hard to start when it had cooled down for an hour, so I thought that my injectors where leaking.3b injectors where hard to find and someone offered me aby injectors. most people agreed that there was a minimum difference in flow. But is this really true is the FPR the same on a aby and a 3b ?. The fuel consumption has even got higher, the starting problem is still there, but the car runs more silence and smoother in high revs .

thanks,

Erik

[Mihnea]

Erik, take them off ASAP if you like your engine and your valves. The 3B injectors flow 320cc/min at 3 Bar, the ABY ones flow 320cc/min at 4 Bar rail pressure, or about 280cc/min at 3 Bar (3B rail pressure).

Your engine is running lean now, this is why it seems smoother at higher revs.

I have personally barely ever seen injector problems on Audi S2s. Fuel pumps, fuel filters, MAFs, old spark plugs, bad gas, etc etc etc, but no injector problems...

Hope this helps,

Mihnea

[Erikb]

ok thanks Mihnea I will get them off as soon as possible.

But how is it possible to it uses more fuel with these injectors?

[Tommy200rs]

Test results at bosch center flow bench:
@3bar the 3B and ABY/AAN injectors produce same amount of fuel. ADU injectors produce 20% more flow at 3bar than 3B or ABy or AAN. There is something else wrong in your car. Remember also that old injectors may glog up and then cleaning is needed. If badly clogged you melt something in that cylinder...

General hint. do not try to overcome problems just pressing the pedal to floor and wondering that something wrong but where. thats the easiest way to broke the engine.

[Mihnea]

Tommy, this is wrong, I've had 3B, AAN/ABY, ADU and 440cc injectors on an injector flow bench and the results at 3, 4 and 5 Bar were:

ABY
3B
ADU
Delphi 440cc/min

At 4 Bar, the ABY/AAN flowed the same as 3Bs at 3 Bar.

HTH,

Mihnea


PS: your package is on its way

[Tommy200rs]

Hard to belive the flow results, because my measurement guru is very good. Results are on paper also. We have also tested the same in 3B car with 3B and ABY injecctors.

Thanks for the parcel delivery. I would like to have a long phone discussion about the XXX -map load vectors and scaling of them. It still bothers me. RPM vectors are not problem.

[Erikb]

Monday I will drive to a company nearby, This company will test and clean my 3b injectors (ultrasoon cleaning) . So I hope to have the aby injectors replaced on tuesday.

Someone looking for aby injectors?

[Erikb]

But I still dont understand why the car using even more fuel. Normally it was 12,5l on 100 km, yet it is 13,2 on 100km.

[Mihnea]

Hard to belive the flow results, because my measurement guru is very good. Results are on paper also. We have also tested the same in 3B car with 3B and ABY injecctors.

Thanks for the parcel delivery. I would like to have a long phone discussion about the XXX -map load vectors and scaling of them. It still bothers me. RPM vectors are not problem.

Tommy: I have seen the same flow information as mine before, and I do believe the numbers I've seen myself on the injectors flow bench at the Bosch Service center I've had them tested at...

About the map vectors stuff: you know who has already explained how it all worked to you, and so have I too. There is nothing more than that. The point is that if you have no real-time equipment, you'd better not mess with all that, otherwise you can run into some bad surprises. Changing one value affects all the others. I can't tell you more unfortunately, wether it's here or by phone. All I know doesn't come from internet forums and it's cost me money to get where I am now. Stupid money if you want to know. All other things are just based on experience, which can't be replaced by a phone call.


Mihnea

[Mihnea]

Erik,

The ECU doesn't know the injector size is different, so the fuel consumption dash display is messed up.

Plus, if you're using smaller injectors, your car is going to run leaner. Approximately 16% leaner. 16% leaner means less power. With less power available, you have to press the throttle more to get the same acceleration as before, thus you use more fuel.

I've BTDT in my early tuning days when I thought running an engine at 16:1 AFR at part throttle would result in better fuel consumption... which turned out not to be true...

HTH,

Mihnea

But I still dont understand why the car using even more fuel. Normally it was 12,5l on 100 km, yet it is 13,2 on 100km.

[Erikb]

Thanks Mihnea I understand !!

The only thing I found strange is that I had another response when i floored it. Sometimes at it frooze for a second you could feel it hold back, and then it went,this was mostly around 3000 revs.

[newsh]

Absolutely agree with this, you can use loads of fuel when a motor is running lean, as Mihnea says, you have to floor it to get any power.

[Tommy200rs]

Check the manufacturing date of your current lambda-sond and vacuum leaks. If sond is original then it is far too old to regulate the fuel on low and mid loads. Old sensor makes the consumtion to increase in mixed driving style. Erik, what sw are you using ?

[audiman]

lambda sensors can work for a very long time in my experience, my car still uses the original one that has now covered 160k miles! But they can give part throttle running problems, even if they appear to working correctly. For the cost of the sensor, i guess it would be a good idea to swap it out. No harm in trying it.

[Billman]

@offtopic
What lambda should b eused and how much does it costs?

Greetings