HEEEELPPPP AFR at idle 19.6 !!!!!!

[RO_SUNNY]

Hi everybody.

Taking inot the consideration that I am the only one with an GTIR in my country and there's no one here capable of answering my question here I go asking through the forums.

After I had the problems with the previous setup where my engine overfuelled badly and there was no solution for that I took the way of making the engine standard.

Reviewal of the current setup:
-standard injectors
-standard ecu
-standard afm
-standard fuel pressure regulator
-front mount intercooler
-gt3071r turbo (I thought that it doesn't make any sense changing it)
-cold air intake (Apex'i)
-innovate LC1 wideband (the standard narrow band was replaced by the wide band sensor)
-Apex'i engine multi checker (this is the gadget where I saw the AFR readings)

So...I have put back the 444 cc injectors, standard AFM and the standard ECU.
Now the engine starts but at idle with a warm engine my AFR is oscilating from 19.4 to 19.6 but the exhaust gases smell really bad like fuel.
When I revved it a little (just until approx 4500 rpm)there was some black smoke coming out the tail pipes...not much but it was.
I have tested the car for a little while and on load, 2'nd gear, 4500 rpm the AFR was going down but just a little bit ( arounf 16 or so).

What can cause the problems which I have now?

During the re build of the car I put some rugs into the intercooler pipes, intake manifold, etc.....but I double checked that they were taken out before the engine start.

 

[Trip]

Are you feeding the ECU with a simulated narrow band signal off the innovate ?

Are you reading the AFR's from the innovate or the Apexi engine multi checker ?

Does your car idle fine 900rpm ?

I do not suggest giving it load with that turbo and everything else standard, even at standard boost. GT3071 will blow more volume (of air) at a given boost pressure. Adjust it to minimal boost for now and do not WOT

 

[Jon Olds]

Am I missing something? 19:1 is weak isn't it?

 

[pulsarboby]

yes its running lean at idle.
maybe a vacuum leak somewhere.
not really gonna cause a prob though at idle as long as she starts to richen up under load and on boost

 

[RO_SUNNY]

Are you feeding the ECU with a simulated narrow band signal off the innovate ?

No I don't think so....because I don't know how to do that.

Are you reading the AFR's from the innovate or the Apexi engine multi checker ?

I am reading the AFR's from the Apex'i multi checker display

Does your car idle fine 900rpm ?

Yes the idle is almost perfect is oscilating between 940 and 955 rpm.

I do not suggest giving it load with that turbo and everything else standard, even at standard boost. GT3071 will blow more volume (of air) at a given boost pressure. Adjust it to minimal boost for now and do not WOT

I just did a small running test for about 400 meters and only in 2'nd gear and at 5000 rpm.....I really hope that I didn't broke something.

......................

 

[RO_SUNNY]

yes its running lean at idle.
maybe a vacuum leak somewhere.
not really gonna cause a prob though at idle as long as she starts to richen up under load and on boost

Yeah Boby it might be an vacuum leak....but where the hell???

I checked almost the entire system............

Damn it ...it's so hard that I am alone in this S%^&^%Y country (the only one with an R)

 

[pulsarboby]

seek and you shall find:lol:

also try dis-connecting the lambda sensor and see if readings change

During the re build of the car I put some rugs into the intercooler pipes

fooking hell how big are your ic pipes, i reckon a baby could crawl in there:lol::lol:

 

[Dangerous Dave]

Could it be anything to do with the fuel pump?? has the pump been changed at anytime for a bigger one?

 

[RO_SUNNY]

fooking hell how big are your ic pipes, i reckon a baby could crawl in there:lol::lol:

) ) ) ) ) loooooooooooool

No mate just some small one so that dust or some other junk can't enter the pipes

 

[RO_SUNNY]

Could it be anything to do with the fuel pump?? has the pump been changed at anytime for a bigger one?

Yeah the pump is an in tank Bosch 044

 

[RO_SUNNY]

Could this be true?
''When the engine is idling low the fuel flow used compared to full power is only approx 15%. Therefore most of the fuel that is sent by the pump will be returned to the fuel tank. When the engine is tuned the optimum efficiency can be obtained with the optimum mixture of A/F ratio. When the fuel pump is too large and the regulator is not strong enough to handle the excess fuel that it is receiving it will then not be able to regulate the flo to allow the fuel to return to the tank. This will cause the fuel pressure to be too high and too much fuel to be pumped into the engine which will lead to over enrichment and poor fuel efficiency and a variety of problems will occur. ''

And this might the reason why my car is 19.6 at idle but still exhaust fumes smell badly like fuel???

If so.......Bob do you have one instock???

 

[pulsarboby]

yes we have them in stock
but your only running 444 injectors arent you?
in this case they should be fine at idle!
if you had a prob with fpr then surely the pump would continue to run when ignition was switched on (as no pressure build up if diaphram split which would allow fuel to return to tank)
and your afr's are reading lean at base idle so i still say air leak, also check your base ignition timing as that could also cause a prob with fuelling if its out as engine wont be firing at the correct time

 

[campbellju]

19.6 is so weak I'm surprised the thing is idling at all. Above 16 on our cars and you start to get lean misfires.

If the car is running badly and the AFR is accurate then this points towards a misfire where you have a lot of air as the mix didn't fire correctly.

Having said all that, if you are seeing black smoke with an AFR of 19 then whatever is wrong the number is just misleading and you should look elsewhere.

I've seen the bolt loosn that holds the reference disc in your dizzy/crank angle sensor loosen that causes misfires and strange things to occur.

I've also see the Throttle position sensor had a wiring fault that meant the car ran badly.

It could be a bad earth to the ECU or MAF casusing the sensors that are working to give bad data.

The fuel pressure regulators are not known to fail (yet) so I'd look elsewhere first.

Have you got a MAF and TPS voltage at idle?

 

[RO_SUNNY]

@ Boby
Yeah I am running stock injectors, MAF and ECU at the moment.

@ Campbeliju

I've seen the bolt loosn that holds the reference disc in your dizzy/crank angle sensor loosen that causes misfires and strange things to occur.
I've also see the Throttle position sensor had a wiring fault that meant the car ran badly.

You've seen that on my car? ( I don't understand where you've seen)
My MAF Voltage is 0.5 volts and tps I don't know.
The car is running brilliant at idle and also on load....but there is some black smoke coming out my tail pipes when I am revving it to 5500 rpm.
Maybe I am just paranoid and the car is fine!



Anyways....I have checked what Boby said and what do you know ....if I am unplugging the Wide Band sensor the AFR it's still 19 )
So that means that Trip's theory applies (I have replaced the narrow band sensor with an wide band and the ECU doesn't recognize it)


Thank guys I really appreciate your help and advices!!!!!

 

[campbellju]

You've seen that on my car? ( I don't understand where you've seen)

Nope, can't say I've been to your house :lol::lol:

 

[Trip]

So that means that Trip's theory applies (I have replaced the narrow band sensor with an wide band and the ECU doesn't recognize it)


Thank guys I really appreciate your help and advices!!!!!

You cannot replace the stock narrowband with a wideband.. The signal is totally different. If the wideband device has an output to "simulate" narrowband signal to feed the stock ECU then it "might" work on Nissans. I have done this on Honda's with positve results.

But not to complicate things add more problems, use the stock 02 sensor in its original location. Tap another hole in the downpipe and fit the wideband sensor just to keep an eye on AFR's.

 

[Braveheart]

Also, do not fit wideband too close to turbo exhaust. You want it 12+ inches away. Most state 18" from outlet.

 

[geoff pine]

(I have replaced the narrow band sensor with an wide band and the ECU doesn't recognize it) I did this with mine fitted a wide band which had a wire to trick the standard ecu in to thinking it still had the narrow band attached It did have a very lazy idle it would almost stall as you pulled away .The a/f figures where all with in acceptable levels it only flashed lean when you lifted off it did alter the base figures on the blatz the o2 went up t0 30 from 6 base a/f went up to 120 from 100 so im guessing that it was not tricking the ecu just confusing it so the wide bands been abandoned till i get another fitting welded to my front pipe .

 

[Trip]

(I have replaced the narrow band sensor with an wide band and the ECU doesn't recognize it) I did this with mine fitted a wide band which had a wire to trick the standard ecu in to thinking it still had the narrow band attached It did have a very lazy idle it would almost stall as you pulled away .The a/f figures where all with in acceptable levels it only flashed lean when you lifted off it did alter the base figures on the blatz the o2 went up t0 30 from 6 base a/f went up to 120 from 100 so im guessing that it was not tricking the ecu just confusing it so the wide bands been abandoned till i get another fitting welded to my front pipe .

The trick you are talking about is called simulated narowband :-D

 

[RO_SUNNY]

So....I have decided to make an simulator for the narrow band and leave the wide band as it is.
I really think that the black somke at approx 5000 rpm is because the ecu is not reading the correct O2 values.