Tuned D40 - Chewing fuel + others..

[Black_Outlaw]

Guys - especially those with a bit of knowledge on the topic.

A colleague of mine has a D40 STX.. He recently had it tuned and the DPF and EGR removed from the code (de-activated)....

Now, he's having a few problems, so its beyond me so I'll ask those that might know.

Car gets approx 300Km to a tank of fuel.. Tuner says it's not his tune, and "go away"..

Car is running HOT when over-taking and "giving it some"... drops back when cruising.

AFR's (according to the tuner) have been set from 25:1 (stock apparently) to his now tuned 16:1 AFR

He has NO O2 sensor.. infact no sensors at all in the exhuast / where DPF used to be.. I thought this odd as I presumed as with a Petrol engine, the O2 allows you to trim fuel - UNLESS it's in full open-loop then the VE tables in the tune then handle the fuel based on load / RPM / MAP

So, can anyone shed any light? are the 02's imperative? Could the tune be TOO rich and causing the EGT to sore when revving a little and as such making the temp rise?

Cheers

 

[BigMik3]

Not 100% on diesels but all my performance cars that have been tuned ran 02 sensor. Im sure they are needed to monitor fuel mix ratio. Tuner should know that. His bad attitude and service tells me take it elsewhere. My tuners in the past have spent hours trying to find issues/faults even if unrelated to tune.

 

[Black_Outlaw]

Mik - I come from a Petrol tuning background (Holden V8s).. And unless you are full open loop with no correction for atmospheric pressure you go closed loop and have the 02's trim that little bit where required.

I thought I read that the YD25's monitor 02 in the exhaust and adjust the injections appropriately.. Having NONE there tells me it would go for RICHEST setting to ensure protection of the engine.

BUT - I'm not diesel savvy, so I said I'd ask for opinions of those that might..

 

[Connaught]

as far as i understand them, most diesel engines do not have oxygen sensors, they will read the air in data, manifold pressure and mass airflow and , in conjunction with the throttle position sensor and a few others will adjust the fuel to match,

i have a manual transmission and therefor no DPF and there isn't any sensors in the exhaust

and with changing the AFR from 25:1 to 16:1 the tuner has enriched it significantly, that's why its chewin the fuel, - the ECU isn't taking the air away, its adding more fuel to make that ratio, also why its getting hot when he puts his boot into it

i would hope that your mate has an EGT guage fitted to see whats happening to the exhaust temps

 

[jimi]

how is the tuner responsible not doing anything about it? unacceptable.....

 

[auggie]

According to everything from Nissan I've read on the D40 the O2 sensor is only there as part of the DPF regeneration system. It does nothing else. Hence why the YD25 type 2 engine aka DPF fitted is the only YD25 with a A/F Ratio sensor.

If not happy with the tune get the tuner to put the stock one back in and ask for a refund. There's alot of tuners poping up now using tunes from the east coast and oversea's.

I get all mine from a local guy here in Perth who's done the R&D and can make adjustments to the tunes himself. Other's have to send there's back and forward over east or over sea's and its a pain in the Bum.

 

[DieselTuner]

I made the mistake of using a company over here in QLD to do a flash tune for a customer that wanted a dpf delete so we could also get rid of any potential codes that might come up etc...

What an absolute nightmare. I now know for a fact that the guys doing these tunes know nothing about what is going into them. They load tunes up from overseas, thats it!
Its been a back and forth effort to even get them to lift the boost above standard like they said they did on the initial tune up.

Also, No d40 will run 25:1 fuel ratio standard, they are at best 19-20:1 at full load.
By tuning you lift the boost and adjust the timing so you can keep the afr at 18-20:1 while having a good increase in power but not effecting egt's to much..

Im pushing to get a refund for it now as they are just clueless and just fit a unichip and use that do stop any further regen for the no longer existant dpf.

 

[Old.Tony]

Diesels have an O2 sensor for DPF/CAT use. The ECM monitors the feedback from this sensor (specifically called the "Heated Oxygen Sensor" or HO2S) and looks for a pattern similar to what the ECM is introducing in the fuel rail, varying the pressure up and down in a rhythmic pattern. If that pattern isn't detected as a change in O2 levels in the exhaust stream, the ECM assumes the HO2S is defective and throws the engine light. Oxygen is needed in the diesels to allow the CAT or DPF to do their thing. The ONLY way to remove the O2 sensors is to remove all of that code from the ECM. If you haven't had the engine light come on, this must have been done.

However, you don't know what else they might have done.

If they're overfuelling it too much, you'll see it - have someone drive it and give it a bootful while you follow behind. Can you still see your car or has the world turned black?

Overfuelling can also be caused by under-turbocharging. That might be as simple as a leak in the vac lines, or a failing solenoid, but might be something wrong with the turbocharger (sticking vanes, damaged rotor shaft or bearings).

It could be muck on the MAFS too - did they change air filters, dropping in something like a K&N filter to improve performance? If so, was it oiled correctly or was it overoiled? Overoiling a K&N air filter will cause the MAFS to read the airflow incorrectly, so the wrong fuel rate will be applied.

 

[Black_Outlaw]

One thing is for sure - his tuner is a dick. He's up in QLD and struggling to find why he's chewing fuel and overheating when overtaking / giving it a little. I've passed on the info to him. I know all the fuel filter is new, MAFS is clean, rubber vacuum lines replaced and a new boost solenoid. That leaves turbo and tune.

 

[77-dogg]

hey guys im new to this site.

#Black_outlaw has done this
post for me. One thing we know for sure here is my tuner is a dick was very helpful until he got my money.

now shes still over heating randomly one minute you can't get it iver 100ks or it warms up next you can sit at 120 with no problems. on a flat hiway. as soon as you look at a hill she starts to heat up again but drops back down as soon as your over it. now it dose have a K&N filter that has been oiled but on that note the MAFS has been out and cleaned since.

it also has a catch can new fuel filter new radiator new boost sensor and also all new vac boost lines with the blue boost hose for supercheap

going in for a compression test tomorrow to make sure its not the head and checking all boost hoses to make sure there are no small holes and cleaning out my intercooler

 

[kernels]

The D40 appears to actually have a pretty decent cooling system, the last two times Aussies had issues with D40s overheating when pushed it was clogged radiators due to mineral deposits.

I would just check the cooling fan (newspaper test) and radiator, just to ensure there is not some other problem that you are assuming is related to the fueling.

Not sure about diesels, but when petrols run very rich like that they actually run cool, not hot.

 

[77-dogg]

just came back from workshop again they have said its not head as its all holding pressure as its ment toooo... what next

 

[Rumpig]

I wouldn't be suprised if he removed the dpf but didn't turn the regen off when mapping it, and it keeps dumping fuel in trying to do a burn off, would explain the poor economy and high temps. Just a guess thou.

 

[Rumpig]

Best option is to tell him to load the stock file back in and test it. Without the dpf you'll probably get warning lights but your economy should come back with better temps. Most obvious solution.

 

[Old.Tony]

^ I like Rumpig's suggestion. Go back to basics. Don't diagnose the rest of the car until you're back at a stable baseline to work from.

 

[DieselTuner]

so how much boost is it running?

 

[77-dogg]

spoke to old mate and he will not re tune it back with out a cost because he is loosing time on other cars ( ****ing them id say) one thing I have noticed my fan evan after a 40min drive its still spins by hand freely is this bad?

 

[77-dogg]

#dieseltuner its running 23max

 

[Old.Tony]

If your fan can spin freely when the engine is hot then your fluid coupling is shot and needs replacing.

 

[Black_Outlaw]

Thanks tony. I've been searching for that!!