Fuel injector

Non-Technical Nissan QashQai chat. Mk2, Mk3
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Jamie3691
Posts: 1
Joined: Wed Sep 29, 2021 3:46 pm
Qashqai Model: Mk.1 Qashqai Facelift - J10b (2010–2013)

Post by Jamie3691 » Wed Sep 29, 2021 3:52 pm

Hi all.

I have recently replaced my fuel injector on cylinder 1 as I had the code po201. Since replacing the injector my car seems to really roughly start worse than before, and when revving there is a small amount of smoke as if air is escaping.

Any help would be great. Cheers

MrSweetE90
Posts: 20
Joined: Wed Sep 08, 2021 12:46 am
Qashqai Model: Mk.1 Qashqai Facelift - J10b (2010–2013)

Post by MrSweetE90 » Tue Oct 05, 2021 9:51 am

Jamie3691 wrote:
Wed Sep 29, 2021 3:52 pm
Hi all.

I have recently replaced my fuel injector on cylinder 1 as I had the code po201. Since replacing the injector my car seems to really roughly start worse than before, and when revving there is a small amount of smoke as if air is escaping.

Any help would be great. Cheers

While I've not personally tried myself, but injectors are typically replaced in pairs 1/3 2/4 so they fire the same. On a BMW you have to code the injectors to the ECU otherwise they won't run correctly and try to match the same revision of injectors at least in pairs. I had a quick Google and some chap mentions the coding procedure for another Nissan using NISSAN Consult so it may very well be the same situation for your qashqai?

https://www.navaraforum.com/threads/con ... ion.21716/
2012 Qashqai 1.6 DCI TEKNA Plus

User avatar
calnorth
Posts: 2357
Joined: Mon Feb 11, 2019 2:01 pm
Qashqai Model: Mk.2 Qashqai Facelift - J11b (2017–2021)

Post by calnorth » Wed Oct 06, 2021 8:35 am

I thought there was a CONSULT type setup for the injectors but Nissan diagnostics don't show it. However, what we are dealing with here is a closed loop control system:

They do measure injector electrical resistance and apart from acquiring the specified injector thats more or less it.

As can be observed there is a distinct reliance on the exhaust system and its O2 Sensor arrangement to feedback the results of combustion. The ECU will adjust in various ways from that based on its internal engine performance map.

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Mk2 Qashqai Facelift - J11b (2017–present)
1.6 Dig-T N-Connecta

MrSweetE90
Posts: 20
Joined: Wed Sep 08, 2021 12:46 am
Qashqai Model: Mk.1 Qashqai Facelift - J10b (2010–2013)

Post by MrSweetE90 » Tue Oct 12, 2021 6:39 pm

calnorth wrote:
Wed Oct 06, 2021 8:35 am
I thought there was a CONSULT type setup for the injectors but Nissan diagnostics don't show it. However, what we are dealing with here is a closed loop control system:

They do measure injector electrical resistance and apart from acquiring the specified injector thats more or less it.

As can be observed there is a distinct reliance on the exhaust system and its O2 Sensor arrangement to feedback the results of combustion. The ECU will adjust in various ways from that based on its internal engine performance map.

.......
That's some good information, I havent came across the term open and closed loop systems so I had to Google that but it appeared to be the same as most other cars whereby the sensors are used to open and close the loop whereas an open system just uses a much simpler and less effective approach which I believe was something like "at x RPM inject x fuel" whereas our systems can use the MAF to determine the incoming air and the 02 sensor to sort of validate the combustion result so that didn't really seem any different to my BMW which does state it needs coding.

So I was doing some more digging around being's as the BMW uses a closed loop and still requires coding and I believe the answer to why injectors require coding is because each and every injector once manufactured can result in miniscule differences such as friction and so forth, therefor with the requirement of strict emissions and what not this website

https://autotronic.co.za/code-not-code-question.html

goes on to explain:

"When an injector goes through the OE test it generates an IMA code which identifies where in the tolerance range the needle and nozzle assembly fit, this allows the ECU to vary the fuelling accordingly and optimize the engine performance. Failure to code in the injectors can result in several issues:

Performance – In some systems it may be possible to drive away and not notice any difference. In reality, if the injectors have not been coded, it is unlikely that the customer will be getting the optimum performance from the vehicle and may well end up back at the garage with an increase in fuel consumption or black smoke etc.

Non start – In newer systems if you do not code in the injectors the vehicle will not start

Poor / lumpy running – as the injectors are not coded, the ECU will carry on fuelling as if the previous injector was still present, which can cause poor performance. The engine management light is also likely to come on necessitating another visit to the garage"
2012 Qashqai 1.6 DCI TEKNA Plus

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