Geekzone: technology news, blogs, forums
Welcome Guest.
You haven't logged in yet. If you don't have an account you can register now.

View this topic in a long page with up to 500 replies per page Create new topic
1 | 2 | 3 | 4 | 5 | 6 
5796 posts

Uber Geek
+1 received by user: 2851

  Reply # 1487907 9-Feb-2016 10:19
Send private message





Ah I see, so it is a "direct fuel injection" engine. The people are saying because the [read: all] injectors are not circulated with engine oil the carbon builds up and craps it out eventually. The thing is, most advanced Euros are direct injected. Maybe they will all crap out too. [Note: I don't know, it's probably a luck thing.]



The problem is that with direct petrol injection there's no fuel vapour continuously washing the top of the intake valves. Exhaust valves aren't a problem because they get hot enough to burn it off.  Some of the carbon probably comes from the EGR system, some oil and crap from the PCV system and slowly but surely it builds up on the top surface of the valves.





Gradually the cars economy and performance drops and it starts running like a bag of bones.


This can be cleaned, but involves removing intake manifolds and usually abrasive-blasting using walnut shell or a polymer grit.  It's going to be much more expensive to do this with a complex forced induction v6 or v8 than a simple 4 cylinder normally aspirated engine because of time taken to remove everything to get access to the intake ports.


Other things equal, then this can be made worse by increasing cylinder pressures (forced induction / turbo) and using low friction materials in cylinder rings and bores to improve economy.  Result of that is more blow-by with oil residues and the faster this build-up happens.   It's not uncommon for owners of new-ish direct injection forced induction cars to report high-ish oil consumption, but then the makers tell them it's "within normal spec".  IMO that's a load of croc - and the probable end result is as per the photo above - due to happen probably just after the car's out of warranty and then an ongoing maintenance nightmare as the engine gets older.


If you google this problem, then you'll see who those makers are.


A potential solution is to run a primary indirect injection system in the ports or throttle body.  I believe Toyota are now doing this with some direct-injected petrol engines.

352 posts

Ultimate Geek
+1 received by user: 36

  Reply # 1488058 9-Feb-2016 13:39
Send private message

Just an FYI, I bought a Toyota Vanguard 3.5V6 based on a 4.3 RAV4 and the same motor as the Highlander late 2014.   Its a great plenty of space inside adjustable rear seats with plenty of leg room, plus the storage areas behind the rear seats the only downside is the lack of spare wheel one of those can of glue and pump generation of cars. Has 8 airbags plus steering assisted stability control, auto lights it comes with cameras etc., I replaced the Japanese Stereo.


Performance wise it a sleeper normal EFI motor non GDI 0 to 100kmph in just over 6 sec, or you can run in eco mode and its sedate.  Makes for safe driving as it can overtake quickly.



1 | 2 | 3 | 4 | 5 | 6 
View this topic in a long page with up to 500 replies per page Create new topic

Twitter »

Follow us to receive Twitter updates when new discussions are posted in our forums:

Follow us to receive Twitter updates when news items and blogs are posted in our frontpage:

Follow us to receive Twitter updates when tech item prices are listed in our price comparison site:

News »

Amazon launches the International Shopping Experience in the Amazon Shopping App
Posted 19-Apr-2018 08:38

Spark New Zealand and TVNZ to bring coverage of Rugby World Cup 2019
Posted 16-Apr-2018 06:55

How Google can seize Microsoft Office crown
Posted 14-Apr-2018 11:08

How back office transformation drives IRD efficiency
Posted 12-Apr-2018 21:15

iPod laws in a smartphone world: will we ever get copyright right?
Posted 12-Apr-2018 21:13

Lightbox service using big data and analytics to learn more about customers
Posted 9-Apr-2018 12:11

111 mobile caller location extended to iOS
Posted 6-Apr-2018 13:50

Huawei announces the HUAWEI P20 series
Posted 29-Mar-2018 11:41

Symantec Internet Security Threat Report shows increased endpoint technology risks
Posted 26-Mar-2018 18:29

Spark switches on long-range IoT network across New Zealand
Posted 26-Mar-2018 18:22

Stuff Pix enters streaming video market
Posted 21-Mar-2018 09:18

Windows no longer Microsoft’s main focus
Posted 13-Mar-2018 07:47

Why phone makers are obsessed with cameras
Posted 11-Mar-2018 12:25

New Zealand Adopts International Open Data Charter
Posted 3-Mar-2018 12:48

Shipments tumble as NZ phone upgrades slow
Posted 2-Mar-2018 11:48

Geekzone Live »

Try automatic live updates from Geekzone directly in your browser, without refreshing the page, with Geekzone Live now.

Are you subscribed to our RSS feed? You can download the latest headlines and summaries from our stories directly to your computer or smartphone by using a feed reader.

Alternatively, you can receive a daily email with Geekzone updates.