Direct Injection engines....learned something today!

[aggie97]

So I figured I would share a little info I learned today as this feature is starting to become more prevalent in modern cars. I had not previously given this much thought but we recently bought the wife a used 2008 Cayenne GTS. It has a direct injection 4.8L V8 making 405 hp. We are VERY lucky to have bought the warranty for repairs and here is why...we've had it 3 weeks.

Gasoline direct injection pumps are ENGINE driven either off a camshaft end or by the oil pump. Porsche has chosen to use oil pressure. These pumps work at 2200 psi and are very similar to the extreme high pressure pumps on modern diesels. No electric pump can accomplish this high pressure.

So that being said, if you are buying a used car with direct injection (gas), be damn sure to buy the extended 3rd party warranty. In our situation the pump alone is $1100 and we don't know the full bill yet. Thankfully, we have a VW dealer locally to work on the Cayenne/Toureg, otherwise we would have to have it towed to Houston.

Anyway, beware of the extreme high costs of some of these new technologies on cars today that will eat your ass at the cashier. This one repair will have paid for nearly 1/2 the warranty cost and yes, I knew a P-car was going to be expensive, but DAMN!!!!

[BP]

Lots of the VW/Audi DI engines have pump problems, sometimes they even take the cam out with them.

Most manufacturers are going to this technology. GM's 3.6 was their first but it's actually pretty reliable. Hopefully their V8s follow suit.

[CexMashean]

Mine is cam driven, lasted 6+ years so far, 75k miles.

[Baron Von Crowder]

There's also the issue of EGR/PCV and no fuel in the intake. So now they are seeing intake valves getting gummed up BMW has a menu service where they pull the intake and blast the valves with crushed walnuts to clean the gunk off. It's not covered on any type of warranty.

[kingjason]

There's also the issue of EGR/PCV and no fuel in the intake. So now they are seeing intake valves getting gummed up BMW has a menu service where they pull the intake and blast the valves with crushed walnuts to clean the gunk off. It's not covered on any type of warranty.

This is the number one reason I stayed away from the 135I twin turbo. Fuel pumps I can kind of deal with. Blasting the valves every so many miles, screw that.

[aggie97]

Lots of the VW/Audi DI engines have pump problems, sometimes they even take the cam out with them.

Most manufacturers are going to this technology. GM's 3.6 was their first but it's actually pretty reliable. Hopefully their V8s follow suit.

interesting. Wife got out of truck to get something off the floor in passenger side while it was idling. Saw smoke, ran around and shut it off. Was leaking oil somewhere on the driver side header. Never saw a loss of oil pressure.

Hopefully, the local VW techs know what to look for as they were jazzed to work on a cayenne which is just a toureg anyway. We finally pick it up today so i will update when I find out more.

Never thought about the EGR/PCV issue if the fuel isn't cleaning the valve head....ain't technology grand?! :FAWK:

[blackedv]

Need to do more fuel injection services to keep the carbon down to a minimum which is why i recommend them at least every 15k on a Di motor. I explain it as would you rather pay 100 now or 1000 later more or less. I see the benefits of direct injection but also see the downfalls as most consumers will not keep up with the maintenance of a di motor at all.

[aggie97]

We were supposed to pick up the truck Monday, get a call today that the seal/cap on the end of the camshaft that drives the fuel pump got chewed up and they have to pull the valve cover and inspect further. Part is a 3 to 5 business day lead.

Crossing my fingers that metal didn't get circulated and the end of the cam is good. Won't know till next week.

[jw33]

Yeah, plan on not driving that thing for a few more weeks....

[dblack1]

We were supposed to pick up the truck Monday, get a call today that the seal/cap on the end of the camshaft that drives the fuel pump got chewed up and they have to pull the valve cover and inspect further. Part is a 3 to 5 business day lead.

Crossing my fingers that metal didn't get circulated and the end of the cam is good. Won't know till next week.

How many miles on that? Is that the same engine that is in the Audi SUV?

I've heard some great things on those Audi. I know a mother and daughter who got a pair the same day. The moms was diesel and the daughters gas. All I know is that the daughters broke down a few times right around a year old and she drives a acura mdx now, lol. The mom got rid of hers after being stranded somewhere without cell signal for a lexus.

[aggie97]

How many miles on that? Is that the same engine that is in the Audi SUV?

I've heard some great things on those Audi. I know a mother and daughter who got a pair the same day. The moms was diesel and the daughters gas. All I know is that the daughters broke down a few times right around a year old and she drives a acura mdx now, lol. The mom got rid of hers after being stranded somewhere without cell signal for a lexus.

72k miles. Gotta love Porsches!

[Aceman85turbo]

VW did the full TSB on my 2011 Jetta TDI

$7300, my contribution was the cost of an extra tank of fuel since they replaced the tank.

[aggie97]

Yeah, plan on not driving that thing for a few more weeks....

Well, I touched the car today finally....still not fixed though. I did get a mirror into the head to see the end of the camshaft. It's not boogered up however, there is a piece of plastic floating around in there (part that broke). Looks like they use a plastic "isolator" between the camshaft and the fuel pump keys to either seal things up or act as a vibration/noise isolator or maybe even as a shear pin to prevent serious damage to the camshaft and making the pump expendable instead. Smart thought, still a stupid design overall.

Might have it back tomorrow.....ugh.

[BP]

I've heard some great things on those Audi. I know a mother and daughter who got a pair the same day. The moms was diesel and the daughters gas. All I know is that the daughters broke down a few times right around a year old and she drives a acura mdx now, lol. The mom got rid of hers after being stranded somewhere without cell signal for a lexus.

I absolutely love hearing these kinds of stories. So many people swear by Audi, Porsche, Mercedes, BMW, Rover, Jaguar, Bentley and whatever luxury brand you want to name.

They've been buying those brands for so long they think it's normal to be driving a rental car for two weeks while waiting for parts to repair something that's clearly an engineering problem. That and they won't bat an eye when it's out of warranty and they get hit with a $4k bill for something that breaks on every one of them at some point.

I mean can you imagine buying a Taurus and being told you need to bring it in every 15k miles so we can pull the intake and blast the valves with walnut shells to correct a random misfire? Oh and it's going to cost you $500 every time we do it. Or how about sorry we didn't realize our fuel injection system would have problems in sub zero climates, if you want it to start you'll need this $1500 set of injectors and 5 hours labor to update the PCM.