Are we taking a step backwards with D.I. Engines?

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Originally Posted By: GMBoy
My daily driver is an 08 Cadillac CTS 3.6DI. I have 146,000 on it now and no problems. I did a UOA around 12k and somewhere around 75k miles and the reports were fine with no fuel dilution. I run 5-6k mile oil changes with Mobil 1 EP until 125k miles when I switched to M1 high mileage. So here is an almost 10 year old car with no DI problems and runs just as strong as mile 1.


Not every engine has the problem with it's DI system.

Besides the 3.6 has been a problem child for GM so it's great that the DI hasn't been an issue but lots of other things have like Timing Chains.
 
Originally Posted By: Nick1994
No fuel dilution in my car, I did a UOA and it came back beautiful. Just changed the oil last weekend, not even the slightest hint of fuel smell.

Ok I’ve heard of carbon deposits, but I haven’t heard of that mattering. Sounds like if the only objective is performance and longevity of a car, and the paint is fading, does it really matter? Is the car not going to run as long because the paint is faded? That’s how I see carbon deposit buildup, as a non issue until I see evidence that it matters.


I think the thing to do is if you want to buy a GDI/TGDI engine go find a rental and do a UOA on it. No fuel dilutions with how people drive and care for rentals, then you are golden.

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Originally Posted By: StevieC

I think the thing to do is if you want to buy a GDI/TGDI engine go find a rental and do a UOA on it. No fuel dilutions with how people drive and care for rentals, then you are golden.

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Mine was a rental
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The DI issues seem to be more prevalent in the Honda engines. It's actually shocking that the oil level can rise due to all the fuel in the oil as reported in some of these Honda engines.
 
Originally Posted By: FZ1
The DI issues seem to be more prevalent in the Honda engines. It's actually shocking that the oil level can rise due to all the fuel in the oil as reported in some of these Honda engines.


Yes it is. On the other hand reports of premature failure are pretty much non-existent. And given the level of maintenance attention the average Honda owner provides makes it even harder to figure out.
 
Originally Posted By: StevieC
Originally Posted By: GMBoy
My daily driver is an 08 Cadillac CTS 3.6DI. I have 146,000 on it now and no problems. I did a UOA around 12k and somewhere around 75k miles and the reports were fine with no fuel dilution. I run 5-6k mile oil changes with Mobil 1 EP until 125k miles when I switched to M1 high mileage. So here is an almost 10 year old car with no DI problems and runs just as strong as mile 1.


Not every engine has the problem with it's DI system.

Besides the 3.6 has been a problem child for GM so it's great that the DI hasn't been an issue but lots of other things have like Timing Chains.



Well, I agree with you there...namely timing chains, oil useage and water pumps.Amazingly I only had timing chains. The timing chain issue was usually only 2008-2010/11 range.
 
Originally Posted By: StevieC
A properly setup carburettor can be just as reliable as fuel injection. They just require more replacement parts such as floats / choke diaphragms etc. in some cases.

The Mikuni carb on my old 2.6L Caravan never gave me any issues in the 22 years it was on the vehicle other than 1 replacement choke diaphram. It started without priming it with the gas peddle and would even start via remote starter that my dad put on the van, even in the dead of cold winters here in February without fail.


I think the 2.6 was more reliable than the Chrysler 2.2. Had that one with a carburetor, had it rebuilt once and it went again a little after 100k so I got rid of the car. Ran awful when it started to go bad. When they came out with throttle body injection, the horsepower and gas mileage increased and in general became less troublesome than carburetors. I ended up with a 2.2 Turbo which used fuel injection and never had a problem with it. Too bad the head gasket blew and that was the end of it.
 
Originally Posted By: Wolf359
Originally Posted By: StevieC
A properly setup carburettor can be just as reliable as fuel injection. They just require more replacement parts such as floats / choke diaphragms etc. in some cases.

The Mikuni carb on my old 2.6L Caravan never gave me any issues in the 22 years it was on the vehicle other than 1 replacement choke diaphram. It started without priming it with the gas peddle and would even start via remote starter that my dad put on the van, even in the dead of cold winters here in February without fail.


I think the 2.6 was more reliable than the Chrysler 2.2. Had that one with a carburetor, had it rebuilt once and it went again a little after 100k so I got rid of the car. Ran awful when it started to go bad. When they came out with throttle body injection, the horsepower and gas mileage increased and in general became less troublesome than carburetors. I ended up with a 2.2 Turbo which used fuel injection and never had a problem with it. Too bad the head gasket blew and that was the end of it.


No way, the 2.2 was the always the better engine. The 2.6 had a terrible Mikuni carb and a timing chain that was 3 miles long with a bunch of nylon guides. The Carter carb on the 2.2 was no prize, but once it got TBI it was a solid little motor.

Fuel injection is the best thing that ever happened to domestic autos.
 
Originally Posted By: 5AcresAndAFool
Originally Posted By: Wolf359
I'm not sure how it's a step backwards. It's supposed to give you better mpg and more power or pick one over the other. Mercedes went to DI in 2012 in their E class. Went from 268hp in the previous 3.5L engine to 302hp in their new engine and it got better gas mileage too. Went from 17 city/24 highway to 19 city/28 highway afterwards.


It's a step backwards in my book IF there are reliability issues, or longevity issues, or if the vehicle needs 3k OCI to deal with dilution...

People driving an new E class could care less what the engine looks like in 15 years, 200k miles.

I do because I'm poor and I drive old junk.



No, E class still has 10k oil changes, they use synthetic and the sump is like 7-8.5 quarts.

The 2012 E-350's start at about 18-20k for a used one and they're about 6 years old at this point. Some of them have over 100k but I haven't seen any with 200k yet.

Some people are still picking up older E-320's from 2003-2005 in the 5-7k range depending on mileage.
 
My last carburetor vehicle was a 79 International with a good engine but had a piece of carp Holley carb on top. Between replacing floats twice a year because they would get fuel logged or constantly adjusting it because it kept running rich, I spent a lot of time at the local mechanic. The pollution equipment at that time was in its infancy so there were loads of issues. The air pump kept [censored] out.

Next vehicle had FI. No issues there.
 
Originally Posted By: dishdude


No way, the 2.2 was the always the better engine. The 2.6 had a terrible Mikuni carb and a timing chain that was 3 miles long with a bunch of nylon guides. The Carter carb on the 2.2 was no prize, but once it got TBI it was a solid little motor.

Fuel injection is the best thing that ever happened to domestic autos.


I never said the engine was good. We replaced 2 heads and overhauled the whole engine once on top of that to get the 460,000km out of it. It was a big pile of [censored] but the carburettor was never touched aside from the choke diaphragm which was common on them. Ours was an 86.

The Chryco 2.2L / 2.5L with the Holly carbs were absolute garbage and required frequent repairs. When they later replaced it with the Throttle Body Bosch Injection system that was the bees knees.

The 2.2L Turbo early models suffered from head gaskets which they later fixed by drilling holes in the heads/blocks for additional coolant flow to even out temperatures. Turbo bearings were also a problem for Chrysler until they learned from the Japanese how to make them last.

I can't even being to count the 2.5, 2.2, 2.6's and the 3.0L Mitsu V6 my dad and I replaced, rebuilt, repaired from the 1980's to just before the 2000's Then we got into 4 speed transmission rebuilds thanks to a poor design there. We remedied them by modifying the transmissions so it wouldn't go into partial lock-up and also with external coolers. No one could understand why after we rebuilt the transmissions they would last the life of the vehicle but when done at the dealers / other shops they wouldn't last at all.
 
Originally Posted By: StevieC
Originally Posted By: dishdude


No way, the 2.2 was the always the better engine. The 2.6 had a terrible Mikuni carb and a timing chain that was 3 miles long with a bunch of nylon guides. The Carter carb on the 2.2 was no prize, but once it got TBI it was a solid little motor.

Fuel injection is the best thing that ever happened to domestic autos.


I never said the engine was good. We replaced 2 heads and overhauled the whole engine once on top of that to get the 460,000km out of it. It was a big pile of [censored] but the carburettor was never touched aside from the choke diaphragm which was common on them. Ours was an 86.

The Chryco 2.2L / 2.5L with the Holly carbs were absolute garbage and required frequent repairs. When they later replaced it with the Throttle Body Bosch Injection system that was the bees knees.

The 2.2L Turbo early models suffered from head gaskets which they later fixed by drilling holes in the heads/blocks for additional coolant flow to even out temperatures. Turbo bearings were also a problem for Chrysler until they learned from the Japanese how to make them last.

I can't even being to count the 2.5, 2.2, 2.6's and the 3.0L Mitsu V6 my dad and I replaced, rebuilt, repaired from the 1980's to just before the 2000's Then we got into 4 speed transmission rebuilds thanks to a poor design there. We remedied them by modifying the transmissions so it wouldn't go into partial lock-up and also with external coolers. No one could understand why after we rebuilt the transmissions they would last the life of the vehicle but when done at the dealers / other shops they wouldn't last at all.


Hmm... I think they did go back and forth over which was better. I had the 84/85/86 engines. I got the turbo after the 84 went out with the carb. Didn't have a problem with the transmission on the 2.2, but then again, I think the car was done by about 120k or less. The 2.2 turbo was a stick with fuel injection and never had a problem with fuel injection. When I bought it, it had a replacement engine which I thought was a good thing. Then that engine went and I got another one for $500 and had it replaced, did the clutch at the same time. Then when that one blew the head gasket, it was time to give up, had about 140k at time I think. I tried to get another one, but the ones I test drove seemed somewhat slow til I realized that the previous owner had put in an aftermarket turbo computer so it was probably getting more boost than standard which may have lead to the previous two failures. I worked at a place that had a truck scale so I drove the car up on it once and it weighted about 2600 pounds. Now cars weight more like 4000 pounds and they're about the same size.
 
My 07 335i is at 186,000. I've replaced the injectors once. I won't lie; it's not cheap. That's been the only DI-related issue, aside from cleaning the intake this summer for what looked to be the first time. I don't think there's much to be afraid of, and I love the performance.
 
Originally Posted By: antonmnster
My 07 335i is at 186,000. I've replaced the injectors once. I won't lie; it's not cheap. That's been the only DI-related issue, aside from cleaning the intake this summer for what looked to be the first time. I don't think there's much to be afraid of, and I love the performance.


Would you blame port injection if you had to replace the injectors at 186k?
 
There are ways around DI problem, mainly the intake valve deposit.

Toyota started using dual injectors (port + direct), that's the best way to do it IMO but costly. Others try to keep the valve hot to burn off deposit, and then some try to overlap the intake opening and injection so fuel spray on the intake once in a while to wash it.

Fuel dilution is easy to fix: big sump and frequent change interval. Is 6.6 qt for a 2.5L enough? If not I've seen a Korean research paper that said Group IV base stock helps. I personally upgrade from 0w20 to 10w30 with low Noack and it has been good so far.
 
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