Mileage & Power GONE - Tough for Ali to shift under load

[ssybert]

Hi Everyone,

My truck seems to have been losing power over the past few months. Symptoms included boost not coming up like it used to... stomp on the pedal and WAIT while the turbo creeped up to 16-18LBS or so. It used to launch right up to 20+ in about 2 seconds; much different now. The next problem I encountered was much less power. Just the truck pulling itself down the highway is VERY weak. getting up to 65 in enough time to merge after pulling out of the ramp tolls is sometimes sketchy. If I try to pass someone and keep that pedal on the floor, it will never shift up to 5th unless I let off the throttle; seems like there's not enough power to make the transmission shift. Next is mileage. In the toilet. No matter how hard I try, 12-13 is the absolute BEST I can get. Towing, forget it. It's close to 10 then. Last problem is I hear a mild surging @ idle. Nothing rediculous but I can definatly hear it and it never goes away.

I had the truck brought in for injectors a few months back (they did all 8) to try and resolve this and it didn't help at all. They also did a fuel filter at that time.

My information center is broken for some reason so i dont know if there are any codes. Just whatever indicator lights there are on the dash, seperate from the information center. At this time, none of those have ever come on other than the self-test at startup.

I'm reading alot around here about FPRV's and PDM's. I dont know which is the likely candidate or where I should be starting but I have to do something NOW. With diesel @ $3.45/gal around here, me buying a new home and having to make MANY 2 hour round trips, i think the cost of parts will pay for themselves in fuel savings in the up coming weeks.

Any suggestions anyone? My dealer and their mechanics are a bunch of knuckleheads and would rather GUESS myself than pay them for nothing. Any some REAL professionals can offer would be very appreciated.

Thank you,
Scott

[Duramaster]

Do you have access to a GM TECH 2? If so, try ramping the fuel presuure to 160 MPA. See if the pump can actually develope that much pressure. After the injector replacement, did you have power for awhile? What DTC's is the engine setting? It is possible that you simply have a restricted fuel filter again. At the very least, you could remove the filter and dump it out into a clean container. You should find nothing but clean, clear diesel fuel. Hopefully you are not using any BIO-DIESEL and if you are it is no more than B-5. And of course, don't forget about the air filter. ;)

[Dakster]

Duramaster,

Is there a confirmed problem with BioDiesel in the older or newer Chevy Diesels? I know that cold weather is an issue for BioD that doesn't have additives.

I agree that ssybert needs to get a hold of a code scanner/reader to see if any DTC's are set. That would defenitely help in the internet diagnosis department.

[Duramaster]

The City of Portland (Oregon) uses B-20 in their fleet. They always bring their trucks in at 3k - 5k with plugged fuel filters. I just had one last week that only had 5k on it and it was on its third filter at least!!! B-5 is mandatory in the Multnomah County area and that doesn't seem to cause too many problems. I'm not against going "GREEN" but, when I see all the problems that this poorly refined fuel is causing.............. well.......... FORGET IT! I guess a customer called in last week and told the foreman that he has a 2007 DMAX Classic that he has converted to "VEGIE OIL". HA HA HA HA HA HA HA HA! Actually I really wanted to see it. THe problem is the fuel leaked into the crankcase and gelled? I don't know if there is any engine damage, but he wanted us to take a look at it. The foreman said NOWAY. You never know what you will come across when working on something like that. Especially when our shop rate is $94 an hour soon to be $99!!!

Anyway, back to the question........... Nothing good ever comes of Bio any stronger than B-5! The DMAX wasn't engineered for anything stronger. I sometimes wonder if the engine manufactures are forced to say that the engines can do something that they really can't? :o

[Dakster]

OK. I jwas just wondering. I would be suspect into thinking that were making their own fuel and/or it is not to spec...

There are another two issues here as well. One is that if you didn't go to Biod in the beginning then you are cleaning the crud out of your fuel system and it is going to plug fuel filters. Same thing will happen if you switch back and forth between BioD and D2. EIther you run Biod from the beginning or you don't.

Then again, as you mentioned before the Pacific NW is known for poor quality fuel. I also wonder if the Bio that is blended is made from virgin oil, animal fat, or WVO. That may make a difference as well.

[Duramaster]

I am pretty sure that the City of Portland has used B-20 since new on their 2006 C-4500 trucks as well as their W-4500 trucks. They are always in for plugged fuel filters. That is why I have a hard time believing that the Bio fuel is actually "CLEANING". How dirty is the fuel system going to be on a NEW truck? Oh, It's their money and it is work for me (easy at that). :p

[Kennedy]

They need to filter it before it reaches the vehile tanks.

They could also do a lift pump setup to help get more miles from the filters, but my experience has been similar...

[Dakster]

Interesting results. I will let you know when I look at my Fuel Filter this coming weekend. I didn't get a chance this weekend. My fuel is crystal clear and is filtered several times before it gets to me. The commercial BioD plant filters it. It get's filter as it is pumped into the transfer truck, which filter it before it goes into a holding tank. One more time it is filtered while it is pumped into my truck, car, or 5 gallon jugs...

If it is clogging fuel filters, I'll be going back to D2. Don't need the extra maintenance costs or the worry I will be unexpectedly stranded. The wife's fuel filter was PERFECT, looked like it was just installed. When her filter is changed you look at the actual filter media. (I changed it out while I was there, but there really was no need to)

I think it may be a case that Bio and D2 don't mix well. The other difference as I previously stated is that they are using Palm Oil, which is adundant in Florida. What plant does the oil you are using come from? (Soybean? Corn?)

[MikeC]

I have run as much as 100% bio and routinely run B20 in my TDIs. I have not had one single problem with my filter or performance. I also have topped off with B20 from a can in my DMAX (cover your eyes GM), and also have had not one problem.

I'm being the "Devil's advocate" here and would like someone to explain to me why a VW TDI can run without issues but the BioDiesel seems to target the DMAX/GM filters.

Mike

[DmaxMaverick]

Doesn't the TDI have a fuel lift pump? I'm asking, because I don't remember. The Duramax doesn't (OEM pickup). A little supply pressure would allow for longer filter use. Once the filter starts getting a little restriction, outgassing occurs, and during a shutdown period, that air will accumulate at the pump suction (high point) and ergo....

[MikeC]

I do not have the answer but will quiz a friend/coworker that races and maintains TDI's.

Mike

[Dakster]

MikeC,

I'm not sure about whether your TDI's (00 and 02) have lift pumps, but I know for a fact the newer ones do. Your expert will know for sure when the change over was made...

There are topics at lenght on the VW forums about adapting "lift pumps" on the older VW's to help out. However, the lift pump only supplies 10psi to the injection pump. I don't know when the change over happened and you could very well have a "lift pump" in both of your TDI's.

[steak2k1]

I find it very interesting regarding the fleet of vehicles that is mandated to run on B20 having significant filter plugging problems.

In my humble opinion it seems to me that the Biod is either of very poor quality (not washed properly or not fully cracked: or just can't pass the Warnqvist test), or the dino diesel they normally buy is very poor quality or a combination of varying degrees of both. I do not buy the inference that it is "biodiesel" itself and as a separate entity that is causing this issue. There are literally thousands, myself included that not only use Biod but make it ourselves. BioDiesel has been proven to be an effective, environmentally positive product for use in todays common rail diesels. So before anyone goes on a rant and decides to dump on & claim it is garbage .. do some research...K.?

Yes there is the initial issue with clogged filters and this product does gel at much higher temps than winter diesel. But I still run it in winter..and I am talking WINTER. Mix rate is B2 - B5...no issues. Besides it is the Absolute BEST additive you can run in your motor - hands down.

BTW: I do not work in the Biod industry, nor do I own shares or any other such stuff. but I am an unashamed proponent of Biod.:D

cheers,

stk

[PaulChristenson]

I do not have the answer but will quiz a friend/coworker that races and maintains TDI's.

Mike

Check with these guys... http://www.tdiclub.com/

[MikeC]

My year TDIs DO NOT HAVE lift pumps. The newer TDIs (PD version) do have lift pumps.

The TDI filter is drastically smaller than the DMax filter but it also sees 1/3rd the fuel in the same mileage.

I wonder about the quality of the fuel that is plugging the filters.

Mike