Should I remove Post Cat fuel filter before going to dealer for fuel smell from engine? I'm positive that leak is not from the Cat filter setup. Can't find any fuel leaks that would be obvious to the naked eye. Smell just started--4500 miles on post Cat system. Seems like the lopy idle is just starting too. Will dealer give me a rough time because of the added fuel filter?

If you've got a post OEM fuel filter and a problem with the fuel system, your dealer may go ahead and troubleshoot it. Some dealers are okay with that kind of stuff, others are not.


Basically a post OEM filter means you've broken into the engine's fuel system and officially I doubt GM is going to approve.


It's one of the arguments for a pre OEM filter...http://www.dieselplace.com/forum/smileys/Ermm.gif

I began noticing a mild raw diesel smell after installing my pre-OEM Mega. I looked and looked and cleaned and cleaned. The truck's mileage and performance were excellent.


I bought my truck in June of '02. It had a mildly lopey idle when warming up. After it was warm it was fine, and when it was dead cold it was fine. In Apr of '03 I had the dealer reflash the ECM for the lopey idle. It seemed to fix it. In Sep of '03 I installed the Mega and alonmg with the fuel smell, I noticed the lope had come back. In Feb of '04 I began experimenting around and disconnected the Mega. I had a huge amount of lope until I got all the air out of the system. When I re-installed the Mega, the lope was a little worse than it had been before I started experimenting.


In Mar of '04 I installed a lfit pump, and the lope went away completely. Early this Jul I took it to the dealer. I called ahead of time and explained my situation. I told them of the Mega, my fuel additive, and the lift pump. I didn't mention the Juice and removed it--they seemed to know enough not to ask about chips and such.


They told me worse case they woudl charge me $70 for the diagnostic fee if they determined the fuel smell was due to the mods. They thought the mega and the additive were good ideas, and weren't bothered by the lift pump.


They wound up visually inspecting my entire system--including the lift pump and the Mega, and hooked it up to the machine. They said everything was working well, form the fuel tank through the regulator to the injectors. They also found I had a leaky batterey and they replaced that batterey and the cable. All of this was done under warranty.


I do have to admit DMaxAlliTech and JK both told me this fuel smell was nothing to worry about. They said a fuel leak would leave evidencelike pooling fuel or something. The tech at the dealer told me the same thing.


Hope this all helps.................

My truck has had a raw fuel smell since shortly after NIck installed my filter. The truck runs like a watch. I'm not worried about it.

TC

Yeah I had a fuel smell pop up after I installed a home brew pre-OEM filter in the second alt position. It happened about a month afterwards. When I hose off the engine it is gone for a couple days but then comes back. I have not found any obvious leak. Performance (no mods) and milage are all within range. (if you take the middle of the wide range in the milage threadshttp://www.dieselplace.com/forum/smileys/HiHi.gif) Only issue I have with the pre-OEM filter is a vapor lock after a long run on a hot highway. Start it up and it dies about 15 secs later. About 8 or so pumps on the primer pump and your back in business. I found if I open the hood a couple feet to leave the hot air out all is fine. I suppose a lift pump will help that situation. Until I see fuel pooling somewhere or have other evidence of a problem I'm just to lazy to take my pre-OEM filter off to troubleshoot. Besides that part of the system is under vacuum and I don't see how it can leak, even with the engine off and hot since you still have the head back to the tank. So like the experts say, don't worry, be happy.

Oh yeah, it has been to the dealer a couple times and not a peep about the filter.

JimEdited by: jholly

Jim ~ vapor lock? Thats a newun for diesel? Perhaps its our CA fuel? Sounds like you have conducted sufficient research on it and suffices for me. I'll be on the lookout for it.

I also notice a slight diesel fuel odor occasionally when the engine is warm. Other diesels I've owned have also had a hint of diesel smell around the engine compartment. Like Blaine I checked and rechecked connections on my Mega filter, looked over the whole fuel system, cleaned everything, and found no leaks. The smell seems strongest on the front passenger side of the engine - especially near the air filter. I've thought the odor could be from fuel vapor wafting out the intake manifold through the air filter (??). Truck runs great with good mileage and no visible fuel leaks so I stopped worrying about it.

http://www.dieselplace.com/forum/smileys/Geek.gif

I had a fuel smell problem a while back. Traced it to the tube to injector that is under the computer on passenger side of engine. Very slight weeping from where tube goes into the fuel rail. Tightened up the fitting(real bitch to get too without some disassembly), and weeping has stopped. Run your finger along all of the lines from the fuel rail to the head on both sides, and I bet you will find your smell source.

... Traced it to the tube to injector that is under the computer on passenger side of engine...

precision37
Thanks for the tip http://www.dieselplace.com/forum/smileys/Approve.gif The FICM (Fuel Injection Control Module) on the passenger side valve cover does cover an injector and that's one area I didn't check to well. What's involved in removing/lifting the FICM to get to the rail & fuel lines feeding the injector?

I didn't remove it, I just contorted my hands enough to get a wrench in there and tighten the fitting. Tight squeeze. Slip your hand under the module and run your finger along the fuel line, starting at the top of the head and work up. If that line is leaking, you will find a tell-tale greasey smear on your finger. It will smell like diesel. Good luck.

Jim ~ vapor lock? Thats a newun for diesel? Perhaps its our CA fuel? Sounds like you have conducted sufficient research on it and suffices for me. I'll be on the lookout for it.

I don't think it has much to do with the high quality CA fuelhttp://www.dieselplace.com/forum/smileys/HiHi.gif I think it has more to do with the fuel being really hot and then having a vacuum pulled on it. A few pumps on the primer (with the screw closed) and all is fine, or just crack open the hood to leave the heat out. Never had the problem around town. So I'm not sure what to call it, but vapor lock seemed to fit.

jpblock - mine is strong on the passenger side also. I gave some thought to the fumes comming from the intake.

precision37 - good hint. Guess I have something to do this weekendhttp://www.dieselplace.com/forum/smileys/Big Smile.gif

Jim ~ vapor lock? Thats a newun for diesel? Perhaps its our CA fuel? Sounds like you have conducted sufficient research on it and suffices for me. I'll be on the lookout for it.

I don't think it has much to do with the high quality CA fuelhttp://www.dieselplace.com/forum/smileys/HiHi.gif I think it has more to do with the fuel being really hot and then having a vacuum pulled on it. A few pumps on the primer (with the screw closed) and all is fine, or just crack open the hood to leave the heat out. Never had the problem around town. So I'm not sure what to call it, but vapor lock seemed to fit.

jpblock - mine is strong on the passenger side also. I gave some thought to the fumes comming from the intake.

precision37 - good hint. Guess I have something to do this weekendhttp://www.dieselplace.com/forum/smileys/Big Smile.gif


I have experienced what seems similar. I have no additional filter but after towing heavy for 9 hours in 90-100 degree temps, the next morning, I got the 15 sec start then die and 8 pumps got her going. Was the day after filter change. Had it happen a month before but the bleed screw had loosened.

Just a thought about the "vapor lock" problem. It could be entrained air in the fuel that gets forced out by the heat. Lots of air in fuel, partly why it foams so much at the pump when you fill up. try buying fuel at another place.

Just a thought about the "vapor lock" problem. It could be entrained air in the fuel that gets forced out by the heat. Lots of air in fuel, partly why it foams so much at the pump when you fill up. try buying fuel at another place.

Could be entrained air getting forced out.

On the road I'm always buying at another placehttp://www.dieselplace.com/forum/smileys/HiHi.gif

Jim

jpblock,


I want to thank you publically for your helpful diagrams/pics and your advice when I installed my lift pump. I wound up not doing mine exactly like you did yours, though very close, and you posting your experiences made my job go a lot easier.


Blaine

http://www.dieselplace.com/forum/smileys/Ermm.gif Uh, where were all you guys when I was chasing this down and hearing no one else had this "problem"? Edited by: afp1

Blaine,


http://www.dieselplace.com/forum/smileys/Embarrased.gif Your very welcome http://www.dieselplace.com/forum/smileys/Embarrased.gif and thanks for the feedback...http://www.dieselplace.com/forum/smileys/Approve.gif