'01 smoking after changing fuel pressure regulator

[loosedrag]

(In case there's any doubt after reading the statement below, I know very little about engines of any kind, but I can follow directions.)

About 8 months ago I was experiencing regular "pulsing" of my 2001 2500HD 6.6 Duramax (330K miles at the time)when traveling down the highway, and was advised by a mechanic that my Fuel Pressure Regulator needed changing. So me and a buddy looked at some youtube videos and changed it. I put in a stock FPR from the local parts house. And I changed out my thermostat while I was at it.
When I started the truck back up, I immediately saw light-colored smoke coming from the exhaust. I figured it was because now that I was getting good fuel supply, maybe my injectors were showing up as bad.
So I took it to three different diesel mechanics, none who could confirm that my injectors needed replacing. Turbo was fine, (no oil inside? ) The truck runs fine, no rough idle or rpm, zero poor performance. One guy hooked up an analyzer and said that without actually pulling injectors and testing each one, all he could tell me was to live with the smoke. "It's an old truck and it smokes. Keep driving it." My mileage per gallon is holding steady, around 16 in town and 18-19 on the highway if I keep it at 65. Will still pull my 6000 lb trailer on 1,000 mile trips without complaint.
Great, except that it REALLY SMOKES, and is most evident at idle when clouds of smoke fill the intersection. Embarrassing at a stop light. The smoke is whitish-grey, not dark. Certainly not black. I have NEVER needed to add oil. The smoke smells like diesel in my opinion.
Is there something I could have done/not done when I changed the FPR? Do I have to go spend $2000 to pull injectors to find out why my truck is smoking even when there's no indication that it's injectors? Can anyone offer any advice?
One final note: I put on a BullyDog in '05, and it doesn't seem to work anymore. I can't adjust the program. One person told me that could be the problem, that I didn't get it hooked back up right when I put the truck back together.

[rapidoxidationman]

Your final note would be where I'd start if i were you. Remove it. Physically. All the way. Then see what happens.

[loosedrag]

Thanks for the reply. That makes as much sense to start there as anywhere else. And the price is right. I'll post a followup if I notice anything significant.

[More Power]

What was the manufacturer of the parts house FPR?

[loosedrag]

I'm looking for records but can't find them. I believe I purchased from OReilly or Advance auto parts: They sell BWD.

[Kennedy]

I would highly recommend using ONLY genuine Bosch/OEM regulators. This is all that we stock and sell.

That said, it sounds like your regulator is working and coincidentally, you have the typical blue-white smoke caused by the VCO style nozzles seeping/leaking. Worse when warm than cold, stinky, and probably worse at idle, but eventually it gets worse.

[loosedrag]

Thanks for the reply. I'm convinced after seeing your post that I did use Bosch, but still can't find the details of the purchase to confirm.
So in your opinion would the next step would be to pull/test my injectors, replace any not up to specs, in hope that this would solve my smoke issue?
I've been hoping to avoid this expense without being sure it would fix my problem.
Thanks in advance for your reply.

[Kennedy]

Replace all 8 with fresh injectors that use the SAC type nozzles OR if you want to roll the dice you can try a set of the VCO with the "enhanced durability" nozzles and see how they last. We can provide either, but prefer the peace of mind with the SAC type.

[More Power]

The operation of the FPR can be verified by using a Tech II scan tool. I'd recommend having a dealer tech give it get a clean bill of health before worrying too much.

I was dismayed a year or so ago when our local NAPA and Oreilly's didn't have the OE parts I needed. Truck loads of Chinese crap, but not what I wanted.

We went through this recently when replacing the water pump on my daughter's Malibu. I had to order the ACDelco part...., which was considerably more expensive (but not so expensive as to cause me to gamble on my daughter's ride).

[dieselbreath]

hello loosedrag
I too am experiencing smoke after replacing the FPR. I replaced it with a Bosch. My vehicle is a 2002 chevy duramax 6.6 turbo. Have you found a fix other than having to replace the injectors? It gnaws at me to have to replace injectors because it was not smoking until after I replaced the FPR. Mechanic says injectors all show to be running in spec and that I have fuel in pipes and need to run it for a while but its been about 500 miles and it is still smoking. I have a few acres outside the city limits, if I have to replace injectors there is going to be a bonfire! So any other ideas are certainly welcomed.

[Kennedy]

When the VCOI nozzles start to seep pressure can influence the severity. Odds are you are now holding a steady and likely lower pressure.

To solve the repeated LB7 injector issues we offer two solutions:

1) Brand new VCO style with enhanced durability coatings on the needles

2) SAC 45 which is the end all fix

[DieselDavy]

I would advice both of you guys to get with Kennedy and get the good parts!
He carries the good stuff and knows what he is talking about.
AND you can trust him!
Dave

[markelectric]

Question to John, Why do you think the SAC injectors are the "end all" fix? They have not been around all that long ( for the Lb7 ) to have that kind of a track record. My nephew works for S&S, builds the injectors. He says that this is still being "tried" , not proven.

I ask because I have an 01 smoking out intersections now also. That means It wants me to buy yet another set of sprays for it. Wondering about being a rolling Ginnie pig for them.

[loosedrag]

I ended up buying a cheap set of "reconditioned"injectors on ebay from "injectorsdirect.com", reasoning that even if they only lasted me 10,000 miles, I would get an education in how to install a good set on my truck next time. I spent $1200 on parts, another $200 on tools, and at least 40 man hours (me and a buddy) doing the work. The truck started, ran fine, but was spraying fuel inside the engine compartment. I'm not a mechanic, so I did what I thought I should do: I redid the install making sure I observed all torque specs instead of "winging it". When I attempted to restart, I could not get the truck to fire up. I could fill the filter then the truck would run, but I could not get it to self-prime. After a couple of weeks of realizing I was not a mechanic and could not get solid "how-to" info off of youtube, I had my truck towed to my mechanic.
He told me he checked my fuel system all the way from the tank forward to the injectors, and he was at the stage where now he had to pull the injectors to see if they were the problem. I was into him for nearly a grand even if he just put the truck back together and towed it back to my driveway. So I let him at it. He pulled the injectors, had them spec'd at the local bosch-equipped injector tester, and their tests revealed 4 out of the eight injectors I had purchased were below spec, one so bad that it was, according to my mechanic and the testing facility, a probable cause for my truck not starting. Did I mention I'm not a mechanic?
My mechanic said that in order to warranty his work, I'd need to let him install injectors he trusted, at $300 each. In less than a week, my 17-year old truck, with 350K miles on it, was running fine, no smoke, with a $5100 bill hanging off the tailgate. Net cost of the injector repair on my truck was close to $7000.
Since then I've had several "qualifed" folks tell me I was taken for a ride. I know I got zero cooperation out of "injectorsdirect.com", eventually having to get my money back via my card-issuing bank rather than "injectorsdirect.com", who wouldn't even return a phone call or email once they realized I had provided them with bosch-certified specs showing their injectors were bad.
Long story short: I have some nice tools now like crows-feet ratchets and tiny finger ratchets I may never use again, and $5000 less in my bank account, a boatload of too-late experience, and a truck that runs fine again.
If you aren't a mechanic, don't change out your own injectors. That's my advice, and I paid dearly to be able to offer it to you for free.

[loosedrag]

hello loosedrag
I too am experiencing smoke after replacing the FPR. I replaced it with a Bosch. My vehicle is a 2002 chevy duramax 6.6 turbo. Have you found a fix other than having to replace the injectors? It gnaws at me to have to replace injectors because it was not smoking until after I replaced the FPR. Mechanic says injectors all show to be running in spec and that I have fuel in pipes and need to run it for a while but its been about 500 miles and it is still smoking. I have a few acres outside the city limits, if I have to replace injectors there is going to be a bonfire! So any other ideas are certainly welcomed.

Dieselbreath, After changing out my FPR, I took my truck to as many local diesel mechanics as I could find (not the dealer) and none could give me solid reason why my truck was smoking so profusely. The consensus was that the truck had 350,000 miles on it, with 240,000 on the current set of injectors, so injectors were the likely culprit. No one could say without pulling them and testing them. As I just narrated in a separate post on this feed, I elected to go the cheapest route thinking I was smarter than the average non-mechanic. Maybe I was, maybe I wasn't. But I learned first-hand that I definitely wasn't as smart as folks who do this for a living. (The local bosch injector dealer would have tested my current set for $50 each and sold me remanufactured bosch for $300 each to replace the ones that needed replacing, with no testing charge on the replaced ones. In hindsight that's the deal I wish I'd taken.) So my non-educated, experienced opinion is that you probably should change your injectors if they have lots of miles on them. And avoid "injectorsdirect.com", no matter how much "good press" they say they've received. I know first hand they're not someone I'd deal with twice. Hope that helps. BTW, six months after the injector replace, my transfer case went out. Yippee!

[More Power]

BTW, six months after the injector replace, my transfer case went out. Yippee!

Experience is priceless. Maybe someone here can report what a new monthly truck payment is these days. My guess is that you got your truck back for a lot less than a year's worth of truck payments. Not bad for 16 years of mostly no repairs.

We've saved GM diesel owners many millions of dollars through the years. You can trust what you read here. Experience is priceless.

[Kennedy]

Question to John, Why do you think the SAC injectors are the "end all" fix? They have not been around all that long ( for the Lb7 ) to have that kind of a track record. My nephew works for S&S, builds the injectors. He says that this is still being "tried" , not proven.

I ask because I have an 01 smoking out intersections now also. That means It wants me to buy yet another set of sprays for it. Wondering about being a rolling Ginnie pig for them.


First I trust my expert contacts in the fuel system business. It's not difficult to see the merits from there. The VCO design is unique to the LB7. The smoke at idle is also unique to the LB7. The SAC type nozzle is used in all other Dmax injectors and does not do the idle smoke deal.


We don't do a ton of these jobs, but when I saw 40k fail points on several sets that we did in house WITH mega filter and lift pumps I knew something was not right.

I will reserve comment on the "tried not proven" statement.

[cabletech]

When I bought my 2017 High Country the dealer showed me options from no down payment to 50% down. The no down option was $1100 plus for a $66k truck. At that rate if his truck was in otherwise good shape $5k was a good investment compared to a new truck.

Jay