LOST JEEPS :: View topic - Fuel economy pre- and post-thermostat replacement

Removing or blocking off the EGR system should not cause excessive smoke! Keep in mind that operating the engine for years with the EGR system functioning, soot is being dumped into the intake and can mix with oily gases coming from the CCV and make huge amounts of sludge buildup in the intake manifold plus adds additional carbon (soot) in the exhaust system.
So after removing or blocking off the EGR system, it may take a while to burn out or blow out all the accumulated excess carbon in the exhaust system.

Excessive smoke can also be a sign of low boost! :roll:

Many on LOST every so often do what has been nicknamed an "Italian Tuneup", which consists of several full throttle acceleration runs to blow out any excess carbon that has accumulated...

A dirty or defective MAP sensor can also play a huge roll in smoke and boost control. You may want to consider replacing it to see if helps with your issues!

Keep us posted as to outcome! :wink:

Well, since you asked... :mrgreen:

Ended up taking care of a couple of things, as it turned out.
First: popped the hood and noticed that I had a brain fart and did too thorough of a job installing the thermostat - the plug to the MAF sensor was reconnected. Yanked that one as soon as I spotted it. All I can figure is that I was a little too attentive to detail during reassembly.
Second: pulled the MAP sensor and cleaned it. On the plus side, it wasn't as grody as it was the first time I did this, but it was pretty oil-soaked. The real fix for this will be a Provent, so for now I'll just live with cleaning it every few weeks until that happens. There's no point in replacing it until the Provent is in, but I will toss a new one in at that time just to be sure.
Went to the further of the two diesel stations I fill up at around here, topped off, and headed back. Throttle response was noticeably improved (go figure), but on the 40-50mph roads between here and there, average fuel economy was 24.9mpg when I got back to the house. Granted, that's only over a 4.5-mile distance, but it's a definite improvement.
We're taking the KJ on a roughly 200-mile geocaching round trip tomorrow, so I'll have a better idea of where things sit after that. Based on what I've seen right now, though, there should be some significant improvements.
WWDiesel, thanks for the reminder on the MAP sensor. I'd meant to clean it last weekend when I was in there doing the thermostat, but completely blanked on it.

I ran Torque Pro and found the boost was running high at about 22. I wish on a stock setup! The MAP was showing 1.5 psi at idle. That is not right. Should be a little vacuum, about -.3 to .5. So changed out the MAP sensor and now reads correctly. BUT I cannot get the boost higher than 17 psi. Also I have a small lope at hot idle. I think it is time for new rockers, oh joy! It has been about 110k since I put the new ones in.

So not the tunes fault! Weak off the line, little smoke through the power range up to about 2800 rpm, and the boost not reaching peak.

Author:	casm [ Sat Jan 06, 2018 11:44 am ]
Post subject:	Fuel economy pre- and post-thermostat replacement
Some background: we've put around 5000 miles on the CRD since picking it up three months ago. About 1250 of that was bringing it home, and was virtually all highway driving at around 75mph. On that return trip, with a shot fan clutch and (then-unknown) dying thermostat, the KJ averaged 27mpg; the fan clutch was replaced after the trip. As the weather cooled off, the dead thermostat started revealing itself and fuel economy dropped into the 19-20mpg range. The thermostat has since been replaced with an HDS Model 001 unit running at 203°F. Fuel economy is currently hovering at around 23mpg. That's with a mix of 60% highway driving, 40% town driving, and a Weeks Stage 1 kit in addition to the HDS thermostat. Air filter is clean, PCV puck and hose were recently replaced, and there's a fuel filter sitting here waiting to go in on a warm weekend. There is antigel in the current tank since we have had single-digit temperatures recently. I didn't notice any torn or damaged hoses when I replaced the thermostat, but suspect that there may be an intake leak somewhere due to soot on cold startup; double-checked around the Weeks kit and everything seems tight. The soot does not appear to happen under part throttle, but at WOT the soot is quite impressive. Not rolling coal, but more than I might expect. Power delivery overall seems OK, but not having had one of these before I really don't have much of a benchmark for what it should feel like. So, my question: is what I'm seeing normal behaviour and I just haven't quite adapted to what's expected from the CRD, or is there something I should be looking into beyond what I've already tried / identified?

Author:	r1perk [ Sat Jan 06, 2018 11:50 am ]
Post subject:	Re: Fuel economy pre- and post-thermostat replacement
I just removed the egr and the plate from FCV. I put one of the tunes from here that was supposed to be stock with egr and fcv delete. Now it smokes like crazy on acceleration. Does not seem to be a stock tune? I have not had time to put the stock tune back in to see if it is the tune or the erg delete. Also seems to be a little slow off the line and then a big burst of power. I don't like the smoke and the off line should be better.

Author:	WWDiesel [ Sat Jan 06, 2018 12:27 pm ]
Post subject:	Re: Fuel economy pre- and post-thermostat replacement
Removing or blocking off the EGR system should not cause excessive smoke! Keep in mind that operating the engine for years with the EGR system functioning, soot is being dumped into the intake and can mix with oily gases coming from the CCV and make huge amounts of sludge buildup in the intake manifold plus adds additional carbon (soot) in the exhaust system. So after removing or blocking off the EGR system, it may take a while to burn out or blow out all the accumulated excess carbon in the exhaust system. Removing the plate out of the FCV should have no effect on anything you have mentioned... Excessive smoke can also be a sign of low boost! Many on LOST every so often do what has been nicknamed an "Italian Tuneup", which consists of several full throttle acceleration runs to blow out any excess carbon that has accumulated... A very small about of lag on a quick takeoff is normal on turbo diesels until the turbo spools up and provides boost... A dirty or defective MAP sensor can also play a huge roll in smoke and boost control. You may want to consider replacing it to see if helps with your issues!

Author:	casm [ Sat Jan 06, 2018 3:09 pm ]
Post subject:	Re: Fuel economy pre- and post-thermostat replacement
WWDiesel wrote: Removing or blocking off the EGR system should not cause excessive smoke! Keep in mind that operating the engine for years with the EGR system functioning, soot is being dumped into the intake and can mix with oily gases coming from the CCV and make huge amounts of sludge buildup in the intake manifold plus adds additional carbon (soot) in the exhaust system. So after removing or blocking off the EGR system, it may take a while to burn out or blow out all the accumulated excess carbon in the exhaust system. Good points. And given that oil vapour (no Provent - yet) from the PCV system will be softening up the crud accumulated in the intake, this may explain a few things. OK, I'll worry about it if it's still doing it in the Spring; that should give more than enough time to clear a good amount of the arteriosclerosis out, and let it be warm enough that I'm motivated to actually install the Provent Quote: Excessive smoke can also be a sign of low boost! Thought about that. Thing is, it's only happening under the conditions I described - if it was low boost, I'd expect to see it across more of the rev / throttle range. Not ruling it out, though. Quote: Many on LOST every so often do what has been nicknamed an "Italian Tuneup", which consists of several full throttle acceleration runs to blow out any excess carbon that has accumulated... Yeah, this (and some Seafoam) used to work wonders on my Fiats and Alfas! It also happens to describe my normal driving style, so won't be hard to work into the routine Quote: A dirty or defective MAP sensor can also play a huge roll in smoke and boost control. You may want to consider replacing it to see if helps with your issues! And it just occurred to me that there's about a two-month gap between when that sensor was last cleaned and when the Weeks kit went in. That one's quick & easy to pull; I'll check it later today or tomorrow and see if it's encrusted again.

Author:	WWDiesel [ Sat Jan 06, 2018 3:29 pm ]
Post subject:	Re: Fuel economy pre- and post-thermostat replacement
Keep us posted as to outcome!

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Author:	casm [ Sat Jan 06, 2018 6:25 pm ]
Post subject:	Re: Fuel economy pre- and post-thermostat replacement
WWDiesel wrote: Keep us posted as to outcome! Well, since you asked... Ended up taking care of a couple of things, as it turned out. First: popped the hood and noticed that I had a brain fart and did too thorough of a job installing the thermostat - the plug to the MAF sensor was reconnected. Yanked that one as soon as I spotted it. All I can figure is that I was a little too attentive to detail during reassembly. Second: pulled the MAP sensor and cleaned it. On the plus side, it wasn't as grody as it was the first time I did this, but it was pretty oil-soaked. The real fix for this will be a Provent, so for now I'll just live with cleaning it every few weeks until that happens. There's no point in replacing it until the Provent is in, but I will toss a new one in at that time just to be sure. Went to the further of the two diesel stations I fill up at around here, topped off, and headed back. Throttle response was noticeably improved (go figure), but on the 40-50mph roads between here and there, average fuel economy was 24.9mpg when I got back to the house. Granted, that's only over a 4.5-mile distance, but it's a definite improvement. We're taking the KJ on a roughly 200-mile geocaching round trip tomorrow, so I'll have a better idea of where things sit after that. Based on what I've seen right now, though, there should be some significant improvements. WWDiesel, thanks for the reminder on the MAP sensor. I'd meant to clean it last weekend when I was in there doing the thermostat, but completely blanked on it.

Author:	r1perk [ Sat Jan 06, 2018 8:19 pm ]
Post subject:	Re: Fuel economy pre- and post-thermostat replacement
It is usually is driven like it is stolen. 218k, heavy towing, this baby has been beat! Still runs great. Maybe I messed up the tune? It seems to run better before I put the tune in. If my son ever brings it back I am going to put the stock tune back in and see if the smoke goes away.

Author:	WWDiesel [ Sat Jan 06, 2018 9:54 pm ]
Post subject:	Re: Fuel economy pre- and post-thermostat replacement
casm wrote: Well, since you asked... Ended up taking care of a couple of things, as it turned out. First: popped the hood and noticed that I had a brain fart and did too thorough of a job installing the thermostat - the plug to the MAF sensor was reconnected. Yanked that one as soon as I spotted it. All I can figure is that I was a little too attentive to detail during reassembly. Second: pulled the MAP sensor and cleaned it. On the plus side, it wasn't as grody as it was the first time I did this, but it was pretty oil-soaked. The real fix for this will be a Provent, so for now I'll just live with cleaning it every few weeks until that happens. There's no point in replacing it until the Provent is in, but I will toss a new one in at that time just to be sure. Went to the further of the two diesel stations I fill up at around here, topped off, and headed back. Throttle response was noticeably improved (go figure), but on the 40-50mph roads between here and there, average fuel economy was 24.9mpg when I got back to the house. Granted, that's only over a 4.5-mile distance, but it's a definite improvement. We're taking the KJ on a roughly 200-mile geocaching round trip tomorrow, so I'll have a better idea of where things sit after that. Based on what I've seen right now, though, there should be some significant improvements. WWDiesel, thanks for the reminder on the MAP sensor. I'd meant to clean it last weekend when I was in there doing the thermostat, but completely blanked on it. Replace the MAP sensor! They are cheap! Get yourself a part number GM 55206797 map sensor. Many on LOST are running the GM Map including myself. They can be bought for ~20 bucks or even less. I keep a spare just in case I need it! https://www.gmpartsdirect.com/oem-parts ... r-55206797 or Google the GM part number! 55206797

Author:	r1perk [ Sun Jan 07, 2018 6:20 pm ]
Post subject:	Re: Fuel economy pre- and post-thermostat replacement
I ran Torque Pro and found the boost was running high at about 22. I wish on a stock setup! The MAP was showing 1.5 psi at idle. That is not right. Should be a little vacuum, about -.3 to .5. So changed out the MAP sensor and now reads correctly. BUT I cannot get the boost higher than 17 psi. Also I have a small lope at hot idle. I think it is time for new rockers, oh joy! It has been about 110k since I put the new ones in. So not the tunes fault! Weak off the line, little smoke through the power range up to about 2800 rpm, and the boost not reaching peak.

Author:	ryanchris [ Sun Jan 07, 2018 7:22 pm ]
Post subject:	Re: Fuel economy pre- and post-thermostat replacement
r1perk wrote: I ran Torque Pro and found the boost was running high at about 22. I wish on a stock setup! The MAP was showing 1.5 psi at idle. That is not right. Should be a little vacuum, about -.3 to .5. So changed out the MAP sensor and now reads correctly. BUT I cannot get the boost higher than 17 psi. Also I have a small lope at hot idle. I think it is time for new rockers, oh joy! It has been about 110k since I put the new ones in. So not the tunes fault! Weak off the line, little smoke through the power range up to about 2800 rpm, and the boost not reaching peak. I have a small lope too I think. But it could be this engine sounds a lot different than I am used to. My vac reads around -1 ish and my boost can goto 20 maybe but hangs around 18ish for the most part. My maf reading say the rockers are fine though according to what I have read. 17 to 18 g/s normally. I have recently changed my pinion to correct the od miles and Speedo ... I need a few tanks to get a good mpg since ... But I am pretty sure before with my corrections for miles and speed being off best I could ever get mpg size was around 17ish mpg mixed driving . GM map but I do drive like to stole it (like to hear turbo sounds ha) and have a high lift and big nobbie tires..

Author:	casm [ Sun Jan 07, 2018 7:52 pm ]
Post subject:	Re: Fuel economy pre- and post-thermostat replacement
Did the 194.7-mile round trip at an average fuel economy of 25.8mpg. Driving was mostly 50-75mph (into headwinds for around a third of that) on the highway, and somwhere in the region of 10% of that distance was trail riding in 4PT in crappy weather so lots of low-speed no-traction situations. Definitely need to take care of a couple of things, but overall not a bad result. Will probably order the GM MAP sensor to have around as a spare / eventual replacement for when the Provent goes in in a couple of months.

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