Aggravated Compass and Mileage Computer

[Greenlee]

From the time I bought my Cummins the trip, compass, fuel mileage computer that is located between the visors has been a screw up. The compass always has CAL and the direction is always incorrect. I have calibrated it according to the manual and what is posted on Geno's. The Calibration resets has long as the truck is running but always goes back to CAL mode when I restart. My average mileage is stuck on 15.3 but will change when I reset it and give much better readings but again when I turn off the truck and restart it goes back to the original numbers.I am hoping that I will not have to purchase a new one, most are selling for $200 on ebay. Any ideas or suggestions would help.On the same note I am tryinng to get the best mileage I can. I just installed a Blue Chip Special X with NEW computer and 22 horses at the rear. Now with this pump I am told I can not install a tuner because the pump is already mechanically advanced and does let go of a little smoke between shifts. I was counting on the computer to help keep up with mileage. On my second full tank I have gone 550 miles, 80% highway and 20% city with 3/8 of a tank left. This is at 65 to 70 MPH. I did not want to add any add-ons but I already have a cracked exhust manifold which can with the truck. I am thinking of the same air filter than MoparMan uses and later going to the 50HP injectors to get mileage and quite the engine down a little. I am new to this forum so if this is in the wrong place just let me know and I will see how to get it corrected.

[Mopar1973Man]

Even if you do straight out the overhead computer it will never be correct in MPG. The only time its even close is a purely stock truck but with that Special X it no longer even going to be close. Now like a ScanGauge you can calibrate both flow and distance and get a corrected number that is closer or dead on the money.Perosnally I would give up on the over head pull it out and put the blank back in there. Then get a ScanGauge or Ultragauge and be done with it.MPG = Speed MPH / Flow GPH22 MPG = 55 MPH / 2.50 GPHSo as you see from the math is speed or flow is off then the rest is off. Since there is no way to calibrate the flow in a overhead computer it will always be incorrect. As for the special X I suggest you don't add a timing module on top. You could use a TST fueling box or a Smarty (without timing) and be fine. Excessive timing isn't good either. Hence why with Edge Comp and Smarty with timing is not suggested either for the same reasons. But i'm sure there will be people saying they done it. I look at efficiency and longevity not HP/TQ numbers and racing two different stories.

[Greenlee]

From the time I bought my Cummins the trip, compass, fuel mileage computer that is located between the visors has been a screw up. The compass always has CAL and the direction is always incorrect. I have calibrated it according to the manual and what is posted on Geno's. The Calibration resets has long as the truck is running but always goes back to CAL mode when I restart. My average mileage is stuck on 15.3 but will change when I reset it and give much better readings but again when I turn off the truck and restart it goes back to the original numbers. I am hoping that I will not have to purchase a new one, most are selling for $200 on ebay. Any ideas or suggestions would help. On the same note I am tryinng to get the best mileage I can. I just installed a Blue Chip Special X with NEW computer and 22 horses at the rear. Now with this pump I am told I can not install a tuner because the pump is already mechanically advanced and does let go of a little smoke between shifts. I was counting on the computer to help keep up with mileage. On my second full tank I have gone 550 miles, 80% highway and 20% city with 3/8 of a tank left. This is at 65 to 70 MPH. I did not want to add any add-ons but I already have a cracked exhust manifold which can with the truck. I am thinking of the same air filter than MoparMan uses and later going to the 50HP injectors to get mileage and quite the engine down a little. I am new to this forum so if this is in the wrong place just let me know and I will see how to get it corrected.

Well this gives me some ideas but I hate to loose the Compass but I do have an GPS that will do the same thing. According to Blue Chip the Mechanical advance is minor and not a race add-on at all. I bought it for one reason and that was to get a new computer with it. I hate to say that I heard some bad problems dealing with some of the other vendors that held me back but I did and up close. So did I make a good decision, I don't know being so new to this type of diesel. My truck runs great and for the first time in some crazy traffic I had to run upwards of 80 to 85 or get shoved to the side of the road. At those speeds the interior was super quite with lots of power still on hand. I do appreciate your input MoparMan and I have giving serious thought to the big honker and injectors to get a little more mileage out of mine. I will have to investigate the boxes you suggested but I am sure if they are what you suggest it is good enough for me. How do I add more infor on my truck since I have upgraded my VP44 and lift pump? Thanks again

[Mopar1973Man]

Just go to the User Control panel and edit your signature. :thumbup2:As for the timing thing. I would be careful I know that the pump is modifed its timing and stacking more on might or might not case issues. This one of the few reason 80-90% of people say to get get a stock SO pump then you can do anything you wish module wise but have a Special X or Hotrod Pump there is added timing on the pump and could be risky adding more on with a module and then work the truck hard towing. The problem is no one know exactly how much extra the pump is giving then how much a module is giving in timing combine who knows? I'd rather error to the side of safety...

[flagmanruss]

When stock my overhead was spot on the MPG figured by hand. Then I put the XZT on & it wasn't anymore. Then the clearance lights leaked water into it & now it's dead.

[Greenlee]

When stock my overhead was spot on the MPG figured by hand. Then I put the XZT on & it wasn't anymore. Then the clearance lights leaked water into it & now it's dead.

When I bought the truck off a lot it was stock and the overhead was working the same as it is now. The VP went out on me which caused me to look for another injector pump and I replaced the lift pump as well. Thanks for sharing how yours went out. I didn't want to change up a lot of stock items on the interior but if the overhead compass is not worth fixing it will have to go and be replaced with something better.

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Just go to the User Control panel and edit your signature.

As for the timing thing. I would be careful I know that the pump is modifed its timing and stacking more on might or might not case issues. This one of the few reason 80-90% of people say to get get a stock SO pump then you can do anything you wish module wise but have a Special X or Hotrod Pump there is added timing on the pump and could be risky adding more on with a module and then work the truck hard towing. The problem is no one know exactly how much extra the pump is giving then how much a module is giving in timing combine who knows? I'd rather error to the side of safety...

Words of wisdom for a dummy like me. I concentrated more on the new computer, telling myself I would never be able to purchase a tuner or other goodies with the exception of a fuel gauge, maybe the "Big Honker Air Filter", and a set of 50 HP injectors way down the road. A good exhaust manifold is the next item, then I will concentrate on the mechanical fuel gauge and get some help on putting it in. I think I am pretty limited on the rest due to the Special X I bought, once again, live and learn.

[flagmanruss]

I don't think you mean "exhaust manifold"... Possibly Exhaust system? When my stock tail pipe rotted out & removed the banging part before it could jam & do damage... I just kept running it... the muffler was intact. Until the whole rear of the muffler fell off. So I was determined to not have that happen again.I bought a SS kit off ebay... 4" turbo back. (Stock is 3.5" into 3" after the muffler.) The straight through muffler in the kit was fine until I hooked up a trailer. Most recently I added a SS FTE (4" x 36") spiral resonator. I wish I'd bought the resonator in the first place. Nice sound but not bad towing.

[Greenlee]

I don't think you mean "exhaust manifold"... Possibly Exhaust system? When my stock tail pipe rotted out & removed the banging part before it could jam & do damage... I just kept running it... the muffler was intact. Until the whole rear of the muffler fell off. So I was determined to not have that happen again. I bought a SS kit off ebay... 4" turbo back. (Stock is 3.5" into 3" after the muffler.) The straight through muffler in the kit was fine until I hooked up a trailer. Most recently I added a SS FTE (4" x 36") spiral resonator. I wish I'd bought the resonator in the first place. Nice sound but not bad towing.

Yes, I did mean exhaust manifold, this truck had and still does have a cracked exhaust manifold. The worst part is when I first crank it and the fumes come in the cab. I don't know how the previous owner cracked it but he did tow a bumper pull and from reading the records of maintenance he did they traveled all over the West and East coast. I have to be careful what I spend but now that I have the VP44 replaced and a new lift pump I can replace it next. MoparMan expressed to add a mechanical fuel pump ASAP to keep an eye on my new fuel system. I don't have the knowledge or experience you Cummins owners have right now with this 99 being my first one. The 5 speed NV4500 is great and I am looking for Max mileage and a little fun driving as well. I am adding 2 cycle oil to my fuel after MoparMan posted the link on test results and what a difference it makes on the noise. It is not recommeded by Blue Chip Performance but most additives seem to be harmful if they can't lubricate the system. I am coming up on my first oil, filter change and want to get it right the first time. I have been reading entire threads from front to back on all topics to stay informed. I will probably leave the exhaust pipes alone for now but I would like to cut out the first smaller muffler if that is what it is and put a straight pipe in later. One step at a time and read all I can from what all the experts are sharing like you sir, thanks for your input.

[flagmanruss]

OK. I think I read that exhaust manifolds are prone to cracking. Maybe someone with more knowledge will chime in here.

[Mopar1973Man]

Yes, I did mean exhaust manifold, this truck had and still does have a cracked exhaust manifold.

It's a sign of high EGT's what typically cracks the exhaust manifolds. So you might want to change that I know they are not cheap but I'm sure digging around on the Internet or forums you'll find a used one for sale. With the cracked manifold your losing drive pressure to the turbo so boost pressure is going to be weaker. Not to mention the exhaust fumes in the cab. (cough, gag, cough). With your mild mods you should consider installing a EGT gauge with the new manifold.

[diesel4life]

There certainly is nothing wrong with the pump you bought, so dont be down on yourself. You could have gotten away with a cheaper unit from Chip but more than likely you would not be seeing the kind of mileage your getting. 550 miles with 3/8 of a tank remaining is doing quite well. I bought the standard SO pump with a new computer from Chip and have seen similar mileage (20 to 21 mpg) but thats also with a Smarty. Running the truck with the Smarty removed definitely decreases my mileage. The Special X pump simply advances timing so you don't have to add a programmer, there are lots of people out there that this pump caters to for that reason. He explains the pro's and con's of each of his pumps pretty thoroughly on his web site.If ever your looking to do some mods now that you have that pump, you might want to consider doing injectors first, then if your still looking for more possibly a programmer like the Smarty where you can run catcher tunes with no added timing. A programmer wont hurt your pump anymore than a standard pump, you just wont see as big a jump in performance since it's already running advanced timing.

[flagmanruss]

I think the pump you bought is a good one. I run an XZT+... and normally run in the +35 setting which gives the same timing as you got built in & gives better MPG & slightly better performance. When towing on hills I occasionally kick in the +70 hp setting but 99% of the time... no. So you did well. And you got a new computer, not some used one with who knows how many heat cycles on it.

[Greenlee]

OK. I think I read that exhaust manifolds are prone to cracking. Maybe someone with more knowledge will chime in here.

Thats what I am looking for, I noticed the cracked exhaust manifold when I first looked the engine over. No big deal at first but then the VP44 went out after driving it 250 miles...I was sick. Let it sit for a couple of weeks trying to educate myself on injection pumps. MoparMan was a big help on this and some members on the Dodge Cummins Forum. When I crawled under the truck I noticed I also had the #53 block casting...I thought what kind of dumb luck do I have. No cracks on the block so far and I hope it stays that way. This is a great Forum and a great bunch of experienced Cummins owers, thanks for all the info.

[bry1216]

Advance Auto Parts has ScanGauge 2 for $139.99.

[Greenlee]

It's a sign of high EGT's what typically cracks the exhaust manifolds. So you might want to change that I know they are not cheap but I'm sure digging around on the Internet or forums you'll find a used one for sale. With the cracked manifold your losing drive pressure to the turbo so boost pressure is going to be weaker. Not to mention the exhaust fumes in the cab. (cough, gag, cough).

With your mild mods you should consider installing a EGT gauge with the new manifold.

I didn't think about the EGTs when I was looking at the truck, too excited about the find. It hit me later as to why that manifold was broken or could have broken. The previous owner did good maintenance but that doesn't tell me his driving habbits or know how with this truck. I have a nice wish list but I have to do things in steps. I want to get the EGTs under contorl along with the fuel pressure by installing gauges. Yep, it does get your attention when the fumes first come in the cab but it goes away as I start to move forward. I have to save my threads just to go back and re-read to make notes on the various suggestions and vendors to use. Thanks men for all the input.

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There certainly is nothing wrong with the pump you bought, so dont be down on yourself. You could have gotten away with a cheaper unit from Chip but more than likely you would not be seeing the kind of mileage your getting. 550 miles with 3/8 of a tank remaining is doing quite well. I bought the standard SO pump with a new computer from Chip and have seen similar mileage (20 to 21 mpg) but thats also with a Smarty. Running the truck with the Smarty removed definitely decreases my mileage. The Special X pump simply advances timing so you don't have to add a programmer, there are lots of people out there that this pump caters to for that reason. He explains the pro's and con's of each of his pumps pretty thoroughly on his web site.

If ever your looking to do some mods now that you have that pump, you might want to consider doing injectors first, then if your still looking for more possibly a programmer like the Smarty where you can run catcher tunes with no added timing. A programmer wont hurt your pump anymore than a standard pump, you just wont see as big a jump in performance since it's already running advanced timing.

I feel like I might have made a mistake about the pump, but honestly when I made my mind up I told myself I would not have the income to buy tuners or other goodies and bought the pump because it was already set up with some SAFE advance????? and the advertised increase in horse power which isn't much with 22 HP at the rear wheels. I don't know what that equates to at the flywheel but it can't be much. I do appreciate what you wrote about the pump--Special X I can't tell you how many times I have gone back to Chip's webb page to re-read the facts to convince myself that it was not a bad choice at all. I do think MoparMan is on the money with using a stock VP44 and then you can do what ever you want. I know that I am limited but I studied a lot of signatures as I was reading this forum and what stood out to me was the Big Honkin, basic gauges, 2 cycle oil, 50 horse injectors....and now scangauge to help with the true mileage. Most of the time I am not logged in because I get up and down a lot and when I am logged in I am logged out after a short break....so I just get on and study.

I hit a lot of THANKS but when I do I mean it. I would like to say thank you to everyone on the Forum. I can't do this everyday but let me tell you it is nice to have some conversation especially when it comes to Cummins Trucks. So Thanks everyone!!!

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I think the pump you bought is a good one. I run an XZT+... and normally run in the +35 setting which gives the same timing as you got built in & gives better MPG & slightly better performance. When towing on hills I occasionally kick in the +70 hp setting but 99% of the time... no. So you did well.

And you got a new computer, not some used one with who knows how many heat cycles on it.

I am starting to believe that I did buy a good one based on the little bit of knowledge I had about it. The most important thing is the new computer. I looked at all I could find on the internet and the biggest percentage of computers were simply reused from the crashed VP44 they came on, heat cycles and all. I also knew that I would be putting this monster in, well not really, it went well even if it took me 3 days but I worked comfortable and was not in a hurry. I have come to find out that I don't always agree with Blue Chip on somethings such as additives but I am not an expert and don't want anyone to take it the wrong way. Chip Fisher is in a leauge of his own but then people like MoparMan are also in a leauge that Chip Fisher as no clue about just because of the goals they are both seeking...performance vs longevity. And I know there more of you guys that have so much expertise that it would give me brain damage to even try and understand half of what is shared. If I stay alive long enough I will someday be able to join in and get off the porch.

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Advance Auto Parts has ScanGauge 2 for $139.99.

That is a great price, I use Advanced a lot. Maybe that price will hold long enough for me to pick one up. Appreciate the tip.

[diesel4life]

It can certainly be overwhelming to sit and read of all the mods and what each person does and why he does it. Just remember that these trucks rolled out of the factory with no gauges, tuners, and stock sized injectors and many of them stayed that way and ran a long long time. The real important mods in my eyes are the fuel lubricant as todays fuel is so much drier than it was 12 yrs ago and a strong lift pump along with a fuel pressure gauge to make sure you don't have any unfortunate problems and wipe out that new injection pump. Other than that, everything else can wait. Heck you might drive it for a while and decide not to add any performance upgrades. The truck will certainly get on down the road great just the way it is, so try not to fret over it and enjoy the truck! I truly do enjoy geting behind the wheel of my 2nd gen every day. It still brings a smile to my face everytime I lay into the throttle and hear the ol girl build boost. Most of the time I don't even bother turning the radio on, I just crack the window and listen to the music under the hood

[Greenlee]

It can certainly be overwhelming to sit and read of all the mods and what each person does and why he does it. Just remember that these trucks rolled out of the factory with no gauges, tuners, and stock sized injectors and many of them stayed that way and ran a long long time. The real important mods in my eyes are the fuel lubricant as todays fuel is so much drier than it was 12 yrs ago and a strong lift pump along with a fuel pressure gauge to make sure you don't have any unfortunate problems and wipe out that new injection pump. Other than that, everything else can wait. Heck you might drive it for a while and decide not to add any performance upgrades. The truck will certainly get on down the road great just the way it is, so try not to fret over it and enjoy the truck! I truly do enjoy geting behind the wheel of my 2nd gen every day. It still brings a smile to my face everytime I lay into the throttle and hear the ol girl build boost. Most of the time I don't even bother turning the radio on, I just crack the window and listen to the music under the hood

It can be overwhelming, I had a heartattack when mine went out because I didn't have a clue what I was now dealing with. After reading and looking at the Forums I started to understand just enough to begin the learning curve. My biggest concern is putting the 2 cycle in my tank because Blue Chip is totally against it. I do not want to cause any damage to my VP44 especially when I paid so much for it. I have read many of the threads on 2 cycle on this Forum and trust what I looked at. I filled up yesterday afternoon, 600 miles on 30 gallons with 1/8 of a tank left. It dawned on me that I am only putting 16 oz. in the tank per fill up, about half of what I should be adding. I can still tell a big difference in the sound of the engine and how much smoother is runs with just a 1/2 per gallon. I need to get my act together and buy it a gallon at a time and find a container that will be easy to measure. Since I took the old lift pump out of the tank I am concerned about getting any lower than 1/8 on fuel. Like you I enjoy just driving my truck, most of the time the radio is off and the sound of the engine is what comes over the speakers. You are also correct on the add-ons, I might not need to do anything else except install a good EGT gauge and fuel gauge and let it go. I thought about injectors only to gain a little more mileage. It was good talking to you, have a great day, and thanks.

[bry1216]

It can be overwhelming, I had a heartattack when mine went out because I didn't have a clue what I was now dealing with. After reading and looking at the Forums I started to understand just enough to begin the learning curve. My biggest concern is putting the 2 cycle in my tank because Blue Chip is totally against it. I do not want to cause any damage to my VP44 especially when I paid so much for it. I have read many of the threads on 2 cycle on this Forum and trust what I looked at. I filled up yesterday afternoon, 600 miles on 30 gallons with 1/8 of a tank left. It dawned on me that I am only putting 16 oz. in the tank per fill up, about half of what I should be adding. I can still tell a big difference in the sound of the engine and how much smoother is runs with just a 1/2 per gallon. I need to get my act together and buy it a gallon at a time and find a container that will be easy to measure. Since I took the old lift pump out of the tank I am concerned about getting any lower than 1/8 on fuel. Like you I enjoy just driving my truck, most of the time the radio is off and the sound of the engine is what comes over the speakers. You are also correct on the add-ons, I might not need to do anything else except install a good EGT gauge and fuel gauge and let it go. I thought about injectors only to gain a little more mileage. It was good talking to you, have a great day, and thanks.

I use the 16 oz bottle as my measuring device for the gallon jug. Just need a handy wipe and a paper funnel.

[diesel4life]

Does Chip recommend against any lubricants or just againsT 2 cycle oil? Where did you read that at? There is a link floating around somewhere about a test that was performed in a lab with various different additives/lubricants and 2 cycle oil was one of the lubricants tested. It actually tested very well, better than many big name lubricants. Between the good test results and the relatively cheap cost and availability the 2 cycle oil is the preferred choice for alot of people. Chip has some deep roots with some very influential people in the early days of the CTD, I'm pretty surprised he would be against adding the proper lubricant to the fuel for our trucks.

[flagmanruss]

I hadn't looked a BlueChip Diesel for some time... but their site was a wealth of knowledge. I just noticed that BCD is just West of Springfield, Mass. Within travel distance for me... In this section: http://www.bluechipdiesel.com/injectionpumpfailures.html Chip discusses VP44 failures... in non-upgraded VP44s (1998-2000)... with a galling problem: "What actually happens when the rotor seizes, and this is from a Bosch Factory Rep, the slot in the rotor interferes with the distributor because of an inferior deburring process. In layman’s terms “deburring” is eliminating sharp edges."... "I should note here that all rotary pumps have this potential problem, to varying degrees, so this is nothing new to the injection pump world." Now the improved post 2000 VP44s may have improved parts & coatings... BUT Chip says ALL rotary IPs have this potential issue. To me it makes sense, for the modest cost involved, to run a lubricant in the fuel to REDUCE galling & extend the life of the VP44 IP. I don't care what additive you choose to run in your VP44. But consider that TCW3 (2 cycle oil) is engineered to not only lubricate but also burn and burn clean. I think we'd be hard pressed to find a better lubricating additive. TCW3 standards have been in place since I was in the boat business... It is still active though last updated in 1993. Chip also mentions the upgraded (post 2000) VP44s feature larger heat sinks on the computer board... which he describes as the 100% source of failures in the 2% of his pumps returned.