Tractorman

Thanks to this forum, I have heard about the thee cylinder high for very cold days. However, I have never experienced this occurrence until last week during an overnight low of 20 degrees at my property near Baker City, OR. I fired up the truck, turned on the exhaust brake, and went inside. A couple of minutes later I heard the engine slowly increase in RPM. Then all of a sudden it started making such a wild clatter that I thought I was going to have to shoot it and put it out of its misery. After thinking about this for a couple of minutes, I realized that this must be the three cylinder high idle feature. I touched the throttle and the engine went back to a normal idle. I had to do it again a few minutes later. I have had the Smarty S03 programmer on the truck for about three years, so I'm guessing that it has the high idle feature included. I actually do not want this feature. Is there a simple way to disable the three cylinder high idle? Thanks in advance for any help. - John

Check all of your battery connections - especially on the driver's side. With that many codes, you may have a loose wire or a ground problem - again, inspect wiring near the area where you were working when you repaired the fuel leak. Coincidences happen, but are rare. Many times I have repaired something and then found that I unwittingly created another problem. - John

I would be looking a problem either related to the work you just did or triggered by the work you just did. I say this because you said the truck was running fine before you performed the work. An example could be that maybe the lift pump has not been operational for awhile (and you didn't know that before you opened up the filter housing) and now the gear pump inside the VP44 is trying is trying to draw fuel from the fuel tank instead of being charged with fuel from the lift pump. I would start with the basics. Re-inspect your work and confirm that you have lift pump flow. If you need further help then you will need to let us know if there are fuel modifications on your truck and what those fuel modifications are. - John.

I have been told the opposite - that the six speed transmissions are stronger. I have a NV5600 with 320,000 miles on it and it has been trouble free and still operates like it is new. I tow frequently (12,500 - 17,000 lbs gross combined weight). The six speed does solve you "missing gear" problem. It seems to me that a six speed transmission and your 4:10 gears would be a great match for your towing and mountain grade issues. - John

I am having the same problem when I try to post. I put the same radiator in my truck last March, 13,000 miles ago. It seems to be doing its job well. Most of the miles have been towing throughout the summer months over lots of mountain grades. - John

Interesting. My radiator had the same failure at 309,000 miles. I guess we can't complain - that is a lot of trouble free miles. - John

If your hard starting truck is a '99 (as in the signature), then you will have better luck with help if you post in the 2nd Generation category. If the truck is hard starting when pointed uphill, then there is likely to be some fuel draining back to the tank while the truck is parked and not running. A small fuel leak can let air in, but not necessarily offer a visual fuel leak. Do you mean that you have to hold the key on for 10-15 seconds before the starter starts cranking? or do you mean the starter is cranking, but it is 10-15 seconds before the engine starts firing? This is an important clarification. Usually "turning over" means starter is cranking, but engine is not firing. - John

You're not hen-pecking the foremans, are you? - John

@Mopar1973Man, I think @Evanis referring to the 12 valve engine here. - John

I replaced my APPS with a Timbo (my truck has a manual transmission) and I seem to recall that there was a note about the Timbo not having an idle validation switch to control additional after-market devices, such as an exhaust brake. I don't know this for sure, but it is something that you may want to check out. - John

All turbos have some play when they are stationary. To correctly assess for excessive side to side movement, you would need to have one hand on the compressor wheel and the other hand on the turbine wheel and then move the shaft side to side without rocking it. Moving the shaft from only one end will give you misleading results because you are rocking the shaft like a teeter totter with the bearing being the fulcrum. My guess is that your turbo is fine if there are no witness marks showing contact of the shaft to the housing. I have 316,000 miles on the OEM turbo and it does not feel any different now then when it was new when I check for play. - John

@dave110, thanks for your response. I would expect to see reduced voltage to the lift pump (consequently lower fuel pressure) even if the relay doesn't cycle because there woud be significantly reduced voltage to all electrical components (including the lift pump) during engine cranking. My question is: Does anyone know if the ECM controlled relay actually makes the relay contacts cycle rapidly to reduce fuel pressure? - John

I agree with @dripleyregarding the key on scenario - about one-half second. I am not so sure about the performance of the ECM modulating the output voltage to the lift pump during engine cranking when a relay is involved. With the OEM fueling system the ECM modulates the lift pump directly, so I can see how that would provide reduced voltage to the lift pump. But, with the ECM modulating the voltage to a relay coil, I am having a hard time believing that the mechanical portion of the relay would be rapidly opening and closing its contacts to reduce voltage to the lift pump. It would seem that the relay contacts would have a very short life if this is so. I can see a reduced voltage to the lift pump with or without a relay during cranking just because battery voltage will be reduced to around 10.5 volts during cranking. That alone will reduce the rpm's of the lift pump which would result in a lower pressure reading while cranking. Can anyone demonstrate proof that a lift pump relay controlled by the ECM actually does reduce pressure by rapidly turning the lift pump off and on? @Leaky88, your wiring diagram looks like it should work to keep the lift pump out of the loop while cranking the engine. - John

Sounds like your failure was identical to mine. About 1/3 of the pilot shaft bearing area was worn to undersize on my transmission input shaft. I elected to not replace the transmission input shaft (right or wrong) since I am my own warranty station. The rest of the transmission is in excellent condition for 300,000 miles. My next scheduled clutch replacement will be at 200,000 miles of operation - not 297,000 miles like the first time. Hopefully I will make it 200,000 miles without transmission problems. I have 316,000 miles on the truck now and so far, so good. - John

I used two ratcheting straps to secure the transmission to the transmission jack. I think in your case the ratcheting straps would work well. - John

@dripley, the Napa part number is NCF 1105179. The clutch and pressure plate were Luk stock replacement (organic disc). I chose to stay with stock because the original truck was run with the Smarty tuner for about 50,000 miles with no issues. The Luk replacement clutch now has logged 17,000 miles with the Smarty (11,000 of those miles with the Smarty and RV275 injectors). Most of the miles logged are towing. The trailers I tow usually weigh in at 4,000 lbs to 8,000 lbs. These are real weights as I use scales to weigh axles during trips. I occasionally tow 10,000 lb loads usually less than 20 miles. My trip from Salem to Baker City using Hwy 22 and 26 crosses over six mountain passes (6% to 7% grades). Most of these passes I pull in 6th gear at about 60 mph. I drop to 5th to slow for curves or traffic in some areas. So far, the clutch has been operating flawlessly with no indication of slipping - just like the old Luk OEM clutch. - John

My original clutch lasted for 297,000 miles. The clutch didn't fail - the pilot bearing did. As hindsight, I now know that I should have done the clutch job around about 250,000 miles because when the pilot bearing failed (same symptoms as yours), it damaged the pilot bearing surface of the transmission input shaft - a very expensive item to replace. I chose not to replace the transmission input shaft, but the new pilot bearing may now have a shorter life because of the damage. I replaced the clutch disc, pressure, flywheel, throwout bearing, and pilot bearing. I used a new Luk clutch assembly from Napa. I am still running the original clutch hydraulics. So far, so good at 314,000 miles. Because of my experience, I recommend that you do a full clutch job now, before more potential damage has a chance to occur. - John - John

The 175 lb/ft is not preloading a bearing. This torque is securing the splined axle shaft through the hub assembly by clamping the inner bearing races to the machined shoulder of the splined axle shaft. No forces on the bearings. Not sure what's going on with your vibration. Did you have any vibration before you replaced the rotors? - John

What is the low pressure reading when the compressor cycles off? If it is around 25 psi, that would be normal. The compressor should cycle back on when the low pressure side rises to somewhere around 50 psi. If the compressor still does not cycle back on as the low pressure side continues to rise well above 50 psi, then you may have an electrical problem - anything from a faulty pressure switch, AC relay, wiring, or even and faulty PCM. One easy check for a faulty AC relay is to swap the AC relay with another good relay. If the problem goes away, you have found your problem.. I believe the PCM controls when the AC compressor operates based upon inputs from various sensors. - John

@beren, my perspective is different than most regarding the lift pump fuel pressure minimums. My understanding of the VP44 pump operation says that your 10 to 14 psi at the VP44 pump inlet is fine. As soon as that fuel enters the VP44 pump, it enters the inlet of an internal fixed displacement gear pump (a vane pump). This vane pump is operating at cam shaft speed, so when the engine is running, more than enough fuel is always being delivered from the internal vane pump to supply injectors, controls, timing piston, AND the 14 psi relief valve that returns fuel to the tank under any operating condition. Any fuel that is not being used by the afore mentioned items is returned to the suction side of the internal vane pump via a relief valve that is set at over 100 psi. As long as there is positive lift pump pressure at the VP44 inlet, the VP44 is always being cooled and should operate normally. Your P0216 code is probably a failed timing piston operation and each time the failure occurs the engine goes into limp mode. Unfortunately, you will probably have to replace your VP44 pump. I had the same timing piston failure (code P0216) when my truck had 64,000 miles on it and the lift pump was fine according FSM specs. I drove the truck for another 23,000 miles by downshifting (as you have learned) when the limp mode occurred. At 87,000 miles the VP44 pump replacement and the in-tank lift pump conversion was done under warranty. I performed a lift pump pressure test following the conversion that showed half of the operating pressure that the previous block-mounted lift pump showed. I really didn't care and continued to drive the truck for over 150,000 miles before installing a frame-mounted standard FASS pump. I did this conversion just in case the in-tank lift pump failed - it was still working fine. I just did not want the in-tank pump to leave me stranded on the road in case it failed. I have since added a Smarty tuner and RV275 injectors. I currently have logged over 225,000 miles on the replaced VP44 pump. I know that it will fail sometime (probably sooner that later), but it has given me excellent performance for a long time with the "low" lift pump pressure. Just another opinion... - John

That makes sense as the air temperature dewpoints in the South are much higher on a daily basis than they are around most of the nation.. The additional moisture from blow-by would take longer to vaporize in the surrounding humid air, so you would see the blow-by evidence linger for a longer period of time.. - John

@Alexio Auditore is right about checking for a vacuum leak, but using HVAC system for troubleshooting may not be conclusive because there is a check valve in the circuit so the HVAC system can hold vacuum after the engine is shutdown. There are other vacuum circuits that could be leaking - the transfer case, the CAD unit, and cruise control if you have an automatic transmission. I woud go directly to the vacuum pump, disconnect the vacuum hose and place a cap or plug on the vacuum pump inlet. Start the engine. If blow-by decreases, you will know that you have a vacuum leak. If blow-by remains unchanged, then a vacuum leak is not the source of the problem. - John

That would work!

Sure the top two gears are the same - so is first gear. But, sometimes there are conditions such as @keithb7's 3.5 mile, 30 mph hill that makes having three gears (instead of two) to work with between first gear and the 1:1 gear a real benefit whether going up or down that hill with varying loads. Sort of like the benefit you mentioned about improving the final drive ratio when you went from 265 tires to 245 tires. So, I still think the six speed transmission is the best choice for towing - just my opinion. Personally, I wish there was at least an eight speed manual transmission that would just drop right in. And yes, @dripley, I also occasionally go for 7th gear. - John

I think you added your ratios; you need to multiply. 2.45 x 3.55 = 8.70 2.45 x 4.10 = 10.05 My personal preference for safely towing in hills is with a manual transmission and an exhaust brake. The manual six speed gives you the best performance. You will have a gear for every kind of hill (up or down) and you will always be operating the engine in an RPM range that will be do the job efficiently. One option for you is to sell your truck and buy a truck with a manual transmission and install an exhaust brake. This would be a very effective way to solve your issues with your truck. The other option is to continue to put money into your existing truck by beefing up the transmission and torque converter and installing larger brakes. You can only hope that whoever builds the transmission for you can lock up the torque converter in every forward gear with controls that are simple to operate. In the end you still have only four gears to operate the truck and you will never optimize the performance capability of the Cummins engine for going up and down hills. - John