Tim Waldo

DT, I've got a couple of posts all tied to my VP dying in January... the IAT did NOT show up until after he did the initial work. Had to pull the VP44 and send it back to the company that sold it and then he put in the 2nd VP44.. I am presuming that he dropped something in the intake, so that wouldn't have been originally posted... just the end result of following the path... I didn't pull the original IAT sensor until after the 2nd VP44 was installed... thought gee , how odd that it is melted... put the new one in... continued to throw codes... pulled the new one out and it was melted as well... then I started digging and found a post where someone had a similar issue..... Truck gets delivered to a diesel shop tomorrow and MAYBE by Wednesday I get an answer.

Will do...

Guys thanks a TON... shipping it to a reputable diesel shop today or tomorrow should have done this when I had the first VP issue but tried to save $$$ by having a mechanic come to me... this will end up costing me (already has actually) than if I had just sent it to them in January.... Just hope I haven't done irreparable damage by running it as much as I already have. This all started after he replaced the VP the first time and dropped something into the air intake.... is when I started throwing IAT codes.

SO I went out this morning, started at the air filter and examined everything but the intercooler... all seem to have good air flow... so I resigned myself to removing the IAT again.. (I know, it isn't that hard, just greasy) I also started and checked the IAT temp and again watched it ramp up and then start falling when engine was turned off.... removed the IAT and THIS is what I found... I'm going to buy a retractor (push button jaws extend, release button jaws close) this afternoon and see if a mechanics towel got sucked in... SO how hard is it to pull the entire air chamber? did some more googling.... found this... https://www.cumminsforum.com/threads/ait-sensor-melted.978842/ What would you guys suggest I do?

John, key on, engine off immediately after running and throwing the code... it took a few minutes to throw the code and then ran a few minutes more. I left key on so I could watch the reported temp... at first it didn't drop any (thinking it was so high out of range) and then slowly started dropping 2 degrees at a time and then finally it ramped up to 5 degree drops (I watched for 5 minutes if not more). The sensor I replaced would swap between 142 and 293... typical response to a thermistor that has gone bad... that or hanging on one resistance. But AGAIN... this was not an issue before the VP44 failed... so it is something that happened while I've been swapping VP44's Based on what I've read so far the plan of action tomorrow is to replace the air filter and examine the full path of the intake air (have an S&B cold air system) I bought a dry filter to replace the oiled filter but wasn't going to do it till the truck is running... Here is the kicker... none of this was a problem until the VP44 went down and I basically parked the truck.. I am THINKING that there is a blockage at the air filter OR in the air intake system... we have rodents (not sure they are squirrels) of some sort and now I'm wondering if they did something (they built nests in my sons jeep, but not in the engine compartment.... this could account for the air starvation I have been keying on thinking there was a split in the intercooler boots causing the whiteish grey smoke... it is sucking as much air as it can get , but it isn't enough to pull down the air temp at the IAT sensor (no I wasn't paying attention to my EGT's)... I'll watch both boost and EGT's next time I start the engine up.... boost was slow to spin up but it did spin up.... anyway I may go as far as pulling the intercooler out if something doesn't jump out as DUH on first inspection. Thanks for reviewing, your response just justified where I am going to start.... any other ideas would be much appreciated because honestly I studied up on this engine quite a bit when I first got the truck and then never had a problem with it... I think I dropped 5th gear pretty early on... and had a ton of issues with the brakes until I realized the shops were using non-synthetic brake flue and I was baking it off .. I've changed a couple of alternators... but NOTHING else... so now I'm struggling to recall all the possible things that could cause the issues.

I will check that...maybe a cloth got stuck in the intake.... tomorrow though, I'm busted for today

DT, so it builds boost... not as much as before but I'm also babying it right now so I wouldn't expect boost past 10psi the plug end was gummy, not "melted" but yes it got warm. MM it does shake a little on starting but immediately goes away, but I THINK it always did this... I mean I havent' really driven my truck since the end of January and those things don't stick with me. I don't think it is running backwards, seems like that would be VERY obvious. What about loose valve train? the mobile mechanic said my lifters/valve assemblies seemed loose and he felt should be replaced.... is this really a thing? I'm not running it now except for short runs for test, definitely not driving it... should I have it towed to a shop because I am done with mobile mechanics.....

John, did you look at the photo of my old IAT?? it was MELTED.... I don't think this is a matter of a grounding issue.

would that then allow the "temp" to slowly drop back down? that was the part that confused me... its like it honestly was cooling off.

So the last code I had to deal with was one for the IAT... ordered a replacement and put it in... The old one looked "melted" https://photos.app.goo.gl/T5s5ek2kwEQnGqBE6 and I discounted because I haven't touched it since 2008.... WHAT would make the temps in the IAT chamber go up so fast? Burnt valve? I don't have an exhaust brake... ECM??? would the ECM somehow confuse the interpreted signal? I mean I did watch the temp slowly drop when I turned vehicle off. Vehicle did get new injectors, it is possible valve clearances got "changed", guy doing the work stated the rockers appeared "loose" but I don't know on which valves. I don't think this is a new thing, no codes were being thrown BEFORE I had the VP44 issue.

we glued the key in because he lost the first one.... new injectors so that shouldn't be the problem, I mean can you install them wrong and the engine still run? it didn't smoke this much with the bad (new) vp44..... though I did NOT check the placement of the key, just verbalized that the arrow pointed towards the injector pump. The MAP shouldn't have gone bad... just because an injector pump was changed...besides no codes. oh... just to re-state... I am showing NO boost..... I will order a new MAP from the online store (yes it is a good price) It has been a few years since I replaced it so no sadness over ordering a new one..... so if it isn't the MAP... still think its the key?

So I've ordered new air horn gaskets from Geno's, didn't have them when installing the new vp44... I THINK I hear an air leak... would I get similar smoke if one of my inter-cooler boots was split?

all in all I've been happy with Thoroughbred Diesel, wouldn't have had any issues had I purchased the pump that stated it had new electronics.... Not happy about having to add in a new set of injectors thinking that was the problem... but that was me chasing ghosts...

Then based on the way the vehicle ran it had to be the RPM sensor because it would while on the breakout box lope.... like a 360 with a cam in it....

Well they finally got back to me, said it was the IAT ON THE PUMP..... now I am confused because the IAT is not on the pump... tried googling it and couldn't find anything OTHER than the intake air temp sensor that is NOT on the VP44... either way it is in the electronics package that is installed on the pump and I upgraded to a pump with all new electronics....

it was the round module that actually was connected to the "tap" wire , when I get the replacement I'll take a photo of it and share, just for clarity.

There is a sensor mounted on the VP44, I don't know if it feeds the ECM or the PSG... but running on the ECM or on the breakout box the VP44 runs the same... like it is out of time. They are bench testing the VP44 they sent me and I am upgrading to a VP44 with new electronics.

I"m sort of stuck at this point, from listening to it they believe it is the sensor that gives the PSG timing information... but won't know until they put it on the bench... and even though I'm going to pay the difference to get new electronics, I'm going to specifically ask what exactly failed on the original pump I purchased.

after hooking up the breakout box, the engine ran the same with or without it, they had me pull the VP44 out and send it back for a run on the bench, I am upgrading to a pump with all new electronics... rather than the refurbed pump only.

Just talked to TD, where I got my pump and injectors... they said based on the original code that started the issue P1689, that the ECM was very likely at fault... they are sending me a breakout box to see how the truck runs with the ECM out of the picture... they also suggested cleaning the MAP and IAT sensors. I do not believe that I have air in the fuel lines. Honestly I don't see how the pump running independent of the ECM would make a difference, but willing to try it.... I guess the ECM could be telling the pump to do things that are out of band....

The one thing I wished I had known was the gasket for the intake air heater... I believe it takes two... and yes the tappet cover gasket can't be done without pulling the VP.. though when mine was done they had issues with just the gasket, ended up needing a full tappet cover and gasket.

So after new injectors it may very well come back to the timing is off on the VP44 (shift issues are in a manual transmission, power loss anyway). the W-T mod has been mostly completed, ground wires specifically. My code reader can't see both the IAT and ECT (what is a suggestion on a code reader that will give me everything I need specific to this truck). What would have made the truck just die with no other codes? Also, other than low fuel, what could be letting air into the system? Thanks, Tim

Ok, I know things can cascade, now I'm wondering what all sensors I SHOULD replace. Started with a replaced VP, was running rough and lots of white smoke.... so replaced with remanufactured Injectors and new tubes... still white smoke but was improving. Scanned for pending codes and nothing showed up. Took for a test drive the smoke cleared up A LOT but still loss of power going into 3rd gear and again going into 4th gear... and then it just shut down on me with a code of P0112... fired right back up and got it home with the same power loss on gear changes. Can an IAT shut the engine down? Should I replace any other sensors? I replaced the IAT, MAP and Crank position sensors all in 2008. Just because, no codes were being generated, Crank position sensor was replaced in or about 2013 because it was throwing codes. Thanks, Tim

What are your suggestions on getting them checked out? Dealership?

SO the voltage the scan tool is getting is some not standard report.... Checking Pin 7 with a DMM I get 12ish volts. I don't know where the scan tool is getting it's voltage from. I apologize for the confusion, it took being on the phone with Thoroughbred to have me actually check the plug at the back of the vp44. They suggested it might very well be the injector lines not quite seated on the injector(s) or possibly one or more injectors just don't like the new pump... Truck does have 430k+ miles and the injectors have not been touched since I have owned the truck (right at 220k miles)