How To Troubleshoot HEUI Systems and IAP faults. 164 Faults. 3126, C7, and C9 Cat Engines.

hey in this video we're going to be talking about how to troubleshoot Huy Systems Huy pumps and injector leaks so in this video we're going to be discussing how Huy system works and components to it and basically out of troubleshoot them for CAD engines all of these principles apply to all Huy engines so what CAD engines had Huy systems well basically at the very end of the 31 16 s run they had a proto Huy system but really we're talking about 31 26 is c7 and c9 and then towards the end of the c7 and c9 engines life they had the regen motors which used high pressure fuel systems now we're just talking about the Huy systems which are given RV or a smaller truck with a cat engine odds are very likely it has a Huy system in it so let's go over just a real quick rundown of our Huy system works so Huy stands for hydraulic electronic unit injector that's why they say Huy so what that is is normal you know 40 50 60 psi all pressure is pulled from the oil rail in the block it's sent up to the Huy pump which then is electronically controlled even though it's gear driven pump and it's applied high-pressure oil to the injectors so these injectors don't run high-pressure fuel they run high pressure oil through the rail in the head and then the injectors are electronically controlled by the ECM and it uses that high-pressure oil to fire the injectors so you don't have high pressure fuel anywhere except where the injectors firing it give high pressure oil so on these systems you want to do oil changes more often opposed to going you know 10,000 miles I recommend six or seven six or seven thousand mile oil changes you know run clean oil these systems are very expensive so the systems are pretty easy to troubleshoot and I'm going to be going over and showing you the components and where they're located for what you need to do on troubleshooting these systems there's really not many components at all there's injectors which all diesel engines have and these there's not much difference between these injectors and a high-pressure common-rail injector or camshaft actuated one and really the only thing that's different is the Huey pump itself so let's go over and I'll show you what what they are where they are and what you need to know about so this is a 3126 Huey pump it's located above the air compressor on the intake side of the engine there's a c7 or c9 UE pump same location it's on the frontier housing above the air compressor the purple line is the high pressure oil line of 3126 and the Green Line is the quick-connect oil supply line on a c7 the oil supply line is the green line and the Purple Line is the high pressure line going so here we have a 31:26 injector the green arrow is pointing to the top o ring and the red arrow is pointing to the lower o ring that seals the Huey system in the head so what are some common complaints with the Huey systems well since they control the injectors there's a lot of different things that these can do they can give you a check engine light they can cause the engine to crank but not start they can give you low power engine miss pretty much all power complaints and engine mounts starting can be caused by the Huey system so hopefully you have a way to communicate with these engines because what you're going to need to do is see what those Huey pressures are and I'm going to be going over what codes to look for what the pressures need to be okay so here we have a download 31:26 now these principle law applied with C 79 or 31 6 and we have injection actuation pressure signal erratic pulse and they're fairly recent they've happened within the last hour of the engine running now we also have injection actuation pressure system faults and there's 255 occurrences which is the max count so this person obviously has a problem with their hue a system somewhere so now we're going to be showing you how to troubleshoot that so here we have a status screen we're viewing most of the engine information as this engines running and the first thing you're going to want to check is engine oil pressure because if there's no oil pressure it's obviously not going to be scented oil to the Huey pump now the next things we're looking at is desired injection actuation pressure injection actuation pressure an injection actuation output now what you want is the desired and the actual to be really close you typically don't want to see them have a 100 psi difference ever so this one you can see is kind of jumping around see it went up mm there and desired to not move so that's typically caused by the Huey pump itself so typically two Huey pump after that it's usually the injector seals and it does there is a injection actuation pressure sensor but I've never seen that be the cause unless it says injection actuation pressure sensor voltage high what I'm doing here is I'm going into cat has a way of controlling the Huey pressure in their diagnostic tests called injection actuation pressure test so when you turn this test on it's going to drop your hew pressure the lowest setting which is desired is 870 and what you can do is you can step up or step down the pressure and what that will do is it'll see if that pump can keep up with demand and like I said you don't really want to see the desired and the actual pressure change very much when you jump it up it should jump up to like 3300 and when you pop it down to 2100 it should state see right now it's at 1700 actual and the desired is 2,100 now 76 percent output you're probably thinking why isn't go to 100% 76 percent on a Huey pump for some reason is max output so at least on these 13 126 that it is on a c7 or seen on you might 9 percent max output but as you can see the pressure was not keeping with desired there on that second step it's kind of bobbing around when we drop it here again it's going to change and like I said you don't want to see it typically be over 100 psi difference so how do you distinguish if it's the Huey pump or the injector seals itself well typically the injector seals the leaks will get worse at a higher pressure so when you pump it up maybe it will never reach the 3300 whereas this one is reaching the 3300 with no problem it seems to have a step problem at the 1400 and 2100 problem or a pressure setting so that seems more in line with the Huey pump going bad other things let's say let's say your engine won't start you hook up to it it won't build Huey pressure at all that might be an injector seals went out so what you want to do in that case is pull the valve cover and you're going to crank it and you're going to look for a stream of oil because that pressure is going to be typically under very high pressure so if your injury won't start you see you got on a few pressure pull that valve cover keep a little bittle back away from it crank it and see if you've gotten a huge pressure oil leak you can also do it with the engine running but it makes a humungous mess if you suspect an injector leak so we've got a 31:26 here and what we're going to do is we're going to test that driver so the c7 c9s also have a driver I'll show you where it's at but this is a 31 26 and on 3126 the drivers are replaceable they're about I want to say they're about $240 but usually it's the pump itself so what you do is you oh my out the driver and on a 3126 it should be between 4 and 16 ohms on a c7 or a c9 it should be 8 plus or minus 2 so basically 6 to 10 ohms of resistance there's your injection actuation pressure sensor there on the top makes the valve cover base I was just point it now yeah if you pull this valve cover and you were to check for oil leaks I'm not going to do that on this one because it's the key we pump just the way it was running and wasn't keeping up with demand that's not indicative of a leak leaks are it will never build pressure or it will not build higher pressures it makes a big mess even if there are no leaks those in those Hughie injectors spray oil everywhere so just be cognizant of that and this oil line here on the 31:26 there's an update kit for it and you see the cracks there's a steel line update for this rubber hose and if you're changing your pump you should change the kit so here we have a c7 c9 pump and here's the Huey driver it's actually on the top it's not on the side now I have a video showing you how to change your Huey pump and how to change your injectors if you find an injector seals leaking you can actually just change the seals you don't have to change the injector itself although the injector themselves can also fail and leak the pop itself is the number one cause of huy issues the pumps are fairly expensive you're talking I think they're around 1200 hours for a c7 pump out they're not very difficult to change like I said I have a video describing how to change the pump and how to change the injectors or we seal them if in fact that's what you're going to end up doing I hope I showed in this video enough to be able to troubleshoot it now obviously you're going to need a way to communicate with the engine in order to troubleshoot these this isn't something you can do with you know just some some basic hand tools but if you are troubleshooting the Huey issue hopefully this video helped you out if you have any questions you cannot leave them in the comments section thank you you

Channel: Adept Ape

Views: 219,238

Keywords: HEUI, HEUI fuel system, Cat HEUI system, Injection Actuation Pressure, Cat C7, ACERT, 3126, C9, 164-02, 164-11, Cat Troubleshooting, Diesel Mechanic

Id: nQ0XYpZtl_M

Length: 10min 56sec (656 seconds)

Published: Thu Jul 14 2016