Bryce C
DFW
My RPM gauge gets weird when I turn the water pump on. It works perfect when the tm is running at low, medium, or high. But when I turn the main water pump on the gauge maxes out and no longer reads the rpms of the machine.
Gauge goes crazy
- Thread starter Bryce C
- Start date
When you say waterpump and main water pump you loose me. I have no idea what your talking about. Transfer/ supply/auxiliary supply pump??? Those terms would make me think that you carry water and is supplied to the machine by this pump . Where as ,main/pressure/ high pressure or name ie:cat/general/ hipro would make me assume that you're talking about the pump that supplies soulition to your wand . Then there's the wastepump i dont know what else you can call that one but waterpump pump and main pump can be interpreted differently . But with that said i don't know about your machine specifically but generally speaking the tachometer has a magnetic pickup and so machines mount this pickup on the main pressure pump and attaches a magnet on the back ( pump side) of the clutch pulley that pulley generally speaking again , turns much slower than engine or blower and is compensated electronically with a setting button on the tach. Perhaps with the work you have recently been doing in that general area youve inadvertently knocked this outa whack . I tack my machine off the driveshaft and measure blower speed below is a picture of mine yours will probably look different but worhs the same ill try to find another picture and edit with it couldn't easily find it but Google says the location is on the blower drive pulley
Last edited:
Bryce C
DFW
Thanks for setting me straight with the lingo Dwain. I didn't see anything like the magnetic pickup near the blower pulley, maybe it is on the high pressure pump. Now that I know how it operates and what it looks like I'll be able to spot it next time I uncover the power pack and check things out. Its happened a couple times now where the machine shuts down for no reason at all. Then it just starts right up and continues running fine. I wonder if the tachometer going far enough out of whack could've triggered a safety mechanism.
It's really cool slowly demystifying this machine and seeing how it all works. I really like this CDS 4.8. Such a cool design...
Jim Pemberton
MB Exclusive.
- Joined
- Oct 7, 2006
- Messages
- 12,673
- Name
- Jim Pemberton
When I first became aware of your troubles with the unit you purchased, I nearly texted you to recommend that you get it to a nearby service center.
I'm glad that I didn't....
What Dwain has so unselfishly shared with you has saved you thousands of dollars in labor charges, and what you've done by learning to do this work on your unit yourself, will save you thousands more, plus days of downtime.
I am amazed and the amount of in depth knowledge Dwain has, and even more impressed with his selflessness.
Bryce C
DFW
Thanks Jim. Wise words. Dwain is both seriously knowledgeable and immensely charitable. And here I am an undeserving goofball with grace pouring out on him. With the help of Dwain and others here I have gone from barely knowing how to turn this thing on to having a decent working knowledge of it in a short period of time. Trial by fire, I thank God for you all.
Jim about going to a local service center... I did! The folks you know very well that you and I have talked about. They said no, we won't work on it! After I drove 2 hours round trip twice! I really just wanted them to get it in good working order so I could learn the basics and figure out how to repair and maintain it later. When the engine idle wasn't correct those guys said they won't touch that part of a pto style system
So Robert that you introduced me to at MF and Dwain here helped me get that fixed promptly. Then the rest of the needed repairs followed 1 after the other, with Dwain saving my arse, and teaching me precious knowledge.It's working well now. Occassionally the machine shuts down without having tripped any recovery tank or water box sensors. I am hoping it has something to do with the tachometer when I look into that soon. Otherwise turning it off and rebooting it seems to get it working fine, then it runs as long as I need it to.
Does your machine completely shut down or does the van engine drop to idle?Thanks Jim. Wise words. Dwain is both seriously knowledgeable and immensely charitable. And here I am an undeserving goofball with grace pouring out on him. With the help of Dwain and others here I have gone from barely knowing how to turn this thing on to having a decent working knowledge of it in a short period of time. Trial by fire, I thank God for you all.
Jim about going to a local service center... I did! The folks you know very well that you and I have talked about. They said no, we won't work on it! After I drove 2 hours round trip twice! I really just wanted them to get it in good working order so I could learn the basics and figure out how to repair and maintain it later. When the engine idle wasn't correct those guys said they won't touch that part of a pto style system
It's working well now. Occassionally the machine shuts down without having tripped any recovery tank or water box sensors. I am hoping it has something to do with the tachometer when I look into that soon. Otherwise turning it off and rebooting it seems to get it working fine, then it runs as long as I need it to.
Bryce C
DFW
Van engine just suddenly drops to normal van idling of about 600 or so rpm. But the machine stays on. Good question, I stated the issue incorrectly.
I thought maybe the OBD plug from thr throttle controller came loose. I wrapped a piece of electrical tape around it to make sure it is snug and it is still occassionally doing it. All the connectors on the throttle controller itself are snug too.
My machine does that every once and a while about once every two weeks or so. It has to do with the throttle controller. I think it loses momentary contact some how with the engine control module or ground/brake set.
Thats where the led lights on the controller would come on handy. Till you restart the controller will self diagnose. In my case its buried deep in my dash and not easy to see.
You might check the wire on the machine end. Mine is connected to the on /off or more correctly the clutch in/ clutch out switch on my machines dash.
There's only three wires/circuits that can cause this from the machine, the wire that supplies power ie: tells the controller the machine is clutched in, next world be ground witch would kill the power to controller third would be the emergency brake sensor wire making the controller think the emergency brake was disengaged. Other than that the vans ecm is sending error signals ie: foot on brake, transmission in gear etc those would be showing in the self diagnostic leds on the controller. You might want to spend some time with the controller's manufacturers tech support. There always available and very helpful. Mine does it so seldom that i live with it but if it's happening frequently i would give them a call. You could also have a defective throttle controller and they can help you with that too
Bryce C
DFW
Thanks Dwain. This is super helpful. I'll look into it all and report back when I get the time soon. Past few days have been a race. And I need to finish a busy day early enough to replace my serpentine belt, tensioner and idler pulley in the van. Not sure what is causing the squealing all of the sudden. Hoping it isn't alignment because I didn't buy that few hundred dollar laser tool you told me about. Sounds like a have a dozen birds chirping under my hood. Seems to get better when the engine heats up as well as at high speeds. We'll see!
Bryce C
DFW
I'll probably call the manufacturers technical support soon. The previous owner had this wired in a way where the parking brake plug is not used on the controller, yet the emergency brake cutoff obviously works since I need to have the emergency brake fully depressed in order to turn on the machine. Unless parking brake is different and separate from the emergency brake. I'll read the installation manual again and call the company soon.
This thing cut off 3 times in the same job this morning. I released the emergency brake and slammed it down to the floor as much as I could and it worked fine all the way through that job and the next one. Maybe I just got lazy depressing the ebrake less and less. I still want to make sense of this thing. It seems something is off with the install since the parking brake plug is unused...
This thing cut off 3 times in the same job this morning. I released the emergency brake and slammed it down to the floor as much as I could and it worked fine all the way through that job and the next one. Maybe I just got lazy depressing the ebrake less and less. I still want to make sense of this thing. It seems something is off with the install since the parking brake plug is unused...
Bryce C
DFW
It got too late to call tech support today. Not sure I'll have time tomorrow as we have 3 jobs booked. Once when it cut off today the throttle control module was dead with no lights lit up at all. The next time it cut off all the lights were on solid but the rpm setting I had engaged (high) was flashing. Not sure if the e-brake has something to do with it, sometimes I slam it to the floor and then it runs fine uninterrupted for the rest of our job. But other times I thought I had slammed it to the floor and it still cuts off. Weird..
I went to replace the serpentine belt, tensioner, and idler pulley in my van tonight and noticed dried orange splat all over the front of my engine concentrated around my water pump. Bought a new water pump and OEM thermostat (my van has been a steady 210° since I bought it, I think it had an aftermarket thermostat for higher heat...). Removing the fan clutch is hell on earth! I bought the specialty removal tool and an air hammer and it wouldn't budge. I ended up removing the water pump with the fan attached, and then clamping the pulley and finally breaking the fan free. Mechanical work is a trip.
I went to replace the serpentine belt, tensioner, and idler pulley in my van tonight and noticed dried orange splat all over the front of my engine concentrated around my water pump. Bought a new water pump and OEM thermostat (my van has been a steady 210° since I bought it, I think it had an aftermarket thermostat for higher heat...). Removing the fan clutch is hell on earth! I bought the specialty removal tool and an air hammer and it wouldn't budge. I ended up removing the water pump with the fan attached, and then clamping the pulley and finally breaking the fan free. Mechanical work is a trip.
If the controller went completely dead it Sounds like the 12+ wire from your machine to the controller or the ground might need to be checked possibly where they start not at the controller
Bryce C
DFW
That makes sense, a good place to start. Thanks Dwain! I'll dig into this on Saturday.
If you're unsure if the parking brake wire is causing problems that safty feature can be bypassed by removing the wire from the controller parking brake terminal then connecting the park brake terminal to the negative terminal on the controller. that will tell the controller that the park brake is always engaged
Bryce C
DFW
This problem with the van reducing to normal idle of 600rpms in the middle of cleaning is happening on every job now. The driveshaft and tm is still engaged but not enough juice to clean. Turning the van off and rebooting is starting to not work either. My last job this afternoon I turned it on and off several times and the idle wouldn't increase beyond 600 rpm. I called tech support at Inpower and was a bit disheartened with what I heard in light of what I am experiencing.
He said GMC has programmed in all sorts of safety features in the computer so if the van detects something off in the air, fuel, exhaust, or charging systems it will tell the controller to throttle down as a safety feature. I've had a check engine light on and had it read, it's a P0174 fuel lean bank 2 code which is about as generic as they come I found out. Could be MAF sensor, O2 sensor, fuel anything, air anything, vacuum anything, wth... Maybe the van has nothing to do with it and it is somewhere on the tm. I read on Hydramaster fb group a guy said he had a cracked main fuse on the tm control panel that worked fine until it heated up and then it would separate enough to cut power. I'm not great at diagnosis. Not sure how I'll figure this out short of replacing things 1 by 1 until the problem is resolved.
He said GMC has programmed in all sorts of safety features in the computer so if the van detects something off in the air, fuel, exhaust, or charging systems it will tell the controller to throttle down as a safety feature. I've had a check engine light on and had it read, it's a P0174 fuel lean bank 2 code which is about as generic as they come I found out. Could be MAF sensor, O2 sensor, fuel anything, air anything, vacuum anything, wth... Maybe the van has nothing to do with it and it is somewhere on the tm. I read on Hydramaster fb group a guy said he had a cracked main fuse on the tm control panel that worked fine until it heated up and then it would separate enough to cut power. I'm not great at diagnosis. Not sure how I'll figure this out short of replacing things 1 by 1 until the problem is resolved.
Last edited:
Bryce C
DFW
Maybe I'll run a new 12+ ignition to the control module, replace the main fuse, jump the ground and park brake plugs on the throttle control module (releasing and pressing the e-brake doesn't help at all now), and if it still persists start testing and replacing whatever is sending error codes to my van computer in the air, vacuum, fuel, or exhaust system.
Bryce C
DFW
What Gary at Inpower said is that my throttle controller is showing 2 different problems, 1 is just no power when all lights are off (likely bad 12+ ignition), but the other where all the lights are solid but the selected rpm mode is flashing means that there is something off in the van and the computer will not allow the throttle control module to throttle up. I can only guess it is the P0174 code, but that does not seem simple to diagnose. Guys use smoke machines to check for vacuum leaks, fuel pressure gauges to check the fuel system, and more from what I am seeing on YT. Maybe I should just do what Nate mentioned a while back and use an extendable measuring stick with a wheel on it to fix the gas pedal at a decent rpm so I can clean with it until I figure this out.
Their pretty good there at inpower. I thought you had a power problem. Because you said no lights . You'll need to trace out the ground and 12Ă· wire. It's more that likely the connections the probability have crimped fittings , if so my suggestion is to replace and solder and srink wrap. As fo the p0174 code in most cases its something simple. The sensor that monitor lean are the mas air flow and the o2 sensors. Most always its one of these sensors or a vacuum leak. Do you own an engine analyzer? If so will it graph live data? You'll need to see the o2 sensors in action to diagnose . Vacuum leaks can be checked with smoke or starting fluid . I recommend smoke. You can youtube how to build a simple smoke machime with a cigarette andhow to use it mass air flow sensor can be cleaned and should be done regularly only use map or maf sensor cleaner only. The sensor is located on the intake tube after the air filter and before the throttle body. Iclean mine every other oil change the code that is spit out will tell you which side of the engine the problem is on bank one is the side of tje engine #1 cylinder is on . As
Forgot, when tracing the wires make sure that the ground wire is connected to a dedicated body ground( where other manufacturers grounds are attached) not just machine screwed into the body. somewhere, do you have a test light? If not i would recommend you get one but get a low draw led. Read all the information before you buy you want one that is safe around sensitive Electronics like your ecm bcm tcm incandescent and halogen bulbed testers can damage sensitive Electronics
I dont know how mechanically inclined you are, or the extent of knowledge you have of vehicle engines and systems. P0174 code can be something major like head or intake manifold gaskets bad catalytic converter or something as simple as a loose/ cracked or disconnected vacuum hose, dirty or bad maf or o2 sensor. Depending upon your knowledge/ tools/time you might consider having a mechanic look at and repair the van and considerate your energy on the machine side. Eighter way if you need any advice im more than happy to help also have complete factory service manuals for 1998 & 2020chevy vans these manuals are several hundred pages and have all the information that dealers have on there computers but in print form the manuals are specific to the year but the information is good for the model run. Ie: frankinstien is a 2020 but my manuals are for a 2019 & bought my ford ranger service manual for my 2005 ranger but when i totaled it and bought a 2009 i used the same manuals
Heres a simple,backyard redneck non professional way to tell if you have a vacuum leak find a long steep grade to drive up , one where you can drive at least 50mph and your transmission will have to downshift. Now at the bottom of the hill turn your air-conditioning or heater on high. Set controls so as high air blows outa dashboard vents. When you're climbing up the grade be aware of the air flow from the vents. If somewhere when the engine is working hard the air stops coming outa the vents you have a vacuum leak. Now to explain whats going on. When the engine is working hard the manifold vacuum drops. Your vents are vacuum actuated , if the vacuum drops your vents will go to the default setting which is defrost/floor till the vacuum builds and the go back to setting. No this wont tell you where the leak is but you can get an idea how bad by how quick you loose and gain back the air flow your van has a vacuum reserve tank that normally would supply vacuum durning the times the engine doesn't provide adequate amounts but with a leak that will deplete that quickly
