I’m working an a dh4 with some issues... starts up runs and operates as it should . But ... when you turn key on the warning light and buzzer and most display function lights all illuminate . The buzzing and lights stay on after started . Also it will not **** off when turning off the key . You can operate with no buzzer or lights if your turn the key off . I’m a little baffled . All fuses look ok . Breaker under left door seams to be normal . I get a slight jump in voltage at each batter when started at slightly off idle . Go from 12.1 to about 12.35 volts and get about alternator lug when started . It is a 24v system . Any help would be fantastic . I do not have a factory manual or owners manual as of yet . I do plan on getting them .
check the fuel pressure switch and wiring wops I jumped in too early *** is with the id tag? that don't match what's sitting on the float
Do all the same lights that come on along with the buzzer when you first turn the key on also stay on after the engine is started.? Have you checked the voltage at the alternator output side when the engine is running.? It should be somewhere around 27-28v. Look at the 3rd photo Mark – D4H S/N 8PB01405
I looked at the first two id photos, but didn't check the third thinking it was more of the same. the fuel pressure switch or wiring fault will give similar faults as the op is describing as long as he is not talking about the forklift id the fuel pressure switch gives a engine running signal to the monitor system Off track a bit, how is your son progressing hope all is well mark
Please excuse my ignorance ... I’m not a heavy equipment mechanic . But I can hold my own with a multimeter and wrench . I’m just a bit naive to how the sensors work on these . It’s. Seems very simple , I just lack the knowledge of where things are located and how to test them . What would I be looking for for a wiring fault or due switch code
I’m sorry I snapped a photo of all the tags on the machine . I thought it was odd to have those tags on there .the forklift tag is on the left rear of the machine . But I’m sure it’s a dh4 dozer
All lights and buzzer are activated as long is the key is on running or not running . I have about 25v at the alternator post just off idle .
#9 is the fuel pressure switch. It is supposed to close at 13psi with rising pressure and open at 10psi with falling pressure. Measure the resistance across the two terminals with the engine both stopped and also with it running. You should see open circuit when stopped and continuity (0 ohms or close to it) with it running.
Is the Alternator an issue.? Only if it still gives only 25v at High Idle. Measure the voltage and post the results.
27 volts at alternator when running . Can’t find the fuel pressure sensor . Found 2 wires on left side that look like that’s what it should be . Can I jump these 2 wires to bypass fuel sensor ? Update . So after started some of the lights light up bright and then go out . On the right side seconded down from the top stays lit all the time but at 25% brightness . The test switch does not change anything . I have 7.8!vokts at the top post of the test switch until I hit the switch and then I have .02 volts
For sure nothing on the injection pump . I did find the wires with the tabs broke off on the left side of the engine by the spin on filter and primer . No switch there either . There is a capped off fitting on a tee . you can see in my last photo to the left of my fat hand . I’m pretty sure I have a ground issue . I’m getting a back feed too all the lights in the panel including ones that are blank on the outer display . Not for my machine . I’ll have to get better pictures of the engine . Why would someone remove a fuel pressure switch .
Every 4h I was around had mechanical fuel shut off if I remember right
Yes I was looking today and there is no solenoid . It’s manual
Looked again for sure no fuel pressure sensor
hi, unused indicator stations in the monitor are tied to ground ,it is possible you have lost some of your ground contacts Also the monitor test switch when operated puts that circuit to ground this enables all indicator stations for a visual test .check that test switch is ok(normally open) and that the circuit has not grounded somewhere
Yes I think I’m loading ground somewhere . I’m going up today if stops raining and going to run a jumper to ground things and see what happens
Got some time in on the machine today . I have good power and ground at the Infiniti in and panel . 26 volts at the panel . All connectors are clean and don’t see a issue . At some point there was a manual fuel filter pump installed Obote the fuel filter . I believe this is when the fuel pressure sensor was deleted . I did order a new sensor today in going to try and connect it into the fuel line t coming out of the filter . Can anyone tell me what the purpose of the fuel pressure sensor is if there is no gauge or dummy light for the fuel pressure ? I ran the machine for about 30 mins and the light would come in and off at random . Only go off for a few seconds at a time . I’m kind of leaning to a toasted display panel .
The fuel pressure switch will be for the system to sense when the engine is running.
That makes sense . I kind of figured that was pulled from the alternator signal . Does anyone have a photo of the fuel pressure switch installed in configuration with the pump located over the fuel filter ?
Do you have this plug (circled in the illustration below) on your fuel injection pump..? If you check out the upper photo in Mark's post #13 on page 1, the fuel pressure sensor was mounted in that location on the FIP on later machines. It may be easier for you to install it there rather than trying to figure out a way of installing it in the fuel filter/priming pump area because as originally built your machine was not fitted with a priming pump.
Machines S/N 8PB02567-Up had the fuel pressure switch installed on the injection pump. The good news for you is that the Part Number of the switch remains the same - 9W-3187.