P1689

[2000Ram2500]

Did some searching around and figured I would post my experience here. Alot of people replacing the VPs over this it seems like. I went onto the dealer site and found the diagnostic tree for this code. Nowhere does it say replace the pump. It says either electrical/wiring issue which I understand could be the circuit in the pump, or the ECM.

 

Personally I am assuming my circuit board is fine and I have a problem elsewhere. I live where there is an issue with rat damage. My pump is tapped for the Edge. I had a spare APPS to try. I tried the relay swap that moparman suggests. I cant fully rule out alternator noise but i have the BD kit and keep that ground wire routed over my intake tube to keep it off the back of the alternator and I haven't had the torque converter issue in months which I would notice because I have a triple disc converter you know when it locks up. I've been researching all week and finally yesterday had a chance to do some actual work on the truck.

 

I disconnected the batteries and left the key on the whole time to do a reset as I saw someone suggest I just did it for a couple hours while i was working on it and so i didnt zap myself somehow. I got the APPS out of the way so i could really look at the wiring underneath. The plug on the VP looks fine and the terminals had plenty of grease, same for the APPS connector. The APPS sensor itself had a rusted out imprint of the bellcrank arm in it which im sure is to be expected from snaps of the throttle and years of weather and maybe it was causing the sensor some confusion? I changed it anyways.

 

Given that my pump is tapped for the Edge i suspected possibly an issue there but the tap was still in there nice and solid. I looked and felt around as best as i could to hopefully rule out rat damage and I couldnt see or feel any chewed up wires all the way up to the ECM connector. However i did notice a tiny little nick in the tap wire itself right next to where the grid heater wire comes up to the intake horn. I fixed that little nick and got the wire cleaned up. It got me wondering though, could the grid heater have caused the intermittent loss of power somehow because it runs so close to the tap wire, and i know those relays kick on randomly while driving. It would cut out more so right after start up and really only from 25 to 45, and on a longer trip across town by the time i got by my destination the loss of power was gone i had no symptoms of the code anymore other than the light on the dash. I've been running the edge on stock all week just to be safe and even cranked it up to 5 and it was running like a beast.

 

So this is where I'm at with this. Basically Im just wondering if that huge grid heater wire was giving off interference through my edge tap wire and causing my problem. Gotta run errands and will see if what i did yesterday fixed my issue.

[IBMobile]

I doubt the wires running close to each other is causing this but the grid heater put a very large load on the alternator which would produce a higher ac voltage signal.  Try this, disconnect the grid heaters main power leads from the left battery positive clamp and see what happens.  

[2000Ram2500]

After running errands i didnt get a check engine light back on again but i felt it stumble two different times.

 

4 hours ago, IBMobile said:

I doubt the wires running close to each other is causing this but the grid heater put a very large load on the alternator which would produce a higher ac voltage signal.  Try this, disconnect the grid heaters main power leads from the left battery positive clamp and see what happens.  

 

I'll try disconnecting the grid heater before i drive it next. That should be easy to do because i have optimas with the side posts and i had to isolate most of the terminals that go to the batteries and not by choice. Probably about 2 years ago now the battery hold down was broken and I hit a bump and my passenger battery fell out and the ground came off stalling the truck which then touched positive side which was shorting to ground using the positive lug through the ground cable. I had molten lead all over it was dripping on the radiator hose and intercooler boot and then the top of the battery caught fire for a second and at that moment is when i popped the hood and saw all this going on. I had to redo 90% of my battery wiring after that but i was lucky and had no other issues caused by it.

 

The new APPS sensor made a difference in itself though the throttle feels alot better probably because its a new sensor and its newly calibrated. Im assuming i was successful in resetting the computer as well and maybe thats why too. We'll see what i find probably tomorrow.

[2000Ram2500]

So I drove it a couple days with the grid heaters disconnected. Hooked them back up yesterday. I was getting the same symptoms and it was getting progressively worse each day but no p1689 code. Finally this morning on my way to work it gave me the code. So I'm back to the beginning with my diagnostics.

 

I'll do a search on the how to for the reroute of that ground wire and do that this weekend. I need to do it anyways I never fully trusted that BD kit or the idea that simply putting a diode or resistor or whatever it is inline will fix all your problems. I'm thinking I might as well eliminate alternator interference before I throw a ton of money at this thing.

 

The reason I'm thinking alternator interference is because replacing the sensor actually helped it. Even now with the symptoms getting bad it's like it's barely there. I barely notice it but I can tell. So if replacing an old apps with a new apps made the problem get better but not fix it then it has to be related. I hope anyways..

[2000Ram2500]

Made it around to doing the W-T wiring mod this weekend. Alternator now charges the passenger battery and the ground goes to the timing case with an extra ground to the drivers side battery. Did a fair amount of running around yesterday and have yet to have it act up but it took a whole week for the code to come back last time so it make take some time but for now it seems to be doing well. I disconnected the BD APPS noise isolator while i was at it to see if this really did solve the issue as the torque converter lockup was really bad and noticeable before the kit hence the reason i bought it. Will report back if any issues persist with this.

[2000Ram2500]

So Ive been doing great up until this morning. It hasnt thrown the code yet but its definitely acting up again so its only a matter of time before the code comes back. 

 

I have not done an actual AC interference test on it yet as I am lacking the proper tool. Should I just go ahead and throw a diode at it and cross my fingers? Is there anything else I should check out?

[2000Ram2500]

I dont have a good volt meter and I was avoiding buying one for no particular reason but I dont have one. Did the W-T wiring mod. Swapped alternator diodes. Now hoping its an electrical problem somewhere. In looking at the factory schematics it references pin #2 on the VP as being two things the Data Link CAN + circuit and it also calls it the fuel pressure sensor signal. Edge has a built in fuel pressure sensor gauge Im assuming its pulling this data from that circuit. Im wondering if anyone knows how accurate this is. I dont have an actual fuel pressure gauge to check it with but it seems to consistently read 33 psi no matter what. I will be pulling connections apart and looking into possible issues there this afternoon before I condemn either my ECM or the injection pump as the cause for this

[dripley]

The fuel pressure from the VP is not what you would monitor. You need a sender on the fuel line from the lift pump after you last filter. As far as what the edge is seeing, I have no idea if you have no sender for it.

[Mopar1973Man]

1 hour ago, 2000Ram2500 said:

In looking at the factory schematics it references pin #2 on the VP as being two things the Data Link CAN + circuit and it also calls it the fuel pressure sensor signal.

 

No such sensor exist on the VP44. From the Dodge FSM book.

 

[2000Ram2500]

This is the pinout im looking out its from the dealer site. Pin #2 being called pressure sensor signal here but everywhere else they call it the Data Link + circuit

 

Any ways its looking like its going to be my ECM that is my problem. I have followed the diag trail for the P1689 in its entirety as well as the one for P0215 which i never had but its relevant and points to the relay and then the ECM. Diode didnt change anything. W-T mod worked great for about 3 weeks but now every time I give it more than 20% throttle it starts glitching and getting real hesitant unless I floor it then it acts normal but Im sure its just not noticeable under alot of throttle. But its consistently 20% throttle and very noticeable and doesnt act up at all below that.

 

I went through all the connections for everything. Cleaned and used dieelectric grease on all of them. I pulled the tap wire off the VP and reconnected everything else. Gonna drive it tomorrow and see how it goes but im almost certain at this point that its gonna be the ECM everything else checks out. All the resistances and grounds pass the tests.

 

Im at a loss here unless theres something else I should be checking before i order up an ECM.

Edited October 8, 2018 by 2000Ram2500

[JAG1]

What did you say you had for fuel pressure? Try to stay between 15 and 19 if you can. I say 15 even though 14 is okay, but in testing both of my trucks I'm finding variations with fuel pressure gauges, so to be safe........

 

Also don't get in a hurry buying an ECM just yet wait to try some more things as a new ECM could present even more problems.

[2000Ram2500]

The edge was just showing a constant 33 psi until i turn ignition off then it goes to 0. No variation at all even under full throttle it only read 33 psi. Aside from an unknown fuel pressure i have no idea what else to try. Im hoping theres something else i can do to test for a wiring problem or the VP.

 

Are there any more wiring tests? Ive checked resistance between VP ECM PDC and ground and voltages test lights etc. Data link + and -. Relay circuit. Relay. Tried swapping between known good relays in case my readings were off. Inspected connections for damage wiring for rats pins all looked good in the connections. Right now im hoping that cleaning and using dielectric grease and pulling the tap wire gets this to clear up because the diags keep pointing to ECM. Is there something im missing as far as a wiring check? Maybe a way to figure out of the chip in the VP is fried?

[JAG1]

I heard one guy found a problem with one main connection that has a 'baylene' clip to it. He was under similar circumstances as you.

 

Its on the harness up high near the top firewall and cowell and has a white retaining clip that swivels or swings out of the way to disconnect. He said his wasn't in all the way and clicked it in and his problem went away.

 

If your fuelp pressure is 33 that is way too high and may be damaging your VP44. Pressure that high can blow out some seals and I'm wondering if thats what your experiencing and then the seal goes back in place after shut down. Shooting in the dark here.

[Mopar1973Man]

1 hour ago, 2000Ram2500 said:

The edge was just showing a constant 33 psi until i turn ignition off then it goes to 0.

 

I would have to say the sensor is blown. Most likely tapped in right at the VP44 which usually kills the sensor in a short order. Like my fuel pressure sensor is 5 feet away and the snubber is at the tap point so by the time you travel the last 5 feet to the sensor the water hammer pulses are nill. 

 

[2000Ram2500]

Thats just it though Ive never had a working fuel gauge. The previous owner had one but it was installed entirely with solid core wire and who knows how many places it was broken at. And i had to ditch the place where the sensor was tapped into the line because the line had a pin hole in it and i had to replace it in a pinch so oddly enough oreillys near by was able to build me a hydraulic line with the right fittings. I just thought it was odd that i dont have a sensor and somehow the edge is producing a signal so i was wondering if it was being pulled from the can+ circuit somehow.

 

So far i've only got one 20 minute trip into work with the tap wire disconnected and all the connections cleaned and greased and a hopeful computer reset with batteries disconnected and key on but it didnt act up at all this morning and normally it would act up like crazy if i tried to get it to actually accelerate. But knowing how intermittent this can be im just gonna cross my fingers i guess. It did take 3 weeks for it to come back last time.

 

@JAG1 i think i know which connection your talking about i'll check that out.

 

Also how about the cummins data link connecter for the edge? The triangle one on older trucks but mines a straight 3 pin connector. It never seemed like it was connected that great to begin with but it was kinda sloppy when i checked it out yesterday. Would that cause something like this to happen? And now that im thinking about it. I remember reading the MAP can cause weird things and this morning for the first time ever i was intermittently getting no boost reading this morning.

[Mopar1973Man]

Edge tuner is built the same way our trucks are. The sensor power lead is 5V and the sense in on the same wire. This means the Juice is looking for ground bias to report fuel pressure. Since the sensor lead was damaged that means the 5V line was maxed out all the time. Hence why you see 33 PSI of fuel pressure. 

 

Just to show the same thing. Unplug the ECT (Engine Coolant Temperature) sensor and turn the key on. You see the Temp Gauge rise to Max and trip the CHECK GAGE light and CHECK ENGINE lights. Again the same thing the ECT is a 5V line with the sensor looking for ground bias from the ECM. When disconnected the gauge goes to max. 

 

So I'm sure you wonder about the low volt code... That when the sensor is ground out now the gauge would be reverse. Same with the fuel pressure gauge on the Edge but there is no code for that just a gauge stuck at ZERO.

[2000Ram2500]

19 minutes ago, Mopar1973Man said:

Just to show the same thing. Unplug the ECT (Engine Coolant Temperature) sensor and turn the key on. You see the Temp Gauge rise to Max and trip the CHECK GAGE light and CHECK ENGINE lights. Again the same thing the ECT is a 5V line with the sensor looking for ground bias from the ECM. When disconnected the gauge goes to max.

 

I actually have seen something similar to this i was swapping clusters in my old ford and left something unplugged i cant remember its been so long but my fuel gauge was beyond pegged like i had no idea it could read that far.

 

Im not 100% sure what your pointing to here though. Did i say a wire was damaged? Im obviously missing something here. The whole 5V signal reference makes sense Honda does it and so does Megasquirt which I know because im putting together a baja bug with a standalone and a honda motor but thats another story. You learn alot real fast when you try to understand how to wire an engine.

 

25 minutes ago, Mopar1973Man said:

Edge tuner is built the same way our trucks are. The sensor power lead is 5V and the sense in on the same wire. This means the Juice is looking for ground bias to report fuel pressure. Since the sensor lead was damaged that means the 5V line was maxed out all the time. Hence why you see 33 PSI of fuel pressure.

 

[Mopar1973Man]

2 minutes ago, 2000Ram2500 said:

Im not 100% sure what your pointing to here though. Did i say a wire was damaged?

 

Wiring is damaged or the sensor. Either way, there is no ground bias for the Edge tuner and the fuel pressure continues to display 33 PSI. Kind of like my ISSPro gauge if I unplug the wire to the sensor it will wrap the needle around till its pointing straight down which means there is no ground bias. Basically trying to show the highest pressure the needle can point to.

[2000Ram2500]

Oh i see so i need to be looking into that circuit then and trying to find a short or break in the wire. I'll have to reference the edge instructions and see what im dealing with here. And obviously get a real fuel pressure gauge. Im going to get an actual gauge and use my open hole in my pillar to mount it, and not with solid core wire either nor will i splice it all into my cigarette lighter outlet and secure it with twisty wire ties... i hate seeing ugly wiring jobs.. fire/safety hazard and all..

[Mopar1973Man]

You might look at the ISPro EV2 which is electric gauge or the ISSPro EV which is mechanical. ISSPro EV2 is USB programmable and you can set the low fuel light for warning measure. The ISSPro EV you can plumb in the gauge using air brake line and never have to worry about electrical. Air brake line is rated for burst pressure of 600 PSI. Just make sure to use a snubber at the tap point and remote mount the electric sensor away from the tap point. If mechanical it automatically remote mounted away from the tap point.