Alright so I've got this 24v project im working on - don't have any exp on them and I heard this is the spot to go...

 

Trucks got p1689 flashing, p0113 codes. Previous owner said it "wouldnt go above 20km/h". I havent tested that theory because I suspected the lift pump. I have a FASS100gph & set of glowshift gauges going in this thing shortly but I wanted to confirm the source of these codes before i mess with them. I also am having, what I believe to be the sending unit act up on me. Fuel gauge at E, but when I disconnect / reconnect connection at top of sending unit it jumps up to half then slowly climbs down. Tested the gauges on the dash, and fuel gauge reads fine on that test. I put fuel in it when I thought it was on E, and it overflowed. So I'm sure it's the sending unit. Anyways looking for some advice on te p1689 and p0113 codes. 

 

What I've done in terms of the diagnostics - 

confirmed vp44 is good by wiring it to the battery from pins 6&7 and idling

Steps 1-3 on the P1689 8 step diagnostic thread... Having trouble accessing the ECM connector so I think I will remove the pump filter and install the FASS before I test that

 

Hoping you folks with all the experience can help out

You really to complete diagnostics for the 1689 code. The hot wire test just proves the pump will idle. You are just putting fuel and power to pump and bypassing the electronics. The computer could still be bad. Is the electrical  in decent shape? Bad grounds or connections can cause issues like this. This can be tricky one and there seems to rash of them here lately.

Edited April 26, 20204 yr by dripley

Yes I supposed by hotwiring the VP, I just meant the pump is getting fuel and I it allowed me to confirm it’s not the VP itself but could be the FPCM or ECM. I took a good look yesterday at the electronics but I’ll have to get my camera in a better spot today and take some good photos of the male connectors on the VP itself. I still have yet to access the ECM. Looks like it’ll be a PITA... Have any tips for getting at that thing 

Take the 2 bolts out of the fuel filter let it lay towards the fender and there it is. But if you have the stock fuel lines you would have loosen them too. I have aftermarket fuel hose so that easy on mine. Another member here went from underneath. He loosened a couple of the clamps that hold the wiring harness so it would hang down low enough to get to.

If you have big line kit just remove filter bolts and it will tip out of the way and ecm ispretty easy 

Thanks lads I will be doing this tomorrow. Will report back!