Archived Truck Won't Start, Help!

[AF4X]

Tonight I started the truck, engine ran very badly, very rough.

Turned it off immediately, tried to restart, no dice.

MIL is on, and following codes are set:



P1693 Companion code DTC-9



P0230 Transfer pump circuit out of range



Transfer pump runs for a few seconds at key on,

and for 30 seconds if you bump starter (normal).

But I noticed once or twice, pump ran for a several seconds after key was turned off.

I don't think this is normal, I certainly never noticed it doing that before.

When pump runs, fuel pressure is perfectly normal.



Does the P0230 code disable starting (via the injection pump or some other way) because it's not happy?



Please help, Important doctor's appointment day after tomorrow,



Thanks

 

[ToolManTimTaylor]

Can we have an idea of what fuel pressure on the dakota guage you have? Just because the pump SEEMS to be running does not mean it is Filter is O. K?

 

[Gary - K7GLD]

Any idea of what fuel pressure you have? Just because the pump SEEMS to be running does not mean it is



UNNHHhhh... .



fuel pressure is perfectly normal.

 

[Gary - K7GLD]

Only fuel pressure-related issue *I* am aware of affecting starting, is that if too MUCH pressure is registered at engine start, it won't start - happens to some guys when they add a pusher pump and wire it to always be on, instead of cycling like the stock LP does...



Sure hope the VP-44 hasn't gone TU... .

 

[AF4X]

Tim & Gary,



Fuel pressure goes to about 4 PSI at ignition on, then falls to zero, like it always has.

If you bump starter, it goes to 12 PSI, where I have the pump set to (it's adjustable).

I have a tapped banjo at the input to the VP-44 (Post fuel filter) that is piped to a manifold through a snubber. The manifold feeds the sender for the Dakota digital gauge, as well as a liquid filled dial gauge. The two gauges are in agreement, so I know I really have correct pressure at the input of the VP-44.

Pump is powered by the original lift pump wiring harness.



Late tonight after sitting for a few hours, truck started with some difficulty, then ran fine. But it wasn't warm when it refused to start earlier this evening. Guess I'll drive it around tomorrow and see if the codes go away? Maybe I'll buffer the power coming from the ECM with a MOSFET.

 

[Gary - K7GLD]

HMMmmm - your pressures sound normal - which brings us closer to a failed VP-44...



Some guys have found corrosion or bad electrical connections at the ECM or VP-44 - as a last resort, you might check those...



Good luck.

 

[AF4X]

Gary,



My plugs / connectors look clean as a whistle, don't want to break the warranty void seals though. I hope the VP-44 is OK, (no trouble codes related to it) but I did have to run on the original lift pump for a short time at very low pressure when it failed at 28K Miles. That's when I went to the edelbrock pump.

The best clue I have, is the pump still running after the key was turned off. It only draws about 1 or 2 amps more than the stock pump, but maybe that's enough of a difference that it needs a buffer circuit. I'm gonna add a toggle switch that will let me select whether to run the pump from the ECM power or directly from the battery. That'll be handy after fuel filter changes to purge air.



Thanks for your help,



Drew

 

[ToolManTimTaylor]

The ECM sends a pulse signal during cranking to regulate starting pressures. Case in point My old PE4200 setup would fire off 12 psi during cranking only then once tach signal is recieved by the ecm she lit off to a steady 18 psi (Or whatever full on pressure your pump can produce. ) Just make sure you do not backfeed the ecm with that toggle.

 

[AF4X]

Well the truck is working again. MIL is off now, but codes P1693 & P0230 are still present.



They will go away after ?? many restarts? Or a trip to AutoZone to have them cleared.



I measured fuel pump current at 4 amps versus 1-2 amps for the stock pump. Does anyone know what the current window is for the P0230 "Xfer pump circuit out of range" error?

Well I scoped the drive voltage coming from the ECM. At key on it's a short pulse of +12 volts, not a PWM voltage as I've heard.

So I just used a relay to buffer the voltage. That should insure that the ECM never has to supply more than 1/6 amp to the Xfer pump circuit. I used a relay that has an internal damper diode, to prevent any "reverse kick" back into the ECM when the relay de-energizes. So, thanks everyone for all the help! If the problem returns, I'll post again.

 

[Bob4x4]

The 230 code is about amperage for pump too high or too low,if the wiring is good replace the lift pump. Straight forward.



Bob