The dealer just replaced my lift pump. Tonight I get a stumble from the engine. When I check for codes I have the P0628 again. After replacing parts do they have to clear the codes or do these stay for a while. When I told the dealer about the code last time, he said that the 3-key turn codes were only a starting point for the problems.

Any suggestions?

 

I wonder if something is wrong with these conversions. I had to have my truck towed to the dealer shortly after the conversion and I saw two other threads on here when I was searching. My truck died and one of the others I read about also died, neither would restart. I did not troubleshoot it but I wish I would have. The dealer surely didn't help.

They also do a TSB on the ECM after the retrofit, perhaps yours doesn't have it?

FWIW after the in-tank conversion and a new filter I see 10psi at idle and ~7 or 8 cruising.

Andy

 

The service engine light will go out after 5 starts if the problem is gone. As I said it will clear it self aftre the 5 starts. If you have done the 5 starts and its still there then the problem is still there

CRIS

 

It's been started more than 5 times, but the service light didn't originally come on for this problem. The truck lost pedal and the P0628 code showed up on the 3 key turn. They have replaced the lift pump with the in-tank type and now the code still is there.

Yesterday the truck stumbled twice on me. Coming to a RR crossing, I pushed the clutch in and the truck stumbled and recovered. It didn't set the CE light. It did it yesterday also while backing up. It stumbles, then recovers.

Any thoughts on if the P0628 code is causing this still? I'm going to check for a TSB light mentioned above.

 

Sounds like a fuel delivery problem, almost like the position of the in-tank pump is either not getting fuel to it at all times. When you pulled up the railroad crossing, you were slowing down...then when you were backing up, it was shifting the fuel in the tank in a different direction. It's almost like the draw straw problems I've heard people talking about. But in your case, it's probably the lift pump position (where it's pulling the fuel in) IN the tank that's the issue. Try to see what it will do when you do a hard take-off. If it stumbles, then it's probably got to do with the lift pump position in the tank. Where is your fuel level right now? Are you close to empty? If so, then filling up with more fuel will probably make the issue go away. If that's the case, then the lift pump probably has a problem with drawing fuel at low levels. If your tank is full, then it might not be the problem.

 

I'm at 3/4 full right now. It only happened the two times so far. I've taken off pretty hard and havn't had any more stumbling.

Does anyone know if codes stay displayed for a while or should this one have gone away?

 

I just took a look at the sticker on my truck (on the underside of the hood) and it says:

ECM upgraded to part number 12305051AH - trans pump

According to my service manual the lift pump was powered directly from the ECM (no relay, no fuse) and that makes sense because the dealer put a relay on there to power the new pump. The pump also runs for about 30 seconds with the key on but not started since the retro fit was done to my truck.

P0628 seems to be an open-circuit condition. The next time the truck dies go unplug the relay and see if the ECM is powering it. On mine the relay is on the firewall on the driver's side by the hood hinge, very easy to get to. I'm hoping that mine dies again so I can actually troubleshoot it. The relay is a generic one that you can get at any auto parts joint and the fuel pump power comes straight from the battery next to it.

Remember that the ECM can't see the fuel pump anymore, just the relay. The only way it knows something died is if the engine dies or can't maintain rail pressure.

If the ECM is current-sensing it's possible that the new relay doesn't draw enough current and the ECM gets stupid and doesn't keep powering the relay. I would think if this was the case that the ECM upgrade would have changed that. Who knows?

Andy

 

read this link
http://www.turbodieselregister.com/f...d.php?t=173062

might be some of your problem, who knows.

 

Well, the truck died on me tonight. I started it and drove out of my work parking lot, onto the street and at the stop sign I pushed the clutch in and the engine died. The dealer has it tonight and will look at it tomorrow. I'll ask him if they did the ECM flash. It's frustrating...

 

That's how mine died, too. Strange! Good luck with it and I hope the dealer doesn't just wiggle some wires like they did on mine.

Andy

 

it isnt just 5 starts. it is complete warm up/cool down cycles that will clear the cel if the problem has gone away.

 

kertoncol and realsquash,

If you read the link I posted you might find your problem.

 

Bluebull,

I read throught that page, thanks for posting it. The first thing I checked was the connections made by the tech to the battery. I haven't been able to go all the way down the harness because it hasn't failed since the dealer wiggled the wires.

Andy

 

Have someone bump the starter to make the fuel pump start and then wiggle the wires to see if it stops or fluctuates. You don't have to start the truck, just bump the starter like you would when priming the system after a filter change.

 

I'll read that link again and see if the dealer ends up doing any of that. The dealer called and wants to keep the truck overnight. He is wanting to check fuel pressures while the engine is cold and hot. I'll post more when I know more.

Thanks everyone!