'03 Hot start problem

[Melvin P. Thorpe]

Recently I have been having trouble starting the DMax after it has warmed up. Dealer re-flashed computer and said there were no codes. It was ok for a week or so and it has now returned. The only way I can start it is to flip the accelerator a few times. I have an appointment with dealer next week. Any ideas I tell them?

[DmaxMaverick]

Welcome to the Forums!

How many miles? Last fuel filter change? What do you mean by starting trouble? Long cranking, or slow, intermitent fire? It's very likely a service item issue, poor fuel quality, or an air leak, being there are no codes. Before shoveling out $$ to the dealer, there are several things you can check. Try pumping up the primer before a start the next time you experience the problem. If it starts normally, it's probably just sucking in some air.

[Melvin P. Thorpe]

I have 75,000 miles. A month or so ago I had the filter changed and went on vacation and traveled over 1,000 miles before it would not start at all. I took it to my mechanic and he checked all the fuel system components but there was nothing wrong. He thought there was an air bubble somewhere so he bled the system and changed o-rings thinking air was getting in the system. It happened again so I took it to the dealer since my mechanic said they would probably replace the injectors under warranty, the dealer replaced the filter under the warranty and re-flashed the computer but after a couple of weeks I still have the problem. He said there were no codes and he thought the re-flash would cure the problem, it did for a week or so but now it is back.

[DmaxMaverick]

If bleeding cures it for a while, I'd stay with that diagnosis. You have to have air getting in somewhere. The primer pumps have been known to leak. A hot engine can soften seals, and allow air to leak in. Do you have fuel/grime staining around the primer? If so, clean it well, and watch for it to return. If fuel can leak out, air can leak in. The fuel system is suction from the tank to the HP pump.

[Melvin P. Thorpe]

Could this be injector related? There is no staining or wetness around the pump.

[DmaxMaverick]

Could be, but without any other symptoms, it's hard to say. What do you mean by starting trouble? What does it do (or not do)? What happens when it finally starts? While injectors can cause starting issues, there should also be issues under running conditions.

This could also be battery related. If you have a bad battery(ies), it wouldn't be the first one with problems. These rolling supercomputers are very sensitive to voltage quality.

[Melvin P. Thorpe]

It cranks just like normal, not faster not slower. When I tab the throttle a few times it starts right up and runs just fine after that. The only problem is when it has already started and I start it again like going to the store where it sits there for a little while. Once it starts it runs normal.

[DmaxMaverick]

Probably not it, but.....

Another thing to check is your fuel filler cap. If it's not venting properly, it can prevent the pump from drawing fuel easily. The cap should vent both ways, and easier inward venting. Can't verify, but it's been discussed and suspected the cap vents 2 PSI out, and 2" in.

Interesting. Tapping the pedal should have no effect at all (coincidence, maybe?). The PCM controlls throttle before it's running. The pedal isn't mechanically connected to the fuel system. It's electronic.

[Melvin P. Thorpe]

Well, the truck wouldn't start this afternoon so I had it towed to the dealer. I will report back what they found.

[Kennedy]

This hasn't been all too common as of late, but I've heard of several 2003's that would not start due to injector issues ie excessive fuel return.

[Melvin P. Thorpe]

The dealer called me friday afternoon and said that the injector pump was bad so they ordered a new one. National back order on the injector pump so I guess it is a common problem. Another interesting thing the service writer told me is that the injector pumps are vehicle specific. Perhaps there are a few different versions to fit different states or production changes. Interesting!

[Melvin P. Thorpe]

PIcked up the truck yesterday. They replaced the injector pump and all is well now. When discussing the issue with the service manager he told me that the pumps are specific to different states and that they are not made anymore because the newer trucks use a different model. Evidently they have a re-manuifacturing facility and the dealers get re-man units.

[Melvin P. Thorpe]

Well it still has a problem when it is hot. It cranks and cranks before it fires. It is at the dealer again.

[Melvin P. Thorpe]

Dealer called and they are replacing all the injectors.

[Melvin P. Thorpe]

Injectors replaced and good so far. It starts much better!!!

[Bai Qui]

My dad has an '03 with the same starting problems you described. Cranks over a lot before it takes off when it's hot. The problem seems to be intermittent. Did replacing the injectors fix the problem? Or has it resurfaced?

[Melvin P. Thorpe]

It's been 3 months and about 5,000 miles and it is still running like it did when new. Awesome!

[Kennedy]

Sounds good!

[Bai Qui]

Thanks for the info. He's been trying to figure out what it is and of course the dealer just checks for codes and says they can't find anything. Hopefully he can get them to swap out the injectors. It only has 60,000 miles on it.

[Melvin P. Thorpe]

My dealer did a bunch of tests and replaced the injector pump but after a week or so it went back to not starting. They did other tests and replaced the injectors under warranty. I now have another 5,000 miles on it since the work was done and it still runs like new.