ECU Fault Codes - Having issues climbing hills 1999 Concourse

[mrfiat]

1999 Chinook Concourse Triton V10. I was originally getting codes P0171 and P0174 (system too lean). The shop did diagnosis and while doing a smoke test found vacuum leak on intake manifold which they claimed was causing the fault codes. The intake manifold bottom gaskets were replaced and I had them replace the elbow vacuum line that causes these codes at times. The fuel filter was also replaced. Smoke test was done again and passed.

I these codes after the repair: P0171, P0174, and misfire codes on Cylinders 2 and 10. Shop says fuel pressure was too low. (25 psi) The shop then said it was the fuel pump. They replaced the fuel pump. (old pump had a hole in the fuel in inside the fuel tank)

I just got back from an RV trip (60 miles) from 5,000 feet in altitude to 8,500 feet and some hills. On the way there it seemed to be missing while climbing hills. Then when I was almost at the RV park, I got these code:

P0171, P0174, P0302 (cylinder 2 misfire), and P0300 (Random/multiple cylinder misfires detected. Fresh fuel in the tank. Tank looked clean when they did the fuel pump.

Any ideas as to what is causing these faults?

Thanks!

[JabberBox]

Did you check the fuel pressure regulator? You also have a fuel pump driver mounted on the frame rail back by the gas tank on the drivers side. Was it replaced when they did the fuel pump?

[mrfiat]

They claim that they tested the fuel pressure regulator. Maybe they didn't. They didn't mention replacing a fuel pump driver. It sounds like that can be replaced without dropping the tank, correct? Also they were unable to source the entire fuel pump with the frame so they replaced the just the pump and the hose in the fuel pump frame. (not sure if that matters)

[caconcourse]

Misfires are also caused by faulty ignition coils if they haven't been replaced recently.

[mrfiat]

The ignition coils have never been replaced. Is there a howto on here that shows how to remove the doghouse cover?

[JabberBox]

As long as they replaced the pump the basket doesnt matter. A bad coil isnt going to throw a lean code. Thats not to imply that you dont have more than one issue. The fuel pump driver is mounte don the frame rail on the drivers side, it isnt inside the fuel tank. You could also have a bad fuel injector.

[mrfiat]

Thanks. Isn't it unlikely to be the fuel pump driver since it is only having problems climbing hills? I'm thinking I should have them replace the ignition coils and the fuel pressure regulator since it appears to be a fuel pressure issue.

[JabberBox]

Its the fuel pump drivers job to vary the voltage signal to the fuel pump base don fuel demand/engine load. If you think its a coil just swap the one that shows misfire with one that isnt showing misfire and see if the code follows the coil. Lean conditions are caused by lack of sufficient fuel. If a coil was bad it would show a misfire but not a lean code because that cylinder would not be burning the fuel being injected to it.

You can also swap injectors around to see if the lean condition follows the injector. If the lean code follows the injector you know the injector is bad, same thing with the coils.

[mrfiat]

I called the Ford dealer and they are unable to find a fuel pump driver for my VIN. Autozone says it is this part #: ECC1999M

https://www.autozone.com/engine-managem ... 558543_0_0

Is this the correct part? I have looked under the RV forward of the fuel tank along the frame rail and found nothing. (on both sides of the RV) Where is the fuel pump driver located exactly?

Thanks!

[JabberBox]

I stated it is mounted on the drivers side frame rail not fuel rail. Some vans have them mounted beside the fuel filter. On my chinook its mounted on the frame back by the fuel tank. Im not a parts dealer so dont ask me if you have the correct part numbers, thats between you and your parts guy.

I would suggest you try a different Ford dealer. Mine is a 2004, maybe they didnt use them in 1999.