Codes P0170 and P0173, Fuel Pump Control Module part not available anywhere?

Tiny
EVA JEAN
  • MEMBER
  • 2000 MITSUBISHI MONTERO
  • 3.0L
  • 6 CYL
  • AUTOMATIC
  • 32,000 MILES
Diagnostic testing on the vehicle listed above Sport XLS came up with two codes: P0170 (fuel system too rich bank 1) and P0173 (fuel system too rich (bank 2). Two recommendations: 1) replace pump with filter and 2)replace pump control module.
They have no problem replacing pump with filter but they cannot locate he part for the fuel pump control module.
My question is, what are the alternatives if the pump control module cannot be located. And will it be worth it to replace the pump with filter if a pump control module cannot be located?
Wednesday, June 14th, 2023 AT 1:10 PM

5 Replies

Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 108,300 POSTS
Hi,

If you have a rich fuel mixture, the pump isn't the problem. It could be several other things such as a failed fuel pressure regulator. If it is rich, you are getting too much fuel, so the pump is working but something is causing the engine to over fuel.

I attached pics of the regulator below. It should be mounted on the fuel rail. Do you know if this has already been checked?

Let me know.

Take care,

joe

See pics below.
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Wednesday, June 14th, 2023 AT 11:44 PM
Tiny
EVA JEAN
  • MEMBER
  • 3 POSTS
I also got this info, from the mechanic place: "Fuel pump low (should be 48psi and measured at 40PSI) Fuel pump Control module has excessive resistance (should be 4-6 ohms and measure at 8 ohms) / Fuel system evens out when adding alternative fuel.

Not knowing what else to do, we already called them and told them to fix part one and questioned if it would run or be ok if we do not do part 2, since the fuel pump control module nowhere to be found. He said it should but could not guarantee. At that point he also said he could start checking around salvage places to look for the part. So that's where we're at. Thank you so much!
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Friday, June 16th, 2023 AT 9:16 AM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 108,300 POSTS
Hi,

Thanks for the update. Let's keep our fingers crossed that this will take care of the issue.

If you have a chance, could you let me know how things turn out for you? I'm interested in knowing.

Take care and let me know if there is anything I can do to help.

Joe
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Friday, June 16th, 2023 AT 7:59 PM
Tiny
EVA JEAN
  • MEMBER
  • 3 POSTS
We did the part 1 recommendation (fuel pump/filter). The 2nd we could not because fuel pump control module no longer available. As it turns out a non-issue since it wasn't the problem anyway. When we picked it up the service advisor said the service engine light is probably going to come back on. It did. We weren't even off the lot yet.

We turned to another auto repair place. They found the same codes but tested further and found that the vacuum plug was missing. They installed a vacuum cap on the intake manifold and reset the PCM. They did a test drive and rechecked. That was on July 5. Today is July 16th, no red service engine light, running fine.

Paid the first mechanic $150.00 diagnostic test and $867.55 fuel pump, fuel filter. Would have also paid another big chunk if the fuel control module could even be located. Total: $1017.55

Paid the other place: $228. I said to the mechanic at the other place: "So we did the whole replace the fuel pump thing for nothing?". He replied that he does not comment on what other mechanics do, he just fixes what he finds. So, I guess the lesson we learned is to get another opinion. Especially if the recommendation is going to cost several thousand dollars, and the problem is exacerbated by a supposed needed part not available anyway.

Thanks for trying to help Joe.

Eva
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Sunday, July 16th, 2023 AT 5:44 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 108,300 POSTS
Hi,

First, I'm glad to know it has been resolved. However, I feel bad you went through all of that. What is most confusing to me is the codes indicated a rich fuel mixture. When there is a vacuum leak, it allows unmetered air to enter the engine and causes the opposite, a lean fuel mixture. Unless the vacuum affected the fuel pressure regulator. Then it could have caused a rich mixture.

Regardless, I'm glad it's fixed. I just wish it would have been a little easier for you.

Take good care of yourself and feel free to come back anytime in the future. You are always welcome here.

Joe
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Sunday, July 16th, 2023 AT 8:22 PM

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