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Guest Message by DevFuse

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Can bad fuel pump cause misfire in cylinder 1? 2000 OB

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6 replies to this topic

#1 hattiewatson


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Posted 09 February 2005 - 03:27 PM

Question: Can a bad fuel pump cause a misfire code in the SAME cylinder each time?

Problem: 2000 OB auto - intermittently sputters, almost stalls, misfires, occasional backfires? (popping noise from rear undercarriage) - only during acceleration from stop or low speed, always on a slight grade (up) or hill. CEL flashes, sometimes stays on, then will turn off on its own.

I'm not mechanically inclined, nor do I have any tools or a garage, so I'm relying on the DEALER. EEEK!

Dealership said code reads: Cylinder 1 misfire.

Replaced ignition coil, replaced O2 sensor, replaced plugs, had wires checked ($$$$)

Third visit to Dealer with same CEL code and problem. Now they want to switch the cylinders? and see if the misfire occurs in the same place?
They are thinking I may need to have the valve repaired??

I haven't got a clue what those things are..I'll have to get an engine diagram and figure out how it works...in the meantime:

I've read a lot here, and it sounds like it might be a fuel pump, but would I get a consistent cylinder 1 misfire code? Wouldn't the misfire vary in each cylinder?

My first Subaru and I think I bought a lemon. (bought used w/ 150K km).


#2 cookie


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Posted 09 February 2005 - 03:33 PM

I would tend to agree with the dealer from what you say here. I would also try Seafoam and do a compression test before I tore it down.

#3 MorganM


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Posted 09 February 2005 - 03:41 PM

Sounds like they are just throwing parts at it. Maybe time for a second opinion.

Tell them to do an OHMs resistance test on all the injectors. I bet injector #1 is higher than all the rest and higher than specification in their service manual.

Fuel pump wouldnt cuase only one injector to missfire.

They need to check some other things before tearing it down to fix a valve!

#4 Cougar


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Posted 09 February 2005 - 04:41 PM

My momma always told me, "If life gives you lemons, then make lemonaid".

You are correct in your logic about not just one cylinder having a problem. Some things that can be done to pin this problem down are:
1. Swap the spark plug lead with another one and see if that changes things.
2. Swap the coils.
3. Swap the fuel injector.
4. Check the compression.
5. Check for carbon buildup in the cylinder.

Here is a link that shows basic engine operation.


#5 SevenSisters


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Posted 09 February 2005 - 07:22 PM

Cougar has excellent advice, but if you're at the mercy of a dealer with a boat payment, you're in trouble.

All the items Cougar suggested are simple. Buy some tools. All you need is a Phillips screw driver, spark plug wrench, a compression gauge, and the garage.
I can see the last item being cost prohibitive. Got a friend with one?

#6 MorganM


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Posted 09 February 2005 - 07:49 PM

Cougar has excellent advice, but if you're at the mercy of a dealer with a boat payment, you're in trouble

Not at all. Even with a warrenty you are not legaly bound to them for parts or service in any way. It would be illegal for them to force you to use their parts and service. You have the right to use any certified mechanic and certified parts available to you as a consumer. For more details youd have to look up the exact federal law/statute.

#7 Hondasucks


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Posted 10 February 2005 - 09:19 PM

Have them do a leak down test, and a compression test, if they insist on it beign a valve. Labor for that would be cheaper than labor to tear the head down.

Also, a flashing CEL means that a condition exists that will harm the catalytic converter (Usually a misfire, meanign raw fuel is exiting the cylinder). When raw fuel hits the cat, it burns, causing the cat to overheat, and even catch fire! Usually though it just melts the catalyst, clogging the cat and causing the car to run poorly/die becuase of too much backpressure. So if it stays flashing for a while, look at your cat and see if it's glowing or looks real hot, if so shut the car off before it burns to the ground lol

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