So, a few weeks ago, I bought a 2004 Discovery 2 with about 111,000 miles. Since I have had it, we have been reading codes and replacing items in the hopes of getting this thing to run correctly. It has very little power from a standing stop. It will accelerate Ok from a rolling stop. If you floor the accelerator, it barely accelerates. It doesn't knock or make any odd noises. It seems to run better before it heats up to operating temperature.

So far, I have replaced the following less than 5 miles ago:
- All 4 O2 sensors
- Mass Air Flow Sensor (Bosch)
- Camshaft sensor position sensor
- Crankshaft sensor
- Spark plugs
- Air filter

Here is a screen shot of the codes it is throwing as of today, 7/30 after clearing the codes and driving around the block a few times:


Add one more code to it that couldnt fit in the screen shot:
- Canister purge valve fault (power stage) Drive Cycle C

Of the error codes, I am waiting on a Hyundai purge valve to come in - see above.

My questions:
1. Why am I still getting error codes for parts I have replaced - MAF sensor, Camshaft sensor and O2 sensors?
2. Of the codes listed, what should I focus on next (purge valve is inbound)?
3. What should I try next that may not be listed as an error code?

Thanks for the help! Feel free to ask me any questions.

-Burwell - in New Orleans

 

Did you clear the codes? If not it will take some drive cycles for them to clear themselves.

Your performance issue sounds more like limp mode. Do your Sport and Manual mode indicators work on the instrument display? Position 2 on the ignition activates a bulb test sequence. Are you seeing all of the lights light up?

 

Thanks Dave.

Yes, I have cleared the codes too many times to count. I just checked and in ignition position 2, both the S and M green lights light up and go out. If I start the truck and press the Mode button, the green S light lights up until I press the mode button again.

 

OK Good work... I would think the MAF issues would be more the cause than the purge valve. New parts have been known to be bad out of the box...

Hopefully someone with this same issue can chime in.

 

have you checked your battery voltage yet? a low battery can cause all kinds of issues.

check ground connections also to be sure none are loose or rusted.

 

Thanks Jastutte. I haven't seen this before and it could be a possible issue. The battery is an older one, smaller in size and I will replace it today and report back.

-Burwell

 

Thanks Dave. I have put two MAF sensors in the truck The first was a cheap after market brand I bought on ebay before reading they are terrible. The second one, in the truck now, is a new Bosch unit. So far, the error code has come back with both of them.

I am going to try a new battery today. Cross your fingers...

-Burwell

 

Here is an update as of 7-31 11:00 CST

I went and bought a new Interstate battery, put it in, cleared the error codes with my iLand diagnostic tool. I drove around the block a few times, no difference in how its running.

Some of the codes from yesterday have gone away (O2 sensors), but other codes have reappeared.

Here is a screen shot of the codes it is throwing now after the new batter install and clearing them before driving around the block:


Add one more error that didn't fit on the screen shot: Camshaft sensor fault/valve timing error Drive cycle A

Additional information:
- I have about 1/2 tank of unknown gas, other than the woman I bought it from said she never used premium gas in it. I have added a can of 44K to it, about 3 miles or so go. I was trying to run it all out before putting premium gas in it.
- For some reason, when I shift the gear lever into D, it doesn't quite align with the D on the console, nor does the red light light up. Nor does the neutral light on the console light up when the gear selector is placed in neutral, but if I go past either of them (N or D), and shift forward, towards park, they will light up. Its almost as if the gear selector is a tad out of alignment. I haven't climbed under the truck to investigate yet, but can this be an issue? The truck does shift fine, and no gear box error codes...

Thoughts?

And, as always, thank you for the help and letting me vent...

-Burwell

 

the gear issue is well known. search the forum for "xyz switch" -- sometimes they just need aligning; sometimes they need to be removed, opened up, and cleaned inside before reinstalling.

have you tried cleaning the contacts on all of the various connectors to the maf and battery?

 

Hello Mollusc. No, I haven't cleaned the connections to the MAF or battery, but they appear to be good. However, I will clean them anyway this afternoon.

Does anyone know of a way to bench test a MAF? Or, maybe someone has a known, good spare MAF for a 2004 Discovery that I can borrow for a few days - I will of course pay for shipping both ways.

The good MAF in my 2002 is a Bosch, but it is a different part number and diameter (about 1/4" smaller in diameter than the 2004 MAF).

Thanks for all the help!