Author Topic: B6 3.0 V6 quattro auto sedan hesitation before acceleration  (Read 213 times)

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Offline sfkarl

  • Posts: 25
B6 3.0 V6 quattro auto sedan hesitation before acceleration
« on: October 18, 2017, 02:40:58 pm »
Hi all.

Looking for some pointers to find and solve a pretty severe hesitation when asking for acceleration.

Symptoms:
- noticeable delay before engine revs up and gets going when hitting the accelerator
- idles fine
- battery was dead, but output from the alternator is good (14v)
- car has been sitting for 2 months
- delay is coming from the engine, not the gearbox

My prognosis:
- bad MAF
- bad fuel supply (either bad fuel pump, restricted filter, bad fuel pressure regulator, old fuel)
- bad electronic throttle or sensor inputs
- O2 sensors

I don't think it is spark plugs or coils as it idles fine and when engine gets up to speed there is no misfire.
I don't think it is fuel as it would cause bad engine performance at all revs, probably more especially high revs.

It could be the shot battery not holding enough of a charge to run the systems correctly, but I did check the voltage after running the car for awhile and I had driven around the block. With the engine off the voltage was over 12V but started to drop immediately. It did hold enough to restart the car a minute later. So the bad battery isn't helping, but I don't think that is the cause.

I haven't had a chance to diagnose with VAGCOM but will be doing that tonight. What kind of errors or codes should I pay attention to?

thanks!

Offline 00quattro00

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Re: B6 3.0 V6 quattro auto sedan hesitation before acceleration
« Reply #1 on: October 18, 2017, 02:46:42 pm »
Clean the throttle body and do a throttle body alignment
Land Rover Discovery 300tdi
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Offline sfkarl

  • Posts: 25
Re: B6 3.0 V6 quattro auto sedan hesitation before acceleration
« Reply #2 on: October 18, 2017, 02:55:14 pm »
Clean the throttle body and do a throttle body alignment

Is this procedure easy to find on the interwebs?

Offline slowburn

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Re: B6 3.0 V6 quattro auto sedan hesitation before acceleration
« Reply #3 on: October 18, 2017, 10:44:35 pm »
good call asking here ,these guys will know what's up with this car...glad you snapped it up....way more modern than an old black quattro that a colleague of yours drives ;)
89 200 quattro exclusive
85 coupe quattro
85 coupe GT
72 fiat 124 coupe
97 corolla wagon

Offline sfkarl

  • Posts: 25
Re: B6 3.0 V6 quattro auto sedan hesitation before acceleration
« Reply #4 on: October 19, 2017, 04:25:56 am »
We love our cars for the best reasons.

Offline sfkarl

  • Posts: 25
Re: B6 3.0 V6 quattro auto sedan hesitation before acceleration
« Reply #5 on: October 19, 2017, 10:05:33 am »
Is this procedure easy to find on the interwebs?
yes

Offline sfkarl

  • Posts: 25
Re: B6 3.0 V6 quattro auto sedan hesitation before acceleration
« Reply #6 on: November 13, 2017, 06:29:21 pm »
Did the throttle body reset. Didn't help. Didn;t want to do throttle body clean yet as disturbing the frail vacuum lines looks like trouble.
Checked the fuel pump as it felt like a lack of fuel delivery issue. Didn't help. Pump is flowing fine.
Checked the O2 values and fuel trims. Very rich. MAF output climbed up and down with the throttle as expected.
Under acceleration the car would go into Open Loop and crap out. Closed loop it runs pretty good.
Disconnected the MAF and car ran pretty good. Bit rough at idle but could be wacky long term fuel trims.
Inspected the MAF sensor and found some sort of "gum" on it that no cleaners would get off.
Carefully scraped it off with a needle.
Car works fantastic.
Fuel trims are back down to spec. No misfires or hesitation.

Offline slowburn

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Re: B6 3.0 V6 quattro auto sedan hesitation before acceleration
« Reply #7 on: November 13, 2017, 11:43:30 pm »
dope bro, why am i not surprised that you and the the germans got her running just fine....stoked you saved it!
89 200 quattro exclusive
85 coupe quattro
85 coupe GT
72 fiat 124 coupe
97 corolla wagon