[V8] Timing belt change - Fuel pump?

Dave Saad dsaad at icehouse.net
Wed Oct 3 16:46:47 PDT 2012 

For sure get a fuel pressure tester. This is a vital tool. The pump is in the tank and the filter is back by the right read wheel under a plastic dirt cover. I think the round thing by the Maf is the fuel pressure regulator.
If I were me (and I am) I would replace the fuel filter first.
Do you have a service manual?

Dave

Sent from my iPhone

On Oct 3, 2012, at 2:38 PM, John Bysinger <doog at bysinger.net> wrote:

> Follow up after trying a few more things...
> 
> So I sourced a Siemens Hall sensor from a guy on audifans boards, rebuilt
> the passenger dizzy with the new sensor, with no real change to behavior.
> Replaced the drivers side knock sensor (since I had previously only
> repaired the sheathing on the wire), again no change.  Capt Ron suggested a
> possible cat problem, but doing the knock test nothing sounds like it's
> floating around in there.  So I'm starting to wonder if the cut-out
> behavior is fuel delivery related.  So that's going to be my next line of
> investigation.
> 
> So on to the questions, fuel pump and fuel filter, where are they located?
> I assume the pump is in-tank, and the filter is the lovely round thing
> next to the MAF on the fuel rail.  If there's a fuel delivery problem are
> there specific codes related to that?  I'm going to track down a fuel
> pressure gauge and see if I can validate this theory, any other tips/tricks?
> 
> As always, thanks in advance! :)
> 
> -John
> '90V8Q
> 
> On Sat, Sep 15, 2012 at 5:16 PM, John Bysinger <doog at bysinger.net> wrote:
> 
>> Well the wires check out for continuity, and don't seem to be shorting
>> anywhere.  I'm going to re-wrap it and run it inside some wire loom that
>> I've got.  But, disconnected or connected the engine behavior doesn't
>> change.  I think my  problem lies elsewhere.
>> 
>> 
>> On Sat, Sep 15, 2012 at 4:01 PM, Allan Vega <allanvega at comcast.net> wrote:
>> 
>>> That's the knock sensor that Scott mentioned in his last email to you.
>>> 
>>> FYI , that sensor has a torque spec of 11-18ft lbs, certainly not enough
>>> to crack the housing
>>> Allan
>>> 
>>> Sent from my iPhone
>>> 
>>> On Sep 15, 2012, at 6:44 PM, John Bysinger <doog at bysinger.net> wrote:
>>> 
>>>> What sensor is underneath the drivers side header?  orange plug under
>>> the
>>>> engine cover on the right side of the intake, routed by the front and
>>>> timing belt cover and near the power steering pump?  The cable to that
>>> one,
>>>> rubber wire coating is completely disintegrated and the plastic casing
>>>> around the sensor is crumbing.
>>>> 
>>>> -John
>>>> 
>>>> On Fri, Sep 14, 2012 at 9:23 PM, Scott Justusson <qshipq at aol.com>
>>> wrote:
>>>> 
>>>>> The problem with rpm codes, is they can be triggered *from* the
>>>>> intermittent stalling, not the cause of it.  Some have been known to
>>> put
>>>>> some cold water on those sensors to see if anything changes.  This
>>> sounds
>>>>> like a MAF symptom to me, are you sure that connector is secure?
>>> Another
>>>>> issue I've seen with the older v8's is an intermittent grounded knock
>>>>> sensor causing a full max retard of the timing tables.  That DS one
>>> goes
>>>>> into a bracket on the side of the valve cover, and I've seen many that
>>> were
>>>>> grounded against the headers. Also, take a look at night, arcing wires
>>> and
>>>>> cracked distributor caps many times can send you down much more
>>> complicated
>>>>> paths than necessary.
>>>>> 
>>>>> HTH
>>>>> 
>>>>> Scott J
>>>>> 91 v8 Auto 3.6
>>>>> 92 v8 Auto 4.2 ABT Chipped
>>>>> 
>>>>> 
>>>>> 
>>>>> 
>>>>> 
>>>>> -----Original Message-----
>>>>> From: John Bysinger <doog at bysinger.net>
>>>>> To: V8 <v8 at audifans.com>
>>>>> Sent: Fri, Sep 14, 2012 10:46 pm
>>>>> Subject: Re: [V8] Timing belt change - follow up
>>>>> 
>>>>> Ok, after some help from fellow listers, I was able to rebuild the
>>>>> passenger side distributor.  I completely re-wired the connector to the
>>>>> hall sensor, and was able to bench test it with a DC 4.5V source.  I
>>>>> thought I may have assembled the ring on the cam side incorrectly, but
>>>>> again, thanks to you guys I was able to confirm I got that ring in
>>> properly.
>>>>> 
>>>>> But it's still throwing a 2111 and stumbling over ~2500 RPMs in
>>> neutral,
>>>>> and completely gutless and stalling when in gear.  Just to confirm, I
>>> did
>>>>> as SJM's ECU page said and reset the memory by pulling the appropriate
>>>>> fuse, and trying again, same code.  I pulled the drivers side cover on
>>> the
>>>>> timing belt to see if there was any odd movement going on w/ the
>>>>> tensioner/dampener when it got to those RPMs.  No odd movement there
>>>>> either.  According to the SJM site 2111 indicates an RPM sensor
>>> failure,
>>>>> but I just replaced both of the sensors under the driver's dizzy
>>> earlier
>>>>> this year, barely 500 miles ago.  I rechecked their harness plugs, both
>>>>> were secure.  I also inspected the connectors, wiring and hoses that
>>> run on
>>>>> top of the engine, no real visible issues that I can tell visually.
>>>>> 
>>>>> I'm really at a loss as to where to look next.  I have time this
>>> weekend to
>>>>> tinker with it, I'm hoping I can get it figured out before the Seattle
>>> fall
>>>>> rain gets here.
>>>>> 
>>>>> Any tips/suggestions at this point would be very helpful.  I do have
>>> 'an
>>>>> audi guy' who has a shop 15 miles from here I could take it to, but
>>> right
>>>>> now driving it isn't possible with the stumbling, I'm trying to avoid
>>> the
>>>>> cost of getting it there if I can.  I blew my Audi budget on the timing
>>>>> belt and PS hoses.
>>>>> 
>>>>> -John
>>>>> '90 V8Q
>>>>> 
>>>>> On Thu, Aug 16, 2012 at 8:42 PM, John Bysinger <doog at bysinger.net>
>>> wrote:
>>>>> 
>>>>>> Well I got the timing belt completed, thanks for the recommendation
>>> to use
>>>>>> BlauParts, their kit and tool rental made it nearly a breeze.  The
>>> kit was
>>>>>> amazingly complete with seals, pulleys, fluids etc.  I also replaced
>>> the
>>>>>> fan and oil pump bearings, because like everyone else said, I was in
>>> there,
>>>>>> might as well.
>>>>>> 
>>>>>> I used this for reference while I was doing the work, proved very
>>> helpful:
>>>>>> 
>>>>>> 
>>> http://www.audipages.com/Tech_Articles/enginemechanical/A8timingbeltreplacement.pdf
>>>>>> 
>>>>>> It was nearly the same, just different Dizzy setup on the back of the
>>>>>> heads.
>>>>>> 
>>>>>> I also got my leaky power steering fixed while in there, thanks again
>>>>>> spokanehose, that was the third hose I've had them done, worked great.
>>>>>> 
>>>>>> But there's always something....
>>>>>> 
>>>>>> I ended up having to trim about 1.5" off the end of the drivers side
>>> of
>>>>>> the top radiator hose, hose clamp pinched through it causing a leak.
>>> Glad
>>>>>> it was there and not elsewhere in the hose so I didn't have to
>>> replace it.
>>>>>> But the one remaining issue I'm having is keeping me from getting it
>>> back
>>>>>> on the road. It's only throwing one code: 2111.  Which based on a
>>> search of
>>>>>> the list archives is likely the crank position sensor.  Strange.  I
>>> just
>>>>>> replaced it and it's partner about 3 months before the water pump
>>> gave out,
>>>>>> so I'm pretty sure the sensor is still fine.  Behavior is it starts
>>> and
>>>>>> idles just fine, slowly increase the RPMs and around 3k it starts to
>>> act
>>>>>> like it's skipping or stumbling.  When trying to drive, similar
>>> behavior,
>>>>>> idles along just fine, try to give it some throttle and it'll stumble
>>> and
>>>>>> sometimes stall.
>>>>>> 
>>>>>> I tried peaking under the dizzy to see if maybe the plugs had come
>>> loose
>>>>>> while I was putting the cam lock plates on/off but they look plugged
>>> in ok.
>>>>>> I haven't tried re-seating them just yet since there's quite a bit of
>>>>>> engine bits in the way there and I was losing sunlight.  Thought I
>>> would
>>>>>> see if anyone had any suggestions for something to check besides
>>> those two
>>>>>> sensors hidden behind the drivers side header.
>>>>>> 
>>>>>> Only other noteworthy item is on the passenger dizzy there's a sensor
>>> that
>>>>>> the plug socket had crumbled a bit, I cleaned it up and made a clamp
>>> of
>>>>>> sorts to hold it in place, could that be my issue?
>>>>>> 
>>>>>> -John
>>>>>> john at bysinger.net
>>>>>> '90 V8Q
>>>>>> 
>>>>> 
>>>>> 
>>>>> 
>>>>> -- john at bysinger.net
>>>>> 
>>>>> _______________________________________________
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>>>>> 
>>>>> 
>>>> 
>>>> 
>>>> --
>>>> john at bysinger.net
>>>> _______________________________________________
>>>> Audifans V8 mailing list
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>>>> 
>>> 
>> 
>> 
>> 
>> --
>> john at bysinger.net
>> 
> 
> 
> 
> -- 
> john at bysinger.net
> _______________________________________________
> Audifans V8 mailing list
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