jseklund

[QUOTE=tester123;24173854]Today, I checked a bit more on these vacuum lines and the one going to Fuel pressure regulator with those 90° rubber lines seemed to be a bit loose and replaced them and few others that looked on the verge to go. Still, I am coming back with same code, both banks lean. This is getting rather frustrating. I read here on of the threads about "suction valve", could this be a culprit?
QUOTE]

I am not too familiar with the 4.2 - but I would say this could be a source of a leak. In my gf's 1.8T A4, the suction pump broke into two pieces. The way it was sitting between hoses, the two pieces were held together and you would NEVER have known. I happened to find a tear in another hose and as I was reaching down to replace I hit the suction pump and saw it spread apart. This could def. cause a leak.

Also, I have seen hoses that have long rips along the length of the hose that when they were not inspected by turning the hose and looking carefully, you would never see. It's like there's no rip at all and then you twist the hose a little and the hole is so large you don't know how you missed it.

tester123

Well, the gremlin has been elusive thus far but, the codes didn't come back and with on/off rain and other tasks, didn't check the car. I took it for a drive and that was long enough -previously after clearing, codes came back on after similar drive- and the MIL is still off and no codes.

Planning a long 4 hour drive tomorrow... will see if this pops up again.

BTW, the suction pump is available on Amazon for ~$20. But, the part number indicates both "B" and "D" in title so, not sure if I should buy it. Price is very attractive though!

MP4.2+6.0

all Audi's I know of have them, including my 2000 4.2. And yes on the vacuum leak lead. BTDT.

tester123

Ok, after looking around for vacuum leaks to no end, finally got time to look at the "CCV or PCV" valve. Opened it and there is hardened sludge. While cleaning it. A small poke with screw driver made a hole. It was in a very fragile state; read,defective. So replaced it with new one and the lean codes are gone (keeping fingers crossed). However, it now showed "load calculation implausible value ". Cleared it, let's see if it comes back again. For now, gotta get inspection passed so, a bit anxious about how it will behave at the hands of the dmv folks.

tester123

The car did behave well and got through inspection. Thank GOD for that!

However, I jumped the gun too quick. After replacing that "PCV" valve, engine is a bit smooth, felt like had more power. However, now again a slight sluggish and, pulled codes:

17538 - Fuel Trim; Bank 2 (Mult): System too Lean
P1130 - 35-00 - -
17536 - Fuel Trim; Bank 1 (Mult): System too Lean
P1128 - 35-00 - -
17549 - Load Calculation Cross Check: Implausible Value
P1141 - 35-10 - - - Intermittent

Readiness: 0000 0000

What am I missing???

tester123

Does anyone know if the '01 4.2 has a "MAP" sensor? Bentley indicates that the Intake Air Temp (IAT) and MAP are combined into one unit...

I am trying to locate (if it exists) where it is and want to check the hose going to it for leaks.


On another note, this Bentley manual is so poorly structured and compiled that the program must be written by people fluent in "BASIC". First I select the car year, model etc. and search for something. The results include every engine and variations thereof! It is just so frustrating to find the right info in there.

Component locations listing is limited and procedures are buried in deeper levels. I found some topics of interest when searching for something totally unrelated! Further, there is no way to bookmark??? I find something and either have to print it out or pdf it?


Either I don't know how to use this piece of s oftware or it is just so bad.

Please clarify my questions if you can.

tester123

Yesterday, pulled out the MAF and cleaned with MAF cleaner spray and replaced the air filter with OEM filter. Still, the fuel banks 1 & 2 codes lean. The new PCV valve is making a "humming" type noise during various phases of acceleration. The noise can be heard inside while driving. It is obviously sucking in air. Also, the oil cap is tight and cannot be opened when engine is running. I read here that bad PCV valve would make the oil cap tight due to vacuum when running... Even with new pcv valve, it is tight...

Any thoughts here? the next only thing I am thinking of is to remove the intake manifold and check the crankcase breather hoses coming out... running out of ideas here.

SloopJohnB@mac.com

If there was hardened sludge in the PCV you can assume there is hardened sludge elsewhere in the PCV system. Clean it out.

SloopJohnB@mac.com

Naah...it's ****-poor software not to mention content. Kind of the only game in town, though.
I complained to Bentley and their lame-O answer is that they simply publish what Audi gives them.
And Audi often changes things to the technicians' detriment.

One time I had to change out the little plastic coolant pipe from the oil cooler to the block on a 4.2V8....Bentley eBahn had a pretty good picture of the layout. I upgraded to a newer version during the change out and found the diagram was gone!!! Good thing I had printed it out for my own files ahead of time.

God I miss the old hardcover Motor Manuals.

SloopJohnB@mac.com

Re the PCV...the big round thing toward the back of the engine compartment, about 4" in diameter. Mine was buzzing last year so I removed it and checked the diaphragm, holes, etc., and it appeared clear. I stretch the spring that loads the diaphragm and reinstalled the PCV figuring the stretched spring would at least change the frequency of the buzzing upwards if not eliminate it. Yes, it changed the freq but did not eliminate it.

I punted and put in a new PCV and the buzzing stopped. Got it from ECS Tuning.

http://www.ecstuning.com/Audi-C5_A6-.../PCV/ES11585/#

http://c1552172.r72.cf0.rackcdn.com/10659_x600.jpg