Check this out... vacuum related

[lanceputnam]

Drove the 2004 D2 to work today. Turned it on and it was idling not rough, but certainly not normal and kind of had a shimmy to it as I watched it. Drove fine on the road at speed, but while idling I could tell something was awry. Drove the 40 miles (somehow managing to burn 1/4 tank of gas) to work and popped the hood while it was idling. Definitely could hear an air sucking sound coming from the top of the passenger side of the engine. Sounds a lot like what I think a vacuum leak would sound like. Drove it home tonight and just put my harmonizer vacuum guage (digital bmw motorcycle throttle body sync, has gauge function too) on the nipple on the upper plenum. At idle, 660 rpm, I was drawing 3". Yes, just 3". When I started the engine, it was at 2" right away and then after about 30 seconds it creeped up to 3" and stayed there with no fluctuation. This seems very very low to me. What specifically should I be looking at to track down this leak? I don't have a smoke tester but I do have everything else (no test book so don't ask). Also I threw a p1174 code, which I believe is unrelated. Im due for new front o2's and I think my passenger side one it taking a dump currently.

 

[distrovol]

Faulty o2 sensor would cause poor fuel economy. It certainly did in my case but I did get an o2 code thrown for it. The 2 vacuum lines on the pass side I recall are the ones going from plenum to the brake master (hard plastic line gets brittle) and a rubber hose from plenum to top of valve cover. The brake master cylinder line wraps around the back of the engine above the SAI pipes and attaches to some clips mounted to the firewall.

 

[listerdiesel]

Servo pipe, servo diaphragm, cracked pipe, broken non-return valve, any loose hoses on the idle control valve, throttle body housing loose, vacuum feed to the recirc valves and last but not least, the dump valve for the fuel vapour purge.

Peter

 

[crown14]

Didnt you just replace fuel injector o-rings? What was the vac reading before that?

 

[lanceputnam]

I did not replace the rings. I pulled the injectors and thats when I noticed the deal with the little orange disk retainer things. I also had a brain fart and only got 8 new o rings. So... I put them back in and left them alone. This all happened while I was replacing my valley gasket as well.

This vacuum leak is massive, so massive that Im thinking I may have pinched a wire or something between the two plenums. Im getting really good at taking the plenums off so Im going to cigar smoke test it first just to be sure and then just pull the plenum again real quick, fix the leak, reaseal and reinstall. That much vacuum loss with that much non-metered air entering my engine explains the p1174 lean code I am getting as well, which hopefully will fix it so I can go return the $150 worth of o2's I picked up just incase.

 

[Zonkatruck]

My 03' with 54k on it started posting P1141 & 1171 after changing plugs recently. I already changed the wires a year ago. Come to find out the air box was not connected completely to the t-body neck. It was just grabbing with the clamp in full tight position. I just bought the offset socket at O'Reillys and was getting ready to order the upstream O2's from Amazon (best price ~$54.00/ each). So far everything is good on the short road test. If the same codes pop again on the half hour drive I have in the next day the O2's well be ordered. If everything turns out okay I am going to keep the socket for when that day arrives.

Prior to changing the plugs I got a P0441 and replaced the gas cap and Purge valve. It has not come back. One victory for now and hoping the other codes will be gone too.atriot: