KuHL 951

I had a new O2 and cat installed last week. The shop installed it. It now runs richer than before and idles rough. I just found a vac line dangling that runs from under the front DS of the intake and ending near the front side of the AOS. I think they might have popped it off when they fished the O2 wire through since they had a hard time of it. I can't tell where it might go but I did a venturi delete 2 years ago with good quality silicon hose. I thought a vac leak would make it run leaner? Any idea what disconnected fitting or connection could cause this rich condition? The line at the bottom of the throttle body is connected. If it's the TB line off at the other end how would this effect the idle and air mix? I hate to pull the intake to get to whatever it is if there's a simpler answer. I need this car smogged like two months ago.

Thanks

Update and solution in my last post.

krystar

what if u just unplug the o2 sensor entirely? still rich? or create a vacuum leak by undoing the big vac line at the manifold. u should be able to smell the exhaust and get some kinda idea...

KuHL 951

I think I just found it by removing the Laust Pedersen vac block. There's a small black temp? sensor (non-electrical) back there on the head with two black angled ears, one of ears was open and the disconnected vac line fit perfectly over the nipple. I'm curious, what effect does an open on that fitting have on the throttle body and idle? I'll hook it back up and find out after dinner..

krystar

i think that thing is for the emissions equipment. i stripped all of that from my car, but i do remember breaking a vacuum fitting with a Y shape.

xsboost90

my car kept flooding out until one day it would start. I thought it was just from sitting around too much. I checked and found a vac. line off the fuel regulator- fixed it and didnt do it again.

KuHL 951

Well I took the car out and warmed it up. Damn, its' still running rich (sniff test) but vacuum is better at 18 hg hot and the idle is smoother. I'm going to pull the plugs and clean them; the car was running for quite a while I think with a bad O2 so they might be pretty sooty. I don't think my FPR is bad, it only has about 4K miles on it and the injectors the same since Witchhunter serviced them. I'll try pulling one injector plug at a time and see what happens in case one has failed.

choinga

that 'thing' you are referring to for the fuel evaparator system...no idea what it does beyond that - but the line you are referring to goes from there over to the intake right underneath the throttle body - you might want to double check it's hooked up down there...those tend to pop off and it's nearly impossible to get a wire tie on it to provide a little extra security.

choinga

you would know if one of your injectors 'failed'. Your car would run like total crap, not just rich.

choinga

so where did you connect the vac line from under the TB on the intake that normally connects to that thing? There's 2 lines on it - one of them goes up to the contraptions that are right in front of the firewall...just in front of the fuse box.

krystar

only vacuum line i got left is the port coming off the intake manifold going to the brake booster. everything else is gone and the holes plugged. runs just fine...if i can get the oil pressure higher hehe

choinga

seriously? you have no vacuum lines in your TURBO other than the brake booster line off the manifold?? How can that be possible? Nothing to the FPR, regulator, BOV, etc...?

krystar

i don't have a turrrrboo. wanna give me one?

oh yea the FPR and FPD still got a vacuum. forgot about that hehe.

67King

You may try sending a dedicated signal to the fuel pressure regulator. As it T's into another harness that goes to BFE and beyond, a vacuum leak could easily cause it to run rich, as your fuel injectors are pressurized as if you are not runnning a vaccum. Conversely, under boost, you'd be running lean.......which, of course, you usually only do once.

KuHL 951

Thanks. What's the BFE? The FPR already has a dedicated vac line from a 5-port vac manifold and vac is a good 18-20hg (hot), 12hg-14hg (cold). I cleaned the plugs but they were just a bit sooty, nothing that would make it run so rich. Can a bad DME temp sensor cause it to run rich after reaching operating temps? I ask because it's worse when cold but still rich after it warms up. There are only a few things I can do at this point.


1. Replace the new O2 sensor ( I doubt it's bad but who knows?) I taking it back to the shop that installed it along with the cat and will find out if the wires were melted from mis-routing them); Update: Wire routing was fine, no melts, so I'm going to exchange the O2 for another and try again. After that it's onto option 2.

2. Replace the 3-bar and VR chip with the OE 2.5-bar FPR and change back to the stock chip (it passed smog fine 2 years ago with the VR set-up?);

3. Replace the DME temp sensor but that means I have to pull the intake manifold (I think?).

The car runs like the wind and doesn't smoke at all but I can tell by the exhaust smell it's still very rich at idle even when it's warmed up. The weird thing is right after the cat/O2 install it had no fuel smell at all for about a day so something was working right. I always like to work backwards from any changes when tracking a problem down.

67King

BFE is Bum F*&%ing Egypt. When I say dedicated, I meant directly to the intake manifold. If there is a leak in one of the other things attached to the 5 port vacuum manifold, it will affect it. If it goes to a vacuum manifold, it isn't dedicated.

To answer your other question, yes. I'm not as familiar with Porsches as I am Fords (used to be an engineer there), but enrichment on a cold start is definately a common strategy. If your computer never realizes the engine is warm, it is adding fuel to make sure the engine runs reliably, as fuel doesn't vaporize as well on a cold engine.

Another option you may try is to adjust the mixture on the computer. Not sure if you know this, but on the back of the computer, there is a small dial. You can adjust the pre-set enrichment from that dial. I think dialing right adds fuel, and left takes it out.