BoostBuggy

Finally got to the smog station today. To remind all the issue is the car runs WAAAY rich and will not pass CA smog. The numbers are:

HC PPM 371 @ 15 mph & 377 @ 25 mph. Max allowed is 115 & 75 respectively. CO% 6.12 @ 15 mph and 6.63 @ 25 mph. Max allowed is 0.57 and 0.43 respectively.

I have replaced the 02 sensor, the cat, fuel injectors, vacuum lines, FPR, DME temp sensor, afm, plugs, Dist cap, rotor, fuel pump and speed/ref sensors. I have not replaced the TPS (yet) & plug wires (LR "Mag Wire") are about 4 yrs old.

The AFM replacement was(is) a used part but appeared to be VERY clean. No diagnostics were run it. After installing it a short (50 mile) run seemed to indicate fuel mileage had increased to 22 mpg (currently combined mpg is < 18)

Exhaust has a "fuel-ish" rich smell to it.

After replacing the vacuum lines it picked up a odd hesitation under acceleration at around 4k rpm... Doesn't have to be WOT but boost gauge shows between 1 and 2 bar. The hesitation or stumble feels like it's not getting enough fuel and is somewhat momentary i.e. if you get out of the throttle just a bit it then seems OK but getting back into the throttle it hesitates/feels fuel starved again.

I have re-checked the vacuum line routing a couple of times and everything seems to check out ok.

What else could be the problem? I really need to resolve this ASAP.

Van

What FPR do you have on there? (Fuel pressure regulator) And/or chip in the DME?

BoostBuggy

Stock FPR and no mods to DME. Everything is stock.

Van

Coolant temp sensor? I think the computer will richen the mixture before the car is warmed up.

BoostBuggy

Where is that located?

Brantley

Wow, you've done a lot of work so far and are still fairly far away from passing. I've been there though with CA smog as well.

Here is my adventure in getting the car to pass -



Take and look and see some of the work I did to get mine to pass. I never had a problem with CO though so your problem may be different than mine was.

You seem to be running very rich... stock chips?

There is also always the extreme move of running the gas to about empty and putting in a gallon of denatured alcohol. Promptly get the test done and fill it back up just as quickly with gas.

http://forums.pelicanparts.com/porsc...og-idle-2.html

Brantley

I see you mentioned the car has a stock DME - so no chip DME or KLR? That certainly makes a car run richer.

What are the details behind your new catalytic? If you are local, I have a low mileage (70k miles) stock catalytic converter pipe you can borrow. I am holding on to this for my next smog check so would need it back. I am in Orange County.

Also, when I go to the smog shop, I try to go at a time when they can get me right in. So, I'll drive around for 20 minutes to get the car nice and warm, and leave the car idling to keep the catalytic hot right before the test.

kev951

you may be having afm issues via the CO adjustment and or internal spring. If you see silicon around the plastic cover on your afm, it has most likely been tampered with. You need to get a gas analyzer hooked up to the car in idle and check / adjust your CO via the afm CO mixture screw ( i believe its an allen head but is covered by an aluminum plug. also , it's never a good idea to mess with the actual afm settings via the spring wheel under the plastic cover on the afm. As long as you have confirmed no exhaust leaks, vacuume leaks, and any possible mechanical failure ie missfire, stuck injector, valves, no compression, or too high fuel pressure... get a gas analyzer hooked up to the exhaust and adjust CO..

Van

There are two coolant temp sensors in the block - one for the gauge and one for the DME.

I *think* the one with the blue plug is for the DME.

BoostBuggy

@Brantly - Thx for the offer but I'm not local. And the Cat & O2 sensor were installed at the same time within the last 3-4 months. The cat is a Walker that satisfies the CA Executive Order for this car.

@kev951 - both the old afm and the new afm have the plug cap missing. The old afm however had not been touched/adjusted. Can't comment on the new afm but I rather doubt it has been tampered with.

@Van - I kinda thought you were referring to the DME Temp sensor. That has been replaced.

Does anyone have a list of all the sensors?

Van

Not "have a list", per se, but I'm sure we can come up with one...

There's sensing what's going in:
-intake air temp (part of the AFM)(to adjust fuel based on air density)
-amount of intake air flow (AFM)(to adjust fuel)
-requested demand (throttle position)(to adjust fuel and timing)
-boost pressure sensor (in KLR)(to adjust fuel (timing too??))

There's sensing the condition of the engine
-temp sensor in the block (to adjust fuel)
-knock sensor on the block (to adjust timing)
-speed sensor (counts flywheel teeth) (to adjust timing)
-crank position sensor (looks for the set screw in flywheel) (to adjust timing)

And finally there's sensing the exhaust
-O2 sensor (to adjust fuel)

What have I missed?

BoostBuggy

I don't know what you've missed, that's why I asked :-)

I don't understand why with basically all new parts how it can still be running rich. My fuel mileage starting going downhill (indicating rich condition) months ago and nothing seems to bring it back. This is where auto repair frustrates me. i.e. I replaced the part so now it should work. Clearly something remains "out of whack."

Ronin-951

Dang, what a circle jerk! That's some list you have there. Sorry, no list of Sensor's, guess I'd start by re-seating the Throttle Body Idle Air Mixture Screw, 3/4 turn off the Seat is normal. A 'suck' test on the Vac Port's of the FPR AND Damper is next, then ensure Vacuum actually gets there. Wonder if you had the base service, or the 'full boat' spray pattern service done on the Injectors, or if you just swapped them with new, [bout 20 different one's in the 44 lineup btw] - check the Plugs [stock type only] for sign's of a screw-up.

jc85G

Have you done a compression test?
Have you checked the cam timing? Any adjustable cam gear? Stock cam?
What is the fuel pressure?

jmj951

Three things you need to check first:
1) Actual fuel pressure. Hook up a gauge to the rail and let us know what you find.
2) FQS setting. If the chips were never changed, the FQS setting was probably never changed either, but you should check it anyway.
3) TPS check with a multimeter.

I don't think the throttle body area is something to focus on just yet - if it's leaking, it should make it run leaner, not richer.

The spark plug recommendation is worthwhile- make sure they're original spec plugs. If the heat range isn't right, you could be running rich.