I posted not so long ago that I thought my car was running lean. I thought so because my A/F gauge has been favoring the lean side more than normal and it's been acting funny at startup while it's in open loop mode. Also at WOT it does not go into the rich area as it should, but rather it just hangs around the stoich area. I pulled 2 easy to get to plugs and sure enough they were white.

Just to recap, here is the situation, the car was running perfectly, but spewing oil from several different places. I decided to fix the oil leak, in the process I removed the timing cover and oil pan, opti, etc. I was going to replace the opti with a new style and install my pete jackson gear drive. I ended up having to replace the cam because I could not extend the drive pin to catch the new opti. This required me to pull the intake off.

While I had the intake off I went ahead and installed my hand polished, powder coated intake. Everything went back together fine, but except as mentioned, now it is running lean. I thought that maybe my hand fabricated EGR blockoff plate was leaking, so I removed it and re-installed the EGR valve with a fresh gasket. It still runs lean. I've sprayed carb cleaner all over my intake mating surfaces, fittings, and around the injectors, nothing makes a difference in how it idles.

Is there any chance that my porting really makes it flow that much better? I have a really hard time believing that.

Help me out guys.

One more thing, some people had mentioned previously that it might have been an exhaust leak. Double checked that, no. Also none of the exhaust was removed the last time I had it apart.

 

Considering the work done, use a vacuum gauge on the intake to assure good vac at idle. If not find/fix the leak.

A fuel presssure gauge on the Schraeder will tell you if fuel pressure is ok and maintaining at WOT.

Check the O2 sensor. A scanner would be ideal; if N/A jumper ALDL pins A&B and start the engine. After a copla minutes the SES flashes should slow to about 1Hz indicating closed loop. Raise the idle to about 2k RPM for copla seconds. The SES flashes should be of equal duration at base idle and at 2K RPM, indicating stoch and your O2 sensor is OK.

 

A few things I meant to add. I have a fuel pressure gauge, it's fine. Fuel pressure actually goes up at WOT like it always has. The 02 sensors are less than 6 months old as well.

What type of vacuum is it supposed to hold at idle?

 

I just threw my Mityvac on the manifold. I know it's probably not the most accurate thing, but I figured it would get the job done. When I first fire it up it has to fumble around for it's idle around 400 rpms or so and the vacuum is very low, once it figures out it's idle and brings it up to where it is supposed to be the vacuum holds steady at 13 in/hg. Blip the throttle and the vacuum falls to 0, jumps to around 18 as soon as you let off, and then settles right back to 13.

 

Nathan,
Next time you do the spray test for a vacuum leak,you or someone stand behind the car/exhaust and if theres a leak,youre gona smell the (whatever spray you use) burn through the exhaust.

We used to use brake kleen at my job and one guy would stand behind the car for a few seconds and the other guy would spray around the engine and if the brake kleen got sucked into the engine,it made a stink and burned your eyes a bit from the smell coming out the back.

For everyone reading,Use caution as always,not to breathe the fumes or stand behind or more then a few seconds since we all know that stuff is dangerous!!!
If you need to do this,Do this in a well vented area!!
:)
It was one way we had to be sure there was a vac. leak when it was just impossible to tell for sure.It couldnt be heard or found easily with the spray job.

Also use caution which sprays you use as to not ruin any painted or finished surfaces around the engine.

Finally,do you have a scanner?If not,I may be able to help you out with one.
Sometimes the scanner readings can help to guess better or look for something we arent thinking about.
:)

 

ttt