A few problems I can't figure out

[Ybnorml]

I suppose I qualify as a noob.

Here's the condensed version. I had the head done on my 91 GS-T. Valve seals and guides were replaced as as well as everything on the front of the engine. It's bone stock, MBC is to do 10 pounds right now and appears to be holding okay.

Got the head on, made sure vacuum and all was connected. Got to where it started and I drove it around for a while. I found assorted boost and vacuum leaks so those were fixed. I had the timing set to 11 BTDC., put some good gas in it along with new 6ES plugs. I made 2 passes in third to log and went up to about 6 grand.
On the second pass I saw smoke, and the dipstick blew out. I also noticed the exhaust mani was glowing a little, it was night. So I drove slowly on the way home and noticed a small miss. I pulled the plugs the next day and they were a pretty light brown on each of them. I replaced plug wires and went to a 7ES to see if the problem went away. I also changed the PCV valve. Nothing changed except the dipstick tube doesn't come out, but I have oil on the valve cover now. I drove probably 50 miles or so before that started, after I did the 2 hard runs. I still have the miss. It doesn't seem to clear out. I put the 6ES back in just to see if it made any difference but it didn't.

I put a logger on it and did WOT for about 5 seconds in 3rd last night. We killed each injector to see where the problem was and on #4 cylinder when I killed it, there was almost no difference in how it idled. The plugs are burning consistant with each other it looks like.

So now that I set the stage, I didn't have excessive pressure until a few days ago. The miss started after 2 hard pulls, PCV is new,checked for leaks visually (no time for pressure check yet). 6ES plugs look good. Cutting off #4 injector makes almost no difference. It's also not a bonified "dead miss" but close to it.

The car sat up for a while so gas could be bad. I'm going to move inhectors around to see where the problem goes. I'm going to drain the old gas out and trynew gas. I'm doing the K&N recharge thing on the dirty air filter. Could this be bad gas since the car sat up, and possibly a bad injector? The crankcase pressure came around a week or so after the miss so I'm at a loss on that.

BTW, I read on here about an hour before I posted. I just didn't find what I was looking for.

Any ideas or comments? Thanks

 

[ddavisaf]

Honestly, you're on top of this issue in my opinion. Bad gas can definately cause various performance issues, but not nessecarily a missfire. Swapping the injectors around is a good idea. If you're still having the same problem with the one injector, replace it.
Make sure you run a boost leak test and pay attention to the injector seals/intake manifold area. Test from the turbo inlet and the throttle body elbow with soapy water.
Excessive crankcase pressure is a whole different story.
How is your PCV routed? Is it to the stock position or to a catch can?
Run a compression test and make sure the piston rings are good to go still.

Post back with your results.

 

[Ybnorml]

Thanks for the reply. I guess I didn't think that I'm asking for the troubleshooting that I've done already. I'm going to run the gas out as much as possible and drain the tank. Then I'm going to move injectors around and see if the problem follows the injector...hopefully it will. I've not run a leak test yet but managed to lean on the BOV hose and hear it leak so I replaced that. I also replaced the ISC and water coolant temp sensor, no change there, even pulled the ground for a little while.

I'll be sure to post again once I get it all figured out.

Thanks alot.

 

[92awddsm]

At this point, your best bet is to do a boost leak test and a compression test. This will tell you more about the condition of the engine and pyou could probably do both in the time it would take to swap injectors around and retest them.

 

[Defiant]

I'm going to run the gas out as much as possible and drain the tank.

Don't beat yourself to death. Just run it down and fill up. The fresh gas will more than dillute whatever was left over. You might want to run a bottle of gas drier through on a half-tank, but it doesn't really sound needed.