x Wild Bill x

Hey guys, I have a 95 Firebird Formula with just and exhaust and am having some problems with it. When it is cold, it will crank for a while and then start up, once it starts sometimes it will die, other times it will rev to 1500 and then idle back down. It also has a miss. Other than this it is in very good shape. The previous owner installed new plugs, wires, opti, and injectors. I checked the routing of the wires and they are correct and none are burned either. I feel he put the opti on right as the car is clearly well maintained and he was a mechanic. So I have been trying to figure this one out. I swapped the MAF from my 94 z28 and it didn't fix it, not surprised. I think that it very well could be the EGR, stuck open, but I do not know how to test it, short of getting a new valve for it. It is my understanding that it if it is stuck open then pulling the vacuum source wont' change anything.

Anyway you guys know to trouble shoot this would be appreciated!
Or any other ideas. Ohh yeah the car is also an A4 with 125,000 miles.

Thanks,
Bill

trippinholyman

stuck open egr would cause it to stall / not start at all - if its partially stuck open, its a possibility. stuck closed causes bad emissions and sometimes detonation but generally it can pull timing enough to not cause problems. my car's egr is stuck open, for example, and it hasn't exploded yet haha.

http://shbox.com/1/4th_gen_EGR.html for diagnostics courtesy of shoebox.

its easy to replace the valve / solenoid - just as with any other lt1 related thing, its impossible to get to since its a few inches under the cowl

x Wild Bill x

Yeah, sometimes it dies a sec. after starting, then re-fire and run okay. I will try and check it tonight by pushing on those spots he mentioned, I was reading it earlier... Thanks. So if yours is stuck open, does your car die often when starting cold? I've gotta try and find the old one from my 94z to put on there.

Thanks,
Bill

x Wild Bill x

If anyone else has any ideas, please feel free to share them, I'm open to all ideas right now.

Thanks,
Bill

trippinholyman

Well, mine is stuck closed. That's better than being stuck open, because it's restricted enough that it won't let in too much air to dilute the mixture and cause it to stall. I have a 96, so I can just reset the code at the emissions station and it won't throw a CEL immediately and it'll pass since it's OBD2 and has no memory of it being cleared. So in fact mine runs perfectly fine, except I'm killing the environment with my NOx emissions and if I don't run higher octane, I risk knocking. Though I did run regular 87 when I first bought the car and the EGR was always broken on it, and it didn't knock, so who knows!

If it is stuck open then there's probably some crud in there somewhere. Get some regular old wrenches and lay on top the intake like you're Superman, I think it's two 1/2" bolts. Pull it off, get a sideways inspection mirror and look back there. Scrape off the old gasket / any carbon crap, maybe get some Seafoam and soak it or something. Check the valve for any buildup, clean it and then put it on with a new gasket. If it still is stuck open or stuck closed or whatever, just buy a new one. They're like 50 bucks. You could also try looking on Ebay for block-off plates. Just get rid of EGR altogether. It'll run fine, but it'll throw a CEL unless you tune it out. Also, if you run a sniffer you might fail your NOx. If it's OBD2 and tuned out you'll be fine. If it's OBD1 you SHOULD be fine since it isn't as sensitive. Good luck!

bigchevyman24

iTrader: (2)

I deleted my EGR and I have cold idle problems now, so it probably is something to do with it. I am going to get some gaskets for my blockoff plates and reinstall. It's not that hard to get to, just lay on the motor and reach one arm around each side of the intake. It's the one on the drivers side.

96blackz28

iTrader: (3)

Yea do the block off plates, when you get to the two plate behind the intake, you basically just have to 'feel' your way since you cant see anything. Its fun, i did those two while it was on the car.

x Wild Bill x

Thanks for all the suggestions guys. Well I don't think it is the EGR anymore, so I'm back to square one. Last night after I got home and the car cooled down I started it back up and pushed on the EGR valve and it started to run rough and idle down. Now I had to push it in pretty far to get it to do this, so I am assuming that the EGR valve is fine, but if there is still stuff stuck in there it may not be shutting all the way... I will have to pull it off tonight and check for the carbon build up.

Thanks again guys.
Bill