rtmpmm

well i put the heated o2 sensor in seems a little better, but still surges when warmed up, i pulled the vacuum hose off of the fuel regulator and hooked up a guage zero vacuum? also checked vacuum canistor by the charcol canistor has zero vacuum? hooked gauge to air pump vauum hose got about between 15 and 17 hg? what the heck is going on?

AGENT 86

Re check you vacuum line routing, sounds like it's not hooked up properly.


In the above pic, the HVAC line on plenum, goes to the check valve at rear of motor. The check valve tees it into 2, one going to HVAC via large wire loom, the other to cruise/vacuum tank.

black85

You have zero vacuum at the line to the fuel pressure regulator? Of course the fpr will be zero w/ the line off, but if you have no vac at the line it must be broken or disconnected. If you are getting 15-18 hg at other vacuum sources, but not the fpr that is not right. That line goes right from the nipple on the intake plenum to the fpr. Try just hooking up to the nipple on the intake plenum. You have to have vacuum there. I'm pretty sure your FPR isn't the problem, but you do need vacuum in the intake manifold (plenum included).

One thing you need to check if you haven't is the EGR valve. Mine was leaking really bad. I checked it with a vacuum pump. I think that when you apply the vacuum, the car almost died, but I don't remember very well. It was so long ago. That was one of the big things making my idle weird.

You needed that heated o2 sensor, so it wasn't a waste. Once you have the headers, especially w/ aftermarket exhaust all the heat goes out and doesn't heat the sensor enough to function.

I'm sure you will get the rest figured out soon.

rtmpmm

I have no egr i have a accel intake with a egr blockoff plate

black85

I think there is a solenoid for that purge tank, so it doesn't surprise me to hear that there isn't vacuum there.

Did you ever successfully check for stored codes? I don't think they all throw the CEL. I guess I'd start there.

Also, you could check your block off plate for vacuum leaks as well w/ propane or 2+2.

Did you check your minimum throttle plate opening? I assumed so b/c you said you did the TPS and all. Here is the whole procedure (I think you already saw this). http://forums.corvetteforum.com/c4-t...dle-speed.html

rtmpmm

well i got the vacuum hoses hooked up, set the idle and tps, runs better no more surging so far ive changed, intake, plenom gaskets, hoses, fuel pump, cap rotor, plugs wires, cleaned throttle body, iac etc, so i go for drive and floor it, ses light comes on and it seems like its under powered im getting codes 33 and 42 what do i do now? i checked all connections?

rtmpmm

i also forgot to add my oil temp says low now also

AGENT 86

http://members.shaw.ca/corvette86/Code%2033.pdf
http://members.shaw.ca/corvette86/Code%2042.pdf

Clear the codes(remove neg batt cable or ecm power connection by battery) and see if they both reappear.
42 is thrown during timing the motor(EST connector), so if you timed it and didn't clear the codes, that one will still be there.

You might want to check connection of oil temp sender, just above oil filter.

rtmpmm

the ecm was reset i pulled the fuse after i timed it, the car seems week when i floor it. the ses only came on after i floored it?

black85

Did you disconnect your battery after all those changes? I'm just guessing, but maybe making so many big changes at once could throw the light.

That is the MAF sensor circuit (code 33) and the Electronic Spark Timing Circuit (code 42). It would be really nice to swap a couple parts off a different car to see what is going on. It would be easy to test a different maf and esc computer. The computer is inexpensive though. I actually bought an updated one that is supposed to help prevent false knock counts from loud exhaust. I think it is like $45. It would be a good thing for
you to have, but not necesarily why you are getting the ses light. I guess the best place to look for that info is the factory service manual. I could look in mine tomorrow b/c I'm curious where you would start w/ that.

The MAF sensor is pretty expensive. I got one w/ a lifetime warrenty for $200. That is why I say it would be nice to test one to see if it fixes your problem first. I've seen people test them by giving them a tap on top of the sensor w/ the back of a screwdriver. Supposedly, a bad MAF can stall the car when you do that. I don't know if that is true all the time though.

The whole thing you are going through is reminding me of when I got my car. Once I got it straightened out it ran great for a long time

edit: Double check the connection on that esc plug that you disconnected when you set the timing (you did that right?). Maybe it came apart or loose when you floored it.

coupeguy2001

Before all that, you might try just putting in a fresh one wire O2 sensor.

rtmpmm

i have a brand new 3 wire o2 sensor the plugs are tight, this car is turning into a nightmare, fix one thing 2 more promblems come up.

black85

Why would you say that? It is common knowledge that once you put long tube headers on a car, especially w/ an aftermarket exhaust you need a heated on. All the heat goes out the back now. The one wire o2 sensor doesn't reach the necessary 600 degrees to give a reading and go to closed loop. The only difference between a one and three wire o2 sensor is the heating coil.

pr0zac

did you try cleaning the iac?

rtmpmm

yes iac was cleaned