Bought a 94 Z28 has LT4 intake on it causing me to fail emmissions?
12-11-2007, 10:57 AM
#21
TECH Resident
iTrader: (1)
Join Date: Sep 2005
Location: Elko MN
Posts: 833
Likes: 0
Received 0 Likes
on
0 Posts
I doesn’t sound to me that you have a vacuum leak. The motor would run pretty bad and hunt for a stable idle speed or have a very high idle speed. As I recall, high hydrocarbons are caused by too low a combustion chamber temperature. The job of the EGR valve is to raise this temperature. Get that EGR system working well and try another inspection. If you want to make sure it’s good and hot when you go, unplug the left (driver’s side) fan. It comes on first, the other at a higher temperature. While you’re at it, are your plugs good? Poor ignition will hurt you. Also, make sure there aren’t any lurking codes that aren’t triggering the SES light.
Good luck!
Good luck!
12-11-2007, 05:22 PM
#25
On another note, it could be the temperature sender on the waterpump, if its bad it will cause the computer to think its -20 to -40 below and run richer then ****. Even if your guage works it doesnt mean that this sender is good because the guage sender is located on the drivers side head. just a thought..
12-11-2007, 05:36 PM
#26
How can i test it? My new EGR valve will be here tomorrow so i'll replace that although im not sure if ill notice it running any different. I do also plan on ordering a tune. I believe i ordered mine from PCMforless a few years ago. Are they still in busness? And do they still sell email tunes?
12-11-2007, 05:54 PM
#29
Well I cant get the diaphram to budge and the girl said shes never replaced it plus ive already paid for it so its getting a new one. I dont see an email tune from PCMforless anymore. They say they can send you a baseline calibration but i want the same tune theyd do to their ECU same price is fine with me i just dont want the downtime. Any other venders that do email tunes?
12-13-2007, 04:56 AM
#32
Reaplced the EGR valve last night. It didnt even take 5 minutes, i couldnt believe how easy it was. The exhaust smell 100 times better. It doesnt make your eyes water. I did notice that when its cold, like in the first minute, you can hear the exhaust like pinging. it goes Pop!...... Pop! when idling then its fine after the 1st minute. Is that because of the AIR or just because of maybe some build up?
12-13-2007, 06:13 PM
#35
On The Tree
Join Date: Feb 2006
Location: Red Oak,Texas
Posts: 161
Likes: 0
Received 0 Likes
on
0 Posts
the lt4 intake is no longer a lt4 intake. since the top of the runners were milled down it will no longer work on lt4 heads. i went through the same thing a little while back, thought i was going to be able to turn a decent profit on one then took it to lloyd and he said it had been milled to fit our heads. oh well got a red intake now haha
12-13-2007, 11:45 PM
#36
Staging Lane
iTrader: (2)
Join Date: Mar 2007
Location: KY
Posts: 99
Likes: 0
Received 0 Likes
on
0 Posts
The LT4 intake didn't have the EGR because the LT4 hotcam had enough overlap that it didn't need it. Do you know what cam is in it? Perhaps a tune would help.
A useful link - http://www.malcams.com/legacy/misc/LT4.htm
A useful link - http://www.malcams.com/legacy/misc/LT4.htm
12-25-2007, 02:21 PM
#37
Replaced a bad EGR, cleaned the MAF, AIT, replaced ECT, found two less than hand tight plugs, 4 burnt wires, 1 destroyed boot, and the car runs beautifully. Got it tagged and all. It's pretty fast. The 3.73s melt the 275s well into 3rd. Might have to try the telstars/MT slicks from the 68 to see what it can do with some traction. Any idea how well a torsion dif and motive 3.73s will hold up?
Here's a pic of it.
Here's a pic of it.
