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LT4 Aficionados, I had an 96 LT1 installed in an 81 corvette. I came across a great deal on LT4 and swapped the engine. When installing, I noticed that the LT4 had a block off plates where the EGR should have been installed so I removed the plates and installed the EGR. Car will crank but will not start. I have fuel pressure and spark. Checked injectors with noid light and changed coil. I want to remove the EGR valve. Does anyone have a diagram of how to plumb the line on the back of the LT4 Intake manifold or a picture of how the lines are plumbed? Thanks in advance.
LT4 Aficionados, I had an 96 LT1 installed in an 81 corvette. I came across a great deal on LT4 and swapped the engine. When installing, I noticed that the LT4 had a block off plates where the EGR should have been installed so I removed the plates and installed the EGR. Car will crank but will not start. I have fuel pressure and spark. Checked injectors with noid light and changed coil. I want to remove the EGR valve. Does anyone have a diagram of how to plumb the line on the back of the LT4 Intake manifold or a picture of how the lines are plumbed? Thanks in advance.
LT4 engines never came with an EGR valve. That block off plate is factory! The reason the LT4 doesn't have/need an EGR valve is because the LT4 cam has enough overlap that it has a natural EGR effect at lower RPMs.
The LT4 also has a different ECM (OBD2) than the LT1, if you are still using the LT1 ECM (OBD1) that might be the reason it is not running. You can make a LT1 ECM (OBD2) from a 1996 engine work with a JET DST programmer but I am not sure about getting other year ECMs to work.
Last edited by grandspt; Sep 19, 2023 at 07:38 PM.
Thank You. I am using an LT4 PCM. I attempted to wire and plumb the LT4 exactly like the LT1 which i now really wise was not wise. Do you know where I can get images/diagrams on the wiring/plumbing? There is a valve/solenoid that had a hose going to the EGR (Circled in red) Is that Valve/solenid obsolete for the LT4?
Thank You. I am using an LT4 PCM. I attempted to wire and plumb the LT4 exactly like the LT1 which i now really wise was not wise. Do you know where I can get images/diagrams on the wiring/plumbing? There is a valve/solenoid that had a hose going to the EGR (Circled in red) Is that Valve/solenid obsolete for the LT4?
That EGR solenoid is not use for the LT4.
I am not sure about diagrams, but you probably should get a 1996 service manual which will help with your wiring. I believe the manuals are still available on CD. Try member WVZR-1, he may be able to put you onto a manual. He also has a wealth of knowledge as well.
Or someone may have a used set of hardcopies.
Do you have the FSM for the LT1 of any year? Seeing that you're doing a mod of sorts I can supply you with a '96 FSM(Factory/Field Service Manual) for very few $$$$. You'd then have all of the LT4 information. You won't be disappointed. Drop me a PM or an email and we can discuss it. Very inexpensive. I'll also include a GM SPO Parts Catalog for parts research for the LT1/4 etc.
Serendipity WVZR-1, I just found a used 1996 Corvette FSM yesterday. I'm going through it now. Thanks
Most of the '96 FSM for you will be worthless maybe. Did you buy paper or a .pdf? I was going to offer just a 'clipped' section of a '96 FSM just what you needed.
Most of the '96 FSM for you will be worthless maybe. Did you buy paper or a .pdf? I was going to offer just a 'clipped' section of a '96 FSM just what you needed.
Sorry for the Delay but took a mini vacation. I bought the 2 volume book.
LT4 EGR Valve
