TBI EGR issue

[PANCAKE]

Hi guys,

I am almost done with my TBI swap. The motor is a 350ci and I put a Edelbrock Performer intake manifold 3701 with EGR in place of the stock 1989 TBI manifold ( because of the haed bolt angles)...the problem is that the stock EGR that came off the donor truck, (1989 burb), will not bolt up to my new Edelbrock intake. The bolt holes will not line up. I was looking around Rockauto.com and found several EGR valves for 1980-1983 350ci.

My question is:
Can anyone sugest an EGR valve that will bolt on to the Edelbrock Performer intake manifold #3701.

The truck will have a full manual valve body TH400 and will be driven at high altitude (over 10,000). Do I need a high altitude EGR?

This truck is only a trail rig and no emissions are required (registrered in Park county )

Thanks for any help or input, Pancake

P.S. The gasket that came with the Edelbrock Performer intake manifold #3701 looks like this:

 

[dave w]

This truck is only a trail rig and no emissions are required (registered in Park County )

If emissions testing is not required, I personally would block off the EGR. http://www.custombilletworks.com/products.php Heck, I have vehicles that require emission testing that pass just fine (tail pipe only) without the EGR. If in the future, you need to sell to a new owner who requires emission testing or the emission laws change, then install and EGR from a 1980 - 1985 Chevy 1/2 ton pickup with a 350 V8 engine onto the Edelbrock intake.

 

[4X4HIGH]

TBI intakes use a different EGR valve than a carbed engine as you've discovered. Not only is the EGR valve a different bolt pattern it is also a postive back pressure design that uses an EGR solenoid to activate so you cannot just use an early style EGR valve and work correctly.

 

[dave w]

The Edelbrock 3701 manifold is designed for the carburetor EGR.

dave w

 

[4X4HIGH]

The Edelbrock 3701 manifold is designed for the carburetor EGR.

dave w

Yep, and his truck is set-up for the positive pressure EGR with the EGR solenoid. He can make the EGR work BUT it won't be smog legal should he ever need to smog it since his EGR runs through the ECM because of the EGR solenoid.

 

[dave w]

The option of a re-programming the PROM would be possible to convert to a carburetor EGR. See Screen Shot.

dave w

 

[PANCAKE]

If I block off the EGR will I have to get a new PROM burned for the ECM?

What will not having an EGR do?

Thanks for the help.

 

[4X4HIGH]

If I block off the EGR will I have to get a new PROM burned for the ECM?

What will not having an EGR do?

Thanks for the help.

EGR helps to cool the combustion temps which helps to reduce detonation. If you remove it you need to be careful that the engine doesn't detonate otherwise it is destroying your engine when it does.

 

[dave w]

EGR helps to cool the combustion temps which helps to reduce detonation. If you remove it you need to be careful that the engine doesn't detonate otherwise it is destroying your engine when it does.

I flat out 100% DISAGREE that diluting the intake fuel air mixture with HOT exhaust gases will in any way COOL the fuel air mixture. Air Gap intake manifolds are proof that COOL fuel air mixtures have combustion chamber benefits!

Based on my chip programming / data logging experience, the stock TBI timing curve will work fine with the EGR blocked off. Based on my chip programming / data logging experience, performance timing curves can, and will be affected with / without an EGR. If the only change made to a stock TBI engine is blocking off the EGR, then the stock PROM chip timing / fuel maps are OK. It's still possible with the EGR blocked off, the the ECM can set an error code. I always disable the EGR error code in the PROM programming when I disable the EGR, just to make sure I don't set an error code.

One problem I've seen with engine knock is gas quality, vehicles left parked for extended periods of time, can and will cause gas quality to be affected. I also recommend using a 180 thermostat when the EGR is blocked off.

dave w

 

[PANCAKE]

Thanks for the input...

I think I will block off the EGR plate and see how the truck runs..

If I need to I can mailorder a new PROM without the EGR but it sounds like I may not need to.

Thanks again for the help and if anyone has any other sugestions please chime in.

Pancake

 

[4X4HIGH]

I flat out 100% DISAGREE that diluting the intake fuel air mixture with HOT exhaust gases will in any way COOL the fuel air mixture. Air Gap intake manifolds are proof that COOL fuel air mixtures have combustion chamber benefits!

Based on my chip programming / data logging experience, the stock TBI timing curve will work fine with the EGR blocked off. Based on my chip programming / data logging experience, performance timing curves can, and will be affected with / without an EGR. If the only change made to a stock TBI engine is blocking off the EGR, then the stock PROM chip timing / fuel maps are OK. It's still possible with the EGR blocked off, the the ECM can set an error code. I always disable the EGR error code in the PROM programming when I disable the EGR, just to make sure I don't set an error code.

One problem I've seen with engine knock is gas quality, vehicles left parked for extended periods of time, can and will cause gas quality to be affected. I also recommend using a 180 thermostat when the EGR is blocked off.

dave w

I never said anything about it cooling the intake fuel/air mixture. I said EGR helps cool the combustion temperature.

Also, don't get me wrong that you can't run without an EGR valve, my engine has the complete EGR system installed BUT when Brian at TBIchips burned a chip for me he screwed up and turn EGR function off so even though my EGR system is intact it IS NOT working. I am very well aware of what happens when an engine detonates so IF it starts then it's only a matter of backing off the throttle or making sure the engine isn't lugging.

You might want to read this. http://www.aa1car.com/library/egr.htm

 

[Thunder]

Your engine will run fine without EGR valve.
However it will light the CEL and set a code 32.
When code 32 is set.
At cruise speeds timing will not advance as far as It would if EGR was hooked up. Fuel will not lean out as much. This will prevent detonation.
About all that is affected by removing/blocking off egr is fuel mileage at cruise speeds and emissions.
I have never had engine knock issues with an EGR disconnect or failure except if EGR stuck open or leaked and leaned out the AF mixture too much.
If anything removing the EGR and blocking off the manifold will cause less timing to be added and slightly richer AF ratio mostly at steady cruise RPMs. Acceleration & idle should not be affected.
On a trail rig i dont think there will be any issues.