The 1947 - Present Chevrolet & GMC Truck Message Board Network







Register or Log In To remove these advertisements.

Go Back   The 1947 - Present Chevrolet & GMC Truck Message Board Network > 47 - Current classic GM Trucks > The 1988 - 1998 GMT400 Chevy & GMC Pickups Message Board

Web 67-72chevytrucks.com


Reply
 
Thread Tools Display Modes
Old 01-05-2018, 09:13 PM   #1
ChevyTech
Registered User
 
Join Date: May 2004
Location: Minnesota
Posts: 4,620
Answer to MaddMech EGR private message

MaddMech sent me a private message but can not receive a return message.

Here is what I get when I tried to reply to the message sent to me:
MaddMech has chosen not to receive private messages or may not be allowed to receive private messages. Therefore you may not send your message to him/her.


To answer the question MaddMech sent me for a hesitation on a 93 C3500 5.7 stock and a NV4500 tranny. P/N on EGR is 1708718

That EGR number is a port EGR valve.

The EGR solenoid should have three wires to it, instead of two like the negative back pressure EGR trucks have

That EGR valve is a simple diaphram and should open when you put vacuum on it with the engine running or not.

All the modulation on that system is done with the EGR solenoid which is referred to as a EVRV

The only way Port EGR causes a hesitation is if the valve is sticking open or the EVRV has issues which can happen if dirt gets sucked into it and makes it stick at times. Make sure no vacuum can get through the EVRV with the engine at idle.

If I were working on your truck the first thing I would do is test the fuel pressure with the engine running.
__________________
For those of you that are wondering why you are not getting replies to your thread:
Did you give the model, year, engine, fuel system type, and transmission information?
If it is modified from what came stock from the factory, let us know that too.
ChevyTech is offline   Reply With Quote
Old 01-07-2018, 08:43 PM   #2
LT7A
Registered User
 
Join Date: Oct 2015
Location: PNW
Posts: 3,472
Re: Answer to MaddMech EGR private message

They might have a full mailbox.
LT7A is offline   Reply With Quote
Old 03-30-2018, 07:56 PM   #3
MaddMech
Registered User
 
Join Date: May 2011
Location: Blanco, Texas
Posts: 6
Re: Answer to MaddMech EGR private message

Thank you Chevy tech. I did not know that I had private messages blocked, but I think I got that corrected. Any way, I checked vacuum at TBI: 0 at idle and up 20" at more than 1/4 throttle. Checked EGR bi applying vacuum and holds with no leak down. At idle if I move diaphragm the engines stumbles and almost dies. The only thing I see is that at idle with the vacuum gauge now hooked on EGR side of solenoid when I move the throttle, the most I get is just shy of 1" vacuum. I swapped out another, used, solenoid with the same results. I guess it must be a wiring problem. NOTE: I did check fuel pressure running. Had 9.5 at idle or WOT. Changed filter and have 11.5-12.0 at idle or WOT. I have installed fuel pressure port at TBI drivers side fuel line. Timing is at 4 BTDC. New plugs and wires, cap and rotor. It has a 369 ICM installed.
MaddMech is offline   Reply With Quote
Old 03-30-2018, 10:52 PM   #4
95 S_Trucker
Registered User
 
95 S_Trucker's Avatar
 
Join Date: Oct 2009
Location: .
Posts: 2,178
Re: Answer to MaddMech EGR private message

Timing should be set to 0 degrees with the timing connector disconnected.
95 S_Trucker is offline   Reply With Quote
Old 03-31-2018, 09:12 PM   #5
ChevyTech
Registered User
 
Join Date: May 2004
Location: Minnesota
Posts: 4,620
Re: Answer to MaddMech EGR private message

Everything looks ok except the timing.

Put the timing at zero as stated with the connector unplugged.

What problem are you having with the truck?
__________________
For those of you that are wondering why you are not getting replies to your thread:
Did you give the model, year, engine, fuel system type, and transmission information?
If it is modified from what came stock from the factory, let us know that too.
ChevyTech is offline   Reply With Quote
Reply

Bookmarks

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT -4. The time now is 10:22 PM.


Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2024, vBulletin Solutions Inc.
Copyright 1997-2022 67-72chevytrucks.com