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Old 01-05-2018, 09:13 PM   #1
ChevyTech
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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.
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Old 01-07-2018, 08:43 PM   #2
LT7A
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Re: Answer to MaddMech EGR private message

They might have a full mailbox.
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Old 03-30-2018, 07:56 PM   #3
MaddMech
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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.
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Old 03-30-2018, 10:52 PM   #4
95 S_Trucker
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Re: Answer to MaddMech EGR private message

Timing should be set to 0 degrees with the timing connector disconnected.
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Old 03-31-2018, 09:12 PM   #5
ChevyTech
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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?
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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.
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