2003 SES OHC "U" total loss of power

[SES Dad]

The entire exhaust system has been replaced from engine manifolds all the way out.
I'll confirm pressure at the EGR pipe tonight with a gauge attached directly.

Was trying to surf other threads for anything similar.
Can any other sensor cause this issue?

[behlinla]

Originally Posted by SES Dad

Can any other sensor cause this issue?

Nope. The exhaust should be able to handle whatever the engine can put out.

When you do the test, remember to unplug the EVR or EGR vacuum line so the EGR valve won't open (you can see this in the video).

[SES Dad]

behlinla,
Thanks for staying with this one. I see you just picked up another EGR issue on the '07. The lean code P0171 is the only one that I had received.

This is really driving me nuts. I seem to have plenty of exhaust at the muffler now.
But still major hesitation and no power, especially after it warms up.
I'm gonna see if my exhaust guy will at least offer to drop the 'Y' pipe down and double check. I don't think I can do it on my back in the garage.
Rich

[Breeves002]

So you have a P0171 code? I'm confused.

P.S. with the EVR plugged in, the EGR should be closed at idle.

No other codes? No misfire? No flashing CEL? The hesitation could be part of that code, but you still must have something restricting the exhaust somewhere.


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[SES Dad]

Sam,
Yep...the only code I originally had was P0171....for a long time I believe.
Gonna try to request my guy to pull the exhaust down for me just to 'double-check' everything. He assures me it is right, but....
I agree, based on the tube and flow, only an exhaust restriction should be causing this pressure at the upstream side of the EGR tube.
I'll report back later tonight with actual pressure value at the tube.
Rich

[SES Dad]

Rigged up a pressure gage at the upstream EGR tube nipple. Based on an exhaust back pressure video I saw, I would say that I DO NOT have a clogged exhaust. No recordable pressure at idle and only slight (under 2 psi) pressure showing at about 3000 rpm.
So where does that put me?
Let's review where we came from:
1. Car exhibited extreme loss of power (worse after getting warm)
2. Blew off DPFE hoses trying to drive it home
3. Confirmed only P0171 code (lean bank 1) suspect that was on for years
4. Replaced all cats and muffler
5. Replaced plugs and wires
6. Replaced fuel filter
Car still exhibits low power and potential miss. Will get a code reader to determine any new codes set or pending.
Things to do:
Confirm EGR function tomorrow (borrowing a vacuum pump)
Confirm EVR solenoid function
Verify no vacuum leaks at small EGR and EVR tubes

Could this be a bad coil pack? How to tell?

Thanks in advance for the help....I think we are getting there Sherlock

[Breeves002]

You can confirm the EGR function by popping the cap off of the EVR and then putting your finger on the nipple. Or just use a piece of vacuum line and suck on it on top of the EGR valve. If the motor runs VERY rough or stalls, you have proper EGR function (not stuck open or closed).

Put the DPFE hoses back on... Make sure they are on all the way and snug. See if they blow off again. Maybe they were not put back on correctly?

If there is no significant pressure at idle and under 2psi at 3k rpm you shouldn't have a backflow problem. Seems pretty unrestricted to me assuming you did the test right.

[SES Dad]

May have just stumbled upon the solution.
After reading a couple recent posts (Northern) decided to do the cylinder drop test as posted in the misfire diagnosis sticky by Breeves002....
I'm sure the car won't run properly if both 2 and 3 cylinders are not firing.
Thanks for the work Sam.

[Breeves002]

Hey! There we go! I'm curious why you don't have a misfire code for cylinders 2 and 3. Replace the coil pack!

It's a no wonder that your cats were destroyed!!


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[SES Dad]

Hmmmm....true. I too would think those codes would have shown.
Still not sure I don't have a clogged intake due to running lean for so long.
We'll replace the coil pack an see how it works then.
Stay tuned please.