Jump to content
Deere Mack

1996 E7-427 exhaust noise and high pyro

Recommended Posts

Hello everyone, it's been a while.  I hope everyone's doing well.  My 1996 CH613 E7-427 started out making a noise that sounded like a bad exhaust leak, then in a good pull the pyro would jump up to 1200+/- quickly and running at around 900 but will drop on down at idle.  No noticeable lose in power but I was paying more attention to the noise before I parked it.  Can't seem to find any leaks and was wondering about the engine brake? Anyone have any input? 

Share this post


Link to post
Share on other sites

Sounds like you already solved it. Add another two scoops of determination in finding the leak. You got a pressure tester for CMCAC?

Share this post


Link to post
Share on other sites
40 minutes ago, Mack Technician said:

Sounds like you already solved it. Add another two scoops of determination in finding the leak. You got a pressure tester for CMCAC?

Thanks, good to hear from you! No I don't.  Could this make the "exhaust leak" noise?  What part of the Jake do you think is failing, just sticking, solenoid?

Share this post


Link to post
Share on other sites

took her for a spin after going over a few more things and still have the problem with a lightning bolt on the dash now kachow!

Share this post


Link to post
Share on other sites
Posted (edited)

Right back atcha. 

You have no dead holes.....power is good....pyro is high......engine makes a “pich” “pich” “pich” as if it’s a single cylinder and not a constant hiss of steadily escaping boost.... 

The intake has a small square pipe plug with, I believe, 1/8” NPT threads. Run a 1/4” airline compression fitting in and run it into cab window so you can check boost under load. 

let it cool and spray soap water on the exhaust manifold legs to head. Run it and apply more.

Did you extract the active code blink? 

CMCAC-chassis mounted charge air cooler.

Edited by Mack Technician

Share this post


Link to post
Share on other sites
Posted (edited)

Check the little hose at the compressor inlet and under the inlet manifold! those often burst! its a one inch  steel line that runs behind the engine

Edited by fjh

Share this post


Link to post
Share on other sites

when I took it on the last drive, I took my father in law. He's not much of an mechanic but a retired over the road trucker.  He thinks it's an injector.  I'm not sure now because it's worse with an overall loss of power and it seemed to have an rough idle that kind comes and goes.  Pyro is still quick to hit 900 especially in higher gears and I'm sure if I were loaded it would climb back to the 1200 mark.

I have checked for leaks with soapy water but I did not pull the codes or boost. I will this morning.  The noise it's making sounds like a blown exhaust gasket to me, but it's not, no exhaust or intake leaks at all.

 

Share this post


Link to post
Share on other sites
4 minutes ago, fjh said:

Check the little hose at the compressor inlet and under the inlet manifold! those often burst! its a one inch  steel line that runs behind the engine

Good morning and thanks for tip.  I did a visual on that hose and didn't notice anything, but it might take some pressure before that would show up?

Share this post


Link to post
Share on other sites

Their are two one on the manifold end one at the compressor!

  • Like 1

Share this post


Link to post
Share on other sites

Pull your valve covers, maybe you have a bent exhaust valve not closing all the way. With engine running, apply pressure to each rocker and see if somebody isn't working right... A quick visual comparison can quickly rule out potential mechanical failures. A valve not closing would also let combustion continue in the exhaust pipe, which would be hotter than completed combustion. And it'd probably sound like an exhaust leak. Because it kinda is.

Share this post


Link to post
Share on other sites
On 6/22/2019 at 8:13 AM, Deere Mack said:

when I took it on the last drive, I took my father in law. He's not much of an mechanic but a retired over the road trucker.  He thinks it's an injector.  I'm not sure now because it's worse with an overall loss of power and it seemed to have an rough idle that kind comes and goes.  Pyro is still quick to hit 900 especially in higher gears and I'm sure if I were loaded it would climb back to the 1200 mark.

I have checked for leaks with soapy water but I did not pull the codes or boost. I will this morning.  The noise it's making sounds like a blown exhaust gasket to me, but it's not, no exhaust or intake leaks at all.

 

Did you check the intake with pressure or just with soapy water?

Share this post


Link to post
Share on other sites

Extra temps caused by the charge cooler maybe caused manifold studs to loosen a little, causing the exh manifold gasket to leak? My old 2 valve endt676 motor is notorious for having the exhaust manifold nuts loosen. Been a while since the truck has had the lock tabs on it. Glad you're running again!

Share this post


Link to post
Share on other sites

Great looking dog too!

Share this post


Link to post
Share on other sites
6 hours ago, JoeH said:

Extra temps caused by the charge cooler maybe caused manifold studs to loosen a little, causing the exh manifold gasket to leak? My old 2 valve endt676 motor is notorious for having the exhaust manifold nuts loosen. Been a while since the truck has had the lock tabs on it. Glad you're running again!

Exactly my thoughts! 

  • Like 1

Share this post


Link to post
Share on other sites
On 7/2/2019 at 3:42 AM, JoeH said:

Extra temps caused by the charge cooler maybe caused manifold studs to loosen a little, causing the exh manifold gasket to leak? My old 2 valve endt676 motor is notorious for having the exhaust manifold nuts loosen. Been a while since the truck has had the lock tabs on it. Glad you're running again!

 

On 7/2/2019 at 3:44 AM, JoeH said:

Great looking dog too!

Thanks!  I agree with you too.  It only makes sense.Wished I'd thought about some lock tabs, at least all my studs came out and I got some new ones back in.  Might pick up some locks later and put em on.

  Happy 4th of July to everyone!  God Bless America!

  • Thanks 1

Share this post


Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.


×
×
  • Create New...