Go Back  Offshoreonly.com > Technical > General Q & A
496 ho/headers to lean? >

496 ho/headers to lean?

Notices

496 ho/headers to lean?

Old 08-20-2007, 08:27 PM
  #1  
Registered
Thread Starter
 
speedygonzalez's Avatar
 
Join Date: Jul 2005
Location: agua dulce, ca
Posts: 102
Likes: 0
Received 0 Likes on 0 Posts
Default 496 ho/headers to lean?

Has anyone experienced or heard of headers leanning out a 496 ho to the point that you loose power instead of gaining power.
Here is my situation, after installing headers I lost @ 700 RPM checked fuel preasure its 48lbs at idle 50lbs at 4000 RPM, it has a upgraded regulator because it has Raylar 525 kit,timing is 22@4000 RPM throtlle is 100% both visual and at scanner, fuel filter is good and clean.
I talked to lightning( HEADERS) and he thinks I may be too lean and the knock sensor is causing timing to pull back, but ray says 22degrees is normal @4000 RPM.
I only run at Havasu and live 300 miles away so I can't experiment to much. I will try a local lake with current situation and see if richening makes a difference, but they have speed limits there so it may not help me.
Any leads or thoughts are highly welcomed.
speedygonzalez is offline  
Old 08-21-2007, 01:39 PM
  #2  
Registered
iTrader: (4)
 
Nordicflame's Avatar
 
Join Date: Mar 2002
Location: Layton, Utah
Posts: 1,546
Received 4 Likes on 4 Posts
Default

BobL has dyno'd and worked with that exact setup and can assist you. I do know that there was no lean out issues however.
Try PMing him.
Dave
Nordicflame is offline  
Old 08-21-2007, 02:27 PM
  #3  
Registered
Thread Starter
 
speedygonzalez's Avatar
 
Join Date: Jul 2005
Location: agua dulce, ca
Posts: 102
Likes: 0
Received 0 Likes on 0 Posts
Default

thanks ,I have seen that he has experience with 496.
speedygonzalez is offline  
Old 08-21-2007, 02:57 PM
  #4  
Registered
iTrader: (4)
 
Nordicflame's Avatar
 
Join Date: Mar 2002
Location: Layton, Utah
Posts: 1,546
Received 4 Likes on 4 Posts
Default

More than likely your in gaurdian mode which will not allow it to go over ~4300rpm.
Do you have access to a scanner (Diacom)
You may have left a sensor (exhaust manifold temp) unplugged or something along those lines.
Dave
Nordicflame is offline  
Old 08-21-2007, 04:38 PM
  #5  
Registered
 
Join Date: Oct 2000
Location: Spicewood, Texas USA
Posts: 1,382
Likes: 0
Received 3 Likes on 2 Posts
Default

Dave's right. The lightnings won't lean it out that much. You're going into guardian mode. Get a scanner on it to determine what is going on. Probably an exhaust temp sensor or water pressure.
bobl is offline  
Old 08-21-2007, 05:01 PM
  #6  
Registered
Thread Starter
 
speedygonzalez's Avatar
 
Join Date: Jul 2005
Location: agua dulce, ca
Posts: 102
Likes: 0
Received 0 Likes on 0 Posts
Default

I do have Diacom and everything is OK no alarms no codes. Now,the plugs are real clean even with the 525 raylar kit it was just a little on the fat side. Now the question is if the knock sesor is detecting detonation will that cause the sam thing ?
speedygonzalez is offline  
Old 08-21-2007, 05:54 PM
  #7  
Registered
 
Join Date: Oct 2000
Location: Spicewood, Texas USA
Posts: 1,382
Likes: 0
Received 3 Likes on 2 Posts
Default

You should be able to see any knock retard with Diacom. Check the %power available. I bet when you hit around 4300 RPM it is being reduced to 90% or less. If so you should be able to determine what is triggering it. From what I've seen it can do this and not set a guardian event in fault history, or audible alarm. I had a similar scenario that was triggered by an IAC that went bad. It would only go to 90% power above 4300 RPM.

Originally Posted by speedygonzalez
I do have Diacom and everything is OK no alarms no codes. Now,the plugs are real clean even with the 525 raylar kit it was just a little on the fat side. Now the question is if the knock sesor is detecting detonation will that cause the sam thing ?
bobl is offline  
Old 08-21-2007, 06:57 PM
  #8  
Registered
Thread Starter
 
speedygonzalez's Avatar
 
Join Date: Jul 2005
Location: agua dulce, ca
Posts: 102
Likes: 0
Received 0 Likes on 0 Posts
Default

Originally Posted by bobl
You should be able to see any knock retard with Diacom. Check the %power available. I bet when you hit around 4300 RPM it is being reduced to 90% or less. If so you should be able to determine what is triggering it. From what I've seen it can do this and not set a guardian event in fault history, or audible alarm. I had a similar scenario that was triggered by an IAC that went bad. It would only go to 90% power above 4300 RPM.
That's one thing that puzzled me as well, it always said 100%.
Havin said that, even if it was pulling back on timing,fuel or what ever it does to lower the power the Diacom should have read less power.
I know that removing them and putting OEM back is one way to see if thats the problem, but it's some work to do that.
speedygonzalez is offline  
Old 08-21-2007, 09:02 PM
  #9  
Registered
 
kr1276's Avatar
 
Join Date: May 2001
Location: Tampa,Fl
Posts: 589
Likes: 0
Received 0 Likes on 0 Posts
Default

I have triple 496's and installed CMI's and now am having the same problem but the difference is it is only on one engine. I am convinced it is a sensor doing it but I too have not had a chance to find it. Throw out the idea of a lean condition as my other two engines are not having the same problem. Once I figure mine out, hopefully this weekend, I will let you know.
kr1276 is offline  
Old 08-21-2007, 10:13 PM
  #10  
Registered
Thread Starter
 
speedygonzalez's Avatar
 
Join Date: Jul 2005
Location: agua dulce, ca
Posts: 102
Likes: 0
Received 0 Likes on 0 Posts
Default

Originally Posted by kr1276
I have triple 496's and installed CMI's and now am having the same problem but the difference is it is only on one engine. I am convinced it is a sensor doing it but I too have not had a chance to find it. Throw out the idea of a lean condition as my other two engines are not having the same problem. Once I figure mine out, hopefully this weekend, I will let you know.
At least you got another motor to swap whatever you might think to be the culprit, but I can't put in the water untill next week and fatten it up and see what happens.
speedygonzalez is offline  

Quick Reply: 496 ho/headers to lean?


Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service

Copyright © 2024 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.