Go Back  Offshoreonly.com > Technical > General Q & A
500 EFI Transom soot >

500 EFI Transom soot

Notices

500 EFI Transom soot

Old 09-06-2020, 10:25 AM
  #1  
Platinum Member
Platinum Member
Thread Starter
 
Fountain38's Avatar
 
Join Date: Mar 2001
Location: Pryor, Ok.
Posts: 462
Received 2 Likes on 1 Post
Default 500 EFI Transom soot

I know Others have had issues like this. But Iím also having issues and havenít got it figured out yet. . I would appreciate any help as I have just about exhausted my ideas on how to fix it. Boat runs excellent. You would not know there was a problem except for the black transom on the port engine.

This is what I have done.
ECMís have been checked out and they are right on target.
new injectors from BUP. (Heís been trying to help me but still looking for ideas. He has been very helpful)
Most sensors Changed, map, air temp, TPS,
fuel regulator changed out. knock sensor
excellent compression all cylinders
new wires and new coil.

i havenít changed the water temp sensor yet.
I had an ignition trigger go out and I changed it. I have really strong ignition spark too.

Iím at a loss. The transom is not just lightly sooting, itís black. Iím not making any headway. About ready to take it to someone and let them figure it out. I would appreciate anyoneís help or advice. Iím in NE Okla if you know anyone capable and good that may be able to fix it.

thanks everyone😄
Fountain38 is offline  
Old 09-06-2020, 10:42 AM
  #2  
Registered
 
Join Date: Oct 2012
Posts: 1,486
Received 52 Likes on 34 Posts
Default

Have you checked fuel pressure?
underpsi68 is offline  
The following users liked this post:
SB (09-06-2020)
Old 09-06-2020, 10:45 AM
  #3  
Platinum Member
Platinum Member
Thread Starter
 
Fountain38's Avatar
 
Join Date: Mar 2001
Location: Pryor, Ok.
Posts: 462
Received 2 Likes on 1 Post
Default

Actually no. Thatís next on my list. I donít have tool but need to get one. Thank you.
Fountain38 is offline  
Old 09-06-2020, 10:47 AM
  #4  
Platinum Member
Platinum Member
Thread Starter
 
Fountain38's Avatar
 
Join Date: Mar 2001
Location: Pryor, Ok.
Posts: 462
Received 2 Likes on 1 Post
Default

So a dumb question for you. So why would low pressure cause too much fuel and sooting?
Fountain38 is offline  
Old 09-06-2020, 10:59 AM
  #5  
Forum Regulator
VIP Member
iTrader: (1)
 
Sydwayz's Avatar
 
Join Date: May 2001
Location: Worldwide
Posts: 22,924
Received 121 Likes on 64 Posts
Default

What octane fuel are you running?
Sydwayz is offline  
The following 3 users liked this post by Sydwayz:
flat rate (09-06-2020), Padraig (09-07-2020), SB (09-06-2020)
Old 09-06-2020, 11:06 AM
  #6  
SB
Registered
iTrader: (1)
 
Join Date: Nov 2004
Location: On A Dirt Floor
Posts: 10,573
Received 275 Likes on 147 Posts
Default

X 2 on too high octane of fuel. If 87 or 89 is used check fuel psi. Could be high.

These should have been first two things to check/adjust.

Years ago tons of 500EFI soot threads. 2 high of octane was numero uno cause.
SB is online now  
The following users liked this post:
Padraig (09-07-2020)
Old 09-06-2020, 11:15 AM
  #7  
Platinum Member
Platinum Member
Thread Starter
 
Fountain38's Avatar
 
Join Date: Mar 2001
Location: Pryor, Ok.
Posts: 462
Received 2 Likes on 1 Post
Default

Iím running 91. But a bit of background. Iíve owned this boat for 17 years. The starboard engine is fine. Runs 91 as well. All new injectors on it too. Both motors are freshly rebuilt and freshened up. This has been a ongoing problem. I tried 89 a month a go and it didnít seem to help. Fuel pressure seems like a likely candidate to me. Yes Iíve read all the forums too but none have seemed to help me. I do appreciate all you guys help. A case of beer to whoever has an answer. Lol.
Fountain38 is offline  
Old 09-06-2020, 12:23 PM
  #8  
Registered
 
Join Date: Mar 2013
Posts: 77
Likes: 0
Received 1 Like on 1 Post
Default

I had the same issue with a lot of soot and it turned out to be the blend of fuel I was running. I switched to 87 octane and it greatly reduced the amount of soot. I would also suggest to check your fuel pressure. You could have a bad pressure regulator causing it to run rich. The 500 efi is a speed density tune with no 02 sensors to regulate the fuel trims based on whatís coming out the exhaust. Just my 2 cents. Good luck and hope you sort it out.
EMARTELL65 is offline  
Old 09-06-2020, 04:37 PM
  #9  
Registered
 
Join Date: Feb 2013
Posts: 781
Received 46 Likes on 32 Posts
Default

Hose for MAP sensor leaking?

Can you get a scanner on it and see what the sensors are reporting?
zz28zz is offline  
Old 09-06-2020, 04:57 PM
  #10  
Registered
iTrader: (1)
 
Join Date: Oct 2013
Location: SF Bay Area
Posts: 2,770
Received 65 Likes on 49 Posts
Default

Anything over 87 octane burns to slow for these engines leaving a ton of unburned soot out of the pipes.
Baja Rooster is offline  

Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service - Do Not Sell My Personal Information -

Copyright © 2018 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.