Go Back  Offshoreonly.com > Technical > General Q & A
MEFI 1 350 issues >

MEFI 1 350 issues

Notices

MEFI 1 350 issues

Thread Tools
 
Old 05-17-2016 | 06:04 PM
  #11  
Registered
15 Year Member
 
Joined: Oct 2007
Posts: 8,439
Likes: 94
From: yorkville,il
Default

black smoke does not always indicate a fuel problem.a weak ignition that can,t ignite the fuel could be the issue.
mike tkach is offline  
Reply
Old 05-17-2016 | 06:12 PM
  #12  
SB
Registered
20 Year Member
 
Joined: Nov 2004
Posts: 14,154
Likes: 3,714
From: On A Dirt Floor
Default

I agree Mike. Famous one is people using standard reach plugs plugs (MR43T's and MR43TS's) in a Vortec head, which takes a longer reach plug. (MR43LTS)
SB is online now  
Reply
Old 05-18-2016 | 07:38 AM
  #13  
Thread Starter
Registered
 
Joined: Feb 2014
Posts: 43
Likes: 0
Default

that wouldnt account for the over fueling though right?
1 2 NV is offline  
Reply
Old 05-18-2016 | 07:55 AM
  #14  
SB
Registered
20 Year Member
 
Joined: Nov 2004
Posts: 14,154
Likes: 3,714
From: On A Dirt Floor
Default

Originally Posted by 1 2 NV
i should also note that i cannot fire up the motor unless the pump is in water. so i have no fuel pressure readings while the engine has vacuum on it.
You can use a vacuum pump like a mityvac or equivalent.
SB is online now  
Reply
Old 07-03-2016 | 06:02 PM
  #15  
Thread Starter
Registered
 
Joined: Feb 2014
Posts: 43
Likes: 0
Default

well its been awhile since i did any troubleshooting. the FP reads 42psi while the engine is running. i was too busy to check the FP when the boat was going down the river as it was extemely rough and the wife was tending to the little guy who was scared of the river conditions. the only thing to note right now is by the time i got home the FP was almost to 0. it bleeds fuel pressure off slowly.
so at this point im guessing its the MAP sensor.
1 2 NV is offline  
Reply
Old 10-16-2016 | 12:57 PM
  #16  
Thread Starter
Registered
 
Joined: Feb 2014
Posts: 43
Likes: 0
Default

one other thing that came up. someone ran their identical engine to mine with a diacom on it. until it heated up to 165 he was burning 9.8 gal hr according to the diacom. after it reached that temp the fuel usage went down significantly to 8.3 gal hr. most people i know burn 7-8 gal an hr with a 350.
somebody also mentioned it might be the temp sensor. ill have to get a different meter to read the resistance in it.

Last edited by 1 2 NV; 10-16-2016 at 01:02 PM.
1 2 NV is offline  
Reply
Old 10-16-2016 | 01:37 PM
  #17  
Registered
10 Year Member
 
Joined: Jun 2011
Posts: 1,211
Likes: 145
Default

Originally Posted by 1 2 NV
one other thing that came up. someone ran their identical engine to mine with a diacom on it. until it heated up to 165 he was burning 9.8 gal hr according to the diacom. after it reached that temp the fuel usage went down significantly to 8.3 gal hr. most people i know burn 7-8 gal an hr with a 350.
somebody also mentioned it might be the temp sensor. ill have to get a different meter to read the resistance in it.
The reduction in fuel use as the motor is warmed up is normal. There is a table in the MEFI 1 that modifies the Base Pulse Width (BPW, fuel injector time on) vs Engine Coolant Temp (ECT). It is effectively an electronic choke. Richer during cold ECT conditions, leaner while at operating temps.
Trash is offline  
Reply
Old 10-16-2016 | 01:55 PM
  #18  
Thread Starter
Registered
 
Joined: Feb 2014
Posts: 43
Likes: 0
Default

i wish this thing would get figured out. i havent been using the boat much so its my fault. its a pain to haul it to the river so i can test any idea that might come up.

so ive read through the troubleshooting manuals quite a bit. to set timing it says you need the DLC tool. im betting that the DLC jumpers 1 connectors together to set base timing. does anyone know which wires need jumpered? i dont have a DLC.
1 2 NV is offline  
Reply
Old 10-17-2016 | 11:20 PM
  #19  
Registered
10 Year Member
 
Joined: Jun 2011
Posts: 1,211
Likes: 145
Default

Originally Posted by 1 2 NV
i wish this thing would get figured out. i havent been using the boat much so its my fault. its a pain to haul it to the river so i can test any idea that might come up.

so ive read through the troubleshooting manuals quite a bit. to set timing it says you need the DLC tool. im betting that the DLC jumpers 1 connectors together to set base timing. does anyone know which wires need jumpered? i dont have a DLC.
The DLC is simply the Data Link Connector located near the MEFI 1. You can jumper the A / B ports to get the ECM into base timing mode. You can do this with a paper clip.

Start the motor, bring the rpm up just a little (1000-1200), jumper the A / B pin outs on the DLC connector and you will be in base timing mode. Put a timing light on the balancer and adjust the distributor until you get 8 deg BTDC. Lock down the distributor and remove the DLC jumper. Base timing is now set.

The motor may run goofy or rough during base timing mode. Don't freak out, this is normal. It may stall when you remove the jumper. That's ok too. Simply key off and restart.

That's the Cliff notes version. Others may chime in if I've forgotten something.
Trash is offline  
Reply
Old 10-18-2016 | 01:41 AM
  #20  
Thread Starter
Registered
 
Joined: Feb 2014
Posts: 43
Likes: 0
Default

thats excellent info trash. thanks for that info. im planning on hitting the river in the next week or 2 and will certainly time the motor.
1 2 NV is offline  
Reply


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

Copyright © 2026 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.