Go Back  Offshoreonly.com > Technical > General Q & A
7.4 mpi timing issues >

7.4 mpi timing issues

Notices

7.4 mpi timing issues

Thread Tools
 
Old 03-21-2019, 04:51 PM
  #11  
Registered
Thread Starter
 
troc's Avatar
 
Join Date: May 2006
Location: huntington ny
Posts: 244
Likes: 0
Received 0 Likes on 0 Posts
Default

yes sir, My friend 14apache said you were the man to talk to lol
troc is offline  
Old 03-21-2019, 04:56 PM
  #12  
Registered
Thread Starter
 
troc's Avatar
 
Join Date: May 2006
Location: huntington ny
Posts: 244
Likes: 0
Received 0 Likes on 0 Posts
Default

Originally Posted by BUP
you did put the scan tool in service mode ?? for setting and checking the timing Im just checking
Yes sir I used my rinda scanner
troc is offline  
Old 03-21-2019, 05:04 PM
  #13  
Registered
Thread Starter
 
troc's Avatar
 
Join Date: May 2006
Location: huntington ny
Posts: 244
Likes: 0
Received 0 Likes on 0 Posts
Default

Originally Posted by MDG_Jason
How much timing are you getting? Some of those 7.4s did not have much timing in them from the factory
about 28 deg at 2700 then the timing starts to peel off down to 19deg as RPMs increase
troc is offline  
Old 03-21-2019, 05:13 PM
  #14  
Platinum Member
Platinum Member
 
F-2 Speedy's Avatar
 
Join Date: May 2012
Location: Midwest & T-Rock
Posts: 10,562
Received 3,168 Likes on 1,411 Posts
Default

Is this a MEFI 3 ......is the knock sensor connected ?.......seems the ECM thinks there's a problem and is pulling timing out
F-2 Speedy is online now  
Old 03-21-2019, 05:19 PM
  #15  
Registered
 
Join Date: Nov 2009
Location: KY
Posts: 4,137
Received 477 Likes on 372 Posts
Default

with a carb and mechanical distributor and it made 315hp I suggested to put MPI and ecm on and rerun it. It would only make 275 hp
I'm thinking you need to pull the motor apart and find out what was not put together correctly. Even a carb motor with 088 heads should make more then 315hp with fresh rebuild
AllDodge is offline  
Old 03-21-2019, 05:20 PM
  #16  
Registered
Thread Starter
 
troc's Avatar
 
Join Date: May 2006
Location: huntington ny
Posts: 244
Likes: 0
Received 0 Likes on 0 Posts
Default

Originally Posted by BUP
you did put the scan tool in service mode ?? for setting and checking the timing Im just checking
I did , scanner matched timing light on the balancer . timing starts to increase ,then just peels off as rpms increase I swapped out the knock sensor, but im wondering if i should check voltage on the ECM pertaing to knock/advance? I believe its J1-1? waiting for the manual I ordered to show up to verify I appreciate the responses!
troc is offline  
Old 03-21-2019, 05:35 PM
  #17  
Registered
 
Join Date: Nov 2009
Location: KY
Posts: 4,137
Received 477 Likes on 372 Posts
Default

Originally Posted by troc
I did , scanner matched timing light on the balancer . timing starts to increase ,then just peels off as rpms increase I swapped out the knock sensor, but im wondering if i should check voltage on the ECM pertaing to knock/advance? I believe its J1-1? waiting for the manual I ordered to show up to verify I appreciate the responses!
With the MEFI3 (EDIT once its running), you can just remove the knock sensor wire off the sensor and move it out of the way. If power increases, the sensor is picking up a knock and retarding timing. If it does increase power after wire is removed "SHUT IT DOWN" because your destroying the motor

Last edited by AllDodge; 03-21-2019 at 05:37 PM.
AllDodge is offline  
Old 03-21-2019, 06:05 PM
  #18  
Registered
Thread Starter
 
troc's Avatar
 
Join Date: May 2006
Location: huntington ny
Posts: 244
Likes: 0
Received 0 Likes on 0 Posts
Default

Originally Posted by F-2 Speedy
Is this a MEFI 3 ......is the knock sensor connected ?.......seems the ECM thinks there's a problem and is pulling timing out
I think im going to find the ECM input that controlls knock next. TWO ecms doing the very same thing...starting to run out of ideas lol
troc is offline  
Old 03-21-2019, 06:09 PM
  #19  
Registered
Thread Starter
 
troc's Avatar
 
Join Date: May 2006
Location: huntington ny
Posts: 244
Likes: 0
Received 0 Likes on 0 Posts
Default

Originally Posted by AllDodge
With the MEFI3 (EDIT once its running), you can just remove the knock sensor wire off the sensor and move it out of the way. If power increases, the sensor is picking up a knock and retarding timing. If it does increase power after wire is removed "SHUT IT DOWN" because your destroying the motor
agreed , ran some good fuel on the dyno and did exactly that...even with sensor wire disconnected the knock module is still in the circuit, no?
troc is offline  
Old 03-21-2019, 06:18 PM
  #20  
Platinum Member
Platinum Member
 
F-2 Speedy's Avatar
 
Join Date: May 2012
Location: Midwest & T-Rock
Posts: 10,562
Received 3,168 Likes on 1,411 Posts
Default

Id pull the front cover and check the timing marks, pull the distributor, remark #1 and restab the dist .............I dont think its an ECM issue, the engine isn't happy
F-2 Speedy is online now  


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.