DODGE RAM FORUM banner

5.9 Running lean

7K views 11 replies 4 participants last post by  RAMING IT 
#1 ·
Hey everyone. I swapped from a 318 to a 360 here a couple weeks ago. Running the stock 318 computer. The 360 has a hughes air gap efi intake, a mild port and polish job on the factory heads, and flowtech headers. But we're having a problem with a lean back fire. Checked the fuel pressure. Its 50psi on the dot, never fluttered even before the back fire. Its got new plugs and wires, cap rotor cam sensor in the dizzy, new fuel injectors, so im kinda at a lost here. Any ideas? I've sank a ton of money in time in this truck and its real depressing trying to take off from the light and getting that back fire.
Thanks in Advance.
 
#7 · (Edited)
Ditto....

Every single person that I talked with about this swap said it would work? I can't find a 360 5 speed computer. Is there a way to tune this computer to work?
it would work if you had a stock 360 including stock intake... you said yourself you added an airgap. How exactly do you think an intake like that improves performance??... By increasing air flow to the engine, which in turn the pcm has to adjust for by adding more fuel.... they can only adjust up to a set amount higher or less to get the correct Air fuel ratio (+ or minus 33.6%from 0.0 fuel trim)... if you have a 318 pcm the starting setpoint for that is lower than the 360 pcm would be already since they require less fuel so its already close to its limits even with a stock intake setup... actually until the truck warms up its running off preset AF ratios in a open loop mode for a 318 and it would be running very very lean in your case.
 
#4 ·
Without knowing exactly what's going on in the EacM, my thought would be that even with an external tune, the ECM will still think it's feeding a 318. If it could be flashed with the larger displacement, (seems like it should be do-able) that'd work. Rock Auto has the computer you need.
 
#9 ·
So it helped resolve it for the most part but your engine is still running lean in open loop mode on warm ups... you need to take it easy when warming it up or get a custom tune in there to fix right and resolve the lean tune in open loop mode... especially if you add anymore mods to improve airflow and make the engine breath better...
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top