94 Dodge 318

mrvette

Phantom of the Opera
Joined
Mar 24, 2008
Messages
15,207
Location
NE Florida
3/4 ton van, new heads, most all of the sending units on the injection, batch fire DPFI....

engine runs and fires wonderful NOW, good idle, just no power, and IF it try to get it to run, under decent load, it will backfire a bit, not nearly so much as before.....

fuel pressure is 35 and pinching return line to get more will not help....Injectors were swapped for an old set outta the vette long time, stored clean in a can....it runs too well with no misfires to be them, now....

but compression is still at 90 all across the board....I did a timing chain/gearset on it few months ago, so pulled front of the engine this morning...found it perfect, all the dots lines up....SO,

someone suggested at parts house upon calling a mechanic friend that the EGR was open, well it WAS, but not now, it's been blocked.......

there is NO cat, it was cut off by p/owner....O2 sensor is a heated single one in front of the cat...typical location..
TPS and IAC and MAP are fine, act normal on voltage swings...the engine starts and runs fine, HOT or cold....idle is smooth, just no power....it will pull, but just no snap...

so it sounds like the cam is retarded, off a tooth, hense I pulled the front off again.....

been through the timing, it was explained that sender in the dizzy base is just for injector timeing, batch fire....well fine, but it has to obviously deal with the 8 holes in the crank position sensor also,

but it all comes back to the lack of compression....90 sux....TimAT seen the short block there the other week, and said it looked good to him too...

anyone ????

:suicide:
 
The magnum engines were fairly low compression to start with, but Chrysler says minimum to be 100 with 25% difference max for later engines.
 
The magnum engines were fairly low compression to start with, but Chrysler says minimum to be 100 with 25% difference max for later engines.

Well, OK then figger on 200k miles so I know the engine is short life, fine, just run decently for the next 5 years to get him established, then next one is on HIM.....he paying parts anyway....my labor is so FAR, free, paybacks are HELL though....:shocking:

but I still need ideas on that truck, that bogging/backfiring drives me nutz....

I wonder if I maybe induced a problem there, in that I pulled the what I suppose are yellow OEM injectors and put in a set of ~22 lbs units I had from my vette, years ago....engine starts immediately, idles smooth throughout the temp range, when cold it goes like mad, let it get a bit warm and then the bogging/backfiring......actually if you drive it just right, you can avoid the issue, but it's not all that easy to do, and I want it right anyway for economy reasons....

any clues man???

:gurney::beer:
 
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