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howdy again. i got my 74 280se two years ago i only drove it once before having to replace the fuel pump and some other goodies from sitting so long before i bought it. after i changed everything i started noticing a little hesitation or a hiccup is more like it at certain speeds usu in between 35-45mph it wont cut off and it's not a misfire it'll do it once and awhile. i drove a 79 280se before that and the acceleration on that car was quicker it had the air assisted carburator lookin thing, my present one doesnt. well anyway i was just checkin on parts availability for the fuel system and i found out that the pump that was installed in my car is for a 4.5 liter v8, i have V6 2.8. is this the reason my car is sluggish and has the occasional hiccup? or is this pump ok and i should start lookin elswhere for the problem? like i said i only drove the car once before having to replace various items so i dont know if the car already had this issue. anybody got ideas?
 

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Dunno what a 74 280SE is (not a U.S. model), but a 79 280SE and a V8 of the same approximate vintage use the exact same fuel pump.
 

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thanks, and i didn't know that there was a difference in v6 and inline six i just figured its all the same, oh by the way i dont know much about engines. thanks for you info now i know and "knowing is half the battle"-GI JOE lol
 

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You should spend a few hours with the manual (the M110 EFI manual is a bit hard to find, so use the v8 one) and follow through the steps described for making sure the fuel system is working correctly. There should be plenty of threads here about it and over at that shop forum place too.

To begin with
1. Make sure you're pressure regulator is calibrated for 2 ATU (that's 2 atmospheres or 28-30psi).
2. Make sure the ignition system is "to spec". That means setting the dwell and then the timing at 4500 rpm along with testing it at 800, 1500 and 3000 rpm.

The correct numbers and the decisions about vacuum are in the manuals. What follows is from the 1974 Technical Data Manual for the M110.981, 982 & 983:

Dwell: 34-40 degrees (idle & 3000rpm should be same, +- 3 degrees max or have the distributor rebuilt).

Distributor: 0231306002 (stamped on the side someplace).

Adjustment point (AFTER setting dwell) 32 degrees at 4500rpm W/O vacuum
Test @ idle, 0TDC +- 2 degrees (WITH vacuum)
Test @ 1500 rpm, 14-19 degrees (WITH vacuum)
Test @ 3000 rpm, 32 degrees (WITH vacuum)
Test @ starter speed 12 degrees BTDC (W/O vacuum)

The starter speed test is needed when you first install the distributor to be able to get it running about right.

HTH -CTH
 
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