Hello, and thank you to all that responded to the two other posts. I'm still having problems w/ the 1993 3/4 ton CTD I bought on 1/17/03. The problem is with a low RPM Skip. After trying everything all the folks here suggested nothing helped. Now the Dealer's mechanic (which is a Diesel shop) keeps saying that some '93 CTD had a low RPM shake. I have contacted the old owner of the truck and he said it has ony done it for the last 6 months to a year. Also I have found three other '93's in my area and have asked the folks that owned them if I could here and feel the motor run and they run as smooth as silk. Just like my '96 3500 CTD. I have talked to Ted Jannetty and he said with out seeing the truck he would guess Injector pump and or Injectors. After pressing the dealer and his mechanic the mechanic wants another shot at it. He wants to try to adjust the Pump. Do they go out of adjustment? Can he screw it up worse? I'm at my wit's end. Please help! [undecided] ???

 

Ive got a 1995, which I realize is different than your '93. <br>I also have a rough idle. After doing a little diagnosis, I found that I hava a bad delivery valve. <br><br>I took my truck to Cummins. They used an infared sensor to examine my exhaust ports. <br>They found that all exhaust ports were the same temp EXCEPT the Number One cylinder. <br><br>They tested that injector and it tested fine.<br>That led them to believe the pump was at fualt. <br>Since then, I have been able to deduce that it is the number one delivery valve. <br><br>I share this with you becuase a bad injector, or injection pump can cause a rough idle. <br><br>Let the mechanic take another look and have them really check out the injection system.<br><br>Good luck.<br><br>Rich.

 

I have not heard of many 1st Gens with delivery valve problems. The more common problems are the injector(s) or pump damage. That is often caused by cranking the daylights out of it, and running it into the ground, bad fuel including water, dirt,air, or other contaminants. <br>Some centralized issues are the fuel solenoid, and the fuel delivery pin or &quot;guide pin&quot; as it is called in the Bosch Serv. Manual.<br>If the miss is only at low end/or idle then I'd first look at the injectors. You can deliberately cause the roughness, then loosen each inj. line slightly to see if it contributes to the problem (roughness increases) or does nothing. If it does nothing you've found the bad one.<br>Injectors can fall far enough out of balance that they develope a roughness which smooths out at higher speeds/pressures.<br>You will also want to check the fuel supply pressure as well, although you'd have more mid/high end trouble if that was the cause, I would think.<br><br>Do you see any signs of leakage on the pump itself? Look closely at the pump, down near the bottom, and as close to the engine block as possible. On the back side is a cover plate with a seal. It has been known to leak and cause similar problems due to pressure loss. If it leaking the entire pump must come off to repair it.<br><br>If I think of anything else I'll post it.... sorry...<br><br>Bob.