Has my pump been tweaked??

[KHarrower]

Just put gauges on my new to me intercooled 91, 5spd, 4x4, 170k miles, straight pipe. She puts out a big cloud of smoke when started, also smokes when accelerating until caught up with the governer, or when climbing a steep grade (10%) using 10 psi boost. Usually don't see over 2-4 psi of boost in normal driving. It will make 20 psi with foot to the floor, at about 1200 deg. How do I tell if my pump has been turned up and what can I do to reduce the smoke? Maybe I just have dirty injectors. If so, should I consider installing bigger ones? How about the 16 cm turbo housing? I am enjoying 20+ mpg. What is the best bang for the buck without loosing fuel mileage? Also, how many rpm's can I run this 12 valve. Thanks for any info.

 

[bgilbert]

Sounds like normal stock condition. Are the tamper caps/covers still in place over the governor screw and full fuel screw on the injection pump? Stock my pump with full throttle travel WOT I was turning about 2600 rpm. After cranking on the governor screw I'm now around 2900-3000 rpm. 20+ mpg with 4x4 I'd be happy. Bill

 

[dpuckett]

KHarrower-

Your pump has been turned up a little, and if it was done like 95% of the turn ups out there, it was just a turn on the full power screw, without tweaking the AFC housing. Stock boost on a CPL 1351 engine runs 14-17psi, due to the excessively large exhaust houring (21cm). The covers can be put back to look stock, so dont depend on that.



To reduce smoke, try some injector cleaner, about a 3X dose for 2-3 tanks.

A 16cm housing should help clear up the bottom end and allow for quicker spooling.

You can also tighten the tension on the AFC spring (take off the cap on the housing and turn the gear looking wheel upwards). Careful of the AFC hose (coming from the intake to the pump) when removing the cap- it is pot metal, and will break if you breathe on it too hard.

Back off the smoke screw. THis is the T-25 (T-27? I forget) torx set screw (13mm jambnut) under the tin cap on the outside top of the housing. Loosen it up and back it out till the top of the screw is level with the top of the depression.



If none of that works, get it timed to about 1. 5mm @TDC. The advance will help make a cleaner burn and give you a little botttom end pep. But you can go too far and start to lose bottom end, and it will rattle like crazy. If it still smokes, it's time to pull the injectors and get them pop tested. IF they are bad, go for some EDMs, or PODs (if you can live with a little smoke), or Bully Dog injectors Oo.



Adjust the valves- . 010" intake; . 020" exhaust

BUT..... if you can drive it so it wont smoke, you can leave it alone and enjoy the 21-24MPG.



Bill- our trucks (nonIC) had a combination of smaller housing and hotter flowing injectors, so we will make more boost in stock form. The hotter intake air keeps our actual power levels down, though.

Daniel

 

[phillips5]

Yea what he said