Engine/Transmission (1994 - 1998) Injection Pump Timing

[Tom C]

Hi all. It has been a few years since Ive had a 12 valve truck. But I sold the 2001 24 valve (poor performance, fuel mileage and a lemon!) and have returned to the beloved 12 valve motor (see sig). The previous (one) owner said he had the pump timed at a fuel injection place in Redding CA. but did not know to what degree. How can one find out what the pump is times at? Truck pulls normal until about 1/3 throttle then its like someone hit the nitrous . Pulls hard and consistent into red line. another question: is there a rev limiter on this model? I have not found it yet and don't want to push the rpm's too far into the red. The only odd symptoms Ive noticed are when its cold (just started) with ambient temp about 50°, If I go to rev the motor it Will pop and sputter but will not do this when hot. Is that a symptom of pump timing? Not that I usually rev the motor when cold but I'm trying to learn this trucks habits and will try alot of things to see what it reaction is.



One more thing (sorry for the long post). I had a '97 that I had put a TST kit in and it ran great with it. Will a TST kit work good with the tweaked injection pump or have people had problems.



I look forward to your comments and suggestions. Thanks.



Tom C

 

[fox]

Tom, you need to ask these questions at TST or Piers.

It is definitely modified but do you need more?

If you put it in neutral with a warm motor will it run up to 3000 or 3400 rpm? I bet it is near the defuel point/governor.

It is not good to rev a cold motor, let it idle a few minutes then drive away . with-in a block or two there will be enough heat in the comb. chambers to run smooth.

 

[Joe G.]

Tom,



That sure doesn't sound like a stock '95. You might pull the AFC housing off and see if there is a number on top of the plate. Also take a look at the boost elbow and see if it has a set screw. Checking the timing requires a special tool set.

 

[M Barnett]

If it goes to redline, it must have gov spring kit in it. Sure sounds like its got some mods in it. Will be important for you to have boost and pyro temp gages.

Michael

 

[RHARVEY]

Here is what Cummins told me. .



On a cold motor with it in park/neutral... rev'n it up(high rpm's)and you get the popping sound. . pump has some wear in it. As it warms up. . it settles down and runs smooth when you are rev'ing it up. I watch machanic at Cummins Southwest(Little Rock, Ar) put the throttle to the floor after changing the lift pump and filter. The rpms stopped at 3400 rpms!!!:--) :--) :--) . It had hit the governor and stopped. . Again according to Cummins. . it will run like that ALL DAY and not hurt it. Thats the reason for the govenor. I do not rev mine up that high when its cold. . I dont rev it up that high when its warm.





Rick

 

[Berrigan]

I have read this before, and dont understand. I have a stock gov. on my truck. It to will rev to 3k.



Am I stating this correctly that even though I can hit 3k the engine is in fact defueling well before that. maybe about 2500.

And with the addition of a 3kgsk I will feel and get more power(hp only because we are already past the peak tork rpm) from 2500 to 3400 rpm. And if so how much of a kick in the pants will it be.



Has any one dino'd or 1/4 et before and after the addition of a 3kgsk. Will it feel like the power improvement my #11 plate gave.

Thanks for any info.

 

[Andy Redmond]

Tom:



To verify timing you need a dial indicator and other special tools to verify the lift (in mm) (which a chart will convert to degree's), in relation to engine tdc.



The other method is the spill port method where fuel from the number one delivery valve is observed for open and closed position in relation to TDC.



There is no rev limiter except the governor. If its working properly ok, however, you can overspeed on a downgrade.





Sounds as if you have a good running truck. Do you have a pyro to monitor egt's? If not if someone has been fueling, you would see some warm temps that need monitoring under load.



DC, Cummins or an independant would likely charge $250-350 to verify timing and reset as necessary.



However, they might adjust it down, if it's advanced. Leave it alone as long as its not more than 15 or 15. 5 deg.



You'll be happy with it.



Good luck

Andy

 

[Andy Redmond]

Tom:



Sorry for post two. . type twice hit reply once!



Ck. the fuel psi. A worn overflow valve (you want the Bosch number to end in 093) a worn lift pump and or a clogged filter or other fuel restriction can cause this.



There is a bosch tsb out on this (1995-1997 vintage). I'll dig it out and fax it to you if your cummins / bosch shop can't lay a hand on it.







It's possible your grid heater (air intake heater is not operating). Do you notice the light dimming and brightening at idle when cold? If so the heater are coming on and off and sucking pulling some amps. This is normal.



Good luck

Andy

 

[drice]

so poping when its cold is due to a worn injectoin pump NOT GOOD I was hoping that is was due to bad timing. is there any way that bad timing could do it. PLEASE SAY YES. I don't want to spen that kind of money. :{

 

[Tom C]

Thanks for the repley, comments and suggestions.



Grid heater appears to be working.



I got a box full of fuel filters with the truck so i think I'll put one on. The previous owner said he did not change them as often as suggested. It has a PrimeLock on it and at the end is a little green glass. what is that?? the PrimLock I had on my '97 did not have that site glass.



I will be adding temp,boost and fuel pressure gages.



I did not see any mods on the AFC housing. still has the breakoff screw and not boost elbows present (except stock).



there is a rev limiter... . stops at 3300 rpm. revs right up to limit in neutral or gear.

 

[R.ebel]

Timing

Retarded timing will cause a popping and or missfire condition.

 

[drice]

thank goodness hopefully that will fix itl.

 

[radixr]

Green glass

Tom C,



That green glass is a fuel restriction gauge. If it turns to red, your filter needs changed pronto.