Is my cummins up to par for a stock motor?

[TGiambro]

Hello. I recently bought a 93 CTD D350 Dually / Automatic / 3. 55 Rear.

Is there any way any of you can think of to measure my truck's performace compared to another truck of this vintage (IE: Stock Rated Power)? I'm just not sure if the engine is producing enough power as it's supposed to be. I don't know anyone else around here that has a truck like this to compare it to so that's out of the question.

Another related question: Can an injection pump become "weak" or do they usually go all together?

I brought my truck to a Dodge dealer and they said they couldn't do much because they lack the proper tools for my year cummins.

-Tony

 

["Mad Max"]

I think we'd need to know more details about what is happening with the truck. What are some of the symptoms? Any smoke?, no smoke?, no power?, won't rev up?, there are several possible reasons why a truck may feel lax when it could be purely stock, especially when compared to the feel of a newer rig.

If the engine and transmission are bone stock, the transmission will feel tired, but that's most likely because of the stock converter. If the engine doesn't seem to have much power, that's most likely a stock pump.

Can you give us more insight into the issues you're having?



Oh, and don't bother with the dealer - you will become the chief mechanic for your truck, and after a while you'll want to be verses relying on anyone else to do the small upgrades.



A few well-placed upgrades for your rig will make it feel and act new(er), including the power.



- M2

 

[dpuckett]

The injector pump can go downhill on a slow slide, and they can go all at once. Most of them wear out slowly, and thus the performance goes slowly. You may notice some slightly lower MPGs, lackluster performance, etc, etc.



You made a wise decision by ponying up the cash to joint the TDR- advice is often free and worth the same. (ATF in the tank ring a bell? :-laf).



As for performance, the stock trucks were lethargic. I had a TDR member get a 93 after years of driving a slightly hopped up 89, and he asked if it was right. I told him it was a typical stock truck.



There have been MANY recent threads dealing with injection pumps (ULSD implemented last fall was unkind to many, my 2 included), transmission issues, and front suspension. Do a search for the last year and set aside most of a day to read. The auto will likely need a torque convertor and valve body (at least you'll enjoy the benefits of it), injectors may or may not be in need of cleaning and recalibration. Check out the front suspension.



DItto on the becoming your own mehcnaic. I hate to pay someone $60/hr, then have to spend the same amount of time I just paid for, fixing their screw up or incompentence. It seems the shops/ mechanics are only after your money, or they just see a 15 year old vehicle, "so the owner wont care if we cut corners. "



Daniel

 

[TGiambro]

I think we'd need to know more details about what is happening with the truck. What are some of the symptoms? Any smoke?, no smoke?, no power?, won't rev up?, there are several possible reasons why a truck may feel lax when it could be purely stock, especially when compared to the feel of a newer rig.

If the engine and transmission are bone stock, the transmission will feel tired, but that's most likely because of the stock converter. If the engine doesn't seem to have much power, that's most likely a stock pump.

Can you give us more insight into the issues you're having?



Oh, and don't bother with the dealer - you will become the chief mechanic for your truck, and after a while you'll want to be verses relying on anyone else to do the small upgrades.



A few well-placed upgrades for your rig will make it feel and act new(er), including the power.



- M2

Well see that's the thing - I'm not sure if there really are any "symptoms" because I'm not sure what this truck is supposed to be like stock. But I'll tell you this - It's seems to me as if the engine won't rev as much as it should. It just starts pulling and you feel it cut off as if the fuel runs out. I don't have a tach so I can't tell you the RPM's at which this happens. However, I can tell you that if I hold it in first gear, the max speed is right about 25MPH (Automatic, 3. 55 gears, 245/75/16 tires). Sound normal?



My transmission was rebuilt just 500 miles ago. I had a shift kit and 4 (or 5?) pinion steel planeteries installed. I bought this truck knowing that it needed a transmission (wouldn't shift into 3 or 4). I drove the truck two times before having the transmission rebuilt. The first time was last fall and it seemed to go very well from my recollection. The 2nd time was last month going to the transmission shop. This 2nd time is when I noticed the engine didn't seem to rev as high as I had remembered it did before the winter. This made me suspicious of the fuel system maybe getting clogged up over the winter so I changed my fuel filter with no results. The truck always had addatives in it when sitting and always started up with no problem even in the cold.



I brought the truck to Lee Dodge. The tech of 25 years experience told me that the truck runs very well but does seem to cut off a little earlier than it should. He then suggested to adjust the timing of the injection pump. He turned the pump about 1/8" and said he didn't dare go any more. I drove the truck after and it does seem to have _slightly_ more power.



That's basicly the story of my truck so far. I'm just trying to figure out if the way that it's driving is normal and my memory of how it drove last fall is a little "off" or if I'm missing out on some power that should be there.



Any input would be appreciated. Thanks.

-Tony

 

[TGiambro]

The injector pump can go downhill on a slow slide, and they can go all at once. Most of them wear out slowly, and thus the performance goes slowly. You may notice some slightly lower MPGs, lackluster performance, etc, etc.



You made a wise decision by ponying up the cash to joint the TDR- advice is often free and worth the same. (ATF in the tank ring a bell? :-laf).



As for performance, the stock trucks were lethargic. I had a TDR member get a 93 after years of driving a slightly hopped up 89, and he asked if it was right. I told him it was a typical stock truck.



There have been MANY recent threads dealing with injection pumps (ULSD implemented last fall was unkind to many, my 2 included), transmission issues, and front suspension. Do a search for the last year and set aside most of a day to read. The auto will likely need a torque convertor and valve body (at least you'll enjoy the benefits of it), injectors may or may not be in need of cleaning and recalibration. Check out the front suspension.



DItto on the becoming your own mehcnaic. I hate to pay someone $60/hr, then have to spend the same amount of time I just paid for, fixing their screw up or incompentence. It seems the shops/ mechanics are only after your money, or they just see a 15 year old vehicle, "so the owner wont care if we cut corners. "



Daniel

What's the easiest way of telling of an injection pump is getting weak?



I'd love to work on my own truck. I'm a mechanic by trade but not a diesel mechanic. Diagnosing things on this engine is a bit' frustrating without any any experience working on diesels. I was referred to this website by a fellow cummins owner that I met last week at my ASE testing. I'm glad I joined already :-laf



I had been looking for a cold air intake for my truck for quite some time and had no luck until I joined this site and found asa modifieds. Now I'm just waiting for fed-ex to deliver it

 

[PToombs]

The first thing that comes to mind is the throttle linkage! Have some one push the pedal down, and then look the lever on the pump, see if it goes to the stop. If not, try to adjust it so it does. Don't forget to check to see if the floor mat or carpet is holding it.

 

[TGiambro]

The first thing that comes to mind is the throttle linkage! Have some one push the pedal down, and then look the lever on the pump, see if it goes to the stop. If not, try to adjust it so it does. Don't forget to check to see if the floor mat or carpet is holding it.

Forgot to mention that I already checked that. The linkage seems to operate just fine.

 

[TGiambro]

At what RPM does the governer limit fuel supply? Could a governor malfunction? Is there a way to adjust it to raise the RPM limit a bit' ?

 

[CBeeman]

its been awhile since i looked at a first gen truck but i think there is a small line that goes from the head to the top of the injection pump(toward the back) for the afc that are prone to breaking. if the pump doen'st get boost you wont get full fuel. just a thought

chris

 

[Jefff929]

check this out pre 94

 

[JLEONARD]

At what RPM does the governer limit fuel supply? Could a governor malfunction? Is there a way to adjust it to raise the RPM limit a bit' ?

Around 2400/2500 the fuel will start to cut out. You will get a few more rpm in the lower gears as it overruns.

You can move the stop screw at the pmp. That will get you a couple hundred more rpm but that's about it without doing a gov spring.

 

[paccool]

Get a boost gauge installed and see what you have. You will need to do this sooner or later so it might as well be sooner! Stock is anywhere from about 12psi to about 18 psi. Mine was running 14 before I started playing with stuff. Based on what you are describing, I'd say the truck is performing about right for a stock truck. One item that could be causing a loss of power is injectors. They may not be spraying properly. How many miles are on the truck?

 

[TGiambro]

168k on the truck as of today.

 

[TGiambro]

where's the cheapest place to buy a set of good gauges? summitracing.com?

 

[Moab4x4]

Welcome Tony, I started this slippery slope a couple of years ago with no more diesel experience than running the old farm tractor. My mechanical experience is that of a home mechanic / hobbyist. I was initially quite intimidated by the whole diesel thing, but now I prefer it to my gassers.
TDR, the FSM, and the truck itself have taught me tons! (and enticed me to do a few things I probably couldn't afford. )

The folks at Piers Diesel Research, Genos Garage, and Jeremy at Texas Diesel have all been very helpful to me in addition to those on this site.
I bought some gauges from Piers, others from Genos. I looked everywhere online and they were competitive and know our trucks. Get the 4k tach, I am glad I didn't get a 3k.

The GSK or governer spring kit for the 1st gen pump is cheap and easy to replace and makes a world of difference. You have to ask for it as it is not on the websites.

Use the search engine here and make sure you change the default search setting to a lot longer time frame than just the past 3 months worth of posts.
Enjoy!!
Ken

 

[bmoeller]

Is there any way any of you can think of to measure my truck's performace compared to another truck of this vintage (IE: Stock Rated Power)?

Time to hit the dyno. Then you'll know if power is low for sure.

 

[DSteimle]

my stock truck defueled at 2200 rpm. the pyro would steadily rise then suddenly drop at 2200. engine would keep going above that, but i always pulled the next gear. you can feel it nose over when it defuels. now with the 3200 spring, i havent felt it defuel yet (to be honest, the tightening feeling in my rear end makes me shift before i see it defuel:-laf)