1993 D250 performance with new Bosch Performance Injectors

[hwebster]

Greetings one and all TDR'ers...



(Piers - I sent this to you as an email before I figured out the posting process!)



It has been a long time since my last visit (had to remember how to post!)



Well my old girl finally started complaining a while ago, basically reduced power, poor fuel economy and very poor acceleration. After a long period of denial I finally had to bow to the inevitable and take her to the trusty Cummins dealership for some work.



They found that:



1 - I had a small fuel line leaking at the pump;



2 - A broken and missing timing pin;



3 - A coolant leak at the head and



4 - 3 injectors that weren't cracking... Groan.....



To make a long story short I had the head gasket replaced, the head rebuilt and planed, the fuel line replaced and the injectors replaced with the Bosch Performance version. ( I had to convince the guys that there were such injectors!!)



Baby is back on the road and sounding lean and mean, with very obvious get up and go. Lots of pickup at the lights and pulling like never before. BUT... ...





I didn't expect to see such a big drop in my fuel consumption. I did a quick 600k (about 360miles) and burned almost 3/4 of a tank. (I estimating 75 liters) I've also noticed white smoke when I am accelerating. I'm hitting the road again of Friday and will be putting about 3500k in the next few days and will track it closely but I'm concerned that I'm taking a big hit here on fuel... Any comments?



Also, I've notice a lot of posts suggesting a pyrometer? By modifying the injectors, should I consider putting this in too?





Thanks All... Harrison...

 

[Greenleaf]

Injectors/pyro /fuel mileage

No pyro Twenty horse power deduct for you! It would behoove you to install said device along with boost guage as a means to "guage" your truck's performance. [I hope the "Pastor " doesn't hear about this]



I don't know what for injectors you installed. The same injector can be known by several different names, depending on where you purchase them. Call around for injectors and you'll see my point. The ones your using are probably a Bosch marine injector [?]



The installation of performance components on your truck's engine will only serve to increase mileage. I wasn't sure if you meant your drop in fuel consumption was a drop in fuel used or a drop in miles per gallon.



White smoke is unburned fuel . Raw fuel if you will. Timing and or cold engine operation are contributors. Steam from the exhaust caused by a leaking gasket can be mistaken for smoke. Perform a search using "white smoke" as the key word. It's been discussed.



greenleaf

 

[hwebster]

Curious... Typically I'd get anywhere from 850 - 950k/tank on the highway crusing at around 120kph (close to 600miles per tank). So I am noticing a drop in milage or an increase in fuel consumption.



I'm thinking that my pump might not be properly set. I'll track it over the next few days...



I have never seen any white smoke from my rig (except the time when a line on the pump started sucking air - fogged a lot of mosquitos then ) So now when I am accelerating( with a warm engine) I do see white smoke until she's cruising. .



Thanks for the info Greenleaf, I'll look into a pyro (Asked Piers for info!)



Harrison

 

[Tim1]

milage

Harrison, I too noticed a drop in milage with the pod injectors, however if I don't over fuel (obivious cloud of black smoke) it is certainly better than not being able to hold my own towing! Moving the timing advanced a bit helped. Basically, more fuel,less milage. We all know the horespower equation. Tim

 

[AlK]

Basically, more fuel,less milage. We all know the horespower equation.

It couldn't be the right foot, could it? :-{} OF OURSE NOT!!

 

[JLEONARD]

Yes, but is should be based on horsepower used, not horsepower available. A diesel is a precise machine that will use a set amount of fuel based on horsepower acutally used.

Generally, an engine with higher horsepower available will get better economy when used at a reduced horsepower level.

In other words, it takes X hp to maintain 70 mph with a given vehicle... no matter what level the engine is capable of producing.

The real problem is how fast we get to 70...

Of course we know what all that black smoke is..... :>)

Jay

 

[Greenleaf]

Ya,,,what he said,,,better mileageIFyou take it easyyyyy.

 

[hwebster]

Well,



I've got to admit that I really did take it quite easy checking things out, altho there was this Ford that... . well... leave us say that hills seemed to give the poor guy trouble...



Bottom Line, I kept her pretty consistent, at about 2,200 RPM for most of the way and expected that, under those circumstances, my fuel comsumption should have been better than recently but possible a little more than when she was new... .



I'm going to have the pump set again, and see what happens...



It's nice to be back!!!!

 

[bflood]

I agree with J Leonard's post. To add to it, everything I have done to increase my hp/torque has resulted in better mileage. When I got the truck I was getting 16 to 17mpg unloaded "around town". Now I get 19 to 20mpg in the same conditions. Last month I went on a 1400 mile trip, unloaded, and got 23. 5 mpg on the highway at 65-70 mph.

 

[RGT]

hwebster, I notice your from pretty far north, any chance they have switched to winter fuel already? I get 2-3 mpg's less on winter fuel(do they ever not use winter fuel up there) I was up in northern sasketchuan(? spelling) fishing this summer quite an awesome experience

 

[jbolt]

Sheesh! you guys and your high mpg 4x2s



I'm happy to get 17mpg :{



JAy

 

[hwebster]

Thats what I hoped..

That is what I expected to happen, however it might be that the organizaton that did the work is not tune into the finer points here. Piers Harry said

"You need to advance the timing, when you go to the bigger injectors, the timing needs to be at 1. 4-1. 5mm of lift. Also do you know what thickness of washers they put under the injectors?



I'm hitting the road tomorrow for a few days but will try and determine the thichness of the washers. Not certain what the impact of the washer size is... Harrison

 

[dpuckett]

Harrison-

First, about washer thickness. It can have a profound effect on your performance. It basically determines where in the combustion chamber the fuel spray goes. If it is too high or too low, you CAN get smoke, rough idle, poor mpgs, etc. The only way to determine washer thicknes is to pull the injecotr, and then you ahve to get a new washer to reinstall the injector.



Also, when you get your timing set, RUN, dont walk, from any shop that relies on the timing pin to determine TDC. It is a well known fact the pin can be up to 5 deg off of true TDC, so in other words it is useless for timing adjustments, though ok for valve adjustments. White smoke can be either timing or air in the system, though I'd be more inclined to think timing. Do a search- it has been discussed many times before.



jbolt- I had a w250 with 230K that got 20-22 mpg- 3. 54 5 speed

 

[jbolt]

Originally posted by dpuckett



jbolt- I had a w250 with 230K that got 20-22 mpg- 3. 54 5 speed

Oh ya go ahead and rub it in



Jay

 

[BushWakr - RIP]

I'm Baaaaackk... . and ..... I HEARD THAT !!!!!... ...



No Pyro OOOooooo that's at 20 RWHP deduction for just plain "not paying attention in class... "



Ok I want to hear one verse of Our Lady Of Acceleration Church theme song and 5 male harries... errrrr... hail mary's... .



I get about 17 mpg (US) if I drive like a normal person... . whatever THAT is... .



Yup, get a pyro, yup get the timing reset/checked. The mm rating is about right and so is the degrees advance system if you aim for 15. 5-16 degress. Either way it will get you into the range that the high perf. injectors preferr and will eliminate (mostly) the timing issue for your white smoke...



Pastor Bob ~ O. L. A. C.



Oh Man,,, you guys been busy while I was away..... I gotta catch up ... .

 

[jbolt]

Dang Bob you're barely back and already dingin a poor fella 20rwhp. Didn't get to kill anything... . eh?



OK now lets clear something up. You said 15. 5-16 degrees of advance. "Properly" done timing is set with a dial indicator in millimeters. So does 15. 5-16 degrees equal 1. 55-1. 6mm ?



Jay

 

[Greenleaf]

Man,,,,,,,, He is strict Well,,,,,,,I tried to warn ya.

 

[hwebster]

Seems like more bad news!!

I went out this AM and noticed some coolant on the ground. Seems like the leak I just had repaired is back!!!!!!!!!! Problem is I can't really determine if the leak is from the head gasket or the flange that attachs to the block and receives the top hose from the rad!!!!!!



Now I am concerned. . Should I hang tough and drive back home later this week to get it fixed or do I need to get it done now??



Comments are anxiously awaited. .



Harrison:{

 

[BushWakr - RIP]

I'm not strict, just diligent... . or. . errrr obsessive... no wait, committed,... ya that's it... . Dave, don't you dare say I SHOULD be committed either..... geezzzz



Harrison, if the leak is manageable then carry some mixed coolant with you and wait till you get home.

The obvious things like keep an eye on coolant temps/levels etc apply of course, but if it's not too bad you should be ok.

Am I correct in understanding that the leak is isolated to the rad hose fitting/area???



Bob.

 

[BushWakr - RIP]

Hey jbolt... . I have found that the 1. 5mm setting has come out to darn near right on 15* advance on 2 or 3 pumps. Now I am waiting to get hold of an "official" conversion/equivalency chart.

I am fairly certain there is some departure from mm to degree's setting though.

I mean that while 1. 5mm seems to come out to very near 15* advance 1. 6mm may not be as close sort of thing... .

I have a chart/cross reference for the second gen trucks and I'm waiting to get one for us guys with first gens.

I'll post it as soon as I have it.

In the mean time you are well withing the safe zone using rough equivalency at this point.



Keep in mind though, that some shops set pump timing based on "hundredths or thousandths" of a mm... . much more precise to be sure.



Bob.