I'm considering the installation of new injectors based upon the 94K miles that are on the truck. Are there specific symptons that are usually associated with bad injectors? Would a Tech 2 be able to diagnose worn injectors? If injectors are worn, would that result in greater than normal fuel delivery? My logic being that if the injector orifice is larger because of wear, the larger opening would allow greater fuel delivery. Or, maybe I don't understand the internal design of an injector. http://www.dieselplace.com/forum/smileys/smiley5.gif

I have 100k on mine and it rus as good as the day it was new (actually better due to exhaust, boost and Heath reprogram) Still gets great mileage. I have used a additive with lubricant since it was new which I think helps to prolong a lot of things.


My son's 95 has 180k on it with the original injectors and it starts and runs great so who knows. If I don't have problems or a milege drop I'll keep on running them.

i just sent my oil in to get analyzed and will look at the results to see if i need to change mine this winter. if the fuel dilution is high, i will probably change them since there are 107,000 miles on these ones. that is i assume these are the stock ones.

Spin


Injectors mechanical functionality can't be seen on a T2, need to be tested on a injection bench, I'd say pull them and run them by an injection shop probably low charge for cleaning/testing, may give you credit on work towards new ones. HO injectors run $500-600 depending on vendor, stock ones about half that.

in regards to high flow injectors...i am unfamiliar with the topic. with the stock pump wont this actually decrease your injection pressure? i would assume so, this would decrease atomization and with it, the fuel economy would go down the tubes. maybe power would increase, but at the expense of fuel economy. is this correct logic?

You would get a slightly retarded fuel pulse whith high pops and a stock pump. The chip shoud increase fuel pressure enough to work together with it.

SD


With worn injectors you will lose 'POP' pressure. Also spray pattern will be less than ideal. Should consider Hi Pop/Hi flows. Supposedly next biggest bang for buck after ECM. Varying opinions on when to change. How does it start? Smoke? Tim is right - Tech II not much help here.


Definately my next purchase.





pfloyd


Injection pop pressure is determined by injector. Economy goes up I'm told.


QM


Chip increases fuel pressure? Huh?

Chip does nothing to increase delivery pressure, all that is determined by IP & spring setting of Inj, On OBD II (not sure on OBD I chip) reflash can change max delivery command rate 80 mm up from 63 in L56 or 76 in L65, and keeps boost and command rate active longer as seen on my scan tool. Only way to know actual delivery rate as installed, is put a flow meter on the supply and return of the injectors.


Leads me to a question is there an inductive device that can be put on an injection line that generates a pulse, where the pulse frequency can be converted to a value indicating ammount of fuel actually being delivered/used at the injector?

Spin I called my local Stanadyne shop, clean and test injectors is $8/ injector so you should have something similar in your area, I'd go that route 1st if on a budget, if you have funds a set of HO injectors is a NICE addition to your quest for power AFTER a reflash which you already have. Might be worth checking all Inj replacing 1 or 2 bad/weak stock ones, and save for a full set of HO Inj.

If the Chip increases the fuel delivery to 80mm3 from ~63-75mm3, then I'd have to argue that you'd have increased the line pressure.

If the Chip increases the fuel delivery to 80mm3 from ~63-75mm3, then I'd have to argue that you'd have increased the line pressure.


NOPE you can increase Volume and not increase pressure, The injector controls the pressure. It only pops when you get to the preset pressure. The IP controls how much fuel comes out at that pressure. maybe by using longer or shorter strokes I' betting.

IP regulates fuel quantity via FSOL referenced by the HI/LO res tracks. Lo Res is start of injection, PCM converts desired fuel quantity to Hi Res 'ticks', counts to that number and de-energizes FSol ending pumping event.

Well, it appears that I need to tell...the rest of the story.


I had the opportunity to attend a Dodge Get Together this past weekend. Other than being entirely amazed by the power of the Cummins and wishin' I had one in the Burb, I had a great time, with one other exception. My truck had three runs on a DynoJet 248C. My best run gave me max power of 206 RWHP and max torque of 396. The stock truck is rated for 195 HP and 425 torque. Granted, the stock numbers that GM provides are taken at the flywheel, but even so, I thought I would have had better runs than I did.


So I touched base with a buddy of mine that knows dynos. The type dyno I used is one which has the truck accelerating a heavy, under floor flywheel-mass. The dyno measures a 'rate' of acceleration to provide a 'hp' figure. Torque is then computer-estimated from the performance measured.


I was told that the best kind of dyno is a two roller setup (like the Mustang) and one which features load cells which are used to pull the engine down from max rpm to measure the actual torque output curve. From this torque curve, hp is calculated. Apparently, there is a huge difference in cost between the two types of dynos.


This is what led to my original post about the injectors. Given the mods to my truck, I would have thought my numbers would have been better so I was/am concerned that something, such as the IP, fuel lift pump, or the injectors, is amiss in the inards of the motor. The IP was replaced at 90K, so it can't be that.


My buddy told me not to get hung up on the DynoJet numbers since there is great variability among dynos and dyno operators. But still...206 HP http://www.dieselplace.com/forum/smileys/smiley3.gif !!


So I'm wonderin' whether I should put my peanut at ease by having the truck dynoed elsewhere, or, should I start somewhere else?

Ok some one out there should know this, what percent of fly wheel H/P is lost getting to the rear wheels. I'd bet you are up around 250 H/P at flywheel. If you happy with the trucks performance and workablity then I wouldn't sweat the numbers. I perfer the total package approach for me. Edited by: bowtie

You can't place a percentage on HP lost between flywheel and rear wheels. There are too many variables.


Up 150 HP at flywheel? Are you kidding? You're saying 350 at Flywheel?


He's Probably losing about 50 HP through the drivetrain.





Spindrift - Be more specific on conditions. Did you spray Water/Alcohol?

Billy,


That is the great mystery right now. I'm sorry to say I don't know. I energized the system when I pulled the truck into the dyno bay. Had to hand the truck over to the operator at that point. After hearing that engine screeeeeam for each of the three runs, I got back in and pulled her out to the lot when I noticed the power switch light was off. Asked the operator about it...he knew nuthin'. I'm bummed.


Regarding the earlier comments about the Tech II's ability, my question was really about whether the Tech II has the ability to read actual flow rate. Are you and TD saying that fuel flow rate is controlled by what has been programmed into the ECM? Which is to say that flow rate will always be limited by the parameters that have been programmed into the ECM. The truck doesn't smoke worth a wit. Truck starts fine. Even on the dyno when the operator put the pedal to the metal...no smoke to speak of.

50-60 Hp Lost across final drive is numbers I've seen, so 150 at wheel would be approx 200 Hp at flywheel, wrong dyno or even how the load is applied will set you back. I ran mine on a dynojet looking for some good numbers only put down 150 at wheel, this was no flow across IC, no reflash, and no HO Injector, so basically a fooler, 3.5" Banks exhaust and Amzoil air filt.


Spin did your boost stay active or clip back, mine hit 13 then cut back to 7 found out later the MAP sensor was giving false hi boost even with the fooler and PCM went into engine self preservation mode. JK says also important to get good lock up, if you will look in Ronnie Joes run pics you will see a T2 I'd be willing to bet the TCC command was set to lock the TCC.

Regarding the earlier comments about the Tech II's ability, my question was really about whether the Tech II has the ability to read actual flow rate. Are you and TD saying that fuel flow rate is controlled by what has been programmed into the ECM? Which is to say that flow rate will always be limited by the parameters that have been programmed into the ECM. The truck doesn't smoke worth a wit. Truck starts fine. Even on the dyno when the operator put the pedal to the metal...no smoke to speak of.





Fuel seen on a scan tool is showing request of fuel delivery schedule by PCM not actual output, which is dependent on lots of "Stuff" engine/IP speed, pump wear, Fuel sol, you can't get more fuel though than asked for, which is why you need a reflash to smoke more than a "whit". I'll have to look that unit of measurement up, I've never taken a service call "Tim my turbine is making to many whits of smoke" http://www.dieselplace.com/forum/smileys/smiley36.gif


Actually amount of smoke isn't always a good measurment, normally its an indication of overfueling, what you want is heavy smoke turning to light grey as turbo comes up giving O2 to the fuel, looks impressive though, the only time I've ever belched a lot of smoke was pulling about 18K of trailer & load and blowing a IC tube, looked like a mosquito fogger until I backed off of it. I would not get hung up on smoke output.

You can't place a percentage on HP lost between flywheel and rear wheels. There are too many variables.


You can find about an avg. for the loss not with everything else being the same.


Up 150 HP at flywheel? Are you kidding? You're saying 350 at Flywheel?


He's Probably losing about 50 HP through the drivetrain.


Ain't that what I said?Edited by: bowtie

SD


That's too bad about the switch. If the water was 'off', those numbers are very impressive for 2 reasons. ECM may have cut back on fuel and you didn't get added power of Water/Alcohol.


206 is in the neighborhood of 250 at flywheel. Stock Piston. GM-8. Not Bad. Not Bad at all...


396 Ft Lbs at rear wheel is impressive as well.


Tim has a very good explanation on ECM operation concerning fuel delivery. While I'm not 100% sure, I believe what he says is correct.


It also sounds like your injectors are not really in need of replacement. Same goes for mine. From what I've read, Hi Flow/ Hi Pop will give it a noticeable improvement. I'll bet you could see 10 more hosrepower from it.


The thing about having a controlled environment like when JK dyno'd RJ's truck is that you get to see ALL the information during the run. Boost/EGT/Fuel Rate/Temps...everything that affects numbers.


bowtie


If you 'Dyno' numerous truck similarly equipped, then yes, you can place an average percentage on HP lost through the drivetrain. It would be a rough guess though.


What you said and the way I took it may be 2 different things. I took it as you were saying Spindrift's numbers would be 150 better at the flywheel meaning(to me) that he was making 350 there.


In actuality I can't go back to your original post because you've edited it.

yeapper I thinking we all on the same page here and most in agreement.

[/QUOTE]


Fuel seen on a scan tool is showing request of fuel delivery schedule by PCM not actual output, which is dependent on lots of "Stuff" engine/IP speed, pump wear, Fuel sol, you can't get more fuel though than asked for, which is why you need a reflash to smoke more than a "whit". I'll have to look that unit of measurement up, I've never taken a service call "Tim my turbine is making to many whits of smoke" http://www.dieselplace.com/forum/smileys/smiley36.gif


[/QUOTE]


TD,


Billy had asked me earlier about the truck's smokin'. I was trying to explain, with my usual Joisy humor that the truck doesn't smoke at all...not when I fire off the engine, not even stompin' it when I'm goin' down the road feelin' bad.


Mr. Webster says:


whit - The least bit; an iota: Doesn’t give a whit what was said; not a whit afraid<?:namespace prefix = o ns = "urn:schemas-microsoft-com:office:office" />


<CITE>That's the problem with those Dyno Days. The shop pushed thru over 45 trucks that day. Didn't really have any time to monitor the truck. When I'm towing, I always maintain boost; don't know why it would have been different that day, but you never know. All I had a chance to see was the speedo on the truck. She was cryin' when it hit nearly 100 MPH. I'm assuming that the TCC was locked up that point, no?</CITE>

I have the pre-v2.0 Heath chip, and I see light smoke when I punch it at 30mph and 15psi, but the powertrain is in overdrive 3rd - T400 - at that point, much like 'lugging' a manual trans.


I get the sudden urge for dual stainless stacks, with the cd player blarin' a Red Sovine tune about 18-wheels, long roads, and a good woman waitin' back home.....http://www.dieselplace.com/forum/smileys/smiley2.gifEdited by: gmctd