power loss

[JB]

hello there im new to the intergalactic network and im not a mechanic so im apologizing before hand... anyhow im experiencing mostly high end power loss... after installing a vegetable oil conversion kit on my truck 91 4x4 auto. . ive driven it it approx 5k miles or so and cant stand it anymore im not able to pass on the highway or go faster than 80 mph down hill ive replaced the lift pump and checked all of my lines for leaks... rebuilt the injectors, bled the injector lines changed fuel filters and no real results... whats strange is that it seems to be running better on vegetable oil than diesel fuel... im hoping its not ip problems, but yeah i cant for the life of me figure this out. . any imput would be appreciated

 

[JLEONARD]

Is there any smoke when you are leaning on it? Have you ever turned up the pump or is it still stock settings?

 

[Tippin Spotted Cow]

With 4. 10s your truck will start to wind out at those speeds. These motors stock have a top rpm range of 2700. I know, I know... its strange if youre switching from a gasser. After 2700 it doesn't bounce off the rev limiter, or float the valves, or anything like that. The injector pump defuels and doesn't allow the motor to wind any higher. at about 2500rpms youre truck is going to start to seem like you're towing a small planet behind it when you try to pass.



If you really need those higher rpms, invest in a "366" governor spring. It will allow your pump to rev up to 3200 or so before defueling, and give you a lot more high end power. The spring is about $16 and takes probably 2-3 hours to install. I did it and I would never go back. Should I even get my hands on another one of these motors, thatll be one of the first things I do.

 

[JB]

no there is no smoke at all only at start up and maybe if i were to drop the hammer from a dead stop going up hill or something... and no the pump is still at stock settings... although before i turn it up should i get some gauges? if so who makes decent gauges and where could i order them?

 

[JB]

on the 366 gov spring where could i order one and what is involved when installing it. im very interested although is there anything else i should do before adding stuff like this?

 

[Greenleaf]

hummmmmm... .



The fuel control pin that rides on/against the profile of the fuel control cone. That baby is known to become sticky/stuck/siezed. Then low fuel setting is the result.



W/O giving away secrets, be sure to observe your travel of the injection pump throttle control arm... ..... yeah! You still have the gov speed limit(ing) screw???..... Hummmmm



There are tons of tweaks/mods. Just do them systematically and over time.

 

[Tippin Spotted Cow]

PDR, dynomite diesel, and I believe also ATS sell the spring. You can try any of those, or, it is a Cummins part, you can tell them you need the governor spring for the Bosch VE 6BT pump with the P/N of the spring ending in "366"



The usual gauges are good to get before anything of course... pyro, tach, boost. Don't bother with the tachs that you have to buy and mount a sensor for, the Cummins already has a sensor on it and Dodge has a wire harness under the dash you can tap into to get the signal. If you need anything else as far as that goes, or anything else for that matter, ask away.

 

[JGrefenstette]

yea as far as the gauges, I run Isspro's. i like em pretty well. they nice and colorfull, bright, and dependable, from what ive seen. also pretty affordable. if you want the info on the tach and the wireing harness, check in the stickies of this forum, under "Factory Tach" everything you need to know is in there. also i would invest in a good air filter to help your motor breath easier. i run the ASA modifieds intake set up, so do a number of guys on here. you can get them at PDR. they give some power increase, little more boost, and an awesome sound. our stock exhaust is also very restrictive. if you can do away with the muffler and as many bends as possible. that will help you get lower EGT's, more boost, better low end power, etc.



gauges are the place to start though, i would deffinatly do it in your case, first, that way you can check for boost leaks, and other things to help you diagnose the problem.



good luck.

 

[JB]

thanks guys your awesome... i really appreciate your knowledge ive got some work to do on this thing im gonna look into everything you posted i had my injectors rebuilt at a local shop here in kc and those guys are pretty cool, ill ask them about the fuel pin being siezed... how could i check that on my own? as for the governor spring how hard is that to replace or should i take it to a shop... anyhow thanks again.

 

[JGrefenstette]

JB, i have a 366 ive yet to install. but from what every guy on here has told me, its very doable. like Matt said, probly 2-3 hours. theres another first gen thread, "1st gen FAQ's" thats at the top of the page when your looking at the list of topics. its got all the specific info about tons of things there. a TDR legend (PastorBob) did a fantastic thread on the 366 installation. read through that. itll give you a good feel for what needs to happen

 

[JQuam]

Greenleaf, what/where is this governor speed limiting screw you speak of?

 

[AABEN]

You Can Get All The Gauges You Will Need At Geno's Thay Will Have All The Mounts You Will Need. I Have The Three Post Mounts. I Thank It Looks Good. I Am Runing The Isspro White. put In 03 Trouble Free.

 

[Tippin Spotted Cow]

The governor spring ain't terrible. If you got a good head on your shoulders itll go fine. Just pay attention to what youre doing when you take the pump top apart, and remember that it goes together the same way it came apart. Don't bother with loosining and turning the pump like mentioned, you can do it all without doing that. I needed to bend an allen wrench to get it in that way though.

 

[dpuckett]

The governor screw Greenleaf spoke of is also called the high idle screw- it's on the opposite side of the pump from the low idle screw.



Do you have an auto or manual? If an auto, you may just not have enough umph with the new fuel, torque convertor, and age of the truck. My 92 will only go 88mph in OD with 3. 54s- 2400rpm. It still has these funny-looking caps on the adjusting screws. If I keep it, I'll adjust some things.



Where can a 4K ISSPRO tach be bought? Geno's has the 3K.



The 92 and 93 trucks are the only ones with the tach hook up under the dash. I had a magnetic adaptor on my 91, and it worked just fine. There are also tachs that pickup from the alternator.



Governor spring isnt hard to do, but it is easy to mess up if you have some little pieces fly out as you disassemble it.



WElcome to the TDR.



Daniel

 

[JGrefenstette]

Here are some of my posts from the Sticky on this topic.



The 4k rpm tach P/N : R8503

Wiring kit for pre-94 Dodge Cummins P/N : R8912-92



hope this helps (if i recal i got both for a good deal. USDieselParts.Com is fabulous, their where i got the tach and wiring kit and my other gauges... easy site to use and great prices. customer service is great too. )



i think in total it set me back right near $160 for the tach and harness. if you get the set up make SURE you get the R8912-92!!!! the "92" on the end is crutial. they offer a R8912 that is for pre-92 trucks. the R8912-92 is for 1992 and UP models.



4k Tach : $115. 41

Sensor Harness : $38. 54



best of luck my friend

 

[JGrefenstette]

take note of what i mentioned about the part number for the wiring harnesss. this was from another thread where the guy had a 92. in your case you want the R8912, the one with out the "92" at the end of the P/N, because yours is pre-92.

 

[JQuam]

Thanks daniel. I thought that was a throttle stop. Is there anything to gain on backing it off?

 

[JB]

thanks guys i feel welcome and i hope some day i can help you out... but i think it should be noted that i recently had the trans rebuilt... and the shop i took it to talked me out of buying an after market torque converter... long story short, i had taken my truck to a shop because the flywheel broke and i needed it on the road asap for work, so i took it to a shop that was able to have me in and out in a few days... they seemed knowledgeable but didnt seem to want to listen to me when i sugested that i would like to have a tci torque converter installed... because they offered a product that would out last the oem one and perform like the tci... anyhow its been in the back if my mind since i had it rebuilt, infact the very first time i drove it after i had it rebuilt i called them and said that it seemed like it was driving in slow motion and didnt want to kick down... but ive been back there since because it has been holding shifts, when you floor it going approx 20mph in lets say... 2nd gear it will seem to almost either drop out of gear or hold the shift... now... i had the owner of the shop drive it and he says thats NORMAL? "because they adjusted the trans for longevity"... i thought that was a load of ***** but now its starting unravel... . i think im gonna be mad here in a minute... could you guys explain to me how this could be the case... so i can go back there with some info... and a baseball bat... thanks

 

[DValentine]

I got my gauges right from Isspro's web site. Fast and good service. I had some tech. problems and they were very helpful.

 

[dpuckett]

For some reason, I missed the "AUTO" you had in your first post.



Without a tach, you really have no info to go to the shop with. If you had documented a 2100rpm stall speed (ideal with a near stock truck is around 15-1600), that would point to the transmission and not the engine. As it is, the shop just says the engine has no power.



Demand that they test the transmission pressures- there are about 4 or 6 ports that will give you pressures from the lines and all the other internals related to performance and shifting. If they have a photo tach (doubtful), have them do a stall test. If it stalls at 1700+, the convertor needs to go.



"Tuning it for longevity" is a line of bull, and will not make the truck slower. If anything, it should make it faster, as you'd have greater power transfer to the ground. Normally, performance and longevity go hand in hand if the performance is used sanely.



I just hate shops that dont know diddly, then try to pull one over on a customer after they ask for details. My girlfriend is a service writer, and she has attended some classes where they actually DISCOURAGE getting too technical either over the phone or in person. What a crock!!! Granted, most Americans cant differentiate the transmission dipstick from the oil dipstick, much less know what they are looking for or looking at, but when someone asks good questions, he is entitled to a straight, honest answer. The shops are almost as bad as lawyers.



DP