Engine/Transmission (1994 - 1998) Do I have a Low Fueling Problem

[EGILLILAND]

Seems like my truck isn't performing quite up to snuff. Here's the situation. 80deg, go pedal floored, in overdrive at approx 72mph with an 8000# trailer. The most EGT I can get out of her is 800 deg (post turbo), w/boost at 29psi, RPM at 2200. I swear last summer I could have run the temps right to the limit (my personal is 1000 post turbo) and would have been able to generate as much as 32 psi boost.



In 3rd gear, if I run the RPM right up against my limit, at about 2800 rpm I can get to 31 psi and climb the EGT's to 950+.



Basically I have to wind the motor more than I think I used to in order to generate EGT's/boost numbers I'm familiar with.



Here's one more piece. I was tagged in the front end by a semi last winter. Almost everything forward of the water pump is new.



I was concerned about my pump after the wreck because of some throttle linkage binding. But after we got the bent sheet metal out of the way everything appeared to be working great.



My theory is that for some reason I'm delivering less fuel than before at higher rpms. I don't think it's a leaky intercooler for two reasons. 1. I'm still able to generate my same old max boost and 2. If I was leaking air but still delivering the same amount of fuel... . I should have no problem maxing out my EGT's... instead of coming up short.



Any thoughts out there on evaluating whether my pump is delivering it's full and normal fueling? Specs on throttle lever movement etc. ?



How about my AFC? Could there be a problem with the boost feedback part of the fuel control?



I won't argue about checking my new intercooler... . I'll check it. Any good techniques out there that don't require a professional plumber to check the integrity of the intercooler? I do have the air compressor.



I almost hate to chase this. The truck runs great... . just seems to come up short when asking for max power out of her in overdrive.





Thanks ahead of time for the thoughts fellas,



Cheers,





Gill

 

[Andy Redmond]

I'm betting on the accident repairs. I road tested a 96 auto trans that would make about 30 psi boost under load (TST #8). I tested several things and found several issues with it, but most importantly... innercooler leak.



I then tested the innercooler and found leaks on the radiator side about the third core row up from the bottom on the passenger side, about six inches from the tank. It would hiss pretty good, and you could feel a breeze between the innercooler and radiator with your hand. I disconnected the air supply and the regulator would fall to zero in a hurry. I noted about 10 - 15 psi of drop from the turbo to the intake (boost gauge reading) , 2-3 psi might be/likely is normal.



For this test I have a "fernco" 4"x3" adapter and reduction fittings to come down to a air hose quick connection that attaches to my regulator (inexpensive from a Parker store) and an air supply. I removed the air horn and attached the fernco to the turbo inlet. I didn't exceed 25psi as the fernco will swell significantly, make sure its clamped on good or it might pop off and cause you injury!



I usually lay a shop rag over the back of the altenator and a couple of fender covers over it should it pop off...



You can also make an adapter to go in the charge air line on the output of the turbo and before the innercooler. A piece of exhaust tubing with a cap welded on the butt end and a raised lip where it slides into a rubber boot (use an existing clamp to hold it in) would work well, drill the end and install a schreater (sp) or male fitting to connect to your pressure regulator.



The most recent issue of the TDR has some photos and parts list on how to assy one too or do a search under "fernco" and you'll have some pics and ideas.



Onto the throttle linkage, assure that max accelerator travel = the pump linkage touching the high idle screw/stop, adjust it if not and reset the TPS as necessary. If you remove the shut down solenoid its easier to see what your doing. Assure you have good fuel pressure and also under load, no filter restriction etc.



Also assure no a/filter restriction.



Hmmnmm and you thought the ole ram would have no problems with GM/Hummer parts put on her! I learned my lesson and will do w/out those sexy wheels after all for fear of my ole ram feeling sickly and depressed!





Good luck and let us know what you find.





Andy

 

[Forrest]

Originally posted by EGILLILAND

(my personal is 1000 post turbo) and would have been able to generate as much as 32 psi boost.

:--) Been there ... done that. Equated to 1500+ pre turbo.

 

[EGILLILAND]

Ok here's what I've done so far. I plugged the waste gate line to generate max boost. I'm now able to generate 35psi by 2500 rpm pulling a load in 3rd gear. When I shift to O-drive at this point, I can generate up to 30psi by 2200 rpm... IF I CAN GET THERE. I am definetly down on power, which I would equate to a lack of boost or fuel. Now since I think I can show that under equitable rpm/loads I can still get the boost. Only now the most EGT I can get out of her (post turbo) is 700. Which under the conditions I just test drove her, go pedal maxed, 10000# trailer, 2100 RPM, 30psi... ONLY 700 deg EGT?



I think I'm gonna take a hard look at my throttle linkage. I don't think I'm getting to full WOT. Any links/pictures procedures anyone has on making sure I get this checked correctly... . I think will lead me to my solution.



Andy... thanks for the headstart on the troubleshooting...

You don't happen to have any good links to "monkey proof" pictures describing the finer points of throttle linkage adjustment?



Thanks everyone





Gill

 

[Andy Redmond]

H2.com/help my ram! he-heh! Sorry I couldn't help myself.



Gill:



if you can get an assitant to help you this will be easier. You should have 5 in from the center of the "stud" (cable attachment at injection pump) to the edge of the bracket that holds the cable at the injection pump. At idle throttle position...



Have your assistant floor it (with the engine off) reach under the fuel filter and notice the "speed lever" or throttle shaft on the back bottom of the injection pump. While the asst is holding the throttle at max can you rotate this lever counterclockwise towards the front of the truck any more or does it seem like its hitting the stop on the pump? It should just touch the high speed/high idle screw/stop.



After you have verified this have the asst release the throttle and floor it again. Grasp the bell crank (lever where cruise, throttle and transmission kick down cables attach) and see if you can move it towards the firewall or if the accelerator pedal moves it completely.



Remedying incomplete throttle travel can be achieved several ways. . at the "dogleg" at the center of the throttle linkage (rod travels down the side of the pump) break the nuts loose (the one end is left hand thread) adjust the length of the rod, then re-ck the tps voltage range (FSM gives good instruction on this one) and for full throttle travel.



Some pumps have a slot on the speed lever we discussed earlier and several holes. Likely the ball stud that holds one of the throttle end links attaches at one of these points. Move it to the slot and have the asst move the accelerator until full throttle travel is achieved.







See this pic of the back of the pump.



http://www.dodgeram.org/tech/dsl/adjustments/2nd_Gen-Idle.htm



Although the lever we discussed is removed for illustration clarity you can asimilate what we have discussed.



Good luck

Andy (who envies Gill's super cool wheels)

 

[EGILLILAND]

Thanks Andy I'll get after this adjustment and let everyone know how this goes.



Yup I guess I found my sensitive side when I found the H2 tires/wheels. Hey what do a think maybe I should start a TDR offshoot... whitepastyrapperswithH2rams.com?



Not sure if you're familiar with the link I started on the wheels. .



Cheap Tires/wheels



You'll note one revelation I had early on:



"The H2 caps look OK…buy they’re kinda like ladies underwear…they might feel good but you don’t want your Dodge buddies catching you using them "





Hopefully with my Dodge centercaps it will take longer for people to realize my "weaknesses" for H2 stuff on my truck

 

[Andy Redmond]

You were kind enough to email me photos off the site, see now you got me wanting some before the Michelins are worn out!



How much do they hang outside the wheel wells vs. the oem combo(not counting the fender flares)?



One other thing. . Do you know anyone that has a pyro tester? Some times the thermocouple will begin to fail and offer cooler or warmer than usual numbers. . but it sounds like this might be a red herring since it doesn't want to rev and work like it did last season. Not that this is a performance issue, but to assure the pyro is accurate.



Andy

 

[plangone]

What kind of fuel pressure do you have?

 

[EGILLILAND]

I'll confess on the fuel pressure angle. Don't know, and I'm not equiped to find out very soon (no guage etc. ). The thought of cutting up the stock lines and plumbing in a guage is a little scarey to me.



If someone has a "pilot proof" setup for fuel pressure monitoring (aka pic's etc) I'd love to see the setup(s).



Thanks everyone.



Gill

 

[Andy Redmond]

Gill:



Order the adapter from TST for $25, this converts the bleed screw on the output of the top of the fuel filter base from the M6*1. 0 thread pitch to male/female pipe/compression fittings so an old boost gauge can be used. . If you have friends with a wakeon master fuel psi test kit, it has a nice adapter that will thread into the port aforementioned.



You can also purchase a spare oem banjo bolt for the fuel line that enters the side of the injection pump, drill, and tap (leaving no fod to possibly enter the injection pump) for whatever fitting it takes to adapt to the gauge of your choice. I've often tapped the oem bolt and tapped to 1/8 NPT, then installed a plug with small amount of liquid teflon, teflon tape etc. then the customer can remove the plug at will to attach the temporary gauge. Usually the sealing washers are re-usable.



Others have used a gutted overflow valve (the ones that you can disassy).



I have a liquid filled gauge and hose setup I had made at a Parker hose store. The liquid filled gauge will provide easy reading and a non-filled gauge will pulse radically, but will work.



I like to see 25psi under load on a test ride, at least 20 at idle. You may have restriction in the filter, all of the above will offer pressures after the filter. The overflow valve could be weak allowing the pressure be returning to the tank before sufficent pressure is achieved. Gently squeeze the rubber return line with some smooth needle nose pliers etc. . if the psi was low before and increases, it may indicate the overflow valve is bleeding off too soon. If no change it may indicate a weak lift pump or restriction in a line somewhere.



"briarhopper" also sells a kit. Tom is a good guy!



Miller SPX (dealer tools) also makes a nice kit to test with and is likely less than $100.



If you really have time on your hands you could take a grade 8 metric bolt m6*1. 0 * 10mm and drill the center and braze a fitting to the top of your bolt to attach to a gauge.



Ok my . 02 worth. Go forth and find pressures and tell us your prognosis!