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1994 454 3500 Low Power

 
ArtLange
I love my Chevy Chevette!
Posts: 4
Joined: 10/08
Posted: 10/14/08 09:15 PM

Hello Folks,

I am brand new to the forum and my first entry will probably be a no brainer as I will be stating the obvious when I complain of poor power from a 1994 Chevy 3500 dually 4x4 with the big block.  This is a cherry truck with 38K miles and the NV4500 tranny with 4:10 gearing.  I am the second owner and it already had an MSD distributor, K&N breather, Jet chip, and a 4" Flow master exhaust.  I could not pull an empty 20' car hauler 65MPH on a level.  I pulled the exhaust and dropped down to 3" Flowmaster with a cat added and the added back pressure has helped, but needless to say it is still a gutless swine better suited for turning fuel into throaty noise than power.  Summit recommended an Edelbrock multiport EDL3563 with a crane 134112 cam.  Your thoughts?  Will that add significant power or should I save my money and invest in a 502 crate truck motor?  My goal is to pull a 20 footer with 2-4 Harleys in it and a slide in camper and be able to maintain 65MPH with reasonable ease.  I will try to keep the amusement level down by not saying I'd like fuel economy too. Any ideas?  Thanks.  Art  

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SMOKESHOW
I mow my lawn and find Chevys
Posts: 1001
Joined: 09/08
Posted: 10/15/08 11:41 AM

Has anyone messed with the rockers? How does your timing look? You could always install a roots blower!  

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shootnrats
My first time was in a Chevy
Posts: 177
Joined: 08/08
Posted: 10/15/08 12:30 PM

I would check the obvious first...plugs, wires, as stated timing, fuel pressure, filter. it could be so many small things. maybe it just needs a good tune up.  

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JW454
I have an SS396 tatoo
Posts: 345
Joined: 07/08
Posted: 10/15/08 01:29 PM

95 is a Gen 5 engine, so there are no rocker adjustments to be made. The were very gutless from the early seventies due to super low compression and small lift, short duration camshafts. If you wanted to work with your current engine, you could spice things up with a cam in the range of 205-220 deg. duration@ .050 and a lift at valve of .480-.500. Use a LSA of 110-114. You didnt mention headers in your parts list. They would help imensely, especially with the new cam as would the aluminum intake. Like the last guy said, it could be a number of small things being out of tune but the power ratings on the stock 454 in your truck are pathetic. JW.  

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ArtLange
I love my Chevy Chevette!
Posts: 4
Joined: 10/08
Posted: 10/15/08 09:04 PM

Thanks Folks,

I am going to start with the obvious fuel filter, locate a stock eprom and a comprehensive tune.  I fear I am polishing a turd, but we shall see.  I am now deployed overseas so I have to work through my wife and a garage and I will not have the self gratification of greasy wrench twisting. Trust me there are worse things than than a lack of intimacy with a Snap-On box end.  I think a cam swap, headers, and a new fuel delivery will be in the future, if I have to go deeper it is probably financially advantageous to just buy a long block in a box. Thanks again.  Art  

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55Guy
Big Block power for the win
Posts: 895
Joined: 08/07
Posted: 10/16/08 06:36 AM

The best thing for one of those engines is a cam swap. Change from the factory flat tappet cam to a good hydraulic roller, in those motors it's worth at least 50 HP and will increase your towing power.  

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stempak
V-6 Camaros rule!
Posts: 47
Joined: 11/08
Posted: 11/08/08 03:49 PM

Ya cam and headers check the tune. after the cam and header's a supercharger but it might  make excessive heat. check the chip possibly bad the thing is still pretty fresh I'd figure out what's wrong first but definately a cam and headers stock is pathetic. I don't think you want any of that edelbrock injection bs the stock stuff should handle 400-500hp. pretty much any stock 454 should be able to do 500hp and 500ftlbs of torque! your probably at 250hp and 300ft tops in a BIGBLOCK?  

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mechelement
I love my Chevy Chevette!
Posts: 3
Joined: 08/09
Posted: 08/07/09 09:07 PM

Art's son here...

His truck is still a dog. The chip was re-burned and it did help. They cleaned the injectors, etc. IMO, it's gutless at 50mph and up... It just doesn't have anything left. Art's trailer does have a flat front and no doubt, it's like pulling a brick into the wind. Regardless, that motor should pull the trailer and maintain highway speed limits.

Correct me if I'm wrong, but a '94 454 is a Gen V. I assume something has been bastardized on these motors to keep them from putting out major hp and torque like the 454s from the '70s. Can those '70s 454s handle towing?

This issue must be resolved. I'm against a GMPP fuel injected motor if it has a fuel injection system like the MPFI Ramjets have. I'm all for an aftermarket fuel injected or a carbed motor build or crate motor.

Any thoughts? Jason  

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waynep712
I have an SS396 tatoo
Posts: 264
Joined: 01/08
Posted: 08/07/09 10:54 PM

first off... i would invest in an OBD1 scan tool.. that will talk to this system and display live data... so you know where and what the system is looking at...

there are so many things that could cause lack of power...   like incorrect mods to the system that takes it out of closed loop....

exhaust leaks into the upstream air.. messes with the O2 sensors... that messes with the air fuel ratio...

coolant temp sensor, its pigtail and the thermostat...  all have to work properly.

i don't know what was programmed into the chip... but in a normal system... if the engine coolant temp sensor does not reach 200 to 225F .. when looked at with a scan tool... the engine will not run properly...

i know that there are replacement intake manifolds for the  small blocks with TBI bosses .. but i am not sure if they are made for big blocks...   one could even install a better design intake manifold and bolt on a TBI adaptor...

since you are looking for increased power..     you might also want to see if there are any larger flow fuel injectors...   since the 454 was the largest factory motor that i know of... but i don't know the flow rates of those... you might have an option there..


if the check engine light is on.. it will not be in closed loop... closed loop is where it is drivable...     open loop... power is restricted..   and that might be where your are at...


all these power products do NOT.. if the system is not in closed loop...   feeding back exhaust oxygen sensor data from the burned  combustion...  to properly set the fuel ratio being sprayed in...

this is feed back...

open loop... the system runs on pre programed data...  and that has limp home power restrictions... preventing you from damaging stuff...

if after you get it up and running... and into closed loop... there is a guy in gasoline alley who does fuel injectors... and has a large selection of them... all flowed and matched...  including TBI units..     his stuff came in handy a few years back...  with engine swaps with 4100 cads to 4500 and 4900 motors...  

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Dmwvr32
I love my Chevy Chevette!
Posts: 1
Joined: 08/12
Posted: 08/16/12 06:16 PM

No help here but my 94 454 pulls my horse trailer (six horse with dressing room) loaded around  just fine.   I experienced a loss if power once and it was a simple exchange of plugs and wires.  This is a stock truck with no upgrades.  

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skyeking
I mow my lawn and find Chevys
Posts: 2738
Joined: 08/09
Posted: 08/16/12 10:13 PM

Hi there,
The Albanians who were shown on T.V. a few months ago
had the Opinion of their politicians...
You Can't polish Shyte..Close enough...
 If you did get a crate 502 you would not call the
 King your Uncle as we once said.All the very best...  
skyeking

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pepsi1
I mow my lawn and find Chevys
Posts: 1718
Joined: 09/11
Posted: 08/18/12 02:00 AM

I would see if the cam went. Pull the valve covers and see if there is 1 or 2 rockers that are not doing their job. If it go away there are many cams out there to choose from...

Skyeking did you see the Mythbuster's when they actually polish elephant dunf to a mirror finish.  

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