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97 7.4 vortec out 84 454 carburetor in !

E.J Morgan

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I have a 97 3500 dually 4x4 7
4 vortec, it swallowed a valve and destroyed it, I bought an 84 RV with a 454 with 30k and after working out a little fuel pressure bug it runs great,but here's the all too familiar problem, the speedo and tach work sometimes and the tranny won't shift, I was really hoping the computer was mainly for fuel management, but maybe I was Wrong, I've read just about every post on the topic, the question is, can I make this work? despite the fact that it takes off in 2nd gear it smokes the tires, I appreciate all input, I can be the only one out there to try something like this can I ?
 
The transmission is doing what it should- 2nd gear limp mode- where all you get is 2nd and reverse to get you home. Hoping @THEFERMANATOR chimes in incase there is a third sensor I don’t remember....

You have 2 options. Adapt the 2 sensors required to have the computer control the trans, or buy an aftermarket transmission controller.

Option 1.
hooking up the tps throttle position sensor. Pull the one off the 7.4 snd do some fabrication so that the carb throttle operates the tps. The tps doesn’t require tons of torque (almost none) so good ol jb weld will work here. Make sure you can get full range of adjustment because Once you have it on, you will need to do the adjustment to get proper voltage with pedal at proper position.

I am 95% sure you will also need the cps -crankshaft position sensor. I don’t think the 84 454 has a reluctor ring. It is just a thin 4 prong unit- open up your 7.4 and grab it out. Now the hard part- you need that installed on yours somehow- or you need something to take it’s place. It is just counting 4 pulses each engine revolution. Off the front of the pulley somehow? By the harmonic balancer?

I had this dilemma on my 6.5 diesel for different reason but I could use the newer timing gear and reluctor wheel from newer engines in my older one. I don’t know if that’s possible on yours or not. You would need to use the reluctor and probably timing cover from the newer engine. A pain to do, but then you can do a new timing chain while you are at it and eliminate future maintenance at least. Don’t forget the front main seal at the time. Sonif you pull it apart and see nothing can’t be done- at least it isn’t for nothing.

Those two sensors are the two - I THINK- that will solve your issue. I don’t know of any others that the transmission cares about.

Otherwise option 2:
a stand alone trans controller is your solution. Here is one from - even though from a diesel shop- same transmission 4l80e. https://leroydiesel.com/products/optishift-transmission-controller/. Other places like summit and jegs sell them too- but do your homework before buying. Although this sounds like the easy button- there are things you have to deal with as well.
 
The transmission is doing what it should- 2nd gear limp mode- where all you get is 2nd and reverse to get you home. Hoping @THEFERMANATOR chimes in incase there is a third sensor I don’t remember....

You have 2 options. Adapt the 2 sensors required to have the computer control the trans, or buy an aftermarket transmission controller.

Option 1.
hooking up the tps throttle position sensor. Pull the one off the 7.4 snd do some fabrication so that the carb throttle operates the tps. The tps doesn’t require tons of torque (almost none) so good ol jb weld will work here. Make sure you can get full range of adjustment because Once you have it on, you will need to do the adjustment to get proper voltage with pedal at proper position.

I am 95% sure you will also need the cps -crankshaft position sensor. I don’t think the 84 454 has a reluctor ring. It is just a thin 4 prong unit- open up your 7.4 and grab it out. Now the hard part- you need that installed on yours somehow- or you need something to take it’s place. It is just counting 4 pulses each engine revolution. Off the front of the pulley somehow? By the harmonic balancer?

I had this dilemma on my 6.5 diesel for different reason but I could use the newer timing gear and reluctor wheel from newer engines in my older one. I don’t know if that’s possible on yours or not. You would need to use the reluctor and probably timing cover from the newer engine. A pain to do, but then you can do a new timing chain while you are at it and eliminate future maintenance at least. Don’t forget the front main seal at the time. Sonif you pull it apart and see nothing can’t be done- at least it isn’t for nothing.

Those two sensors are the two - I THINK- that will solve your issue. I don’t know of any others that the transmission cares about.

Otherwise option 2:
a stand alone trans controller is your solution. Here is one from - even though from a diesel shop- same transmission 4l80e. https://leroydiesel.com/products/optishift-transmission-controller/. Other places like summit and jegs sell them too- but do your homework before buying. Although this sounds like the easy button- there are things you have to deal with as well.
I appreciate the input Will, you're right, throttle position sensor is easily enough done, I'm looking at the harmonic balancer right now, and it looks like the timing cover can be used too, now comes the lowering of the oil pan,I really don't want to grind off the inner lip of the timing cover like we used to do with small blocks, but with the front differential 2 inches away, I might have to turn the motor mount bolts loose and slide the floor jack under it, I was really hoping that it was gonna come down to the ignition control module and of course I'm going to test it first, thanks again and I'll keep you posted, this won't be the first time I bit off more than I could chew!!
 
The 0411 has been used for this many times and is tuneable on the cheap. The black box can also do it, but adjusting the shift points is pretty much out of the question. I've read of people doing this, but I've never personally done it. You will have to hook up a TPS to give it throttle input, coolant temp sensor, and provide the black box PCM a tach input(I cannot remember which pin you put the tach signal to though). Then hook up the powers and grounds to the PCM and it should be able to shift it. In all honesty though, aftermarket controllers are far easier to hook up and adjust, but your looking around $500 for the cheapest decent one out there. Or you can set it up to manually shift the trans, but this isn't the cheapest option either to make it work and last.
 
Happy Friday Guys, I wanna say thank you to Mr. Marty 51 for the welcome! Yes I'm still on the 454 carburetor project, but things are looking up, between the input from you guys and more Utube than Anyone should watch it's shifting like it should, it took me half the day to fabricate the bracket for the TPS and have the full range, and despite what I think of most Utube videos, I did get a great tip on the CPS now keep in mind that I was prepared to swap the timing covers, but if you look at the 3 pin sensor plug, on 1 end you'll have 12 volt power supply, a center pin, I don't know what purpose it serves, but the most important is the 3rd pin , connect that wire to the Tachometer wire and it simulates the crank sensor and along with the TPS that you spent most of the day getting right and you just saved a bunch of hard earned money on a TCM ! do you guys have used electric fans to help your trucks run a little cooler? mine got up to 200 degrees when I took it down the highway, granted I ran it up to 90 for a couple miles, but it never cooled down below 195 , I didn't change the thermostat , sounds hot to me , have a great weekend and thanks for the input.
 
Many of us run the 6.5 gm diesel (old one before duramax) and they have HUGE overheating issues. So, we know a trick or two...

The most awesome thing available to us now is using an electro viscous fan clutch that an electric fan controller turns on and off so you can set the temperature you want the fan on at. Also can add a trinary switch so it comes on with a/c if you want. Idiots like me that like to drive through deep water can shut off the fan temporarily to not damage it when the water otherwise destroys fans and radiator from it usually.

adding electric fan can help if you get too hot at a stoplight, but if you ever have problems on the hiway- electric fans will make it worse because they impede the air flow at higher speeds.

starting by removing enough to fully clean radiator and other coolers on the stack is primary.

many gm fans were tiny, while others for same engine have bigger pitch and more blades. What you have now is a good question.

fanclutches are nly good for 5 years, after that performance falls dramatically.

engine and radiator flush helps a lot. Long life coolant doesn’t cool as well as the old school stuff. Run from dexcool.

water wetter helps.

Get a new aluminum radiator and have it ceramic coated from TwistedSteelPerformance - that would have big impact.

I grew up heat of Las Vegas and 50 years old now. I Learned the hard way like many others that electric fans are a band aid on a gapping wound. Don’t waste your time and money.
 
I'm using the 97 radiator, I haven't touched a magnetic to it but it looks aluminum with plastic tanks, ot has a 9 blade fan, but I noticed that when I shut the motor off the fan keeps spinning, but when I move it by hand it feels stiff, the fan blades don't have much pitch to the
 
Yeah, should be aluminum but raw aluminum builds up aluminoxide which is an amazing insulator. If yours was painted when new will do better long term, but most don’t get painted. So if it looks silver- it is not cooling like it used to new.

The coating that TSP does increases thermal output 30-35%.

as to the fan clutch, my suggestion is replace it now. Clean the entire cooling stack when replacing it and if that isn’t enough, do the radiator. 24-25 year old radiator- how long before it blows out anyways. Current money situation always counts but when a person can afford the radiator before it blows is always better than it failing when you can’t afford it and on a road trip.
 
What Will L told Me. The fan clutch is suspect. He said to use a self drilling sheet metal screw and screw through the fan clutch.
Essentially locking it solid. I drilled and tapped three holes, threaded them and installed three machine screws.
Took the truck for a drive at over 100 degrees, 110 IIRC, before the lockup the temp of the engine was running 217 degrees. After the lockup, not over 200 degrees, with 195 stats.
I also am running A new aluminum radiator from Twisted steel performance too.
 
Running a screw threw it ruins it. This is a ‘get you home’ move.

It will show you how well the fan clutch was or was not working.

But figure 5 years is useable life on a fan clutch. If you don’t recall when you replaced it- it is probably due or over due.
 
I know I'm late to the party ,but welcome aboard EJ!

2x on the fan clutch and cleaning the cooling stack (rad, condenser, other coolers) be sure to separate them enough to see between them, you'll find lots of unseen buildup in there. I made me a blow gun for my compressor that had a extreme low profile 90 deg angle with some length between it and the trigger of the gun so I can stick it down in between the stack and blow out both directions. it'll be a jaw dropping experience when you start blowing the stack out! if it's never been cleaned before they'll be a huge dust cloud around you. P.S. wear a dust mask while your at it lol. the neighbors will think you set a silent bomb off when they see the cloud!!

your engine should have the spin-on style fan clutch, so if you plan to replace. now is a good time to go with the electro-viscious style clutch and if it will clear, add the d-max fan. youll need a fan controller for the clutch but it's well worth the investment. I'm currently doing this to my 95 3500 truck.
 
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