What's new
CK5
Register an account today to become a member! Once signed in, you'll be able to participate on this site by adding your own topics and posts, as well as connect with other members.

TBI 454 into 1990 Blazer Q's

tRustyK5

tRustyK5

Elbows up!
 Premium
GMOTM Winner
Author
Joined
Jul 23, 2000
Posts
41,547
Reaction score
13,349
Location
In my garage
I just picked up a TBI 454 for my blazer. Came with pretty much everything including the wiring from the entire truck, computer, lines etc etc.

So, I'm assuming since it has a flex plate it came from a truck with a TH400 based on the year. What are the ramifications trying to bolt this up in front of a 700R-4? I can only assume a TV bracket will need to be sourced, or made. How about TC lock-up and stuff though? It appears the 454 had an A.I.R. pump, which my Blazer doesn't. Going to set codes without it? TBI 350 distributor should work right? It came with part of a distributor, but not all.

I can get the numbers off the computer if that helps...

Rene
 
You can get a flywheel with a dual bolt pattern that will accept the 700 converter pad spacing. The 454 tbi throttle body does not have a provision for the the tv cable. You can remove the linkage lever from the 350TB and tack weld it to the throttle blade shaft of the 454TB to have a place to hook up the cable. You can then modify the 350 cable retaining bracket to work on the 454. If you are using the 350 computer to run the 454 then lockup will still be controlled by the computer via tps signal.
 
I think the 454 is externally balanced, but I have no idea if the bolt spacing for the converter is different between a 700r4 or a th400.

I would think that most everything would be plug and play. maybe a sensor or two might have different plugs.
 
OK, I am gonna run the NV4500 behind this thing...solves a lot of issues and is probably smarter anyways.

new question...the 241 I have is the VSS one. The 203/205 going in is cable speedo. Should I try to find a VSS for the 205 output, or do I even need it for anything more than ABS?

Rene
 
just my $.02 but ive just recently swapped a TH400 where a 4l60E was and the flexplate fit both converters with no problem, i don't want to assume anything but i'd say the 700R4 converter should fit.

and as for the VSS check out Painless Performance part# 60115 i saw it referenced on another forum site pertaining to a similar question of swapping a fuel injection motor with "older" drivetrain parts. here's a link http://www.painlessperformance.com/webcatalog/largeview.php?SearchField=60115&SearchAll=Customs
 
and so it begins.. wish i have a 454 in my truck now.. but i have a caddy 500 in the garage:D

i would say almost everything is plug and play, exhaust defentily will need work, oh and make ur feet lighter so its not leaded. :bow:
 
my .02 I'd grab the TPS adapter and run your existing harness. IIRC in one of the pictures in your other thread, theres a pipe plug in the drivers front lower corner of the block. I'm pretty sure that's where the factory oil pressure sensor(s) were. you'll just have to extend your harness and stick it there. I don't think theres a port at the back like the small blocks. Other than that the only PITA is the tv cable provisions mentioned previously if you plan on a 700r4. Do I dare challenge you to completing 454 swap??:thinking:
 
I would not use the older '7747 TBI ECM. I would strongly recommend using a newer '427 PCM, see thread ( '7747 R.I.P. http://coloradok5.com/forums/showthread.php?t=270253 ). The factory 2 pulse VSS is required when using the '427 PCM. The '427 PCM is a factory PCM from 1995 454 GM pickups with either manual or automatic transmissions. All the 1987 senors / distributor / and electronics work perfectly with the 1995 '427 PCM!:D

For the 1987 GMC 454 vehicle I did the '427 PCM upgrade on, the 1995 454 PROM programming is almost perfect. I actually programmed the '427 PROM as a manual trans, when actually using the TH400. Programming the '427 PCM for a manual transmission disables all the programming for the 4L80E, so all the error codes associated with the 4L80E are disabled in the PROM programming. The only engine changes I made to the '427 PROM programming was to delete the emissions.

dave w
 
I'm looking for simplicity to be really honest. the less I have to mess around to get this in and running the happier I will be.

Right now it appears the harness and wiring for the 350 is pretty much identical to the harness that came with the 454...so I'd like to use it.

The 454 is 1990, and has a flex plate on it...pretty safe to assume it was a TH400 truck. Shouldn't be anything special in the programming for that. I'm hoping to use the 350 wiring and plug in the computer that came with the 454.

I am going to run a NV4500 behind the BBC. For the 90 454 with a manual or TH400 behind it what is the VSS used for other than ABS? If I absolutely need VSS is there something that can be retrofitted to my 205's cable speedo output?

Third question, the 454 had an air pump, my Blazer does not, so if I do as I hope to will the 454 computer set any codes without an air pump?


Rene
 
tRustyK5 said:
I am going to run a NV4500 behind the BBC. For the 90 454 with a manual or TH400 behind it what is the VSS used for other than ABS? If I absolutely need VSS is there something that can be retrofitted to my 205's cable speedo output?
Click to expand...

Rene, the vss is also used to tell the computer when you are coasting in gear. It will cut fuel a bit so the motor doesn't stumble and backfire through the exhaust. It's not a huge deal, but I never like all the sputtering mine did before vss. Im using that painless cable adaptor mentioned above. It runs my electric speedo too.
 
OK, nice specific answer! I'd kind of like to keep the electric speedo anyways...

Rene
 
The VSS does a lot more than that too. Keep it, it's a good thing. Most trucks have one mounted in the speedo behind the dash. The electronic one you see on the transfer case is for the electronic speedo in the 89-90 and later trucks. Truthfully I don't know if the electronic speedo trucks have a VSS or it is built into the speedo or electronic part of the trans.

If the TPS is a diferant shape? Buy the adapter. If it's the same shape swap two wires.

Big block does not have knock sensor or acompnying ESC. Not sure on the later ones that used smaller injectors and higher fuel pressure...
 
Funny that the last post in here mentions the Knock sens.... I was coming here specifically to ask rene if his had one.. I just picked up another 454. an 89 TBI. I noticed that it didnt have a knock sens.. How does the computer compensate without this? I'm gonna dump this motor in my truck the way it sits to see if its any good. I'll be using my factory harness with knock provision. I'll install it, but I was wondering why it didnt have one? Pulled it from a truck with the 7747 pcm. Sorry for the Hijack Rene! Oh and are you gonna make it to BB?
 
POORBOYK5 said:
I just picked up another 454. an 89 TBI. I noticed that it didnt have a knock sens.. How does the computer compensate without this?
Click to expand...

The 454 computer chip does not have the ESC enabled. Use the 454 computer and chip and no knock sensor is needed.

dave w

454 N0 Knock Sensor.JPG
 
so plug and play? no changes needed to pin locations? ESC as in the spark control box mounted on the intake? will that still need to be present? your a genius Dave!
 
POORBOYK5 said:
so plug and play? no changes needed to pin locations? ESC as in the spark control box mounted on the intake? will that still need to be present? your a genius Dave!
Click to expand...

I want to make sure I understand the questions and vehicle information. The picture below is from the 87 GMC 1 Ton pickup with a 454 I removed and replaced the engine in last year. This 87 GMC 1 Ton pickup with a 454 did not have a knock sensor when it left the factory, so the Spark Control Box (ESC Module) was NOT used by the factory. I eliminated the EGR and Air Pump / Smog Pump on the new 454 engine. I added an Edelbrock 454 TBI intake the new 454 engine also. I changed the chip programming to eliminate the EGR.

If the old 350 computer was a '7747 then most if not all the wires will be plug and play into the computer? If I were to do the 350 TBI to 454 TBI conversion, I would check the wiring diagrams of both the 350 and 454, just to makes sure the computer wires were plug and play. I only have the wiring diagram for the 87 GMC 1 Ton with a 454, so I can't say for 100% sure the 350 wiring is the same.

Not all the wires are plug and play under the hood! The IAC connector will be different, and maybe even the IAC wires to computer will be different? There might be wires, other than the IAC wires, under the hood that are different between the 350 and 454? I just can't think of any other wires at the moment.

dave w

DSCN2049.JPG

DSCN2098.JPG
 
I would get a chip burned to get rid of the EGR and Knock Sensor. You will need the VSS. I deleted the VSS because of my Atlas and don't have any issues but it's not street driven.
 
VSS helps with idle so it will help off raod as well.

EGR lets in just a little exhaust to dirty the mixture, this reduces cylinder temps which reduces a nasty pollutant (forgot name) but this also lets you run more advance. So no power loss and still lower cylinder temps.

Knock relly helps when tuning as you watch for knocks counts and back off timing a bit. It works with the ESC to advance timing as much as possable then when it gets a signal it backs off timing. But it has it's own issues like off roading if your frame hits a rock hard it will register a knock and back off timing. I have done this with laptop hooked up and hit frame with a hammer... I have heard that newer knock sensors are smarter than a rock! :haha:
 
I've decided I'm not going FI with the 454. It appears to be way too much headache, and the limitations would frustrate me to no end.

It'll be Q-jet when it's finally installed. I've made an honest effort to learn myself up on all this FI/computer stuff, and have given it up as a bad job. I cannot get my head wrapped around anything more than the basic concepts.

Rene
 
You must log in or register to reply here.

Latest Posts

Top Bottom