code 43 ESC failure on a 1990 454TBI

[Stowburb]

Hey Guys,
I'm getting my butt kicked and i'm hoping some of you guys could point me in the right direction.
Here goes, i'll try to not make this too long winded...

I just bought a 1987 shortbed 2wd with ( and this is what the P.O. told me) a 1990 stock 454 TBI engine out of a 3/4ton suburban.
I bought the truck several states away and drove it 650 miles home. It ran decent not great  but not too bad.
 Well after getting it home I did what anyone would do...start repairing the little things you find wrong,
I replaced the valve cover gaskets ( was clean inside) I put new AC delco plugs in it and replaced to cap,rotor,and wires.
Well, i noticed that the distributor was not in the correct location, it looked like it was turned about 3 towers advanced,
so I turned it back and set everything up to factory TDC with rotor pointing at the number 1 cylinder and installed my wires
as factory (18436572)
Here's where the mystery begins!!!... I set the timing with a light to 4* it will idle just beautiful but when I take it out on the road to test drive it backfires and spits fire out the Throttle body and it acts like its starving for fuel and or the timing is way off.
I discovered that the right fuel tank was full of rust, mud and water, and the fuel filter was the same. the left tank was clean so i replaced the sending unit with a new assmy with pump and removed the right tank. so it is getting plenty of clean fuel,
I have also re built the TBI with all new gaskets and fuel pressure regulator.

I found that the check engine light bulb was removed, so i replaced it and with my old OTC scan tool i find it has a code
43 (ESC failure) that is usually caused by a bad knock sensor. Well my engine does not have a knock sensor,and i cant find any trace of wiring for a sensor!
Well I cant find the ESC module!!!! I remember that the TBI small blocks had it mounted beside the MAP sensor on the intake, its not there on the big block,
Alldata claims that the ESC module for a 1987 truck was mounted on the break pedal brackets, Well Its not there!!!

Alldata claims that on the 454TBI in 1990 the ESC module was mounted on the firewall on the pass side of the distributor
Well its not there either!!!

I call the local dealer and talk to the parts dept. and he informs me that the 1990 454 TBI ESC module is in the distributor and gave me the part number for the ESC module. I go to my parts house and give them the part number and they inform me that it is a ignition module and it's the same as a small block TBI engine.

so my question is...WTH!!! ive done everything i can think of and my truck still runs like shoot!!!
 I'm at my wits end!
I'd love to see a 454 TBI engine and see if it has an ESC module, and where its located.

If anyone has any info! I sure could use the help!!

Thanks,
Chris




 
 

[Captkaos]

To my knowledge none of the 454TBI trucks had ESC or knock sensors.  Wonder if they used the ECM from the donor or the one from the 87?

[Stowburb]

thats a very good point, Chris, is there anyway of telling? the ECM number maybe? the wiring harness doesn't look like it has been butchered. I'm just blown away by the fact that I drove it 650 mile at an average of 70-80 MPH and it seemed to run decent, and even seemed to do decent on fuel, then as soon as i service it, everything goes to heck!
I've owned several TBI smallblocks and an 88 TBI 454 in a R20 suburban and never had any kind of issues even close to the problems i'm having now!

[Captkaos]

You could look up the replacment part number (GM) for the 454, the 350 is a 747 ecm.

[Stowburb]

the ECM number is 1227747 that is in the truck now

[Captkaos]

87-89 used the 1227747
90 used 1228747

So you should be able to use that ECM, check to see what the PROM is?  Are there wires not connected for the Knock and ESC?

[Stowburb]

That's the issue, there are no wires for an ESC or a knock sensor! I haven't looked at the ECM connector yet to see if there is any wiring for those things.  if there is then i can trace wires and maybe replace some connectors and add sensors.I have Alldata for wiring info,but its not very user friendly, anyone have better wiring diagrams?

Where would the ESC module be on a 454TBI? Alldata says its on firewall to the left of dist. Alldata says for the '87 truck the ESC is mounted on the brake pedal brackets, well it is not in either of these locations. as for the knock sensor, my engine does not have one ( weather it did at one time is beyond me, it just has a brass plug where one would mount,and i have not found any evidence of a connector for a knock sensor in the harness that runs to the starter.
So I'm baffled!

[Stowburb]

here is what alldata has for a 1988 454TBI.
 It says for the ESC and knock sensor it was only on the  "LO5" whatever that means...
The prom number in my ecm is...ABHP 7598.
At the 24 pin connector at the ECM  B7 is the location of the "retard wire" that runs to the ESC, well that position is empty, doesn't look like it ever had anything there, and the wiring harness looks to be unmolested.

I'm lost, just cant figure out why it runs so bad!

[Stowburb]

Well, I replaced the ECM with a rebuilt one and the truck runs sooo much better,but it still isn't 100%.
 As soon as i start it ,the check engine light comes on and the fault code is the same as always...43 ESC failure!!
 I have a OTC scan tool from back in the day, and if i look at the data stream, everything seems fine, but it shows "YES" for knock. So i figure that is the reason it sets the code 43, but why and where is the ECM getting this info? this engine does not use a knock sensor, or a ESC module?!?!?
 I'm going crazy trying to figure this out!!! and I'm really tired of spending money on this truck!!!

[Engineer]

Are you sure on the 4° timing? Every GM TBI I have seen you set the timing at 0° with the timing wire disconnected (timing in bypass mode).

This information may not be worth any more than what you paid for it but, I have never seen a GM TBI engine that did not have a knock sensor. I don't see how it could control the timing curve without it.

As far as the esc I'm not sure on that one.

If I had this project I would standardize on a particular model as close as I thought to original then match all components from there. Starting with the ECM with the correct PROM for x then get the wiring diagram for such and go from there.

Also I've noticed not all knock sensors are interchangeable.

[Stowburb]

All data says 4* timing, with the spout connector unplugged. I have never seen a TBI engine without a knock sensor either,
 But the guys in the parts dept at the local dealer says that some 7.4L did Not have a knock sensor or a ESC module, was told that ESC is in the distributor, in the ignition module, and gave me the part # for it. My local parts house crossed the OEM number over and tells me its the same module for big block and small block, and the same ignition module that uses the external ESC module and knock sensor.
 So i'm stumped! I dont have the VIN # from the donor vehicle where the P.O. got the engine and trans, he told me it was a 94 3/4 ton suburban.