Tbi swap build thread

[pancake]

Since I do not have to worrie about emission control, do I NEED an Air diverter valve?

In my orignal post, question #1, for the N/S switch, rfmaster said to leave it open. Can you elaborate? open=not hooked up at all?

If I go with a stock harness, $ is always an issue, for the wires I dont use do I just cut them off?

I do have headers on my blazer. So I will need a 3 or 4 wire o2 sensor. I will also need to weld a bung into the header. I have read keep it within 12" of the head...is this correct?

Can you please explain how to"wire a simple relay controlled circuit to turn heater when ignition is on"?
I am no electrican but did google relay info and have a very basic understanding. Please correct me if I am wrong, but there are always open or always colsed relays....and a relay is just a switch operated by a current?? correct?

[pancake]

Thanks cjracing15 for the pictures of the KS. lol i know what a KS is and what it does....you can teach an old dog new tricks

[pancake]

A question on ECM's....

for ECM 1227747 there are mant diffrent broadcast codes like ASDU and ASDZ?
A broadcast codes is specific to that vehical? example..a broadcast code ASDU is for a 1991 Chevy C-1500 5.7L V8 Auto, and a broadcast code of ASDZ is for a 5.7L automatic? Is this correct?
(See info below from http://www.cruzers.com/~ludis/c3xref.html#1227747)

Is a broadcast code the same as a PROM?

I have a manuel tranny in my Blazer. Should I not get a 1227747 with a broadcast code of ARHT or ASDW? Are they hard to find?

Or, does the tranny type of the broadcast code not matter in my situation?

Thank again folks for all you help!



1227747
Schematic

Application: 1987-91 truck 4.3 V6 TBI “Z” LB4 (exc. “S” & “T” body)
1990 truck 4.3 V6 TBI “Z” LB4 w/ MT (“S” & “T” body)
1990-91 truck 4.3 V6 TBI “B” LU2
1987-91 truck 5.0 V8 TBI “H” L03
1987-90 truck 5.7 V8 TBI “K” L05
1991-92 truck 5.7 V8 TBI “K” L05 w/o 4L80E
1987-89 truck 7.4 V8 TBI “N” L19
MEMPAK IDs: “Z”: ADWD, AKDX, AKSN, APAB, ATKX, …
“B”: …
“H”: ADTJ, AFDY, AJUK, ARPC, …
“K”: ACSU, ACSW, AKAL, AKAJ, AKAR, AMUR, ANLW, ANLX, ANLZ, ARHT, ARJT, ARJU, ASDU, ASDW, ASDZ, …
“N”: ANTZ, AZFT, …
CALPAK IDs: “Z”: 16051637

[rfmaster]

Originally Posted by pancake

Since I do not have to worrie about emission control, do I NEED an Air diverter valve?

In my orignal post, question #1, for the N/S switch, rfmaster said to leave it open. Can you elaborate? open=not hooked up at all?

If I go with a stock harness, $ is always an issue, for the wires I dont use do I just cut them off?

I do have headers on my blazer. So I will need a 3 or 4 wire o2 sensor. I will also need to weld a bung into the header. I have read keep it within 12" of the head...is this correct?

Can you please explain how to"wire a simple relay controlled circuit to turn heater when ignition is on"?
I am no electrican but did google relay info and have a very basic understanding. Please correct me if I am wrong, but there are always open or always colsed relays....and a relay is just a switch operated by a current?? correct?

N/S - Lieve end of that wire unconnected ECM Pin-B10 (Orange-black wire). In automatic equipped cars this line is grounded via P/N when transmission is set in Park or Neutral. This is done to compensate commanded engine idle speed in drive by about 50 to 75 depending on operating conditions.

If you go with stock harness - I would first lay out and id all connections - see my early post elsewhere in this post. IMHO I do not like to cut, but you can choose to remove unused circuits.

O2 positioning was critical for couple of reasons. First the O2 must be heated to about 600F to operate. Placing it further down stream tends to keep it below 600F. Heated sensor gets around this placement requirement. Another reason for keep O2 closer to the engine is what is known as transit response time. ECM operates close loop feedback system which takes into account response delay times. I can go on further into control system theory, but ideally observation points need to be within near proximity of the process to keep close loop operation stable.

I'll post simple relay circuit schematic - it is a bit late tonight.

Automatic calibration or broadcast code BCC (EPROM) can be easily adapted to manual transmission duty. As is automatic calibration is not ideal, but it will get you going. There are several calibration tables that must be changed to make manual transmission operation smooth. This is another subject area that you'll have to research. For now hunt for a 350 based BCC 1227747 ECM as your starting point. .

Relay allows small control current to control large load current.

//RF

[pancake]

Here are the specs for the cam shaft in my 350:

Summit® Camshafts
Camshaft, Hydraulic Flat Tappet, Advertised Duration 252/ 262, Lift .398/ .420, Chevy, Small Block, Each

[rfmaster]

Heated O2 control circuit.

Summit K1101 cam is a very mild mannered cam shaft. I have heard (never used one myself) that it (Summit K1101) works well with TBI. For a stock TBI EPROM idle vacuum must be around 16 to 18 inch at 600 RPM. Large overlap cams or narrow LSA kill idle vacuum for high RPM power. Since TBI relies on MAP sensor to determine volumetric efficiency significant deviation of vacuum at various operating points (RPM/MAP) will result in incorrect baseline fuel delivery. ECM can compensate, but if it is too far off - engine will run rather poorly if not at all.

You should be fine with this cam.....

//RF

[pancake]

Thank you for the relay circuit schematic. I should be able to do that? Can I get these at Radio Shack or do you know of a better place?

I found a guy on E-bay that has a complete unit for $400.00:

It's in a 1990 Chevy 2WD Truck

TBI aluminum intake manifold w/ temperature sensor and EGR valve
Throttle body w/ TPS (throttle position sensor) and IAC (idle air control) valve, Distributor
Ignition coil
EGR solenoid
Sensors including the ESC (electronic spark control) and MAP (manifold absolute pressure) sensor with brackets, knock sensor, and oxygen sensor
Air cleaner spacer w/ valve cover breather tube
Air cleaner assembly including flexible air intake hose
Power brake booster vacuum line/hose
Complete engine wiring harness
ECM engine computer #1227747
Electric fuel pump w/ sending unit
Fuel lines
Nuts & bolts

and will add the fuel tank out of an TBI Suburban for another $40.00

with shippiny to Colorado for everything is ~$500

Can you guys think of anything else I will need right now besides a CCP?

Thanks again for all the help and quick responses!!

I will be putting up pictures of the Blazer soon, as well as the TBI parts when/if I get them.

[rfmaster]

Pancake

Before I did my conversion I put together a spreadsheet with prices for each component. Spreadsheet is all inclusive - as I've captured used and new parts prices. IMHO $400 for a complete TBI setup including aluminum intake is a nice & convenient package, although the same can be done for little bit less provided that you are willing to search JY's. If this is not the case the following questions must be asked before committing to buy:

1) Intake manifold - What is make and model number of this aluminum intake.

2) ECM 1227747 is listed - what the BCC code.

3) Injector part numbers or color codes (did it come of 305 or 350 CID engine)

4) ESC part number.

5) Dizzy - small hat dizzy - confirm.

6) Also confirm that burban tank can fit in your blazer!! I use rockauto.com search engine that has where used feature - very handy when doing swaps.

You can get BOSCH style relay and socket from any worth while auto parts store. Alternatively, look for 80-90 GM cars at you local JY. MY favorite target (very common in So-Cal) are 4.1-4.5-4.9L front wheel drive caddies as they have a bracket with three relays mounted in a row on a driver side strut tower. When poaching harness make sure to get at least 18 to 24" of wire at the socket. These are 30AMP rated relays, just make sure that wires size is about 10-12AWG. You can wire your winch (provided that it does not exceed 30 AMP current limit)

//RF

[pancake]

I will post the #'s as soon as I get them (before buying them).

The dizzy is the small cap type with external coil type.

I belive all thios, except for the tank, is coming of a 1990 2 wheel drive 5.7 liter truck.

I will also get a VSS when I start ordering the stuff for my TBI conversion.

I wish I had more time to look through the yards but I am out of town working Monday-Friday.

All this, except the fuel tank, is coming off the same truck which should make it a little simpler.

As far as the fuel tank fitting my blazer, It should fit fine. The stock tank is gone (clearance issues) and a fuel cell is mounted where the rear seat was. I can put the fuel tank in the "bed" of the blazer.