Tbi swap build thread

[cjracing15]

Originally Posted by pancake

wow...thanks for the quick responses...

A few more questions:
What is a:
DRAC, KS, Air diverter valve, ESC, and EGRV?

Sorry I am very new at this FI stuff

After further review, I might put an TBI adapter plate on my current manifold instead of changing intake manifolds. What are you thoghts on this?

Where does the Charcoal canister go? Is it in the return line to the fuel tank?

As for the camshaft..It is an Edelbrock R/V cam...very mild...do not have the specs with me but can let you know Friday.


If you recomend a factory harness.....I was looking on e-bay and found the harness, TBI, computer and all sensors off a 89 chevy truck. He also has the fuel tank. I might go this route...I still dont know for sure.. can you explain pros and cons of both??

I will be looking for a stock tbi fuel tank because my fuel cell does not have a return line. I would also like the truck to run when it is on its side, happened 3 times already

The 4x4 does not have to have emissions and is not street driven. What sensors should i get rid of and which ones do I NEED?

If I need to get the computer re-programed who can do this, or do I just order a chip for it?


Thanks again for all this great info and the fast replies. i hope this thread keeps going, it has tons of GREAT info.

P.S. Does anyone here live in Colorado?

I have read that people have had very good luck using adapter plates on there swaps.

The canister goes on the driver side is usually mounted on the fender or core support. Mine has three ports. One goes to the gas tank, one is a vent, and the other goes to the tbi.

If you are going to have to buy one anyway I would go with a howell harness. I used a factory harness becaue I had it already. One from an 89 truck will work you will still need a computer and a distrbutor. Like I said in the other post there is a complete setup on the site right now for sale in the clasified section.

The pro for me on using the factory harness was cost because I had it. Plus once you have to sort all the wires to fit it to your truck you will really get to know how the system works.

The con of course is TIME. It takes time to sort all those wires and then run them in a way that looks good. With the howel harness it is just about plug and play.

You just about need all of the sensors for the system to work like it is suppose to. You can get rid of the egr valve I guess but you will have to get a chip made wiht the egr turned off. But I think you are going to need that done anyway because of your cam.

Then that brings us to the computer and chip. I am useing tbichips.com . Check out that site. This guy is awsome.

Again how about some pics of your truck?

[rfmaster]

Pancake

DRAC - Digital Ratio Adapter Controller http://614streets.com/drac.html Not required if you are using aftermarket inline 2000ppm VSS.
KS - Knock Sensor ( http://www.sae.org/technical/papers/9004 88 )
Air diverter valve - A.I.R. used to control if AIR pump output is diverted into exhaust manifold or bypassed out http://www.freepatentsonline.com/3940928.html
ESC - Electronic Spark Control sends a voltage signal to the ECU. As the knock sensor detects engine knock, the voltage from the ESC module to the ECU drops, and this signals the ECU to retard ignition timing. The ECU will then retard the timing when knock is detected.
EGRV - EGR CONTROL SOLENOID


TBI adapter plate = it's OK, but be aware of possible leaks. For a clean installation on pre-87 heads I use Holley 300-49 Intake manifold (if you have funds).

Used factory harness from a pick your part JY is about $30-40, aftermarket new harness $300+. Factory harness is 20 years old - make sure that wires and connectors are in good shape. I have done couple of these conversions and have a collection of PED weatherpack connectors (Look for a connector kit on EBAY)

OEM GM sensors can outlast the car, but I I would not pay top dollar for them. Cheap is the word when it comes to used.

Gas tanks - you'll have to do a bit of research, but look for a tank of EFI burban (30 gal) that mounts behind axle. EFI tanks have baffles. You'll need 3 port fuel sending unit (and possibly in tank fuel pump, which is better than external)


For best drivability keep all sensors - unless you want to learn how re-program ECM on daily bases. Sensors: O2, MAP, TPS, CTS, and VSS. For off road you can omit AIR. Having CCP costs very little and prevents tank fume build up!

TBIchips can get you a chip - if you get ASDU code ECM it should work close enough to get you going.

//RF

[pancake]

after even more research....what is the deal with the o2 sensors? three wire? four wire? heated? Thanks again for all your help folks

[rfmaster]

If you are running headers - either three wire or four wire is must. You'll need to wire a simple relay controlled circuit to turn heater when ignition is on. Heated O2 provide correct O2 concentration in exhaust gas stream faster than old style single wire O2 sensors.
Optimally, four wire heated O2 provides a ground return wire back to ECM. Exhaust system may not provide low resistance path back to ECM. To avoid ground return loops fourth wire is used. (2x heaters, Gnd return, O2 signal = AFS-74)
In three wire O2 sensor you have 2x heater, O2 signal...

//RF

[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?

[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.

[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