Tbi swap build thread

[rfmaster]

AC-Delco AFS-75 wire - functional chart

BLUE SIGNAL + ( D7 )
WHITE SIGNAL - ( D6 )
BLACK HEATER
BLACK HEATER

O2 heater draws about 3-4 Amps when cold and drops down as O2 reaches 300C operating temperature. I set up a simple relay circuit that energizes heater whenever ignition is ON. FWIW in modern cars PCM monitors current drawn by the heater circuit. Once current reaches a certain lower limit (some) PCM will shut down heater circuit as PCM logic deems O2 is fully functional, only periodically checking to make certain. PCM will also shut it down at WOT. I have seen numerous explanations why it is done, but for the sake of our application keeping heater circuit that is always ON solves cold header problem that otherwise plagues single wire O2s.

//RF

[pancake]

Thank you Jamie and RF...

Is this correct:

02 sensor:

One black wire from 02 sensor to ground
One black wire to pin # 87 on relay (purp/blk 10 or 12 AWG)

Relay:

Relay is just like the one in post #219

Pin #86 to ground (blk/yellow 16 or 19 AWG)
Pin #30 to battery w/ 10amp fuse (red 10 or 12 AWG)
Pin #87 to 02 sensor (purp/blk 10 or 12 AWG)
Pin #85 To ingtion hot (brown 16 or 18 AWG)

Also, I do have an aftermarket VSS. The instructions said to ground the vss to the computer. Do I need to do this or ground it to the tranny/t-case/frame?

"A-6 is switched 12volts from Ignition relay" so A6 should only be hot when ingition is on?

Is the stock power wire for the hei dizzy brown with a single white clip on it?

Thanks again for all the help and answering my amature questions

If I am lucky, it will be running next weekend.

[68 TT]

Originally Posted by pancake

Thank you Jamie and RF...

Is this correct:

02 sensor:

One black wire from 02 sensor to ground
One black wire to pin # 87 on relay (purp/blk 10 or 12 AWG)

Relay:

Relay is just like the one in post #219

Pin #86 to ground (blk/yellow 16 or 19 AWG)
Pin #30 to battery w/ 10amp fuse (red 10 or 12 AWG)
Pin #87 to 02 sensor (purp/blk 10 or 12 AWG)
Pin #85 To ingtion hot (brown 16 or 18 AWG)

Also, I do have an aftermarket VSS. The instructions said to ground the vss to the computer. Do I need to do this or ground it to the tranny/t-case/frame?

Thanks again for all the help and answering my amature questions

If I am lucky, it will be running next weekend.

If you run pin #85 on the relay to an output pin on the fuel pump relay it will keep you from overheating the oxygen sensor when the ignition is on but the engine is not running (like when checking codes). The heater will then be turned off when the pump is powered down by the ECM.

[rfmaster]

68 TT has a very good suggestion for a heated O2 circuit! All other connections look reasonable.

Regarding VSS - you can ground one of the two VSS leads at trany. The problem you are relying on ground straps to complete ground return back to ECM. From experience it is usually not a problem provided that all ground straps are in place and you do not have a rust problem.

Good luck tomorrow - let us know!
//RF

[pancake]

Thanks 68TT for the sugestion.

Can you please tell me what # pin is the output on the fuel pump relay?

I had to replace a MAF sensor on the wifes car, 2002 Pontiac GP, and will be doing a beering/hub assembly, because of a broken ABS wire, Saturday. Hope to get the fuel tank in and the rest of the power and 02 sensor wired Sunday.

I still have to weld a 02 bung into the header....It is getting close.

I hope others are pulling some good info from this thread.

If I read correctly, this is Jamie's first build thread, It is a good one.

Thanks again

[pancake]

Getting closer....

Had to order a new sender for the fuel tank, I had a sender for a 40gal tank and I put in a 25gal tank...sender did not fit

Wired the VSS and SES light along with the ADAL connector.

I pulled the header off today to have the 02 sensor bung welded in.

I still have a question on wiring the 02 sensor

What color is the wire for the output pin on the fuel pump relay?

I would like to wire my 02 sensor how 68TT recomended but do not know what wire from the fuel pump relay to attach to pin #85 on the 02 sensor relay.

I should have the Blazer running next weekend....waiting on parts.

Thanks again for the help

[rfmaster]

Originally Posted by pancake

Getting closer....

I still have a question on wiring the 02 sensor

What color is the wire for the output pin on the fuel pump relay?

I would like to wire my 02 sensor how 68TT recomended but do not know what wire from the fuel pump relay to attach to pin #85 on the 02 sensor relay.

I should have the Blazer running next weekend....waiting on parts.

Thanks again for the help

Pancake

See circuit diagram below that should answer your wiring questions.
//RF

[pancake]

yes...that answers all my questions....Thank you.

[bumslie75]

Wow great one this has helped tons thanks guys

[pancake]

Ok...the wiring is done. I bought a digital voltmeter and played with the relays to figure out how they work.

All I am waiting on now is a sending unit for my 25gal tank and I will be ready to fire it up

Does anyone know of a good place to find fuel line? The stuff for high-pressure systems is like $60.00 for 10 feet of 3/8". I need like 25 feet...

I do have to use the high-pressure line right?

Thanks again and I will keep you updated

[68 TT]

Originally Posted by pancake

Ok...the wiring is done. I bought a digital voltmeter and played with the relays to figure out how they work.

All I am waiting on now is a sending unit for my 25gal tank and I will be ready to fire it up

Does anyone know of a good place to find fuel line? The stuff for high-pressure systems is like $60.00 for 10 feet of 3/8". I need like 25 feet...

I do have to use the high-pressure line right?

Thanks again and I will keep you updated

I use the anodized aluminum fuel line from Russell. 25-ft roll is about $30 and it looks really cool too.

Just a few flex points needed with some short lengths of rubber or braided hose. The rest can be hard line that is much cheaper.

[68 TT]

The red anodized line looks great with the blue fittings but where they are hidden from view you can use much less expensive steel AN fittings.

[rfmaster]

During my conversion I bought a 25' roll of summit 3/8" aluminum tubing with wall thickness of 0.035 - rated for fuel service (SUM-G2538). This stuff is more than enough for common automotive EFI applications. Since they do not mention which Aluminum alloy is used for this tubing, as a point of reference, a 5050-0 temper aluminum tubing with 0.035 wall thickness is used on a large number of light aircraft for wheel brake and gear retract hydraulic systems, and fuel systems and has a yield pressure rating of about 2400 pSI.

When working with aluminum tubing use bending tools to achieve correct bend radius and prevent tubing collapse.

//RF

[mcbassin]

On our tbi project I used the 50psi rated hose from autozone. It was around $4 a ft I think.

[ironroad9c1]

Originally Posted by mcbassin

On our tbi project I used the 50psi rated hose from autozone. It was around $4 a ft I think.

Yea, tbi is only about 15psi MAX so about anything is fine.

[pancake]

Ok...i found the 3/8" aluminum tubing at summit and Jegs...and it is much cheaper than rubber hose.

Question:

Do I need to get an assortment on AN fittings to connect rubber hose to aluminum tubing and then to the fittings on the TBI and fuel tank....

or....can I flare the old supply and return lines and clamp it to the rubber tubing and clamp the rubber tubing to the aluminum tubing?

Option two would be less expensive but would it be safe?

The last thing I want is to be stranded on the mountain or have a fuel line break and start a fire


Thanks again.....Pancake

[rfmaster]

To connect rubber hose (SAE 30R7, 30R9) to 3/8" AL tubing you need to 'bead' AL tubing. This is a must since there is nothing to keep rubber hose from sliding of the end of the AL tubing, but a bead will keep it in place. Forming a bead is easy with a right tool. If you are planning to work only with 3/8" tubing than Earl's EZ-BEADER will produces a correct bead per SAE requirements. Look for Earl's part number 008ERL which is designed to bead 3/8" tubing.

If you are planning to do other tube diameters you can purchase additional EZ-EADERs from Earl or go with professional (pricey, but very nice) ATS Tube Beading Kit. I hate to admit, but I am a tool freak. Sorry, it is a weakness

As far as safety is concerned. Fuel supply line must be built to withstand up to 50 PSI. The reason for this is that most TBI service rated pumps are capable of 20 to 40 PSI deadhead. Fuel supply must be either AL tuning (0.035 is good) or -6 size braided fuel line. I used both in my conversion since I had -6 line on hand and later I picked up the spool of 3/8" AL tubing.

Beading tool is a must if you plan to attach 3/8" rubber hose to a fuel line. Otherwise plan to spend on -6AN adapters and hose ends.

//RF

[pancake]

ok....I can get a tubing beader for the AL tubing...but what about the steel hard tubing that is stock on the TBI and fuel sending unit? Can I just flare this tubing so the rubber hose does not slip off?

[rfmaster]

EARLS should be able to handle AL and soft steel used for OE fuel system, but not SS tubing.

//RF

[pancake]

IT LIVES....


Got the truck started today..

It runs but not very well....

It is putting out two codes:

Code 44 and code 42

Code 42 is interminted....sometimes it will show...sometimes it wont.

Code 44 is constant

I did set the timing at 0 TDC with the pin unpluged..

It will idel up then down then up then down ect...and it is backfiring through the exaust.

The injectors also seem to be makin a loud clicking noise...almost like the sound a bad lifter makes. Don't know if this is related.

Any input would help...thanks again for all the help.

[rfmaster]

Pancake

Congratulations!

Code 42 is very annoying and sometimes difficult to solve. This is a good write up on code 42 troubleshooting.
http://www.asashop.org/autoinc/may97/techtips.htm. Also, code 42 will be set when you disconnect EST to set timing. To clear disconnect bat for about 20 sec to clear codes (but you know this).

Code 44 indicates lean mixture. There are numerous reasons for code 44, but I would check fuel pressure first to make sure that you are not starving - i.e. 13 PSI and higher. Cold O2 sensor is another reason, but you have a heated unit. Vacuum leaks, stuck IAC motor are known to set code 44.

Injectors are known to be noisy - check out my video on YouTube.

//RF

[pancake]

I think code 42 was set when I set the timing! It has not come back since then.

I did buy a TBI rebuild kit and installed it tonight...still no difference in performance. I though it could be the fuel regulator from what I have read on the net.

I forgot to mention : the first time I ever started it one of the injectors was not squirting fuel. I tapped on it with a wrench and it started to work.

Could a bad/dirty injector be the problem? I did replace the small screen filter and o-ring on the base of the injector when I did the rebuild.

I did buy a new fuel pump and sending unit along with new feed and return line.

I will buy a pressure gauge to test the fuel pressure...but I don't think that is the issue...could be wrong. Can anyone recomond a fuel pressure tester?

I will keep you posted on the results and please keep the ideas coming

[cjracing15]

Auto zone (at least in my home town) has a press tester for tbi you can rent.

The problem you describe sounds like the one I had when I first started mine. WHat I found was a a pinched rubber fuel line.

Congatulatoins on at least getting it started.
Good Luck, Jamie

[rfmaster]

Originally Posted by pancake

I forgot to mention : the first time I ever started it one of the injectors was not squirting fuel. I tapped on it with a wrench and it started to work.

Could a bad/dirty injector be the problem? I did replace the small screen filter and o-ring on the base of the injector when I did the rebuild.


I will keep you posted on the results and please keep the ideas coming

TBI injectors are not known to fail often, but when gummed up with old fuel residue will stop squirting fuel. Ultrasonic cleaner and replacing screens usually does the trick. A stuck injector may cause lean condition. Dirty injector may cause rolling idle condition as ECM tries to compensate for unstable fuel delivery.

Yes, TBI fuel pressure test set should be available from any parts house. Ideally you want to see fuel pressure at all times - just incorporate fuel pressure gauge into your fuel system with a T. First things first. Check and verify.

Going to Pomona swap tomorrow.

//RF

[68 TT]

The early CPI 4.3's (91 to 95) have a cool fitting in the back of the intake that can easily be adapted to become a TBI fuel pressure gauge port.

Comes with Schrader valve fuel pressure test fitting and female inlet threads to match the fuel inlet line and a barbed fitting on the other side.

I haven't used it yet but I am going to have the local hydraulic shop solder on a -06 male fitting to make it easy to integrate into the fuel supply line.

I planned on tapping the threads in the fuel pod for standard pipe threads so I can use -06 AN fittings on the throttle body and route the test port to where it is easily accessible. From my measurements it looks like 1/4" pipe and 3/8" pipe threads are just about a match for the metric fitting openings.