Tbi swap build thread

[rfmaster]

Originally Posted by cjracing15

Not done yet I have run into a little problem with it. I have had it running and it ran great but for some reason It has stopped gitting fuel to the injectors and since I have went backed to work I have not had any time to get back and check anything. It has a brand new pump in the tank so I don't know why it has quit but I HOPE to get back to it Sat. If I can stop having to running calls long enuff. I am a hvac thec for a rather large contractor for this area and we have been swamped with calls since I got back. (Globlal Warming my A**.) This is the coldest it has been around here in at least five years.

Anyway I will have an update when I get time to work on it. Thanks for asking. ,Jamie

You can verify that FP is functioning couple of ways.

1) When you cycle ignition key from off to run ECM goes through a POST routine during which FP relay is energized for about 2-3 seconds (you shouls be able to hear it run) and subsequently turn off. If all other test check out SES goes from solid - blinks off and turns back on solid until engine starts (after cranking). During cranking FP should be energized.

It is rare, but 7747 ECM have been know to loose FP relay circuit driver transistor (2N2907 ) when FP relay is shorted to ground.

2)To verify if FP is functional you can force FP relay into a test operation via bypass, fuel system prime pig tail at the FP relay socket.

[cjracing15]

Originally Posted by rfmaster

You can verify that FP is functioning couple of ways.

1) When you cycle ignition key from off to run ECM goes through a POST routine during which FP relay is energized for about 2-3 seconds (you shouls be able to hear it run) and subsequently turn off. If all other test check out SES goes from solid - blinks off and turns back on solid until engine starts (after cranking). During cranking FP should be energized.

It is rare, but 7747 ECM have been know to loose FP relay circuit driver transistor (2N2907 ) when FP relay is shorted to ground.

2)To verify if FP is functional you can force FP relay into a test operation via bypass, fuel system prime pig tail at the FP relay socket.

Well the Fuel pump is running. I get gas up to the throtle body on the supply line but it just spits gas out the injector. I can pour gas in the tb and it will run untill it runs out of gas???

[rfmaster]

Gas to TB is good. If injectors are not spraying during cranking there are couple of possible problems.

1) Disconnect both injectors from harness. Check the +B (red and green???) injector wire - it should be +12 when ignition key is on and during cranking.

2) If you have +12V on red wire reconnect injectors, get a +12 volt low current test light (or fast DVM). Probe both injector pins (red and green and red and blue - colors are typical, but maybe different) - red should be a steady +12, while the other side should pulse on-off-on during cranking. No pulse indicates that's ECM is not pulling line low. There are couple of possibilities.


//RF

[bigtruck81]

could also use some injector noid lights.

[408cuda]

Hi guys. Found this site after extensively searching the web on TBI swaps and it seems like a great source of info. I am in the process of converting a friends 59 Chevy Apache pickup from a straight 6 to 350 TBI out of an 88 Chevy 2wd pickup. We are using the donor rigs wiring harness. Anyway, I have the mounts fabbed and engine in and and getting close to trying to wire it up. We stripped the harness and all sensors from the donor but the part I am having trouble understanding is what exactly I need to power up for wires from the harness? I plan to add a 6 lug fuse block just for this purpose. I have some wiring diagrams that are helpful, but don't know what wires I NEED hooked to the fuse block, or elsewhere? We are using the 5 speed manual from donor as well and since we are using the stock wiring do I need to do anything to work the VSS? . For a gas tank we were thinking of an 88 Blazer which dimensionally looks doable, and takes the same pump/wiring etc..

Thanks for your time,
Chad

[cjracing15]

Originally Posted by 408cuda

Hi guys. Found this site after extensively searching the web on TBI swaps and it seems like a great source of info. I am in the process of converting a friends 59 Chevy Apache pickup from a straight 6 to 350 TBI out of an 88 Chevy 2wd pickup. We are using the donor rigs wiring harness. Anyway, I have the mounts fabbed and engine in and and getting close to trying to wire it up. We stripped the harness and all sensors from the donor but the part I am having trouble understanding is what exactly I need to power up for wires from the harness? I plan to add a 6 lug fuse block just for this purpose. I have some wiring diagrams that are helpful, but don't know what wires I NEED hooked to the fuse block, or elsewhere? We are using the 5 speed manual from donor as well and since we are using the stock wiring do I need to do anything to work the VSS? . For a gas tank we were thinking of an 88 Blazer which dimensionally looks doable, and takes the same pump/wiring etc..

Thanks for your time,
Chad

Go back to the first page of this thread. It's not a diagram but a list of wire colors and what they do in the harness. If you use the stock harness you will have to strip all if the harness tape off and trace the wires down. It's not that hard. Good luck if you have any questions just ask.
Jamie

[408cuda]

Sorry for the dumb questions guys. I looked the thread over again start to finish and it covers most of all of it, great info! I have been reading about it so much my mind is numb. Anyway, I have a wiring schematic for a 90 that seems to be pretty accurate to our 88 that has helped. We stripped the harness down today and unloaded the known unnecessary wiring but....

Wires/connectors I am unsure of at the moment:

Two wire connector that dumped at the front of the engine by the temp sender. Pink/black (splices into A6 IIRC) and brown I believe. Was this for air pump or something? Doesn't appear to have been hooked up anytime recently. I don't think it's AC related, looks like a different connector.

Tan 18g wire that went into the cab at the bulkhead under the master cyl. Dumps near the dstrib. Don't think it was hooked on donor.

2nd purple single wire O2 sensor connector on pass side. Ditch or keep for future?

VSS wires coming from bulkhead to trans, purple and yellow I believe. Where do I hook these? I assume coming from near the fuse box at least one is powered? Not sure what I need to do being a 5 spd, and wires sound different than most I have read.

Neutral safety wires also go into bulkhead and not ecm. If I remember right the colors were blue, and green. I'm guessing one must have went to the clutch pedal somehow?

Lastly, there is a large red 12 or 10g wire that plugs in near the ECM under the dash. Goes to the gauges and power strip? needed?

So if I understand correctly all I need from the 3rd (white in my case) connector near the ECM is the diagnostic port wires, orange, white/black (data) black/white (ground) red fuel pump test wire, and brown/white SES wire (one side to a 12v light, other grounded) Am I on the right track?

We have the 747 ECM, 88 1500 truck harness, and 5 speed manual. I don't have the service manual yet (I know) but think we can get it going off what I have dug up.

Also curious if I should wire in a 3-wire o2 sensor while it's easy to do or should I even bother? Engine does have headers and I remember reading a TBI source that recommended upgrading sensors when using headers. I know single wire o2's are slow but if the 3 wire is a waste on the older FI system we'll leave it be.

Thanks in advance! Sorry for the laundry list of dumb questions.

[pancake]

Sorry forgot about the ADAL connector wire questions:


A blk/wht is a ground?
B to A9?
C brn wire is for the Air Divirter? What should I do with it?
E to A8?
F Lt brn/Blk....Where does it go?
H whith wire...Where does it go..looks like it attaches to a few more white wires.

Thanks again