TBI wiring questions

[Shua57]

I was able to get my TBI engine started over the weekend but I had to use several jumper wires to get juice to the fuel injectors. The motor is a 1989 350 TBI made for a Chevy van (G10 or G20?) with the stock wiring harness (PO did a little modifying). After trying to start the car several times, I realized the injectors was not firing. Me and my dad jumped a hot wire from the fuse box to the hot side of the injectors, injectors started firing. So my thought is somewhere along the pnk/blk (hots to the injectors, it is red at the injectors:confused:) the fused power is not connected to the wires. I think that is correct but please correct me if I am wrong.
Next problem is the fuel pump. I finally got it to operate but there is a problem. It will not shut of unless the key is turned off. What should happen is when the key is turned to the run position, the pump should come on and prime the fuel system for 2 seconds. But it just stays on. I know this will be difficult to solve without being by the car but I will try to explain how we wired it. Basically I used my fuel pump hot from the fuse box to supply power to the computer. Fuel pump relay was reconnected and the "Hot fuel in" was connected. We got nothing so we jumped power to the "Hot Fuel In" pnk/blk (power to the fuel pump) and Bam!!. The pump started working. We ended up rewiring the pink black to IGN hot to get it to turn on. So the problem is probably the pump is staying hot all the time and I need to rewire it but I don't understand why the pnk/blk is not hot.....wait, I wonder if the pnk/blk for the fuel pump and the pnk/blk for the injectors are suppose to be on the same fused hot. That may be why neither is working....hmmmm. i'll have to check that out. The power to the injectors and the "Hot Fuel In" is suppose to be fused power, right?
Last question, where can you get the light sockets for the dash?

I forgot to also ask, When the injectors are firing now, I am getting a huge curtain of fuel spraying in. Would that be caused by the nuetral/park switch not being hooked up or something else not hooked up?
Josh

[557B210]

Jason...Sorry I can't be of much help on this one....However, I'll be following along, as I want to do the TBI set-up with mine....Maybe a Holley Prjection set-up would be a consideration for me

[chevman57]

Josh sorry to hear of the wiring problems. I had a harness built for mine and it works great. Wiring is not my thing.

David you can use a stock TBI with no problem. Just get a harness built for your car for that system.
Terry

[Old Buzzard]

"I forgot to also ask, When the injectors are firing now, I am getting a huge curtain of fuel spraying in. Would that be caused by the nuetral/park switch not being hooked up or something else not hooked up?"
If the engine is running, the injs will appear to be constantly on. However, they are pulsing. As for the volume, remember there's only either 2 or 4 injs doing what 8 will do in a port injection system.

Pump on all the time tells me that you have bypassed the ecm control of the FP relay.

[Shua57]

"I forgot to also ask, When the injectors are firing now, I am getting a huge curtain of fuel spraying in. Would that be caused by the nuetral/park switch not being hooked up or something else not hooked up?"
If the engine is running, the injs will appear to be constantly on. However, they are pulsing. As for the volume, remember there's only either 2 or 4 injs doing what 8 will do in a port injection system.

Pump on all the time tells me that you have bypassed the ecm control of the FP relay.

You can see the injectors pulsing when the car is running. At cranking the injectors spit a small amount of full, as soon as the car starts the injectors look like they open full throttle which fills my garage with smoke from the excessive fuel. I've heard that if the nuetral/park switch is not hooked up then the computer can not tell the IAC to idle down and you get a high idle issue. I almost have the switch wired in so I'll give that a try.
As for the fuel pump, I believe I have the ECM bypassed as well. I could not get the pump to come on without bypassing it. I need to figure out why I do not have power to the fuel pump through the ECM. I just have something wired wrong.
JOsh

[D.S.]

Do you have a wiring diagram ?

[Shua57]

Yeah, I have about 4. I have been looking at themway too much, I think I am starting to understand them...lol.
Josh

[acardon]

Josh, the diagram I have (which is not a van, but I think they used the same wiring colors) shows a dark green wire #465 operateing the coil of the fuel pump relay and a blk/white wire #450 which is a common ground.
The injector is powered by a pink/black wire # 439 that is a switched 12 volts. A blue wire fires the injector on wire #467. I think the red wire on the injector ties into the pink/blk wire someplace in the harness. Normally red is always hot 12 volts and pink/black is switched 12 volts.
The picture of your diagram you posted earlier is too small to read. If you look at the #'s next to the ECM you will see the pin numbers that that wire goes to, and can check the wire for continuity from one end back to the computer plug. I have had broken wires where several wires are spliced together in the harness such as wire 439 goes to a lot of different places.

[Shua57]

Don, I was hoping you would chime in. I was able to get the injectors to fire by running a all time hot to the red wires on the injectors. So somewhere there is a hot connection not connected. I'll just have to trace it down. My computer is a 1227747. Looking at a diagram for that computer I see a orange wire that comes from "battery" pin at the ECM feeds power to the oil pressure switch. A pnk/blk comes from the oil pressure switch and splits to the fuel pump relay and a 20A fuse. Then from the fuse it changes to a tan/blk wire to the fuel pump. I think instead of that fuse my motor has a "Hot In fuel" relay/switch like the 88-89 GM-C/K wiring schematic. On the 88-89 diagram A6 (pnk/blk) runs to a hot in start or run 10A fuse that finds its way from the fuse to the injectors. I don't know why my harness seems to have pieces of several different schematics. I am just trying to figure out where I need to hook power to. I do believe that whatever I have hooked up wrong is also causing the fuel pump to stay on when the key is in run when it is suppose to run for 2 seconds and turn off just to prime the fuel system. You are just going to have to PM me your phone number so I can call you and you can walk me through it:D:D:D.
Josh

[D.S.]

This is van wiring diagram, if I put it where you can get to it...

http://www.box.net/shared/bza4q533i6

[carls 56]

congrats on the eng. starting up :tu sorry about the wiring tbls :o

[Shua57]

New update, I got the pump lined out. It comes on for 2 seconds and then turns off till I turn to start. The problem is that I have lost the injectors. I only have power at the injectors if i run a hot to the pnk/black wires that run to the red wires on the injectors but I can not get them to fire. It seems I am not getting the pulse from the distributor to fire them. When I turn the key to run the fuel pump kicks on the I turn it to start and watch the injectors and they do not fire. When I let the key return to run I see the injector fire. When I test the hot at the injectors I have 12V and when I am starting the car it drops to about 9V. I have power to the dizzy but am not getting power to the "Hot Fuel Module". If I jumper the pnk/blk on the Hot Fuel Module the fuel pump will not shut off in the run position. The pump actually sounds like it downshifts. I have read that the Hot Fuel Module can cause fires. How do I remove it from the harness and why am I not receiving a pulse from the ECM?
Josh

[acardon]

Does the ignition have power? Are the plugs firing? The ECM needs to see ignition pulses before it fires the injectors. That's the way the ECM knows the engine is turning.

[Shua57]

Don, the pick up coil does have power and would assume the ignition module gets its power from the ignition coil. I see on the diagram Dave sent to me that the PPL-WHT 430 wire is the distrubutor Referencing Pulse In to the ECM. I wonder if there is any way to check the wire during "Start". I hope I have not fried something.
Another question is why is the hot from the Hot Fuel Module going to the Alternator? Is there a reason behind this or can it be ran to a fused hot? Also what does it mean by ECM 1 Fuse and ECM 2 Fuse? Does it just refer to fused hots at the fuse box?
Getting power to everything seems to be the easy part. I just can't seem to figure out the injectors not firing. They were firing when we bypassed the oil switch, fuel pump relay and I guess the Hot Fuel Mod. I have read alot of post on this subject but none ever give the solution. Some say bad injectors - my injectors work. I can get power to everything but just no pulse from the ECM to fire the injectors. I do understand the ECM basically has to see the motor is turning I just don't know how. Maybe the crank Input? I am just at a loss. I stink at wiring.
Josh

[D.S.]

Just a thought, but you are using an ignition switch that sends power to the ignition in the run and start positions aren't you... Or at least a wire from the solenoid to keep it all hot while cranking...

[Shua57]

Yes, I am using the original switch and I even used a jumper off the switch to power everything the first time I had it started. I had the wires tied to the IGN of the stock switch. It does make me wonder why the voltage drops at starting. I'll have to double check to make sure the switch is still good. It is 50 plus years old but I do have a new one on the way.
Josh

[D.S.]

The condition of the battery and the amps the starter draws will lower the voltage when cranking...

[acardon]

Yes, I am using the original switch and I even used a jumper off the switch to power everything the first time I had it started. I had the wires tied to the IGN of the stock switch. It does make me wonder why the voltage drops at starting. I'll have to double check to make sure the switch is still good. It is 50 plus years old but I do have a new one on the way.
Josh

Dave may be onto something.
The original ignition switch on a 57 does not provide power to the ignition terminal while starting. The "R" terminal of the starter solenoid provided the power.

Some aftermarket switches will provide power in start and run but the original did not.

ECM fuse 1 & 2 are different power inputs to the computer and other things. I think ECM fuse 2 is constant power to hold up memory and fuse 1 is switched power.

[Shua57]

Battery is new and starter is new. Voltage drops from 12 to 8 when it start.

A few things I am going to check tonight:
1. Spark - it obviously had spark when it started but I will double check it to make sure the coil did not burn up.
2. Grounds - I checked the ECM grounds on the block last night but will check them again. I have one ground strap from the engine to the frame and need to add the body to frame ground. I bought 3 ground straps just to make sure:D.
3. Ignition switch - I become suspect of the ignition switch due to it dropping voltage to the injectors. It may have started to go bad being so old. Gene is sending me a new lock set. I had the injectors powered off a 4-way connector tied to the IGN side of the switch to make sure power was being sent.
4. ECM hot - I need to make sure the constant hot is constant. It seems to be but things I thought would be switch hot ended up being constant hot at the fuse box.
5. Hots - I need to verify the oil switch and the fuel pump relay are fused hots. They seem to be as they are working properly.
6. Ignition Module Test - it seems I can disconnect the 4 wire connector from the distr., turn the switch to on and momentarely supply a 12V power to the ECM pulse wire and get the injectors to fire. If they do then the ignition module is bad.
7. I need to double check that power is running in and out of the oil switch and fuel pump relay. It seems to be. I've checked it several times.

I think my fuel pump problem has been solved, it's the injectors that are throwing me off. Either something is wrong in the ignition area or I still have a wiring problem. Oh what fun this is:D. Thankfully it is to cold here today to finish spraying the fender (which I will have to scuff and respray with color before clearing - thanks weather). I need to figure this out so I can continue assemblying the car.
Josh

[Shua57]

Dave may be onto something.
The original ignition switch on a 57 does not provide power to the ignition terminal while starting. The "R" terminal of the starter solenoid provided the power.

Some aftermarket switches will provide power in start and run but the original did not.

ECM fuse 1 & 2 are different power inputs to the computer and other things. I think ECM fuse 2 is constant power to hold up memory and fuse 1 is switched power.

That is interesting. I had power before, maybe the switch was messed up. I'll check it out. Thanks
Josh

[acardon]

Another question is why is the hot from the Hot Fuel Module going to the Alternator? Is there a reason behind this or can it be ran to a fused hot? Josh

I don't know what the Hot Fuel Module does either??? :confused: You need to find out where on the alternator the pnk/blk wire goes. The 89 had a CS130 alternator which has a 4 pin plug. It may use one of these terminals to indicate that the engine is running.

[Shua57]

I don't know what the Hot Fuel Module does either??? :confused: You need to find out where on the alternator the pnk/blk wire goes. The 89 had a CS130 alternator which has a 4 pin plug. It may use one of these terminals to indicate that the engine is running.

It is a CS130 altenator and has the 4 pin connector with 3 wires. The heavy gauge wire mounts on the back of the alt. where the hot wire comes in. The wire next to it goes to keyed hot with a warning light or 3 watt resistor. The third wire is a sensing wire that will be tied into the big wire/hots. I have no idea were the pnk/blk could tie into it. My guess would be the 1st small wire that runs to keyed hot. Thinking about it though, if it is a constant hot then maybe it should go to the alt. power/hots?
Josh

[D.S.]

All the pink/blk wires I see either go to the ecm1 fuse or the alt, looks like they have power at all times...

Here is alt wiring, pink/blk to alt is hot in run and start...

http://www.box.net/shared/b7cu3ugkic

Start circuit if needed...

http://www.box.net/shared/huojpgxm1l

[Shua57]

Dave could you email those to me. My company is still bloxing www.box.net, sorry.
Josh

[Shua57]

I did trick the internet security system to let me get the Alt wiring. I can't get the start. wiring. It caught on the my tricks. That is basically the way I plan to wire the alt. I am guessing the pnk/blk from the Hot Fuel Module will get tied into the fused hot shown as pnk/blk in the diagram. All my wires are black which means it is a generic connector.
Josh

[D.S.]

E-mail sent... :)

[Shua57]

Thanks again Dave. those are some nice diagrams.
I may have to take the whole wiring harness apart but really just didn't/don't have the time but........
Josh

[acardon]

Thanks again Dave. those are some nice diagrams.
I may have to take the whole wiring harness apart but really just didn't/don't have the time but........
Josh


If your getting power through the switch while cranking, that "crank input" on C9 may be what you need. Connect it into the purple wire to the "S" terminal of the starter.

[Shua57]

That is possible. I'll give it a try. Thanks
Josh

[Shua57]

Okay, I'll try to remember what we did to get it to fire up. We did several test and wire configurations. We tried wiring injectors to the IGN side of the key switch. We got power to the injectors but they still were not firing. So we jumped wire from the power to the injectors (pnk/blk) to the EGR sol. (pnk/blk) and what we thought was the Hot Fuel Module (pnk/blk). Well, when we hit the key, the fuel pump came on and then downshifted like it was getting half power when it should not be getting power at all. So I disconnected the Hot Fuel Module. Fired right up and purred like a kitten....great, right? wrong. So we made all the connections because we had most of the wires loosely connected. Turned the key to start, injectors not firing. How can that be, we left it the same way it was and just added the connectors to the wires. So we cut it back apart, hooked it back up and the fuel pump was staying on again......odd. Back to the wiring diagram, hmm, the Hot Fuel Module gets power from the alternator. Let's hook it to the alternator. Tried the hot.....fuel pump ran all the time.....tried the excitor wire...same thing....Brain starts chewing the info....What if the Hot Fuel only needs to be seen during Start. Let's hook it to the solinoid so it will only get power during motor start. First we had to find the wire, for some reason it was tied into the EGR Sol. which means it was not getting any power unless we jumped power from the injectors. Some how the EGR Sol. wire and one of the 2 pnk/blk wires tied into the injectors got switch. We knew the Hot Fuel Module was not getting power we just did not know why. We hooked everything back up, turned the key, fuel sprays, motor fires up:tu:D. It wouldn't idle but I could rev it and keep it running. I would say the timing is off and it is having to try to adjust it to far. At initial cranking there is alot of fuel going in but once it hits the fuel curtain thins down. I believe once everything has been tied in and the timing is reset then it should idle out fine. I have to pick up some max fuses or some inline fuses to tire all the wires I have running from run and/or start. I still can not figure out the alternator. It is a 3 wire (4 prong) connector CS130 alternator. I hook the big wire to the alternator post that the battery wire comes into. The first small wire goes to the excitor wire from the fuse box and i can't seem to attach the thirs wire anywhere. If I attach it to the post on the alt. the excitor stays on all the time. If I hook it to the excitor wire the excitor only stays on during "run - start". Very confusing as is all of this wiring stuff. I'm sure I do not have it all wired up the stock way but it is working right now (if I can get it to idle). I just had a thought, I wonder if I can tie the pnk/blk wire into the crank wire from the distributor...hmm. I need a power supply that is only on when the motor is turning. I guess that is why the hot fuel module ran to the alternator. Because the alt. only pushed out juice when it was running. That may be why the car doesn't want to idle - it's not getting any juice after the power to the solinoid is stopped. Any thoughts?
Josh
Josh

[D.S.]

Found this info on the hot fuel module, you might not need it...

The 20-second primes on some trucks is from an add-on module. It is known as the hot fuel restart module (or something close to that). Wired in parallel to the fuel pump relay and oil pressure switch, it is a simple timer and high side transister to provide power to the fuel pump.


Hot Fuel Modules were common in Fullsize Vans and 3/4+ ton trucks through 1992. In 1993 with the PCM controlled fuel pump prime, it was deleted. FWIW, I would take the Hot Fuel Module off of ANY vehicle so equipped. Word of experience here as I have had TWO of them short out! The 2nd time it almost caused a FIRE!

Found this article that describes a common problem with the module and it's function...


GENERAL MOTORS
TRUCK & VANS W/
THROTTLE BODY
INJECTION-5.7L
HEAVY DUTY, 7.4L
ENGS.- KEEP
RUNNING WHEN
THE KEY IS OFF
These vehicles may exhibit this
symptom intermittently, or it may be a
consistent problem. The problem may be
the Hot Fuel Handling Module. This
module is usually located near the ECM.
Its purpose is to extend the normal two
second fuel pump prime to twenty
seconds in order to eliminate vapor lock
during high temperature operation.
This module has three wires. The first
wire is a black wire with a white stripe,
which is a ground. The second wire is
usually a pink wire with a black stripe.
This wire supplies battery power
while the key is in the "On" position
through the gauge fuse. The third wire is
either: tan, tan with a white stripe, or
gray, which leads to the fuel pump
(refer to diagram #6).
What happens to create this problem
is that when the ignition key is turned
off, the fuel module will create a short
from the pink wire to the tan or gray
wire. When this happens, power is
supplied backward through the gauge
fuse. In this situation, not only does the
fuel pump run, every thing that's connected
to that tan or gray wire will
receive power. The result: the vehicle
keeps running. A quick way to check this
is to remove the gauge fuse to see if the
vehicle shuts off. If it does, you've
discovered the problem. Not all vehicles
equipped with the 5.7L engines are
equipped with the fuel control module.
Only those that are considered for heavyduty
use receive this feature.
John Rogers–Domestic Specialist

[Shua57]

I have read most of that. How do you remove it?
Josh

[Shua57]

I guess, from reading around, that you just unhook it but some reason, when I unhook it, the injectors stop firing. I'm not sure what is wired wrong.
Josh

[Shua57]

After fixing it and had it running for several weeks the problem has returned. After hooking up a crank wire I cannot get the injectors to fire so it is back at it.
Josh