JTNKTZ

iTrader: (10)

Alright, this is going to be long so brace yourselves. I am 17 so taking my car to the shop will not be an option as I have NO money. I am good with my hands and can do pretty much anything (did my own top end job already).

I bought a 1989 vert RS with a supposedly 350 TBI in it, which I doubt because car doesn't have nearly as much pick up as my 91 (350 TBI/700R4). The guy I bought it off was a tweaker. Anyway my wiring is pretty much all screwed up.

The guy had a 12v constant STUCK into the orange wire on the fuel pump relay. Later I found out that that orange wire supplyed the ECM with power along with the fuel pump. I checked the volts on the orange wire and nothing so I tried tracing it back but couldn't do it. I checked the fuse next to the battery holder and it was fine. I cut a little splice in the wire and it was in fact getting 12v after the fuse so I taped it up and continued following it and it led to inside the passenger side then lost it.
So I just put a 12v constant together with the orange wires and put it on a switch because after the car shut down the fuel pump would NOT shut off.

About a week later the fuel pump would not turn on, so I spliced the tan-white wire (Wire going to the fuel pump) and added it to the 12v cons, orange wire hook up. After this happened while driving my car it would run perfect. When you really stepped on it though SOMETIMES it would act VERY funny. It would choke, jump, bog down and it would loose power instantly. You would floor it and it would get very loud and the temp will start going up quickly. It would barely get passed 3k RPMs. Almost like it was running very lean. But if you shut it off then restart it, it would run PERFECT again.

So that worked till 12 AM last night when my car completely shut down while doing 40 miles an hour. I tired starting it but the battery was dead. So after not even 10 seconds before it started it was dead?When Idle my car is at or above 13v. So I rolled it up a little hill and tried popping the clutch and it did not start. Sat there for like 10 mins tried it again and it started right up. Continued driving for 10 mins then it shut down again so I thought I was out of gas. I got gas and filled it up. Started right up and started heading home. then it shut down again. By this time it was 1 AM and I just called AAA to bring it home. I got home and went to sleep.

Now this morning the battery died. I don't know why but it dies on me everyday with a brand new battery. Had the alternator checked at autozone and they said everything was fine with it. So I guess there is a leak somewhere. But when I rev the car up before I shut it down to about 5k RPMs then shut it down it will start fine next time. Just in case I park it on a hill so I can pop the clutch (I have gotten VERY good at it). :P

So I jumped it this morning and ran perfect. So I started driving it up and down my street for a while. After about 10-15 mins it finally bogged down like it was lean. Pulled over and got codes 24 and 43. This is knock sensor. Now I may be wrong but that should not shut the car down would it? The other code I don't know where to begin with, it's a speedo problem and is the least of my worries right now as my speedo works fine.

Started driving it more and then and bout 5 mins later boom it did it again, this time I was paying attention better. The car died completely. The tach went STRAIGHT to 0 but if I hit the gas it sounded like it was still started, but now thinking back it might have been because the car was still in gear. Pulled over tried to start it and nothing. I wasn't on a hill so I got my other car to jump it. Wouldn't start at first. Waited 5 mins jumped it then it started. Unplugged cable and it shut down 30 seconds after. Now I jumped it again and this time it died before I could gety out of the car to disconnect the cables. So I waited even longer and this time it started it and was able to get it into my drive way. And here I am now!

Now, I was just looking at a ECM diagram I found and saw that it goes to a backup fuel pump oil pressure. Now, I have noticed that my oil pressure has been bouncing around to the point that it was all the way to the right. Maybe oil pressure sender is bad and caused it to shut off the fuel pump? Someone told me to check the green wire (Fuel pump relay control) to see if it had 12v for 2 seconds when turning the ignition so it would prime and it would not send it. It will not even send it when the car is running.

Alright so here are my questions:

1. How do I trace this orange 12v wire from the battery that controls the ECM and the fuel pump? Should I just run a new wire right but then again I have that down with that 12v constant hook up. I would rather get the original orange wire working.

2. With just the orange wire and the 12v constant hooked up why did the fuel pump stay on even though the car was shut off?

3. What problem would cause all these systems of bogging down and loosing performance causing overheating but is able to run perfect if restarted instantly?

4. Why does my battery keep dying on me!!!

5. Why does the car shut off then not start unless waited on?

6. Where can I find the back up fuel pump oil pressure thing? Why does my oil pressure bounce up and down?

7. Why doesn't my fuel pump control wire get any current throught it?

PLEASE HELP! I HAVE FALLEN AND CAN'T GET UP!!!

Also included, very very very helpful wiring diagram of the ECM so you can follow what I am trying to say.

I have replaced the fuel pump, fuel pump relay and the fuel filter.

Atilla the Fun

I got lost in all that, so at the risk of insulting your intelligence, let me share a few things. First, you can't connect anything to constant hot unless you include a fuse and a switch. Otherwise you drain the battery, and possibly ruin whatever you connected to constant hot. If you connect a fuel pump directly to a constant hot, the pump will run until the battery is dead. Do this enough, and you'll kill the pump. What you want is ignition hot. Ignition hot, with a fuse, is good for things like fuel pumps and electric fans.
The knock sensor is a common issue with TBI V8s, and it'll pull timing, which hurts power and builds heat. Running lean also builds heat.
If you heat-soak your starter, it doesn't crank like it does when it's cool.
The car was built to kill the fuel pump if the engine loses all oil pressure.

Justin1989

Wow this is just like what mine is doing. However mine is an automatic. Today I picked up a new high performance fuel pump and I'm working on installing it. I can almost guarantee it is something to do with your fuel pump. They will run for about an hour (or less) and shut off from overheating, and gradually get worse and worse until they quit altogether. If this is the case for you you're either going to have to:

A. Drop fuel tank, this means dropping axle & cutting exhaust
B. Cut a hole over your fuel tank and install a fuel pump access door

Good luck, let me know what it is when you figure it out!

Ca[maro]88

iTrader: (2)

yeah like what Atilla said, if its constant hot then your battery will die, sooo that COULD be one of the reasons why its dying. so id say make your fuel pump wire go into your fuse box (radio fuse will work) and then see how it runs.

if that doesnt work (if it was ME) id honestly pull of the TBI stuff and put in a carb and a painless wiring kit. only reason i would do that is cause its very simple, because there isnt any sensors controlling it, and because its easy to work with. but if you really wanna fix this thing, i say good luck.

rgarcia63

First do a search for better electrical diagrams on this board, or on the web, I know I have posted them, but I can only attach them once.

The 20amp fuse in the fuse holder by the battery supplies all of the equipment needed for the engine to run i.e, ECM, fuel pump, relays ..etc. if you have 12v at the fuel pump relay you should have 12v at the ECM. To check for 12v at the pump you must have the meter, or light probe connected before turning the key to on because the relay will time out in a few seconds if the ecm doesn't see any distributor pulses. Check the fuel pump relay out of circuit, or use the bypass in the ALDL Connector to supply 12v to the fuel pump. if it's good then leave it out until you find the problem. If the oil pressure switch/gauge sensor isn't working it should have no effect on starting (it doesn't kill an engine with no oil pressure) unless the fuel pump relay is working for whatever reason.
The fuel pump is controlled by the ECM so don't try to work around it.
Use a manual pressure gauge to check actual oil pressure if it's ok continue troubleshooting the pump otherwise fix the oil pressure problem first because at this point fuel pressure is the least of you worries.
You can only work one problem at a time, oil pressure is the most critical.
Get r done, then post back to go on to the next step.

JTNKTZ

iTrader: (10)

I guess what I wrote was too long as everything everyone has said I have explained but that's okay. It's long but let me explain:

You didn't insult my intelligence. The "constant" is on a 30a switch with a 20a fuse just like the one next to the battery. The fuel pump did not shut off after i turned the ignition off so I added the fuel pump tan wire onto that same switch. I like my switch idea because it is hidden so it is an added theft protection. The knock sensor MAY explain the bogging down BUT I think the car is lacking fuel delivery, which causing it to be lean because if I am right more air less fuel causes lean where as less air and more fuel causes rich. Even when the starter is hot it should be able to turn over. I have never gone passed 230 degrees in my car, and under those circumstances the starter should not be having any problem turning it over for at least 5-10 seconds. I now understand this oil pressure cut off but my question is is where is the sender and/or what do I replace to get rid of this option?


Already replaced with a Walbro 155 lph. Before you start dropping everything and such I would replace the fuel pump relay!!!



Honestly, I am having WAY too much trouble with this damn TBI and that is what it is coming down too. How much for a cheap set-up would it cost to achieve this? By that I mean intake to the air cleaner.


Fuse is fine. BUT there is not 12v constant at the orange wire on the fuel pump NOR the ECM so that is why I added the a 12v constant on a switch. It is on a switch because if you shut the car down it will not shut the fuel pump off thus draining my battery. The fuel pump has been replaced and works fine. I tested this using the tan wire from the fuel pump relay. The green wire, fuel pump relay control wire does NOT get 12v for 2 seconds as a prime. I have a funny feeling this is the problem but no one has been able to explain to me what could cause this!!! My oil pressure has been acting funny lately by that I mean go all the way to the right.

Where can I find the oil pressure sender?

86camaro383

iTrader: (3)

in the back of the block, or right above the oil filter.

JTNKTZ

iTrader: (10)

Alright I will replace that tomorrow. Any other ideas?

freebird87

230degrees would definitely heat your starter thats your problem my tpi 305 does that when it hits 220 which is not good for the engine atilla is right you have a parasitic load on the battery a constant should never be used on a fuel pump etc that would be the load and i don't know if i under stand but does your ecm still have power from the orange wire if not that could be your shutting down problem and also vapor lock could cause the shutting off of the car 230degrees will do that for you i have also had that problem.

Thirdgen Ranch

iTrader: (5)

If you can't get it running after trying some of the things people have suggested I would recommend changing out the dash harness if it's all butchered up. Some cars have had the harness so messed up that it's best to just put a new harness in and get everything set up the way it's supposed to be. It's always a nightmare trying to figure out somebody else's wiring mess. If you decide to go that route, let us know and we can probably get you a harness.

freebird87

agreed

JTNKTZ

iTrader: (10)

Alright so, I have I figured out the orange wire (fuse box was faulty). So now I have 12v to the orange but I am still having the same problem. Now, the fuel pump relay control wire from my understanding is supposed to get 12v's for 2 seconds when the ignition is turned to on but this is not happening. So why isn't it getting 12v? I am thinking my computer is dead but I want to get rid of all possibilities.

rgarcia63

Do you have 12v at the orange wire of the fuel pump relay?
Observe what you hear, feel, and see when the key is turn to on momentarily then, off.

Disconnect the ECM and perform the above step again if it acts then same then the ECM isn't getting 12v, or it's dead.

It gets 12v from same source the pump relays does if, you don't have 12v there you won't have it at the ECM.

JTNKTZ

iTrader: (10)

12v at Org on relay yes. Here is an exact make up of what happens.

• When key position is OFF the green/white wire (green/white wire on Fuel pump Relay [FPR] also called the fuel pump control wire) reads .00v

• When you turn key to ON it goes to .6v, .7v then .10v for approximately 2 seconds then drops to .07v.

• Fan is on, Check Engine Light is on, Brake light is on, volts read a little above 13v (Truck is jumpered with it cause my battery was dead)

• When cranking the green/white wire goes to .11v for 1 second then gradually drops down to .06v.

• Cranked for 5 seconds and the car did not start, FP is on.

• Turn key to OFF and fuel pump (FP) remains on.

• Tan/white wire (incoming fuel pump input wire) stays at 12v and the computer and FPR.

• Red wire on FPR has 12v

• Unplug FPR and red wire no longer has 12v, tan/white and orange wire still has 12v and green/white still does not have 12v, FP is still ON.

• Plug FPR in and red, orange and tan has 12v green does not.

• Unplug orange wires' fuse and everything turns to 0v.

• Plug back in and everything but orange remains 0v.

JTNKTZ

iTrader: (10)

Bump

Justin1989

It turns out my problem was definately the fuel pump. It's all good now.

JTNKTZ

iTrader: (10)

Sweet. Good name btw. JTN= Justin. :P
And I have an 89 too!

Anyone have any more opinions?

PV9685

What about the parasitic electric drain? I assume it's still there? I was guessing a fuel pump issue aswell, my Cavvy had a very similar problem but I sold the car cause I didnt want to risk a new pump and dropping the tank.

If you have a day or so that you're not using the car, I suggest you document what fuses go where, and pull them all. Then you can see if the drain is from a fused circuit.... or something bad. At least if it is from a fused circuit you can use an ammeter in the fuse box and find which circuit is killing your battery. BTW, even if your alternator and battery are good, if your battery cables are bad you will have charging system problems. And potentially kill your alternator.