1989 camaro tpi(anything is possible last owner hacked up wires like a champ)

ok guys, I've gone over everything a hundred times, my "hot at all times" wire has no power, Ive traced the my fuel pump relay hot wire to a connection where 4 others meet (3 are relays)and gos down to three, 2 of those go to the ecm, and one goes to some small weird connector near the back drivers side of the engine but its not hooked up (where might that go?) anyway my diagram says this set of wires gets constant power and that there is a fuse in line, but I cant find a break in the line, or the fuse, or where it gets its power, every part of the wire has a start and end, all the loom is off and I can see everything. also near these same wires is a heavy gauge orange wire that at one end goes to the relays near the battery and goes to the fans the other end comes back across the firewall and to the front drivers side into a small fuse plug and at the other side of the plug is a smaller orange wire that goes back up to the fuel pump relay hot wire. I could really use the help I can get pix if need be. Oh btw if I hot wire that fuel pump relay wire everything works and the car starts right up.

 

That "small weird connector" is the fuse. It's a single fuse holder and it confuses almost everybody.
Try that fuse, it might be popped.

Lou

 

the weird connector looks like this, I could be wrong but I dont think thats a fuse, the fuse that is later on down the line is not blown tho, but has no power on either side of the fuse

 

Oh sorry, I thought you meant the weird connector looking thing at the battery, where you traced the wires to. It is usually attached to the fender and has two wires, red and orange (or maybe both orange). That would be your inline fuse for the fuel pump.

Lou

 

see thats the thing, I traced it and it never connects to the battery so thats what im trying to figure out where does it get its power, do you or someone have a picture of how and where it gets its power?? thankds

 

That one you are looking at should go down to where the oil filter is at, it recoginzes when the engine has oil pressure and allows the fuel pump to continue to run, I believe it has to be plugged in to complete the circuit.

 

Oh that's what the connector is, I didn't recognize it at first. Thanks.
Minor correction, though - the connector does not need to be plugged in. It merely serves as a backup circuit to power the fuel pump in case the ECM fails to turn it on via the relay. But both, this switch and the FP relay, get the power from the orange wire that should come from the battery through that inline single fuse. The fuse might have been detached from the fender and tucked away or something, just trace the red and orange wires from the battery, one of them must go to the fuse. You should be able to find it that way, Bob.

Lou

 

Ok thanks guys, Ive got it running still couldn't find that fuse but things have been moved and even just cut off on this car, so I rewired it and put in an inline fuse and it all looks nice and neat now and im back on the road, oh and Ive got that connector hooked back up too, thanks

 

Awesome.

Lou

 

For others that may read this:

Lou, I believe this is wrong. The connector pictured above is for the oil pressure sending unit (OPSU) - it must be plugged in for the FP to run (assuming everything else is correct). The ECM does send a signal to the FP via the FP relay, but thatis only to prime the pump - after priming, the ECM signal is off, and the FP gets it's power solely from the OPSU circuit the entire time the car is running.

Also note that a bad OPSU can make the FP run constantly, even when car is off and key is in your pocket - the FP gets a direct 12v from the OPSU from the battery, regardless of the ECM and relay circuit. I had this happen on my 1992.

 

This discussion has been here before, newbie (sorry, pun not intended ).
I am too lazy to search for it but it's been a few months since the last time this was discussed.

You are absolutely right, the ECM primes the fuel pump through the relay for two seconds after the key is turned on. Then it waits for a pulse signal from the distributor pickup coil and once it detects it (indication that the engine is turning), it activates the pump relay again.

Which means that the OPSU does not need to work for the fuel pump to pump. A great way to test this is to unplug the OPSU and start the car. It will run. (unless the harness has been modified/hacked).

The OPSU is a back up system in case the relay itself fails. It's for getting you home so that you're not stranded on the side of the road due to a failed $8 relay. That's one cool thing GM did right and I applaud them for it.

I hope this post does not give off a mean vibe or something.
Internet is soulless, there is no good way to see the emotion of others.
I'm really not trying to argue with you or start a fight, I just wanted to correct that statement so that others don't get confused when they read this thread and spread the misinformation.

You're also right about the constant-running fuel pump if the OPSU goes bad and shorts out. I had the same happen on my friend's 89 GTA. We simply unplugged it until he could buy a new one and replace it.

Cheers from cold and rainy Texas.
Lou