Harold Of The Rocks

Ok guys. I've narrowed it down. Scuba you've been awsome but I'm still not getting it. Replaced the fuel pump and fuel filter. Still doesn't start up (22re A/T 89 4runner). When I turn the key to ACC and jumper the Fp to B+ I 'hear' the fuel pump working (it's a low hiss, but easily noticable). When I remove the jumper there is no longer the hiss. So, that means (based on previous posts and my reading) that when I bypass the COR relay fuse I get power to the pump. So.... faulty COR relay is the obvious answer no??? However, the EFI relay could also be at fault (based on previous posts) but that is 60 bucks to replace. The funny thing is though I phoned just to get a quote on an EFI fuse and one parts store quoted 130 as it is a rare fuse that they only 'selectively' carry. I'm getting to the end regards of whether the end is at the stealership.

thook

I don't know what the previous posts were, but if the CEL illuminates with the key on the EFI relay is working. Can you hear either relay "click" when you hit the key? Also, have you tested the AFM to see if the circuit tied to the COR is functioning/getting/sending a signal?

sb5walker

The EFI relay can't be bad - that's what supplies juice to the B+ you're using to power the pump.

The COR could be bad, or it could be not receiving triggering from the start signal off the ign switch (during starting) or the fuel pump switch in the vaf meter (while running).

These posts might help:
https://www.yotatech.com/forums/f116.../#post51127605
https://www.yotatech.com/forums/f116.../#post51130411

thook

Exactly....

scuba

I have a COR for sale along with a efi relay as a trail spare..

I helped as much as I could

scope103

Will it start with the jumper in? If not, your problem is elsewhere.

You can stick a voltmeter on the FP diagnostic connector (to ground), and turn the key to Start. You should get 12v as long as the key is turned, and you should continue to get 12v if air is being sucked through the VAF. If you get 12v (meaning the pump should be running), and it still doesn't start, your problem is elsewhere. If it starts and then quickly dies when the key goes to On, check whether the 12v disappears as soon as the key is no longer in Start position. If so, you may have a VAF problem (which provides the signal to keep the fuel pump running as long as air is sucked into the engine).

If you don't get 12v on the diagnostic FP connector when you turn to start, then the fuel pump relay is a likely culprit.

Not to make things more complex, but you have checked that the fuel pump is running, but not that it is pumping fuel anywhere. You can disconnect the fuel return line (it is not a pressure line, so it just has clamps) and put it into a jar. Jumper the fuel pump and assure fuel is coming that far (be careful; you're splashing gasoline all over the place.)

Harold Of The Rocks

I'll try that for sure. And SCUBA, thanks for the offer but I'm outta the way for your COR. The links to sb5walker are awsome, just take time to go through. Anyone have a minor project that turns into major job? My next post is gonna ask who has had a minor tune up turn into a major rebuild!

Harold Of The Rocks

Odd follow up guys, but I'm looking for the fuel return line to test whether my fuel pump (which is getting power) is pushing out fuel. Scope103 suggested I find the fuel return line and test it, but I'm having a hard time figuring out which line it is. There is a roundish canister located on the firewall that has one line going in saying tank but I can't be sure this is the fuel return line to the tank. Anyway, if anyone with a rough picture could post that would be great. I find my Hayes manual useless, but maybe I'm the only one. thanks

harold

thook

That's the tank breather can.....or whatever it's called. (Edit: EVAP can......tech term)

Just go to the fuel filter and pull the line off going to it on the right side as you're facing it. Or, pull the cold start injector off the plenum. Should get fuel from there (on a cold motor) if you're getting fuel. If none there, then you could try at the filter.

Harold Of The Rocks

THOOK, THANKS. Ok, here's the deal. I loosened the right side of my fuel filter as you suggested. I little residual gas came out but nothing major (certainly less than when I changed my filter). I had someone crank it over. No spurting, nothing. Then, I jumpered my Fp B+ at the diagnostic box to make for sure that my pump was getting power (I ensured this yesterday) and tried turning it over again. Nothing, no spurts, no leakage. Now, I'm not sure how much should be coming out, but I didn't see anything coming out? Am I getting closer to nailing down the problem. Basically, I no my pump is getting power but there was nothing pushed to the fuel filter. Very strange. I still think my COR has something to do with it.
harold

4Crawler

iTrader: (3)

You might want to check the voltage at the fuel pump when it is running. If it is too low, like well below 12 volts, the pump may not be getting enough power to run at full pressure.

Harold Of The Rocks

thanks 4crawler. Even if I could get my hands on a multitester, why would a pump suddenly lose the required voltage to operate? Could a poor ground wire (or the lack of a ground wire) cause that significant a drop. I'm in the sticks so those tools are a little hard to come by

4Crawler

iTrader: (3)

I use an inexpensive meter like below (keep it in the glove box):
http://www.harborfreight.com/cpi/cta...emnumber=92020

But yes, the relay contacts could have become pitted or a power or ground wire could have broken or a connection oxidized and any of that could lead to a voltage drop.

Or as an alternative testing procedure, run a temporary power and ground wire to the pump directly from the battery and see if that makes any difference. If yes, then likely you have a voltage problem. If not, then the pump might be acting up. Often the pickup screen can get plugged up and that can lead to low fuel flow.

scuba

Waiting for you to get help with this rodger

Ok, To test the cor, there's some way of jumping 2 of the pins just like your doing on the diag box..I cant seem to recall it though..

4Crawler

iTrader: (3)

See:
- http://www.4crawler.com/4x4/CheapTri...ORelayLocation

scuba

You da man !!

Harold Of The Rocks

The stealership won't be getting my money this time! Thanks yotatech members! The 4runner is alive. 4crawler, I took your advice and tested the pump directly. Nothing. So I tested the old pump that I pulled out. Worked. I might have replaced the wrong pump or bought a dud. I'll be speaking with UAP NAPA tomorrow. So. The pump works only when I jumper the Fp B+ at the diagnostic port. I can hear it plain as day running. However, I can still start the truck without it jumped. Any ideas. When i jumper I can hear it. When I take out my jumper I don't hear it. But, in both instances the truck can start. Strange, but at least it is going and not a 170 dollar relay (I'll be on the hunt for those at the next bone yard.....unless you're travelling through BC Scuba :')

thook

If I understand what you're saying correctly, that's normal. IOW, with the jumper in, you've bypassed everything......as you know. But, when the key's on, the pump only fires for a couple seconds until ignition and the motor starts. So, you may not hear it. I don't on either of my 4rnrs, anymore. I'd had the COR on my '86 rigged to permanently make contact for several years until I installed a new one several months ago. So, with the key on, the pump always ran.......and, you could hear it. Most of what you'd hear is the pump working against the fuel pressure built up in the line since no fuel is being spent.

Harold Of The Rocks

thook, thanks for the claification. It's running like it was previously so a big thanks to you, 4crawler, and Scuba for taking the time to post follow up info. I've learned that in addition to fixing the fuel pump and fuel filter (PITA!@!) that I should certainly carry spare relays with me or, at the very least, carry a multimeter tester as suggested by 4crawler. Wish I could wield tool like you folks, but I'll be happy with completing small projects :')

scuba

I try