Burns85

I guys, id say this is the first official post. Ive been creeping for quite some time but have finally been so puzzled I had to join to see what everyone said about my problem. To start, 1991 extra cab, 22re, SAS, FJ60 calipers. I bought the truck about a month ago. Put a new (used, but new to me, and ive heard it run) engine in it and am having a few problems. My EFI (15A, under hood) fuse keeps blowing as soon as I turn the ignition on. After tracing wires for two days I saw a post on here about the O2 censor and how that can cause it to blow. I unplugged the censor and now the fuse doesn't blow, now all I have to do is figure out where it is shorting. Easy enough. Next, my engine wont fire. It has spark (tested and was lucky enough to shock myself), and the battery and starter are new. So is the fuel pump. I have tested the pump directly from the battery and it primes the lines and works. When I use the ignition it doesn't kick on. I don't know why, and thought that it had to do with the fuse blowing (except it should still start without an O2 censor) until I read another thread on here. Long story short, anyone know what the pump wont kick on? Ive traced wired for 2 days trying to find a break or short, and today went over all the grounds in my engine bay and still nothing. Help would be greatly appreciated. Thanks

Burns85

and I did search for quite some. I found some similar threads but nothing exactly the same. They did help me diagnose my problems though

Burns85

would the "circuit opening relay" be the fuel pump relay? that aside, where would this relay be located?

Burns85

okay, so I jumped the B+ and Fp and the pump kicks on. Does that mean the relay is the problem? I am hoping that from here I can buy a new relay and be hunky dory, is this true? It didnt fire though. I am guessing that this has to do with the O2 sensor at this point. Given the engine hasn't actually fired in a while and the battery has been off of it so it doesn't remember much. Thanks, you have helped me more than you know, i was ready to break something

shaeff

Most common problem for the EFI fuse popping is o2 sensor wires melted and grounding out. Check all around the exhaust, etc... for melted wires.

Blue_petersen77

That was the culprit with mine a while back. I also tied it up so it couldn't fall back and cause the problem again.

Burns85

UPDATE: Pulled the o2 sensor cables and the fuse doesnt pop. That is solved for now. Engine still wont start. We have spark at the coil, and cylinders, and I jumped the relay for the fuel pump with the diagnostic box. Have pressure at the fuel rail and at the intake manifold. Switched out the fuel pressure regulator but it still wont run. It will start and then die out after about a second or two, almost like it isn't getting gas. We have tried everything. All electrical connections are good. grounds are good. Tank has gas. We have come to conclude that it may be the ECU. I bought the truck without it running knowing it needed a new engine. The truck has definetly been "used" and mudded so i am guessing it may have gotten wet or something. I was going to check the injectors with a node light but havnt yet. Any ideas? all fuses are good, firing order is good. I have never been so puzzled trying to get one of these engines to start. I have had three friends come over who are mechanically knowledgable and we are stumped. ECU?

JamesD

Make sure you have the intake boot on and no hoses going to it disconnected. I have seen many people overlook this before.

James

Burns85

its tight, both at the efi manifold and the air box.

Burns85

I did, the Fp and B+. I just got a new open circuit relay (i think, 12v relay above ECM) so maybe that will help. I stil have the O2 sensor unplugged because the harness going to it needs some help (EFI fuse blows).

Burns85

with the jumper in it still doesn't start. It will start for about a second, then it dies. Even hitting the throttle doesn't help. It is almost like it floods out withing the first rotation of the engine. REAL frustrating. I really really dont want to but I may end up having to tow it to a shop. I am completley dumbfounded to why it wont start. Any chance you know some symptoms of a bad ECM? that may be the problem

Burns85

the tank was pretty much empty, sat for about two maybe three weeks and I put three gallons of fresh gas in it. New fuel pump, strainer, and filter.

Burns85

UPDATE: Sprry, ive been at school so I havent been able to do much. Still havent gotten it started. Bought a new open circuit relay (tested mine and it was blown), ive decided to not worry about the O2 sensor for now. Symptoms:cranks, has spark (to distributor, and to plugs), had gas to fuel rail, and EFI manifold. Replaced the Fuel pressure regulator with one known to work. Dont have any node lights to tell for sure but i placed a screw driver to the injectors and had a friend crank it. No sound or ticking came from them so it seems like they arent letting any fuel get through. What could cause this? any other ideas would be great. I dont have any shops to take it to (local go-to place is moving shops right now, and the other is booked full for three weeks), i am kind of starting to get depressed.

Burns85

just read this:https://www.yotatech.com/forums/f116...d-help-184650/ so im thinking ECU, hoefully that works

sam333

You must be getting some codes. Are you getting a code 14.
Unless you have a heated 02 sensor there is no power on that wire and you would have to have some serious shorts in your wiring to have the 02 sensor blow a fuse when hooked up.

quiggs12

Did you check to make sure your cold start injector? Check to see if there is power coming from the start injector time switch when you are craking it over.

When you pulled the plugs what did they look like (pull them after trying to start the truck)?

Burns85

idk if i am getting codes, i dont have a scan tool or anything. Just basic hand tool and my garage (im 20 at my parents house, you know, college). The wireing to the O2 sensor is absolutely SHOT. it is chaffed and cracked and warn all the way up to the main harness so i plan to re-wire it in the next few days. It is about 15 degrees out so that doesn't help much as far as motivation.
I havent checked for power to my cold start injector. And as far as plugs, i havent pulled them in a while. I replaced them before putting the new engine in. Cant remember what the old plugs looked like. The engine I got ran great (heard it run, rev, and all that fun stuff). So i kow it is something to do with the truck, bought the truck not running.

4Crawler

iTrader: (3)

I'll wager you do have a scan tool:
- http://www.4crawler.com/4x4/CheapTri...CheckConnector

Might have one in your desk drawer:

quiggs12

Check the codes as 4Crawler has provided you with insight for the most affordable scan tool going. Then PULL YOUR PLUGS! That will give you some insight to what is going on... And you still need to check if you have power to your cold start injector (while cranking). Good luck!

runnermedic

first,the efi fuse is blowing becuase a melted wire in the o2 sensor
and second did you verify the vafm,probably a wire or piece of metal is off or broken inside the vafm,check all soldered points in it and measure each terminal before and after reapair,and last a big vac leak,check every vac hose or cracks in the intake manifold