Multiple Misfires, Chasing Cause

[satchel]

Do you have access to your FSM for the electrical troubleshooting? If not, I believe this should be yours. https://static1.squarespace.com/sta...442806549877/1996+Toyota+Land+Cruiser+EWD.pdf

It sounds like you had a problem, and bypassed it, and now that the bypass isn't working either you probably now have two problems.

I'm assuming you no longer have power across pin 2 and 4 of the efi relay since that was previously letting you start the truck but now it isn't. If you do not have power at pin 2 of the relay, then I would check to see if you have power at the efi fuse, and if not, check the fusible link that supplies it. Once you get power going back across that relay you can work on the actual issue of why you don't have power activating the relay itself, or if the relay is bad.

 

[Tools R Us]

Often wiring problems are intermittent, can be fun to find. In this case, likely in the yellow/red circuit (between the EFI relay and ECU), using a DVOM or test light, with the key to run and the CEL off, do you have power at the B+ term in the diagnostic connector? If no, do you have power at the single wire (yellow/red) connector near the distributor?

The harness should be supported to the motor, often the clips break, if the harness is allowed to jump around, long term, supported by the connectors, is very hard on connections. Power interruptions to the ECU will cause various running problems, but also should reset codes, having a miss and stored P030x codes points to more than one problem.

The last two we repaired, had injector connector or pigtail problems. Found by listening to the injector with a stethoscope, should have an even click, if it goes silent with the miss, have found the problem area. Often can wiggle, flex the pigtail/connector going to that injector and cause it to run, then miss, confirming that it is wire or connector. The recent ones were earlier 1FZ, they seem to have this problem more commonly, but have seen it on OBD2 motors.

 

[CRMSCLE]

Thanks everyone for the insight! Was finally able to get back out and re-check for power throughout the circuit.
EFI relay and EFI fuse both have power, but the yellow/red wire in the distributor plug is no longer showing power with key to On and CEL off. The last time I checked this was registering power, so my assumption is that my intermittent short is somewhere between the EFI relay and the distributor. I tried wiggling the loom near the EGR pipe to see if I could get the CEL to trigger, to no avail.
Still need to dig in and try to find any damage there; is there anywhere else I can start to trace if that's not the problem area?

 

[Tools R Us]

Thanks everyone for the insight! Was finally able to get back out and re-check for power throughout the circuit.
EFI relay and EFI fuse both have power, but the yellow/red wire in the distributor plug is no longer showing power with key to On and CEL off. The last time I checked this was registering power, so my assumption is that my intermittent short is somewhere between the EFI relay and the distributor. I tried wiggling the loom near the EGR pipe to see if I could get the CEL to trigger, to no avail.
Still need to dig in and try to find any damage there; is there anywhere else I can start to trace if that's not the problem area?

So, the power goes, from the fusible link to the EFI fuse, to term #2 of the EFI relay, when the relay closes (key to run), goes out on term #4 powering the yellow/red circuit. The first connection on that circuit is the EB1 by the distributor. If there is no power at the input (fender well) side of EB1 with the key to run, the relay isn't closing, is bad, or there is a bad connection. When the key is switched off - run - off, does the relay click, every time it's switched? IIRC, there is no connector or splice between relay term #4 and EB1, should have continuity.

If there is no power at EB1, the harness by the EGR is irrelevant.

 

[CRMSCLE]

Thanks Tools R Us.
EB1 is registering power on the input side, and the relay clicks in sequence with the key. So I've at least got continuity through that part of the harness. Earlier in my digging I had checked the actual distributor harness and registered power in it, but now I do not. CEL still doesn't illuminate at "ON" key position

 

[CRMSCLE]

Satchel, thanks so much for that FSM, I'm doing my best to decipher it and determine where to dig to find my short, but I'm learning as I go so I'm sorry if it feels like talking to a wall

 

[CRMSCLE]

I've ordered new fusible links from Wits End to be safe, and new battery terminals since mine are extremely corroded, but I have power to every fuse and relay under the hood and the dash, as well as to B+ terminal and EB1 near the distributor. I'm going to check again that the ECU is still receiving power, but assuming it is the only other thing I can think of is a bad ECU.
Beyond that, I might have to bite the bullet and tow this thing to a shop

 

[Tedward]

Maybe someone will sell or just loan you an ecu.

 

[CRMSCLE]

Yeah I found a Tampa Area Group on here I just reached out on; looks like I can get an ECU on ebay for $100-150 so hopefully I can test with a good one and find out prior to getting one.

 

[satchel]

I'd check the input voltages, at the very least the top portions regarding power, on page 66 of that link I provided. You should be able to do so with the connectors attached to the ECU.

 

[CRMSCLE]

Thanks satchel, I'll look into that first

 

[CRMSCLE]

Guys, my ECM went out. Does anybody have a source for remanufactured ECMs for a 95 1fzfe?
I'd rather go through mud than Ebay

 

[Tedward]

Classifieds on Mud. Parts or parting out section. I'd send ya one but I wont be home for some time.

I used to look at an online JunkYard site that shows parts from junkyards all over the country. Many for sale on whatever site that is. Has part numbers of the ecu for sale as well as price.
You can an ecu from 95-97. Look up the paper number for those years to make sure ya get a 95-7

 

[CRMSCLE]

I'm still stuck dealing with this issue and I don't know where else to go.
I ended up towing it to a shop who's owner drives an 80 and has a good reputation for electrical issues. In about 3 hours they called and told me the ECU was bad, as they were able to knock it a bit and get the truck to fire up 3 times. I got a refurb ECU on ebay and installed, and I can't get anything.
With either computer, no matter what I do I can't get my CEL to illuminate, but they're adamant they got it fired up and it must be a loose solder point in the ECU.
I've got +12v all the way to the IGSW wire on the E7 plug for the ECU, (plus all fuses, EFI relay, B+ terminal on passenger firewall, and brand new fusible links) and they swear they got it started but I can't believe BOTH of these ECUs are faulty (if even one is).
I'm at the point where I'll have to send it with both ECUs back to them because I think they're wrong, but I am no where near good enough electrically to know where to look from here..

 

[CRMSCLE]

Good news: no start issue has been solved.

Embarrassing news: the issue was a very mildly broken clip in the harness; hidden behind the "cooler stabilizer amplifier" (whatever that is) was a male and female clip in the wiring harness that was plugged in but had been broken so it couldn't 'snap' in as designed. It was just loose enough to not make constant contact but close enough that jimmying the ecu/wiring caused it to connect, hence our misdiagnosis. Clip replaced, truck starts every time now.

Bad(ish) news: I was optimistically hoping this was somehow also the cause of my persistent misfire but alas, not so lucky. Now she's running at least, but I'm back to trying to find the cause of all my misfires