SOLVED: What is this part behind the ECU? (Eventual AFM issue)

[MustangOwl]

Still navigating a cranks, no starts, CEL does not light up on ignition issue… but as I tried a new ECU (didn’t work), I saw the below in the pic. Can anyone identify what this filter looking thing is? I was under the impression the 62 didn’t have a cabin air filter. If anyone has any insight, it would be much appreciated. Thank y’all!

 

[Dubs2017]

That is the interior air duct. If you work the exterior/interior air control lever on the hvac panel you’ll see it open and close to change from interior to exterior air. The foam is on the door, and can be scraped off and replaced along with a few other doors in the section of the hvac controlling the dash/floor/defrost.

This is the interior of the other section.

And this is the interior of the flap you’re looking at.

 

[MustangOwl]

That is the interior air duct. If you work the exterior/interior air control lever on the hvac panel you’ll see it open and close to change from interior to exterior air. The foam is on the door, and can be scraped off and replaced along with a few other doors in the section of the hvac controlling the dash/floor/defrost.

This is the interior of the other section.
View attachment 3405594

And this is the interior of the flap you’re looking at.
View attachment 3405601

Oh wow! Any idea what kind of foam / filter to use to replace it? THANK YOU!

 

[MustangOwl]

if you dont have a DMM, buy one but not a cheap one. You need to test the Vcc wire and ground wire on the ECU. That is the keep-alive memory wires and possibly it also powers other parts of the board. Check ignition wire for voltage going into Ecu. Wait LOL check the fuses first, connectors "remove and reset" no start? no MIL light on the dash? then probe the power and ground and ignition wires into ECU. if no ignition power into ecu, check at the ignition switch.

Awesome insight. I’ve got a great DMM. I’ll run through these checks this week. Thank you!

 

[diesellibrarian]

There are many reasons why your truck might crank and not start. Of these, a failed ECU is the least likely.

Do you have a copy of the service manual? It contains diagnostic decision trees that will help you work your way through the possible causes of your no start issue.

I also suggest putting your questions in a single thread. That way, you can track your progress and the people who are trying to help can see everything you've tried so far.

 

[diesellibrarian]

yes there are reasons BUT, no MIL?? that is bad news unless the bulb is burned out. He can do a quick test buying a can of ether or starting fluid and pray some in the intake to see if it starts. IF not, then the ignition is not powered for some reason and if it does not have a fuse which is unlikely, he needs to check the distributor's pick-up signal or from the crank sensor and cam sensor going into the ECU. perhaps the Crank pickup sensor is bad? he needs to have it scanned for codes. I think that would be the first quick check is scan for codes, and then verify with a DMM. Also, do you know of his truck ECM hasa run-on limp mode electronics if he disables the crank sensor? I know they are common on GM cars. GM has a EEPROM chip where the chip has a mapped default mode voltage it sends to the processor to similar for sample, a TPS sensor. ITs not perfect voltage so a loss of some performance will be noticeable.

Dude, you're leading the poor guy down the garden path. If you don't know anything about these engines, hold off on giving advice lol.

There are no crank sensors on this truck. There are no cam sensors.

Spraying starter fluid into the intake is a very crude way to get no real answers on what's happening.

 

[diesellibrarian]

The fact that you work on many cars doesn't mean you know about this car.

There is no timing belt on these engines.

I strongly advise against smashing the fuel tank with a large rock. That's just a wild thing to say lol.

 

[Spook50]

The fact that you work on many cars doesn't mean you know about this car.

There is no timing belt on these engines.

I strongly advise against smashing the fuel tank with a large rock. That's just a wild thing to say lol.

Also to add: the fuel pump doesn't "pre charge" to pressurize the fuel system on these vehicles. Until the ignition system is actually operating and the ECU is detecting spark via the IGT signal line (which grounds via the igniter at each time the coil discharges to fire a cylinder), the fuel pump does NOT run.

 

[MustangOwl]

To answer some questions (sorry, work has been CRAZY!):

We’ve got an 89 FSM to go along with my 1990 FJ62.

When I bought it, she ran and got about 5 mpg’s, so we knew there was something amiss. Shortly after, my wife was driving it, she died, and threw a CEL code for the TPS sensor. We replaced the sensor (that SUCKED! ), cleaned the throttle body, cleaned the starter injector, and cleaned the valve cover.

At this point, the car would crank, start, idle, then choke and die. No codes.

We suspected a vacuum link and replaced all the rubber and the plenum. Problem not solved.

We removed the EGR and did a full de-smog to eliminate any vacuum leak possibilities. Problem not solved, but when it cranked and idled, it was way smoother and the exhaust was cleaner.

We replaced the charcoal canister and fuel filter, problem not solved.

We replaced the O2 sensors with whatever Rock Auto spec’d for the vehicle (1990 FJ62), the old ones were burned up. Problem not solved.

Finally, I replaced the pump (we had the part, so why not). Pump functions great, we hear it turn on when the key is in ACC ON mode. And then…. SHE STARTED RIGHT UP AND RAN!

We drove her around a bit for 2 days. And then the RPM’s would flash drop to 0 and then fire back up while driving. This happened for 2-3 short drives, but she would start right back up. Then…. She died…. And cranks and does not start.

The CEL does NOT come on when the key is in the ACC ON mode.

This led me to check the EFI and COR relays (all test fine; I’ve got a good DMM). I followed the trees in the FSM and it said I either have a ground issue or ECU issue. So I hard-wired to a new ground from the ECU to see if that would solve anything (it didn’t). Then I found an ECU, swapped it, and still nothing changed.

CURRENT ISSUE: Cranks, no start, no CEL when the key is in the ACC ON mode.

Last month I checked to see if she threw any CEL codes, and she did not. I will check again. But I am majorly banging my head against a wall here. ANY ADVICE IS MORE THAN WELCOME! I’ll even promise Rain to anyone here along the Texas gulf coast… I just won’t promise when it’ll come

Thanks in advance!

PS when we bought it, I could change oil and filters and that was it. So it truly has been a wonderful learning experience. But I’m ready to stop learning and start driving!!

 

[ChaserFJ60]

First thing todo is getting that CEL on with the key on engine off, Make sure the bulb is good.
Its strange that it ran rough like that and died. Make sure your battery terminals are clean and secure, If you can pull or twist a terminal with your hands then their too loose. Every 3 months it seems I have to go and re-tighten my terminals as they're cheap and get loose and cause weird issues. When you test for codes do you get any blinking, it should blink continuously if there are no codes if i remember correctly. also routine maintenance could do wonders here, Replace the spark plugs, check the distributor timing, replace spark plug wires, check the air filter.

seeing that your engine ran with a new fuel pump would make me want to look into possible fuel line issues, is the pressure regulator working well, is the fuel damper in working order, are there any clogs in the line? these are all relatively easy to check.

Also checking for codes in this ECU wont tell you if a sensor is 100% faulty or why your engine is running rough, To my understanding they only tell you if a sensor is completely disconnected or not.

 

[MustangOwl]

First thing todo is getting that CEL on with the key on engine off, Make sure the bulb is good.
Its strange that it ran rough like that and died. Make sure your battery terminals are clean and secure, If you can pull or twist a terminal with your hands then their too loose. Every 3 months it seems I have to go and re-tighten my terminals as they're cheap and get loose and cause weird issues. When you test for codes do you get any blinking, it should blink continuously if there are no codes if i remember correctly. also routine maintenance could do wonders here, Replace the spark plugs, check the distributor timing, replace spark plug wires, check the air filter.

seeing that your engine ran with a new fuel pump would make me want to look into possible fuel line issues, is the pressure regulator working well, is the fuel damper in working order, are there any clogs in the line? these are all relatively easy to check.

Also checking for codes in this ECU wont tell you if a sensor is 100% faulty or why your engine is running rough, To my understanding they only tell you if a sensor is completely disconnected or not.

I checked the CEL bulb (I think the FSM had a procedure to check…?), and it WORKS.

Battery is a new Red Top, so it’s terminals are awesome.

The last time I checked for codes, it was clear (blinked continuously).

I’ve replaced the sparks. By the way, the FSM has a TWO measurements for plugs; that was fun to find. So I simply replaced them with the same gap as the ones it had.

Air filter is good.

I’ve got new plug wires and just haven’t yet done the swap, so I will do that asap. I also have replaced the Fuel Pressure Regulator but not the Damper. I can swap that out as well. I’ve got a replacement that I ordered from Rock Auto a while back.

The no CEL on ACC ON makes me wonder about an electrical issue…?

THANK YOU!

 

[ChaserFJ60]

@MustangOwl Here's from the FSM

 

[AussieHJCruza]

Dude @The Analyst - please stop clogging this thread with non-cruiser specific diagnostics info.
1) If CEL isn't on with the key in the on position, engine not running, there is no power to the ECU. This needs to be fixed before anything else will happen. If the CEL is on with the key in the on/run position, move on to the next thing.
2) Land Cruisers do not prime the fuel system when the ignition is turned to 'on'
3) engine needs fuel, compression, spark to run. Troubleshoot each one of these things individually and you'll find the problem.

 

[AussieHJCruza]

You don't need to teach me the basics of Automotive Diagnostics I was a Automotive technician for almost eight years and was a tech on almost all makes and model vehicles.
It was harder than today as ODBI/II scanners were more primitive than today. I do have an older Snapon Solus pro but without a "live" not processed Scope, it makes it a bit of a challenge to double verify the actual sensor is bad. Chasser, can you show the schematic of the fuel circuit?

The majority of our work is pre OBD vehicles so perhaps we have different approaches, but in any case regardless of your experience, generic troubleshooting advice that is generally not relevant to the vehicle in question isn't helping the resolution of the OP's issues.

 

[Dubs2017]

Oh wow! Any idea what kind of foam / filter to use to replace it? THANK YOU!

I used closed cell foam ordered from amazon for the flaps, along with window foam from home depot for the ducting connections. Not too many pics of my re-foam, as there are a bunch of threads with pics here already. Here is a list if you want to tackle it.

FJ60 gets an EROD and NV4500 - https://forum.ih8mud.com/threads/fj60-gets-an-erod-and-nv4500.1256329/post-14167082

Heater and AC system re-foam. What types work and where - https://forum.ih8mud.com/threads/heater-and-ac-system-re-foam-what-types-work-and-where.1001794/

heater core swap ? / FJ60 1986 version - https://forum.ih8mud.com/threads/heater-core-swap-fj60-1986-version.1138888/page-3

Builds - Hygge's Sawdust FJ62 - https://forum.ih8mud.com/threads/hygges-sawdust-fj62.1062300/post-12176169

And good luck with your no-start. I went through a very similar diagnostic rabbit hole with my 3FE a few years ago (did much the same as you... TPS, fuel pump and filter, cleaning all the items in the efi section of the FSM, etc.), and it ended up being an intermittent issue with the distributer. Pretty sure I finally narrowed it down by doing the test on page IG-7 of the FSM: "Inspection of Distributer" #2 when it wouldn't start.

This is a good thread to reference for 3FE diagnostic, if you haven't found it already.

Also, never too early to start planning for the next step.

Cheers.

 

[MrMacdugal]

This might help you get there as well. @jonheld is the man

General Tech - 3FE EFI Diagnostics

3FE EFI Diagnostics updated for 2020

forum.ih8mud.com

 

[jonheld]

I quickly skimmed through this thread. Couple of corrections regarding the 3FE.

The fuel pump is fired from the starter circuit which energizes the primary coil in the circuit opening relay which fires the fuel pump.
The secondary coil in the circuit opening relay is fired from the flap in the AFM when the motor sucks air.

The fuel pump should NOT run with the key in the ON/Run position without the engine running. If it does then the FP logic has been bypassed on the diagnostic connector on the firewall or has been otherwise molested.

My flowchart for 3FE diagnostics was based off of the 91/92 FJ80, but should still apply to the FJ62 version. There are slight differences between the two, but nothing that should prevent you from troubleshooting. The ECU pinouts are slightly different.

In any case, no CEL with the key in the ON position before cranking the starter=no start. It is telling you that the ECU is not in a "ready" state, and this engine will not run. This can be caused by lack of voltage to the ECU or a short internal to the AFM or a number of other reasons.

The crank position sensor is one of the pick up coils in the distributor housing. My diagnostic has the FSM test for those.

 

[MustangOwl]

UPDATE: Ok. I checked the CEL bulb, it still works (grounded W on the ECU). I get no codes when in diagnostic mode. The CEL DOES NOT FLASH in diagnostic mode. The ECU IS getting power (11V and change; very close to battery reading).

I tried the above with TWO ECU’s (one a new, used one from Specter).

TO DO’s: check the AFM (I checked it a month ago and it checked fine, so I’m not holding out much hope)
Swap in OEM O2 sensors (somewhere on the inter webs someone said improperly spec’s O2 sensors can create this condition)

ANY OTHER IDEAS??

My wife said to sell her (The land cruiser). I said no chance; it’s just personal now….

 

[micruz60]

It really seems to be a grounds issue- check them by tightening and then loosening and smear dielectric grease on the threads. Isn’t there one in the footwell drivers side behind the kickplate?

 

[ChaserFJ60]

UPDATE: Ok. I checked the CEL bulb, it still works (grounded W on the ECU). I get no codes when in diagnostic mode. The CEL DOES NOT FLASH in diagnostic mode. The ECU IS getting power (11V and change; very close to battery reading).

I tried the above with TWO ECU’s (one a new, used one from Specter).

TO DO’s: check the AFM (I checked it a month ago and it checked fine, so I’m not holding out much hope)
Swap in OEM O2 sensors (somewhere on the inter webs someone said improperly spec’s O2 sensors can create this condition)

ANY OTHER IDEAS??

My wife said to sell her (The land cruiser). I said no chance; it’s just personal now….

So when you ground W the light comes on, and when you short TE1 and E1 you get no flashing at all? Sounds like your culprit is here. jumping TE1 and E1 should always cause the CEL to blink something,