Another FJ62 Rough Idle Thread (1 Viewer)

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Took the air intake and a few vacuum hoses off to access the valve cover, painted valve cover and replaced gasket, replaced #2 hose with new from city racer, cleaned the engine bay carefully with dish soap and water making sure I hit no electronics, reassembled everything and now I have a rough idle. Sprayed starter fluid all over air intakes looking for vacuum leaks and no rpm changes. Seems to be fine at higher roms, plenty of power etc. See video below. Help!

 
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Took it in, mechanic says it's pulling codes for the mass airflow meter/sensor and oxygen sensors. They suggested I replace the mass air flow sensor but I understand when they go bad the truck will idle high in my case it is idling very low, smells like fuel/rich, and seems to be missing a beat. Help!
 

bentonrover

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My oxygen sensors gave me all types of problems. Ill start there. Its a lot cheaper then the maf. Also pull the fuse for the EFI. Let everything reset then recheck the diagnostic port in the engine bay for codes.
 

2mbb

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If you don't have the FSM for the 3FE engine you should get it. I think the diagnosis system for the FJ62 is pretty simple. Getting a code that indicates the Mass Air Flow meter may just mean that the amount of air getting into the engine vs what is measured is different. This could be a vacuum leak not the MAF.

Attached are some excerpts from the FSM. One is the troubleshooting guide for rough idle. The other is how to read the codes and what they mean. It might be worth it to repeat what your mechanic did for more information. There isn't a code that say's directly "MAF is bad", but there are codes that indicate air-fuel mixture lean or air-fuel mixture rich. This distinction has some meaning and will help with trying to solve your problem.
 

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  • FJ62 DTCs.pdf
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  • FJ62 Rough Idle diagnosis.pdf
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Thanks I'm working my way through the rough idle troubleshooting:

- Checked oil filler cap (nothing wrong from what I can tell, doesn't run any different when I loosen it)
- Checked Oil dipstick (nothing wrong with it from what I can tell, doesn't run any different when I loosen it)
- 'PCV hoses' - the only PCV hose i know about is the one on the back of the valve cover, when I pull it the engine stalls completely. Hose seems fine otherwise, not sure how to test the actual PCV valve)
- EGR system (not sure how to test this)
- Only code it's pulling is 24 (air intake temp sensor - presumably on the AFM?)

There is still a terrible fuel smell, could it be fuel supply related? It idles really rough but if I hit the gas it takes off just fine and seems to run 'ok' at speed.
 
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morganism

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does that have the FPR and the fuel bumper (dampner damn it) with the screw in it on the fuel rail?

If its like the 4runner, pop the plastic cap and see if a screw falls out. The screw is factory set, if it fails, replace. if it leaks, don't drive it.
It has caused most fires in 4runners, where it leaks down on the exhaust.
 

morganism

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does that have the FPR and the fuel bumper with the screw in it on the fuel rail?

If its like the 4runner, pop the plastic cap and see if a screw falls out. The screw is factory set, if it fails, replace. if it leaks, don't drive it.
It has caused most fires in 4runners, where it leaks down on the exhaust.
PS. if it is that, on a 4runner, it takes a crows foot wrench adaptor for a socket to remove it.....
 
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I had this same issue with my FJ62 just recently, it was hard to start, rpms were very inconsistent at idle and when driving, rpms would drop when I hit the gas, very rough idle, and overall not good to drive. Took it to a place near me in orange county, they also said it was my AFM (air flow meter) since these cars don't have a MAF, they do the same thing just a different way. I was looking at the duralast and cardone AFM since the OEM is discontinued. I ended up finding a used one from CruiserParts.net for a reasonable price. Once I put it in my Cruiser has been driving great all week minus some starting issues. Couple things to note with my case, I replaced the spark plugs, spark plug wires, distributor cap, rotors, fuel filter, and battery. I am also really new to working on all of this so take what I say with a grain of salt, also my AFM had some visible issues that someone had tampered with it at one point. Still worth a try though if thats what they said could be wrong with it, ill link the part from where I got mine. CruiserParts.net AFM
 
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Checked the AFM today per factory manual. Does this mean it's bad (see resistance reading for E2 - THA)?

PXL_20210520_230726363~2.jpg
 
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E2 -THA value looks incorrect to me too (unless it's almost 140F where you were testing).
Well it was hot yesterday (SC) and i had just run the truck so the engine bay was probably 100 degrees... not 140 though. It's interesting that I was able to get a reading for E2-VS and E2-VC for that right E2 pin but not from the right E2 - THA. A short? Need to clean the terminals? I sprayed some contact cleaner in and it made no difference but I haven't used sand paper/etc to clean the pins. Also need to take it off the air intake so I can do the second part of the test (open vs closed resistance).

Any other guidance?
 

gbogh

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Well it was hot yesterday (SC) and i had just run the truck so the engine bay was probably 100 degrees... not 140 though. It's interesting that I was able to get a reading for E2-VS and E2-VC for that right E2 pin but not from the right E2 - THA. A short? Need to clean the terminals? I sprayed some contact cleaner in and it made no difference but I haven't used sand paper/etc to clean the pins. Also need to take it off the air intake so I can do the second part of the test (open vs closed resistance).

Any other guidance?
Removing the afm from the vehicle is the way to go. I use alligator clip test leads for all these tests because they make better/more consistent contact with the pins. That is interesting about which E2 to use. The circuit diagram makes me think they should read the same. Have you removed the cover for the circuitry?
 
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Yes both E2's seem to be wired together on the circuit diagram so they should read the same. I haven't removed the cover, is that a possibility without damaging it?
 

gbogh

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Yes both E2's seem to be wired together on the circuit diagram so they should read the same. I haven't removed the cover, is that a possibility without damaging it?
I know that people have, but I personally have not. Much more commonly done with the 22RE (very similar EFI system).
 
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I was driving through I20 in eastern ga when I stopped at a rest area and noticed my rough idle, which was so bad the front of the car was shaking. a few miles later I was losing the ability to accelerate. Had to get it towed back to Duluth. By the time I got it to Peter Merriam's garage it was giving of gas fumes and was actually dripping gasoline from the exhaust header. Welp, one of my cats had hollowed out and clogged the muffler, the other cat wasn't any better. it was causing a lot of back pressure with the exhaust. this caused the rough idle for me.
 

FJ Silver

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Were you able to find the cause?
When you unplugged the air flow in video the engine took quite a hit, looked like it's working when you plugged it back in.

When removing the head, could you have knocked off an injector connection?
 

FJ Silver

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If you took off the air intake manifold the injectors and fuel rail is right underneath that and next to the valve cover. Not impossible to knock something loose when removing the manifold.

The torque values on the air intake manifold is pretty low as well as the valve cover, but are they all tightened up? Did you replace the gaskets on the valve cover bolts?

You could also try and spray all the sensor connectors that you disconnected with electrical spray, especially the air flow one and follow that wire back to the wire harness. Just tracing back everything you've worked on.
It's frustrating, but usually a simple mistake.

Oh and double check you O2 sensor wires that hook / ground up close to the air intake manifold.
 

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