1fz-fe rough idle/misfire no CEL - Solved - non OEM temp sensor cause (1 Viewer)

[The Moose Trophy]

My fzj80 isn't running smoothly, slight misfire, ticking from the front/top of the engine. No CEL (sadly) and it runs okay. When the engine is cold, and I first start it up it runs absolutely amazing, no ticking, not misfire, no shaking. Once it warms up and starts reading the sensors it runs rough. Idle settles around 650 + or - 50. Idles around 1000 rpm in Drive.

First off what has been done to the vehicle (348k miles): ALL parts OEM unless Stated:

- Engine rebuild (top and bottom full refresh) 15k ago
- new fuel injectors
-new engine wiring loom
- new cooling system hoses, radiator, thermostat, water pump
- new TPS
- new O2 sensors (denso)
- new Mangaflow y-pipe and second cat (my old ones were shot)
- new distributor (cardone)
-new sparkplugs (less than 1k ago iridium)
- new spark plug wires
-new air filter
- new fuel filter
- new fuel pump and sending unit
- EGR delete
- new ignition coil
- new fuel regulator
- newish belts (20k)
- swapped main pulley
- new fan clutch and blade
- new charcoal canister
- new fuel filter cap
- new knock sensors (2x)
- temp sensor (aftermarket unknown brand)

Now you can see my frustration why this thing isn't running like a top... Everything I can think of has been checked against the FSM. Because it runs good when it's cold I assume it's a sensor... But no CEL so I'm running in circles.

Known issues:
- front exhaust manifold middle bolts are slightly stripped and aren't as tight as the rest
- possible issue with the VSV (THIS WAS THE ISSUE)

Issues listed in the comments (condensed for viewers ease)

- Vacuum leak, cracked tube, wrong size (THIS WAS THE ISSUE - replaced entire vac system)
-Oil filler cap o-ring rock hard (replaced due to age, wasn't an issue)
- PCV valve grommet brittle (was replaced not an issue)
- Dipstick o-ring (didn't have time to check before issue was resolved, will be switching it out)
- Intake air tube not cracked (mine was in good condition)
- Timing off a gear (checked and moved, but wasn't the issue)
- IAC (idle air control valve) - ( checked against FSM was bad, but didn't solve my issue)
- Fuel Octane rating too low (didn't check due to gas prices)


Fixing the Issue: $320.53 (from Partsouq and Toyota parts deal not including IAC approx $400)

I replaced all the Vac lines, switches, couplers, everything that was still on the market in one go. Solved the issue and now runs extremely smoothly.

Parts replaced: FOR 1995 1FZ-FE
9099992002 - Vac line (you'll need about 4 of these)
2582013020 - valve bi-metal
9091710049 - gas filter #1
9091005212 - Large vac hose
9613251100 - larger vac clamps
9092503192 - Valve vac control (the thing with the blue cap)
9533306010 - Evap hose
9091012079 - VSV #1
9091012079 - VSV #2
9033903002 - plug

List does not include:
- intake manifold "gas" valve
- any egr components
-intake manifold gaskets (THESE ARE NEEDED)

 

[mudgudgeon]

3 degrees is 3 degrees, regardless of moving a tooth.

Sure, but if you want 6⁰ and the bolt is at the end of the slot, what are you gonna do?

 

[The Moose Trophy]

3 degrees is 3 degrees, regardless of moving a tooth.

A moved tooth would've created a lot weirder symptoms, I moved it anyway so I could adjust it beyond 3 degrees.

 

[studawg]

These engines run just fine on 87 octane. Anything above that is a waste of money, unless you have forced induction.

Yes if your timing is set at stock, but when its advanced considerably, it would need a higher octane correct?

 

[jonheld]

Yes if your timing is set at stock, but when its advanced considerably, it would need a higher octane correct?

Depends if your getting pre-detonation with your timing advanced on 87 octane. If it's knocking then yes.
However, if you do cost benefit analysis on running 93 as opposed to 87 over the next 10K miles, keeping gas prices what they are around me today, it will cost me an additional $900. I'll keep FSM timing.

 

[studawg]

Depends if your getting pre-detonation with your timing advanced on 87 octane. If it's knocking then yes.
However, if you do cost benefit analysis on running 93 as opposed to 87 over the next 10K miles, keeping gas prices what they are around me today, it will cost me an additional $900. I'll keep FSM timing.

Is there any benefit to advancing the timing a few degrees? I thought it was giving me better throttle response and/or power but I could be imagining things

 

[mudgudgeon]

Yes if your timing is set at stock, but when its advanced considerably, it would need a higher octane correct?

I run 10⁰ static advance, on standard petrol.

No pre-detonation issues for me.

Runs a bit crisper, more power off idle, and better mid-range pickup.

If it's not pinging, no reason at all to run higher octane fuel.

 

[gaspain]

did you figure this out. I have similar issues

 

[The Moose Trophy]

did you figure this out. I have similar issues

Still working through it. IAC definitely helped. I'm replacing my entire vac system in a few weeks so I'll give an update on that.

I'd start simple though for your issue. Spark plugs, plug wires, distributor cap and rotor, then vac lines.

 

[gaspain]

Still working through it. IAC definitely helped. I'm replacing my entire vac system in a few weeks so I'll give an update on that.

I'd start simple though for your issue. Spark plugs, plug wires, distributor cap and rotor, then vac lines.

Thank you!

 

[The Moose Trophy]

Update:
After replacing all the back lines and electronic switches and the spark plugs it still has a misfire at idle no CEL.
I swapped in my spare ECM to see if that was the issue, it wasn't.
I hooked the Landcruiser up to a snap on scan gauge and boom, misfire on cylinder 2 when at idle.
Now comes the confusing part. All 6 injectors were replaced 30k ago as well as the wiring loom. Injector two is firing, heard with mechanic stethoscope, and is the correct ohm reading. I'm tempted to swap it with one of my rebuilt spares but that's a pain so I'm holding off.
Sparg plugs are new OEM gapped with a feeler gauge. My last idea is that the #2 spark plug lead has somehow gone bad, but that seems unlikely as it has done less than 40k and only misfires noticably at idle.
Last things I could do is recheck the cam lifter gap for cylinder 2 and check for a vacuum leak.

Let me know if you have any suggestions.

 

[The Moose Trophy]

 

[The Moose Trophy]

The scan gauge was also showing me a weird reading every couple of seconds the timing would drop to -55° and then come back to normal. Maybe it's an old car thing, or maybe there's an issue with the distributor.

 

[Malleus]

Wiggle the wire to the #2 injector. If it doesn't go away...I know you said you swapped ECUs and you have a new engine harness, but if the wire to the injector isn't the problem, the only other place to look is the board.

I need to dig into the SFI description again, it's been a day since I looked at it, but I don't remember offhand that there's another player on the spark/squirt team that could only affect one cylinder.

 

[The Moose Trophy]

Wiggle the wire to the #2 injector. If it doesn't go away...I know you said you swapped ECUs and you have a new engine harness, but if the wire to the injector isn't the problem, the only other place to look is the board.

I need to dig into the SFI description again, it's been a day since I looked at it, but I don't remember offhand that there's another player on the spark/squirt team that could only affect one cylinder.

I'll give that a try tomorrow. Yeah it's doing my head in.

I did replace a valve shim I'm cylinder 1 as it was slightly out of spec, so maybe cylinder 2 has the same thing, but I'm 99% when I check all the other cylinders that it was within tolerance.

 

[Malleus]

Good luck. That's a head scratcher, for sure.

 

[DaviMH47]

I had a misfire on cylinder 2 after replacing the injector clips on the engine harness. Turns out the wires going into the connector weren't fully seated. Pushed the wires in and no more misfire.

 

[The Moose Trophy]

I had a misfire on cylinder 2 after replacing the injector clips on the engine harness. Turns out the wires going into the connector weren't fully seated. Pushed the wires in and no more misfire.

I had a misfire on cylinder 2 after replacing the injector clips on the engine harness. Turns out the wires going into the connector weren't fully seated. Pushed the wires in and no more misfire.

It doesn't look like that's my issue, but definitely something to keep in the books.

I'll report back in a few weeks but I swapped my #2 injector and it seems to have fixed the issue, just had it up to temp and not any long testing.

 

[The Moose Trophy]

Update:
Replaced my #2 injector with a used cleaned and balanced one, bit of a headache to install. After torquing everything and ensuring I didn't miss anything I started her up and wow a massive difference, before it had made a tapping sound like a diesel and now it was smooth as silk, for a bit. During the process I had broken the tip on the bi-metal valve on the block and had to plug one of the vac lines, assuming this was now this issue of it returning back to a random stumble and misfire at idle I replaced it with OEM. No change. Sometimes it runs smooth, with the diesel ticking sound, mine is gas, and sometimes I can feel it shudder and misfire. Idle has also dropped to 580's on occasion.

I rechecked my TPS (throttle position sensor) via the FSM (factory service manual) and my previous work checked out. I checked my maf, no issues there, again by the FSM.

It runs worse the warmer the car is, of it's cold it's idles great but if it's been driving a while then I stop and let it idle it ticks and misfires.

I have a spare non OEM distributor maybe I'll swap that back in and see if it changes anything. I'm at the point of it runs fine, oil test aren't showing engine issues, and there's no codes so maybe it's just an old car.

 

[Malleus]

I wouldn't give up and live with it. The SFI system is pretty simple. You might have to start at the beginning and check the whole thing, but it wouldn't take an hour, two at the most.

Oh and

 

[The Moose Trophy]

I wouldn't give up and live with it. The SFI system is pretty simple. You might have to start at the beginning and check the whole thing, but it wouldn't take an hour, two at the most.

Oh and

I'm replacing some a lot of not all of the grounding wires here in a few weeks, my hope is maybe it's just a bad ground... Probably not but it'll help cope.

I'll dig through the fsm next week to see if I'm missing something, but with a different ECM, new injectors, and new wiring loom (never used with the EGR system), I'm a little stumped. Maybe a cracked intake manifold...