**Resolved** 1FZ-FE poor cold starts and wont idle (8 Viewers)

[petegangies]

Hi all, I've searched around the forum for solutions to this issue, and I am still unsure of how to proceed from here. So any advice is greatly appreciated.

The car can sometimes start really hard, stalling and hunting and blowing white smoke that smells of possibly fuel? Once it warms up, idle is pretty smooth. Thought it might have been due to excess valve saver fluid (FlashLube) in the intake manifold (dad had it pumping too much in, car is dual fuel with LPG). I've also replaced the spark plugs and leads, though I think my spark plug tube seals might be leaking as cylinder 5 and another had a fair bit of oil on the thread of the plug.. (I hope not worn rings, only have 150,000kms). I've checked for vacuum leaks, both visually and with a smoke machine and found a vacuum hose on the bottom of the VSV had popped off. I refitted this and it did not sort the issue. Pulled EFI fuse to reset computer learned trims...again, no difference. The car idles around 800RPM on a cold start.

My thoughts for next steps..

- BK44 fuel system cleaner treatment
- Subaru upper cylinder head cleaner for manifold
- Check timing is at 3 degrees
- remove, check and clean idle air control valve (is it safe to remove this while the throttle body is still installed? FSM says to remove TB when removing IACV).
- Check distributor cover (we replaced the rotor button a while back as general maintenance)
- TK leak down / compression test
- check/adjust valve clearances - replace spark plug tube seals and pcv grommet at same time as valve clearance check
- check ECU + electrics (ecu/engine wiring loom was replaced a little while back after a bad short)
- MAF sensor? Though I'd expect with a dodgy MAF, the thing would run like a pig all the time, not just cold starts)
- 02 sensor replaced with genuine a few years ago (doubt that would affect cold starts)
- TPS? (no idea how I'd check this)
- change fuel filter (doubt an issue, has been replaced at some stage)
- EGR valve clean? (clutching at straws?)

Thoughts?

Many thanks,
Pete

 

[Malleus]

First, what year is your 80? You said it's dual fuel, I assume it's gasoline and LPG?

The '95-'97 service manual has a matrix of problems for troubleshooting (which also applies to the '93-'94 models (although it;'s not in their manuals), which has an ordered listed of areas to check for problems such as this.

Yes, you can remove the IAC wihout removing the throttle body, but the screws holding it on are JIS (+) head crews and if they're stuck, you'll strip the heads getting them off. Plus, there is precious little room to remove the lower one. It can be done, but it's much easier to remove the throttle body first. The bonus is that you can clean the TB while it's off.

The idle air control valve is responsible for smooth cold starts. It is a four position stepper motor which either plugs or unplugs an air intake bypass galley into the throttle body, past the throttle plate (butterfly). If it is stuck closed, the engine will run poorly when cold, due to lack of air. Once it warms up and the throttle plate opens, the idle smooths out.

There are two operational checks for the IAC, one is electrical (performed while installed) and one is mechanical (which must be performed when the valve is removed). Both must be performed to ensure the IAC is functioning properly. The procedure is in the service manual, which is in the Resources section for free download.

Correct idle speed, with A/C off, is 650 ± 50 rpm.

 

[mudgudgeon]

LPG convertec vehicles are notorious for poor starting.
Are you starting with petrol and switching to LPG?
When everything is cold lpg may not vaporise enough for smooth starting.

What sort of lpg system is it?

Plugs in a petrol/ lpg are a compromise. A petrol engine and an lpg engine don't want the same plug.

Your list b looks good,
but start with simple, low dollar stuff like fresh plugs, correct timing, check dizzy cap and rotor.
Clean IAC etc. Double check for vacuum leaks.

I personally would not own an LPG converted vehicle. They are problematic in a lot of ways with preciius few and debatable advantages

 

[petegangies]

First, what year is your 80? You said it's dual fuel, I assume it's gasoline and LPG?

The '95-'97 service manual has a matrix of problems for troubleshooting (which also applies to the '93-'94 models (although it;'s not in their manuals), which has an ordered listed of areas to check for problems such as this.

Yes, you can remove the IAC wihout removing the throttle body, but the screws holding it on are JIS (+) head crews and if they're stuck, you'll strip the heads getting them off. Plus, there is precious little room to remove the lower one. It can be done, but it's much easier to remove the throttle body first. The bonus is that you can clean the TB while it's off.

The idle air control valve is responsible for smooth cold starts. It is a four position stepper motor which either plugs or unplugs an air intake bypass galley into the throttle body, past the throttle plate (butterfly). If it is stuck closed, the engine will run poorly when cold, due to lack of air. Once it warms up and the throttle plate opens, the idle smooths out.

There are two operational checks for the IAC, one is electrical (performed while installed) and one is mechanical (which must be performed when the valve is removed). Both must be performed to ensure the IAC is functioning properly. The procedure is in the service manual, which is in the Resources section for free download.

Correct idle speed, with A/C off, is 650 ± 50 rpm.

Hi, mine is an early 94 model, and yes, it's gasoline and LPG. I have been starting it on gasoline. I have JIS screwdrivers, after reading this in another thread. I have a copy of the FSM, and found the testing procedures. I'm a little confused about the electrical one, as FSM says " (b) Using an ohmmeter, measure the resistance between the terminals (131 -S1 and S3, B2-S2 and S4).", on their diagram, I can find no reference to '131'. Have attached these images for reference. Any thoughts?

 

[petegangies]

LPG convertec vehicles are notorious for poor starting.
Are you starting with petrol and switching to LPG?
When everything is cold lpg may not vaporise enough for smooth starting.

What sort of lpg system is it?

Plugs in a petrol/ lpg are a compromise. A petrol engine and an lpg engine don't want the same plug.

Your list b looks good,
but start with simple, low dollar stuff like fresh plugs, correct timing, check dizzy cap and rotor.
Clean IAC etc. Double check for vacuum leaks.

I personally would not own an LPG converted vehicle. They are problematic in a lot of ways with preciius few and debatable advantages

Thanks for your reply!

I have been starting on petrol and leaving it on petrol to rule out the LPG factor. It's an older LPG system, but not 100% sure, as the vehicle was my fathers and this system was installed quite a few years back. I wish it didn't have the LPG system on it, but removing it and finding another fuel tank, will not be a simple or cheap task. It will eventually be converter back to straight gasoline. I was a tad worried about cleaning the IACV after reading this footnote in the FSM..

NOTICE: To prevent deterioration, do not clean the TP
sensor, dashpot and IAC valve.

Though, I have seen threads where others have done it without an issue. They are just really hard to find replacements for and are very expensive, so didn't want to damage mine, if it's not actually causing the issue. I will try and work out how to do the 2 different testing methods in the FSM as suggested by @

Malleus​

 

[Malleus]

Hi, mine is an early 94 model, and yes, it's gasoline and LPG. I have been starting it on gasoline. I have JIS screwdrivers, after reading this in another thread. I have a copy of the FSM, and found the testing procedures. I'm a little confused about the electrical one, as FSM says " (b) Using an ohmmeter, measure the resistance between the terminals (131 -S1 and S3, B2-S2 and S4).", on their diagram, I can find no reference to '131'. Have attached these images for reference. Any thoughts?

View attachment 3766491

View attachment 3766492

"131" is typo. It should read "B1".

 

[Malleus]

Also, FWIW, if the IAC is defective, since the '93'-94 IAC is no longer available, use the 1995-EoL versions, 22270-66011. It's a direct replacement.

My '94 had this problem, and although I was able to restore it to pass both functional tests, I had to replace it to get a running engine again. This may be something for you to consider.

 

[petegangies]

perfect, thank you for that, and the new part number for the IACV! I will do some testing this weekend and give it a clean while it's out! Even thought about getting a cheap $35 one off Amazon just as an additional test, if no change, then refit factory one and move onto the next possible culprit..

 

[petegangies]

"131" is typo. It should read "B1".

perfect, thank you for that, and the new part number for the IACV! I will do some testing this weekend and give it a clean while it's out! Even thought about getting a cheap $35 one off Amazon just as an additional test, if no change, then refit factory one and move onto the next possible culprit..

 

[mudgudgeon]

Ouch!

 

[Malleus]

That price is well above the US retail price. No idea what it would cost in the Antipodes.

I'd email Dave Stedman at Japan4x4 and ask him what a real price would be.

 

[petegangies]

I'm in Australia, I have no idea what the retail here is, but I'm hoping mine is okay!

 

[mudgudgeon]

I'm in Australia, I have no idea what the retail here is, but I'm hoping mine is okay!

Retail at your local Aussie Toyota dealer is likely 30-50% higher than partsouq.

Definitely try cleaning yours. They are fairly simple, just do it carefully.

Partsouq.com or Japan4x4 as linked by @Malleus are good sources for parts.

Partsouq.com would typically have parts at my door in Sydney in around 5 days, faster than Toyota can usually get stuff from the Melbourne warehouse

 

[petegangies]

Thank you! When you say do it carefully... is there anything specific I should avoid doing when cleaning it?

Retail at your local Aussie Toyota dealer is likely 30-50% higher than partsouq.

Definitely try cleaning yours. They are fairly simple, just do it carefully.

Partsouq.com or Japan4x4 as linked by @Malleus are good sources for parts.

Partsouq.com would typically have parts at my door in Sydney in around 5 days, faster than Toyota can usually get stuff from the Melbourne warehouse

 

[mudgudgeon]

Don't scratch anything internally
I used carburettor/ throttle body cleaner, and some rag. It dries without leaving residue

 

[petegangies]

I've tested the IACV per the FSM, and I believe it has failed. If someone could please double check for me? I had hear the click click click from the IACV when you turn the car off, and if I unplug it and start it, the revs jump right up to near 2000rpm (not sure if that tells you anything). @mudgudgeon @Malleus

IAC resistance check video



Also, here is a video of start up. Hard starting, hunting idle and bad chirp/squeal, but have had all belts replaced and tensioned... bad idler pulley? Also blowing a lot of white smoke that stinks (not like coolant, more like fuel or maybe oil)..

engine start up and idle

 

[ppc]

There is a off vehicle testing procedure in the FSM. Remember this is a stepper motor that only moves in very small increments. You won't see it move put holding on to it you will feel pulsing. The test procedure doesn't mention it takes multiple passes to see in and out movement.

 

[petegangies]

There is a off vehicle testing procedure in the FSM. Remember this is a stepper motor that only moves in very small increments. You won't see it move put holding on to it you will feel pulsing. The test procedure doesn't mention it takes multiple passes to see in and out movement.

I can not see this off vehicle testing in my FSM. What if I pulled off the IACV and had it connected and cycled the ignition?

 

[ppc]

Look at previous posts in this thread there are pictures from the fsm, specifically post #6. Most likely removing but still connected before starting would only push it out. That test would be insufficient.
and

 

[petegangies]

Look at previous posts in this thread there are pictures from the fsm, specifically post #6. Most likely removing but still connected before starting would only push it out. That test would be insufficient.
and

Ah yes indeed haha that's my photo.. I'm an idiot! I'll definitely do this and report back.