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

[Malleus]

You can't leave the IAC connected to the harness and test it. The ECM won't move the plunger to all positions, just the one the engine coolant temperature sensor indicates it should be at.

You can actually see the plunger move, you just need to put a scale, or some other measuring device (popsiscle stick?) next to it so that you have a reference position for the end of the plunger. The total movement is a couple of millimeters.

I used brake cleaner and a piece of crocus cloth (really fine grit sandpaper, usually easily found at a machine shop), @mudgudgeon will have to help with the Aussie name, to clean the bore of the IAC. But, again, I was able to clean mine and it passed the electrical and mechanical tests, and it lasted about a week before it failed to do its job on the engine. I eventually replaced it with a used unit from a '95 and it's still working today.

 

[mudgudgeon]

Emery cloth i think would be the same product.

A small piece of 2000grit wet & dry sandpaper lubricated with WD40 or kerosene would be an option if you want to polish off stubborn grime.
Easier to find. Autoparts stores will have it.

Fold it a couple of times to make a pad.

Clean with carbie cleaner after

 

[petegangies]

I've got plenty of wet and dry both 2000 and 3000 grit, and throttle body cleaner, so should be able to clean it up no problems, though I doubt it's going to be too dirty. When I removed my intake pipe and inspected the throttle body, it was pretty darn clean. The car has been mostly run on LPG for it's life, so there isn't a lot of carbon build up. I'm wondering if the sensor was damaged when the wiring loom melted and was replaced (this was my late father's vehicle).

I'm going to start the car on LPG and see whether I get all the smoke and bad idle that I get with it on petrol.. that might also help point towards some clues. I feel like I'm dealing with a number of issues and not any one single one...but need to keep working through the process of elimination. I hate not being able to solve problems, but am committed to the process... fingers crossed I find some answers soon and get this cruiser healthy again! Such a shame to see it running the way it is, especially with such low kms.

@Malleus - thanks for your suggestions too!​

I sincerely appreciate both of you helping me through this!
Thanks
Pete

Emery cloth i think would be the same product.

A small piece of 2000grit wet & dry sandpaper lubricated with WD40 or kerosene would be an option if you want to polish off stubborn grime.
Easier to find. Autoparts stores will have it.

Fold it a couple of times to make a pad.

Clean with carbie cleaner after

 

[Malleus]

I think, based on what I saw when I opened mine, that the majority of contamination in the IAC is rust. The rest is seal residue from degradation.

 

[petegangies]

I think, based on what I saw when I opened mine, that the majority of contamination in the IAC is rust. The rest is seal residue from degradation.

that makes perfect sense.

I started the car on LPG last night and no smoke. So I doubt the smoke I'm seeing is oil or coolant burn off and more than likely the car running super rich on petrol during start up. Not sure if that provides us any further clues, but is better than it being from oil/coolant!

Would the temp gauge on the dash cluster still work if I had a faulty engine coolant temp sensor? From what I can see in the FSM it's partially responsible for fuel trims by sending signals/temps to the ECM.

I've got my JIS screw drivers and going to pull it out to test and clean this weekend. I can hear a sucking noise when blipping the throttle, I thought it was coming from underneath the manifold, but I checking all the vacuum lines. I actually think it's coming from what I think is the TPS (next to the IACV). Here's a video... should it make this sound?

 

[mudgudgeon]

Temperature gauge, and ecu read from different/ independent sensors.

 

[mudgudgeon]

that makes perfect sense.

I started the car on LPG last night and no smoke. So I doubt the smoke I'm seeing is oil or coolant burn off and more than likely the car running super rich on petrol during start up. Not sure if that provides us any further clues, but is better than it being from oil/coolant!

Would the temp gauge on the dash cluster still work if I had a faulty engine coolant temp sensor? From what I can see in the FSM it's partially responsible for fuel trims by sending signals/temps to the ECM.

I've got my JIS screw drivers and going to pull it out to test and clean this weekend. I can hear a sucking noise when blipping the throttle, I thought it was coming from underneath the manifold, but I checking all the vacuum lines. I actually think it's coming from what I think is the TPS (next to the IACV). Here's a video... should it make this sound?

First aussie voice I've heard in a while!

Try spraying some carbie cleaner, or starter fluid around where you think it's sucking air.
If there's enough of a vacuum leak, you'll hear RPM increase momentarily.

If it's the throttle body, it was really common for carburettors to suck air around the throttle body shaftas the aluminum housings would wear around the shaft. Not sure if the same is true for a throttle body

 

[petegangies]

First aussie voice I've heard in a while!

Try spraying some carbie cleaner, or starter fluid around where you think it's sucking air.
If there's enough of a vacuum leak, you'll hear RPM increase momentarily.

If it's the throttle body, it was really common for carburettors to suck air around the throttle body shaftas the aluminum housings would wear around the shaft. Not sure if the same is true for a throttle body

haha as I watched it back, I thought to myself.. I'm going to cop some flack here for my Aussie accent!

I've also heard an unlight propane torch would do the same thing or brake cleaner, but carbie cleaner would probably be the safer bet. I'll try that this weekend too.

 

[mudgudgeon]

haha as I watched it back, I thought to myself.. I'm going to cop some flack here for my Aussie accent!

Been in usa since February. Have not met another Aussie yet

 

[petegangies]

Been in usa since February. Have not met another Aussie yet

interesting! which state are you in? I have half American cousins (NY and FL) ..my family background is Greek, but born and bred in Oz.

 

[mudgudgeon]

interesting! which state are you in? I have half American cousins (NY and FL) ..my family background is Greek, but born and bred in Oz.

Born and bred on the central coast. Lived in Sydney for way too long.
Now in north carolina, dodging hurricanes!

 

[CharlieS]

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

...with diagnostic jumper in place, wheels chocked, in neutral, A/C off.

 

[petegangies]

Born and bred on the central coast. Lived in Sydney for way too long.
Now in north carolina, dodging hurricanes!

Yeah nice, I grew up in Newcastle and studied at Ourimbah. I moved to Sydney in 2009 and have been here ever since (Crows Nest).

 

[petegangies]

...with diagnostic jumper in place, wheels chocked, in neutral, A/C off.

my idle when warm is good, I'm just not getting a proper cold start idle.. never goes above 900rpm.

 

[petegangies]

Ok so I checked the timing today and now I'm even more confused. Using the following method:

Using a paperclip shorting the E1 and TE1 terminals in the diagnostic port is to place the engine in base timing mode (often referred to as "service mode"). Vehicle at operating temperature and in neutral. Verified in service mode by constant flashing engine light. Timing light connected to ignition lead #1.

First I checked it and timing was about 1cm to the left of the 15....(the base timing specification for the 1FZ-FE is typically 3° BTDC at idle.) So I retarded the timing down to about 5..the car then was absolutely gutless and stalled a few times. So I've advanced it up to around 11 and it's got the power back again.

Few questions..

1. why would my timing be so far out?

2. Should I get 2 different readings if checking timing in service mode and not in service mode? Because mine shows the same timing with timing light regardless.

3. What do I do next?

On a side note, I could not remove the IACV as I could not find a way to get a screw driver onto that bottom bolt due to the crankcase breather and the shape of the valve cover. How on earth are people removing this without pulling the throttlebody?

 

[petegangies]

Oh and I pulled one of my plugs and it was very black, so it's running super rich. These are new plugs (and leads) too.

 

[mudgudgeon]

Its possible the harmonic balancer has failed, and the outer pulley may have rotated in the inner portion, messing up your timing marks.

If nothing else is making sense, definitely inspect the harmonic balancer

 

[ppc]

I havent read the entire thread but has the head gasket been replaced or any other repairs where the camshafts have been removed. As @mudgudgeon suggested there could be a problem with the harmonic balancer. If the cams were pulled the cam timing (not ignition timing) may have not been done properly which would effect the proper installation of distributor and setup for ignition timing.

2. Should I get 2 different readings if checking timing in service mode and not in service mode? Because mine shows the same timing with timing light regardless

Not surprising that would be your observation. It doesn't have to be different but in service mode the timing remains a steady value, otherwise in normal operation there could be small variances at idle. An engine that is up to temp will be more stable than a cold engine.

What observations of timing can make at higher RPMs or when giving the throttle a quick blip?

 

[petegangies]

I havent read the entire thread but has the head gasket been replaced or any other repairs where the camshafts have been removed. As @mudgudgeon suggested there could be a problem with the harmonic balancer. If the cams were pulled the cam timing (not ignition timing) may have not been done properly which would effect the proper installation of distributor and setup for ignition timing.



Not surprising that would be your observation. It doesn't have to be different but in service mode the timing remains a steady value, otherwise in normal operation there could be small variances at idle. An engine that is up to temp will be more stable than a cold engine.

What observations of timing can make at higher RPMs or when giving the throttle a quick blip?

No repairs to the engine or head gasket. I'll have to check timing again while getting the Mrs to blip the throttle and raise the revs.

 

[Malleus]

Ok so I checked the timing today and now I'm even more confused. Using the following method:

Using a paperclip shorting the E1 and TE1 terminals in the diagnostic port is to place the engine in base timing mode (often referred to as "service mode"). Vehicle at operating temperature and in neutral. Verified in service mode by constant flashing engine light. Timing light connected to ignition lead #1.

First I checked it and timing was about 1cm to the left of the 15....(the base timing specification for the 1FZ-FE is typically 3° BTDC at idle.) So I retarded the timing down to about 5..the car then was absolutely gutless and stalled a few times. So I've advanced it up to around 11 and it's got the power back again.

Few questions..

1. why would my timing be so far out?

2. Should I get 2 different readings if checking timing in service mode and not in service mode? Because mine shows the same timing with timing light regardless.

3. What do I do next?

On a side note, I could not remove the IACV as I could not find a way to get a screw driver onto that bottom bolt due to the crankcase breather and the shape of the valve cover. How on earth are people removing this without pulling the throttlebody?

That's exactly why I said to remove the throttle body. There is a Toyota (actually it's a Toyota branded Vessel) screwdriver that is designed just for this, and the cowl panel removal:

I don't leave home without it.

FWIW, the screw is stuck in there after years of engine gunk has landed on it. Even with the throttle body off, it's a PITA to remove...without rounding the head.