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

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robnicko said:
Been reading all the posts,
Has the Air Flow meter been confirmed as good? You mention its been run on LPG the majority of its life and if any LPG backfires have happened could be damaged and the reason for the hunting idle on petrol

as far as timing is concerned mine is a 95 update model on LPG as well and have always run the std 3deg setting and same spark plugs as you are without any problem.

is it injected LPG or vapour through the TBody? I could see the standard intake tube between the air flow meter & TBody so am assuming injected
Click to expand...
Hey mate, it has the plate between the airbox and airflow meter, and the gas converter is on the passenger side (Australian).

Very interesting regarding the timing!

I cannot confirm if the AFM is good, is there a way to definitely know and test? There was a spare one in Dad's shed, but I don't know if it's good either! I could swap them and see what happens. Don't really have anything to lose apart from time I suppose. I should have done it when I cleaned the throttle body and changed the plugs. Just odd, you'd think the car would bog down or hesitate under wide open throttle and normal driving if the MAF was stuffed... but it is running stupidly rich on idle.
 
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ppc said:
I would caution not to make any additional changes until the timing issue is resolved. The more you change the more complexity difficulty to identify root causes of problems. If the poor starting/running is occurring at idle but runs better at higher RPM's the fuel filters, pumps, injectors... are not going to be the problem. The filter can be changed at a later time. What happens when you try to start on petrol, open the throttle manually a small mount. If it starts/idles significantly better possibly the IAC could be a problem but doubtful. Don't mess with it at this time.

At this time the TDC, timing mark at zero and rotor pointing in the proper position then all mechanically is correct. Has to be electrical.
Click to expand...

I'm thinking the same thing, and especially because Dad's dodgy wiring shorted and burn out the original wiring hardness/loom for the vehicle back in 2021. A second hand harness was sourced and wired in by an auto electrician. Here's an excerpt from an email he sent me about the work completed:

"Your dad sourced a second hand harness which was shipped down to us from QLD. The harness that was shipped was not 100% the same as the damaged harness in the car as Toyota has many variations of the same thing in the same year. So we used the new harness in competition and modified it to suit the cars' many aftermarket circuits. This was the body harness we where lucky that there was no damage to the ECU harness or gas systems when the wiring burnt. (this harness the harness for systems like the AC, Starting/charging, Headlights, blinkers and wipers etc) main damage was from headlight is and front harness the fire was believed to be from the aftermarket headlights/driving light circuits.

I recommended to your dad on several occasions in our conversations/ his drop ins to our workshop after the job that the car needed an electrical cleanup/check over especially the aftermarket circuits as he informed me many of these systems are more than 20 years old installed in the late 90's. But your dad told me on many occasions that the age of these components meant little as he didn't use the car more then once or twice a year to tow the boat. We tried to educate him that some of these issues may be linked to these things especially the alarm system as it cuts main power from many main circuits. we also tried explaining that he needs to use the car more often or things gum up/fail if it sits to long (cars are always in a state of deterioration)"

Thoughts?
 
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petegangies said:
Hey mate, it has the plate between the airbox and airflow meter, and the gas converter is on the passenger side (Australian).

Very interesting regarding the timing!

I cannot confirm if the AFM is good, is there a way to definitely know and test? There was a spare one in Dad's shed, but I don't know if it's good either! I could swap them and see what happens. Don't really have anything to lose apart from time I suppose. I should have done it when I cleaned the throttle body and changed the plugs.
Click to expand...
Id try the other AFM and see, its very possible that one could be the original which also may have suffered from an LPG backfire.
can you take a photo of the whole engine bay showing both sides of the engine and LPG items. In the video I could see the converter but not the mixer (usually an Impco 225) hence my assumption that its injected LPG.
Normally the intake tube just prior to the TBody on Vapour LPG setups is replaced with another pipe that has holes in it to allow for any backfire to escape there and protect the MAF. That pipe is usually covered with a BFS backfire sock (stubby holder)

Intake configuration on mine below
Air Filter > MAF>Impco Mixer>intake tube with holes and BFS > Throttle Body
 
ppc said:
@robnicko ,

Care to share what timing values are observed gas and petrol on your vehicle?
Click to expand...
hi PPC,
I have always set the timing at 3deg BTDC when jumpering the diagnostic port.

I will need to check when home with the timing gun to see where it moves to when not in diagnostic mode but recall it moves around as its under ECU control then (0-16degrees)

rob
 
petegangies said:
Hey mate, it has the plate between the airbox and airflow meter, and the gas converter is on the passenger side (Australian).

Very interesting regarding the timing!

I cannot confirm if the AFM is good, is there a way to definitely know and test? There was a spare one in Dad's shed, but I don't know if it's good either! I could swap them and see what happens. Don't really have anything to lose apart from time I suppose. I should have done it when I cleaned the throttle body and changed the plugs. Just odd, you'd think the car would bog down or hesitate under wide open throttle and normal driving if the MAF was stuffed... but it is running stupidly rich on idle.
Click to expand...
Be careful with the AFM; don't unscrew those little screws, no matter how tempting it is to do so.
 
robnicko said:
Id try the other AFM and see, its very possible that one could be the original which also may have suffered from an LPG backfire.
can you take a photo of the whole engine bay showing both sides of the engine and LPG items. In the video I could see the converter but not the mixer (usually an Impco 225) hence my assumption that its injected LPG.
Normally the intake tube just prior to the TBody on Vapour LPG setups is replaced with another pipe that has holes in it to allow for any backfire to escape there and protect the MAF. That pipe is usually covered with a BFS backfire sock (stubby holder)

Intake configuration on mine below
Air Filter > MAF>Impco Mixer>intake tube with holes and BFS > Throttle Body
Click to expand...

80 series engine bay.jpg
 
@petegangies, since plugging the top connector on the distributor in securely have you checking the timing again? On the ODB1 vehicles the distributor supplies a "crank position" signal to the ECM, which if the loose connection involved specific wires would cause great confusion to the ECM. On the new ODB2 vehicle the crank position sensor it a separate device on the oil pan just behind the harmonic balancer.

All this is stranger. If the ECM detected engine knock/pinging the timing advance would be significantly retarded. Timing can not be advanced just retarded.
 
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ppc said:
@petegangies, since plugging the top connector on the distributor in securely have you checking the timing again? On the ODB1 vehicles the distributor supplies a "crank position" signal to the ECM, which if the loose connection involved specific wires would cause great confusion to the ECM. On the new ODB2 vehicle the crank position sensor it a separate device on the oil pan just behind the harmonic balancer.

All this is stranger. If the ECM detected engine knock/pinging the timing advance would be significantly retarded. Timing can not be advanced just retarded.
Click to expand...
that was only not plugged in correctly after I removed the distributor cap to check the rotor button, it was plugged in fine for all the timing checks. I did check timing again after this incident and it was the same.
 
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how do you all feel about cleaning the IACV with it still on the vehicle? The way I would do this, is by removing the intake pipe and with the upper engine cleaner and straw attachment, spray the cleaner down the IACV shaft and into that area, then let the chemical do it's work (designed to dissolve carbon deposits), then add the rest of the can into the intake manifold and throttle body to clean the rest. The only issue I foresee here is that the chemical may not get sucked back out by throttle and could just dry in the chamber along with everything else it "dissolved"..... am I reaching?
 
I had to really grind (with a finger wrapped in crocus cloth) to get the gum out of mine. I don't think it'll work. It won't hurt to try, though.
 
I would remove it. It's not a big job to remove the throttle body.

Worst thing is, you disturb the coolant hoses running to/from the throttle body.
Now is the time to replace them, and any old vacuum lines you touch.
 
...and you will then have a good reason to replace the hoses to your heater pipes. Use the hoses from the 100 series; cut one in half and you get two!
 
So I took the car away with the boat over the weekend, and here are some further observations..

- The car is using a lot of fuel and LPG since retarding the timing.

- to get the car to change down gears when going up a hill, you really have to absolutely mash the accelerator pedal into the ground. I'll need to check the transmission kick down cable adjustment per the FSM.

- my parts guy at Toyota last week, told me that you can adjust the VAF, modifying it via a screw... so I looked at mine on the car and sure enough, it's been filled with black silicone. My dad's best friend then told me he had the car dyno tuned around 15 years ago and they "tweaked the car" and got an extra 15kw. I'd bet my bottom dollar that they modified the VAF to adjust the AFRs then bumped the timing right up to compensate for the extra fuel. The spare VAF I have, does not have any modifications. I think there is a way to bench test the VAF's, so I'll do that to the spare one, and if good, I'll fit it to the vehicle and see what happens (obviously being careful with the timing settings). I also heard the VAF is responsible for an initial signal to the fuel pump for starting...

- I still need to remove and clean the IACV, but it might be a few weeks before I can play mechanic again

- Coolant needs a flush and change (brown under radiator cap)... so this would be a good opportunity to remove and test the engine coolant temp sensor, as it could be faulty and affecting cold starts.

I feel like I'm getting closer......maybe.... haha!

pics of VAF on car, and spare below:

1732487510397.png


spare
1732487584598.png


It looks like the one fitted on the car is an aftermarket one?? The "spare" actually has Denso on it... probably the original..

VAF testing procedure:

1732487793608.jpeg


throttle (transmission kickdown) cable adjustment:

1732487913417.png
 
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looking at my throttle kickdown cable... and trying to work out what's going on here... Is the 0-1mm adjustment in FSM adjustment procedure referring to the distance between the orange boot and the little metal retainer/pip on the cable? or the orange boot and the adjustment screw?

Also, I know my cruise control cable on the far right is shot.. it's loose, but someone must have touched it before as the thread is stuffed and I can't tighten it and have the nuts hold. The accelerator pedal cable (far left) also has a bit of slack, as you can see from the wave/bow in it.

Any help/advice before I touch these (especially kick down cable), would be greatly appreciated.

1732509207817.png


1732508418696.png
 
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Just tested the genuine spare VAF I have with the multimeter.. all values check out. Can't wait to install this and see how the car behaves.
 
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