Fuel Economy - MS112 Crown

[rtrona]

Having no luck at all with this.. It has got a lot worst. Just replaced the fouled plugs and done about 21kms and its back to its old self, missing real bad. Is there a coolant temp sensor for the ECU? checked on Tridon and they only list one for the gauge. Where is the Aux air valve on these things?

[CrUZida]

Get the injectors cleaned, they could be leaking.
Replaced the ECU coolant temp sensor as cambelt suggested. Use toyodiy.com to get a part number, and amayama.com to order one.
Open up the ECU and replace the capacitors with ones from RS Components, they tend to die over time.
Aux Air Valve will be an electronically controlled valve in the intake piping, somewhere between the AFM and the intake manifold. It is a throttle body bypass valve.

[Cresleepa]

1uzfe conversion would be an option too!

[wilbo666]

I can think of a few things to check
-Fuel injectors (as cruz says)
-Cold start fuel injector (might be leaking?) and associated coolant temp switch (cold start injector might always be on? SW START in the below image)
-Coolant temp sensor (see below image for location, it's marked as SENSOR WATER in the below image).

ToyoDIY.com



Re the Aux Air Valve (I call them an ABV or Air Bypass Valve) that cambelt mentions they normally are stuffed, but can be reconditioned with a little bit of work. I remember back in my 5M-E days that fixing my ABV made a huge difference to cold starting! The valve should be 'open' when cold and close when power is applied. It's a pretty simple item that uses a bimetallic strip to close. 22230 in the below image.



Cheers
Wilbo

[crownv8]

Check the diapram in the fuel regulator is not leaking. If it is fuel fouling plugs it must be burning an awful lot of fuel. Pictures of the plugs will help.

[rtrona]

Will get some pictures up of the plugs soon, although they have only been in the car for about 30-50kms if that. It is showing simular symptoms to what my 1jz cressie done when the coolant temp sensor to the ecu was stuffed. Misses on idle slightly,but then when you select a gear it hunts real bad. So will replace that first.

[rtrona]

Got my self a new coolant temp sensor. The car has a faded yellow plug. The new one is green. I put it in anyway. No luck.

[rtrona]

- Actually these plugs are probably on 20kms old at the most. This is from cylinder 6. The same all through.

- The back of the shed wall :-/

- Poor girl, just wants to be healthy

[CrUZida]

Personally I'd get the injectors checked next (unless you have access to another ecu, one that you know is working, then do that first).
About $150ish to get them all cleaned, providing you remove and refit.

I reckon its either going to be leaking injectors, or stuffed ECU capacitors.
But hey, internet diagnosis has its margin of error!

[rtrona]

Opened the ECU, and found not a capacitor but something else which has leaked, sourced a second hand replacement, (was working when removed), and hasnt fixed the issue. May have to send the injectors off for testing.

[rhys80]

how'd you go with trouble shooting the probs with yr ms112? running any better? also how did the change of the front to the dual lamps go? from my understanding you need to change both front guards and bonnet with a series 1 Ms112.

[rtrona]

Nah I haven't. I do think it's the injectors leaking. As it is filling the sump up with fuel. With the twin headlights I have given up on that idea. Lol

[litldv8]

filling the sump with fuel


i am having visions of a apprentice i worked with once that put a old red motor holden dissy im backwards once
kept putting fuel down the carb even though it was backfiring eventually it filled the sump and backfired and the oil in the sump caught fire blowing the sump off with lots of burning oil!!!!!

am i glad it was on the hoist and could lift it up out of the way




anyway moral of the story - be very careful if its filling the sump up with fuel.
neil

[Greasemonkey87]

Check your fuel pressure regulator, mine gave up in my MX62 and displayed similar symptoms.
Failing that, are all the plugs fouling? Or just a few?
Things I'd try:
-air flow meter
-air filter
-egr on top of plenumn isn't blocked
-put hotter plugs in
-failing all of that, check your compressions.
Other than that I'd have to see it to work it out...

[ivandude]

My former 5M-E in a MA61 always did okay fuel fwiw - about 12-13L/100KM. When the O/D was working it managed 450km a tank (55L) mixed city/hwy, when the O/D died it was around 380-400km (55L). It was decently maintained, but did also run a bit rich. Those are decent figures you should head for I reckon, MX73's cant be that bad

Running really rich probably got a host of problems directly giving bad fuel consumption heh, sounds like a lot of servicing to go!