7MGE Fuel Economy

[AKSA]

I have a '91 Grande and rebuilt the engine with bores, pistons, rings, seals and bearing. With Andrew_MX83 we took 1mm from block/head and the car now runs like a dream with higher compression. But it uses a lot of fuel, around 18l/100kms around town driven carefully.

Started cold after 400m down he road the engine lamp comes on and stays on until you shut it down, then restart. It runs fine and the plugs look very clean. I have replaced the oxygen sensor, but can't figure out why it's so uneconomical. Engine and trans use fresh oil, filters are new, brakes are not binding. I had expected it would be around 11l/100kms but it's 60% higher than that.

I'm thinking it might be an ECU issue. It runs beautifully with terrific torque and power, you would think it was a turbine!

Any ideas? Any tests to uncover this issue? The fuel usage is making me broke........

Hugh

[xLOCOx]

have you got a modified fuel system? i cant think, if its so called burning this fuel? without having rich plugs, and it seems to be running right, where can it be going??? is there any leaking (fuel)
what if you let it idle for about 30mins, then check the plugs?just to see what its doing at idle, im asking blind questions, only due to its running right???

[AKSA]

Hi X,
Thanks for answering!
No, standard fuel system, no changes. Can't smell fuel except from the tail pipe, so I'm assuming it's an ECU issue but really can't figure it out, ECUs are beyond me.
I will will try the idle for 30 mins and check the plugs again. But it runs so well it gives me the feeling it's in limp home mode.
HD

[jondee86]

Possible to check for fault codes ?

If MAP sensored engine check engine vaccum at idle.

Thermostat working so engine gets up to normal operating temp ?

Cheers... jondee86

[AKSA]

Yes, runs at correct temp, new thermostat.
How do I access fault codes? Thanks in advance,

HD

[jondee86]

Pretty sure this thread will cover it...
https://www.troublecodes.net/toyota/...ra-3-0l-turbo/

Jumpering the two pins in the diagnostic box is standard procedure for old Toyotas. Here is one with the lid opened... it will be in the engine bay somewhere



I would expect the 7MGE codes to be the same as the 7MGTE codes. but might pay to check.

Cheers... jondee86

[AKSA]

Thank you JD, I will try this tomorrow!

HD

[Hiro]

Pretty sure this thread will cover it...
https://www.troublecodes.net/toyota/...ra-3-0l-turbo/

Jumpering the two pins in the diagnostic box is standard procedure for old Toyotas. Here is one with the lid opened... it will be in the engine bay somewhere



I would expect the 7MGE codes to be the same as the 7MGTE codes. but might pay to check.

Cheers... jondee86

The pins circled in that picture are wrong for diagnostics TE1 (the pin above VF1) and E1 are the ones you bridge for diagnostics via the CEL/MIL.

[AKSA]

Thanks Hiro, much appreciated.