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 Post subject: What to check?
PostPosted: 25 Jun 2009 19:30 
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Joined: 07 May 2009 01:22
Posts: 82
Country: Philippines
My engine runs about 6-7Km/L of fuel on mixed driving conditions. damn..
Can anyone tell me what to do first? Like from A-Z.. since I dont know where to start...
I'm planning to fix this problem in a week. I hope I can get 10Km/L just like what my friend does on his mivec.

No mods on my engine.... pure stock...


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 Post subject: Re: What to check?
PostPosted: 25 Jun 2009 19:41 
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Joined: 09 Dec 2003 10:18
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Location: Hamilton
Country: New Zealand
Start by giving the car a proper service. Change the oil, oil filter, air filter and spark plugs. Adjust the valve lash. If its a 1G, check/adjust the timing. Do a compression test.

Get an engine diagnostic reading done. I suspect o2 sensor is stuffed which doesn't cause the diagnostic light to come on.

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 Post subject: Re: What to check?
PostPosted: 26 Jun 2009 23:50 
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Joined: 07 May 2009 01:22
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Country: Philippines
just gave it today a pretty cheap change oil.. .new oil filter... got a set of new sparkplugs BKR 7E... just what I read on the FAQ...

How can I check timing of this engine? any pics? also we don't have guys who can check taht o2 sensor thing.. can I do that by myself?


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 Post subject: Re: What to check?
PostPosted: 27 Jun 2009 07:34 
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Do you have a timing light?
There is brown connector with single wire on the firewall, that needs to be grounded to put ecu into fixed timing mode. Then point your timing light at the crank and make sure its around 5 degs btdc.

Added 'Do compression test' to first list.

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 Post subject: Re: What to check?
PostPosted: 28 Jun 2009 06:47 
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Joined: 13 Aug 2007 17:55
Posts: 30
Location: Quezon City, Philippines
Country: Philippines
I'm having the same problem right now. What used to be 10-12km/L in mixed driving modes (late 2008) is now just 6-8km/L (noticed March 2009).

Here's some data:
- Gasoline is 96 octane unleaded pump gas.
- Throttle body and ISC cleaned last week.
- Fully synthetic oil (Mobil-1 SuperSyn 5W50) is almost 1 year old; roughly 5000km travelled ever since.
- Spark plugs are 2 years old; high-tension wires have not yet been changed since swap.
- Transmission and rear differential oils are 2 years old.
- Can still rev to redline, but a bit slower (at least from perception).
- Fuel pump is okay; fuel filter is clean.
- Haven't checked timing/valve lash/compression.


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 Post subject: Re: What to check?
PostPosted: 13 Jul 2009 05:02 
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Joined: 07 May 2009 01:22
Posts: 82
Country: Philippines
maybe because were from the same country... hehehehe...

btw hit me up man.. my digits are 09053580995

im doing around 8-10 now. mixed driving conditions... using 95 octane from caltex...


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 Post subject: Re: What to check?
PostPosted: 13 Jul 2009 05:03 
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Joined: 07 May 2009 01:22
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Country: Philippines
btw , dont use fully synthetic oils... it might toast your gaskets.... and there's only one place we can get them here in PI..


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 Post subject: Re: What to check?
PostPosted: 13 Jul 2009 08:26 
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Location: Hamilton
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Mitsubishi don't recommend Synthetic for the 1G, but if you've ever rebuilt the engine it should be fine since the seals etc will now be made of more modern materials. That Mobil1 5w50 stuff is ideal.

Back on topic , another thing to try is disconnecting the battery for a minute to reset the ECU. You might have had a few pings/knocks and the ECU has retarded the timing to compensate.
Try and only use 98 octane fuel and if you have used lower octane, reset the ecu when you have decent gas in it again.

To get basically 1/2 the normal fuel consumption, its more likely to be a mechanical fault such as clogged air filter, worn spark plugs or a combination of the above.

Does the engine get up to normal operating temperature (needle on guage at 1/2) quickly, should only take a few minutes of driving. If not perhaps you have a leaky thermostat. I had one here a few years ago where the rubber seal around the thermostat had perished away, the car ran perfectly just took a long time to get up to normal temp. If driven on the open road it never quite got to normal temp, but it was hot enough for the mivec to work. While driving, the needle on the gauge didn't really show it being any different (ie not very accurate at all) but a log showed the engine running at 5-10 degs lower than normal...more than enough to cause the ECU to keep the cold enrichment going.

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 Post subject: Re: What to check?
PostPosted: 22 Aug 2009 12:05 
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Joined: 24 May 2009 20:06
Posts: 158
Country: philippines
jnry3 wrote:
I'm having the same problem right now. What used to be 10-12km/L in mixed driving modes (late 2008) is now just 6-8km/L (noticed March 2009).

Here's some data:
- Gasoline is 96 octane unleaded pump gas.
- Throttle body and ISC cleaned last week.
- Fully synthetic oil (Mobil-1 SuperSyn 5W50) is almost 1 year old; roughly 5000km travelled ever since.
- Spark plugs are 2 years old; high-tension wires have not yet been changed since swap.
- Transmission and rear differential oils are 2 years old.
- Can still rev to redline, but a bit slower (at least from perception).
- Fuel pump is okay; fuel filter is clean.
- Haven't checked timing/valve lash/compression.


wow 6-8km/l is not bad for a 4wd car :)


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 Post subject: Re: What to check?
PostPosted: 22 Aug 2009 18:42 
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Joined: 04 Jul 2005 13:25
Posts: 1218
Location: Lower Hutt
Country: NZ
Another thing that people don't think about, jap turbo motors are supposed to run on 100RON fuel. I'd guess that a mivec motor is the same.

So if you're running it on 98 then the base timing should be retarded a wee bit(from factory settings), If you're running it on 95 then the timing should be retarded a wee bit more. That will prevent knock and also prevent the ECU from retarding the timing resulting from that.
You won't know unless you're monitoring it with a datalogger.

Steve

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6G72 mivec Twin TDO5 20Gs up and running.
6G72 mivec bored and stroked to 3.4 litres...Frankenmitsi build
6G74 mivec bored and stroked to 3.9 litres....Frankenmitsi build.
6G75 under construction....4.2 litres bored and stroked.Another Frankenmitsi.


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