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L24E fuel issues


boyd1234_5
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Can someone please help, i currently own a MR30 hatch, auto 3 speed and it is just burning fuel like its going out of fashion :flamed: (350km to a tank) i really dont think this is right.

I have a 2 1/2 inch exhaust

K& N panel

and thats all can someone please help, thanks,

josh

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Well, I have a 5sp manual, and get around 400+ to a tank. The MR30 is surprisingly thirsty for an EFI engine.

Perhaps make sure the thermostat is working properly, and the temp sensors are working properly.

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My MR30 is using a a lot of fuel too. My temp sensor (gauge) isn't working properly either, dose this affect fuel usage? I have no idea about the other sensor or thermostat.

Another thing regarding L24E fuel, was this engine designed to run on leaded or unleaded? I see neither specified in the manual and have been running it on straght unleaded like the dealer had been for a while. Am I going to stuff the valves if I don't use LRP or an additive?

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My MR30 is using a a lot of fuel too. My temp sensor isn't working properly either, dose this affect fuel usage?

If the temp sensor is not working correctly then the ECU might 'think' the engine is 'cold' and so richen the mixture causing abnormal fuel consumption. But note that (if I remember correctly) there are 2 coolant temp sensors on these cars - one for the ECU and one for the dash gauge. These don't 'talk' to each other and if your gauge is 'not working properly' this has no effect on way the engine runs.

I had an R30 auto hatch for awhile and could get around 400k's from a tank around town, but that was fairly gentle driving. I'd say anything in the 350-400k region around town would be 'normal'. A manual car should do slightly better.

Another thing reguarding L24E fuel, was this engine designed to run on leaded or unleaded? I see neither specified in the manual and have been running it on straght unleaded like the dealer had been for a while. Am I going to stuff the valves if I don't use LRP or an additive?

The R30 will run on unleaded without any effect on the valves or seats. I found that mine tended to ping under load using ordinary unleaded, but otherwise ran fine. These cars were built before the days of unleaded fuel in Oz and probably would have been run on 'super' in those days which had an octane rating roughly similar to premium unleaded.

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Thanks SteveL :)

Josh,

Extractors will help as far as exhaust is concerned, but I don't know if it will reduce fuel consumption. Extractors are mainly to boost power and I'd fit them to mine anyway.

I think someone said that you could increase the intake air flow by cutting a hole in the lid of the airbox, and I think this will help fuel consumption or power output too.

I haven't modified my airbox but I have run her with the lid off and she growls like a beast :D

Running your tires at the maximum reccomended pressure(glovebox plackard) will also save fuel, as will not using the AC and using engine and diff oils, like synthetic, that reduce friction more than regular oils.

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The L24E's are no real power house but adequate for the market they were aimed at . The MR30 sedan and hatch are reasonably heavy for a 2.4 liter SOHC two vale engine with fairly basic management . This is why complete L28 conversions work well . Its the part throttle torque that feels more effortless to drive . With the low cost of RB30E's I'm surprised more of these don"t wind up in MR30's . A much nicer engine with more sophisticated controlls and great fuel economy to boot .

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My old MR30 used to get around 400km/tank when it was fitted with an L28ET & aftermarket ECU (filling up at 1 needle-width below the 'E' mark on the gauge). That was no worse than when it was stock with the L24E.

There are actually 3 coolant temperature 'sensors' fitted to the L24E lower thermo housing:

Coolant gauge

ECU

Thermotime (which is just a switch).

If you're concerned about economy, you need to do the basics - vacuum leaks & timing. Then when you're confident that these 2 things are sorted, check the mixtures throughout out the load/rpm range. You may find leaky/dirty injectors, a leaky cold-start valve, blocked exhaust or a dozen other potential problems.

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Check your 02 sensor as well for if this is not reading properly the ECU might be fooled into thinking it needs more fuel then it does...There are a meriod of problems that can cause high fuel efficency but im feeling that the main cause may be the amount of K's that the motor has done....

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Mine dosn't have one, and its not in the manual either. The ECU isn't that 'smart' comapared to modern ones and must operate off a set program that only goes by air flow and engine temp to regulate fuel usage?

How 'bout a drop in upgrade package with a better ECU and extractors fitted with an O2 sensor? anyone make such a thing?

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