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What if diesel fuel is used in gasoline operated engine?


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April 02, 2011 1:10AM

It depends upon whether the spark ignition engine is carbureted or fuel injected. It also depends on the ratio diesel:gasoline. If more than a few percent diesel in a carbureted engine it won't run or will run very poorly at best. In a cylinder injected engine it will run well at moderate temperatures up to at least a 1:1 ratio. At ambient temperatures as low as -15 deg. F. engines in good condition will start and run acceptably with up to a 40:60 ratio. Due to the higher specific heat of diesel (energy content of diesel per unit is higher than gasoline) the fuel economy is improved, so long as combustion remains stable. I normally fuel my direct cylinder injected, spark ignition engine with a blended diesel gasoline mixture of between 30:70 and 40:60. My experience using a blend in this range has been an increase in miles per gallon in the range of 10-20% over straight gasoline. If the improvement were due only to the difference in specific heat, then the increase should be only slightly over 10%.

If you accidentally put diesel in a carbureted engine, siphon out as much as you can and fill it with gasoline. You may need to use starting fluid to get it running again. Once you get it started it will smoke until you get all of that initial diesel fuel burned out. If you're down to less than 10% diesel fuel mixed in with the gasoline, it should run OK.

tektuning guy

I have used 1oz.of diesel per gallon of gas for years without any problems and to my surprise it cleans the upper cylinder head and plugs really good.

less engine noise and also feels more powerful , I have to push the gas pedal less to reach desire speed.

keep in mind the diesel has a higher flash point than gas ,which means it burns slower and more heat is needed to ignite, that is why diesels are 14:1 to 22:1 compression ratio ,diesel has more hydrocarbons =C12 H23, Gas=C2 H8 I have

also used 30:70 mixture with full-timing advanced 15 BTDC on 4 cyl no engine knocking no smoke just power (advanced timing creates static pressure) heat to help ignite the mixture . on 10:5 compression ratio like VOLVOLs or BMWs this 30:70 should be no problem and great fuel economy .

The fuel savings come from the torque and efficiency not the ECU ,because less

pushing of the gas pedal is needed for some situations, keep in mind the ECU will always try to maintain 14.7:1 ratio in closed loop operation am sure one

could run an engine @ 17:1 fuel ratio (lean) with a really good spark like MSD and no resistor plugs .Do not try this if you are not experience.