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My ’88 S-15 had the 2.5 four cylinder and a single fuel injector that was visible when the top of the air cleaner was removed. This was called “throttle body FI” and I think your ’87 V6 has the same crude FI system. It was prone to clogged FI pintels and had the same symptoms as yours. The pintel design in these vehicles was poor (I have read). You could see dripping in the spray coming from the injector.
I would check this out first because it’s easy to remove the top of the air cleaner.
My ’88 S-15 was curable by switching to gasoline that had correct detergents for FI. The federal government began requiring all gasoline to include the correct additives for FI in the early ’90s.
If you can see the fuel flow from the injector and it appears OK, you would want to recheck your ignition system. FIRST check your connections. Then take out the spark plugs and look for signs of fouling or misfire.
Find a video for ignition tune-up.
It would be nice if you had the correct code reader and a lit Check Engine light but a 1987 GM vehicle is antique as far as codes are concerned. You’re about half way between 1965 technology and a 21st century tech. You may be able to diagnose the problem using the same methods we used long ago. You may be unable to diagnose the problem if you treat it like a late model vehicle.I’m here in California. I think most of the K&N filter kits for late model cars will pass CA emissions and if they do not, the container will be clearly marked, “For Off Road Use Only”.
K&N filters can create problems for cars that run MAF sensors (Mass Air Flow). Nearly all newer cars have them, but most (or maybe all?) Hondas use Speed Density systems instead of MAF.
Maybe one of the Honda techs will ring in here and let us know if your car has MAF .Dieselman, I’ve had five K&N filters I installed on Chevy and Pontiac V8s – all carbureted modified engines I put together, and all of them without MAF or Speed Density systems, of course. The problem with K&N filters is that they have to be oiled and it is difficult to get get the amount of red K&N oil correct when the time comes to clean and oil a dirty filter. This presents problems for MAF sensors as they can be hindered by small amounts of oil or dust or crud. This robs power and mpg and would fail a CA smog test.
There are a lot of internet forums where you will hear this repeated by guys without any direct knowledge. I’ll tell you how I know this because (as a teacher) I think it’s important to know how to discriminate between those who repeat hearsay and those with relevant experience.
I used to buy stuff from a local speed shop and they carried K&N. They had a K&N display machine that allowed you to compare a typical K&N filter to a stock paper filter and see the difference in air flow. The owner of the shop knew I had a K&N filter on my PU truck and asked if I had cleaned and re-oiled my filter. I had, so he invited me to bring it into the shop and “test” it on the display. It did not flow as well as the paper filter because it had too much oil in it. I took it home and rinsed it out with some water, just enough to turn the water slightly pink, then dried it in the sun and reinstalled it. The PU had gained some hp and I took the filter back and tested it again, and it flowed as well as the other K&N filter in the display. The owner of the the speed shop told me that MOST K&N owners will over-oil the filter.
I would recommend the K&N to owners of carbureted cars, but especially if you live in CA and have to smog test, you should look into another re-usable filter that doesn’t require oil. If you do a Google search for “Mitsubishi Eclipse Forum”, you will find one, and I bet the experienced guys on the forum will recommend another aftermarket intake for you. I have a 2004 Acura RSX with a stock intake, but I have checked out the RSX forums to see their recommendations, so I know there are alternatives to the K&N that do not require oil.
K&N has an excellent reputation because they have been around a long time, longer than MAF systems.
I hope to hear about what you decide and how it works out for you. Best of luck.I like 3 sheets recommendations. I’ve been using the same methods on cars with electronics under the hood since there have been cars with electronics under the hood. The underside of the hood including the cover that reduces noise can also be cleaned up with Simple Green and a light spray of water. I save some plastic clothing covers from the dry cleaner to cover the engine and the fenders when I clean the underside of the hood. I have an old 4″ paint brush I use to loosen dirt or grease after spraying Simple Green. It has long soft bristles that get into nooks and crannies.
I haven’t owned or worked on any late turbo engines, but I would imagine there would be greater risk in using lower octane fuel with a late turbo engine even if it is able to de-tune.
I’d like to know some more details about the latest direct injected turbocharged engines. It seems to me that they would be able to run more boost without damage. With direct injection, you could inject gasoline on the power stroke as well as the intake stroke.
Ford has a line of engines they call Eco-boost featuring direct injection and turbo charging. There’s an Eco-boost V6 available for the Ford pickup that’s getting very good reviews from the automotive press.
The first engine with direct injection and a turbo was the Alfa Romeo 1750 4 cylinder which is about 6 years old now. It makes about 250 foot pounds of torque and around 235 hp. Alfa (Fiat) has announced they have a new 1800 4 cylinder making 297 hp. They haven’t mentioned a torque rating and they haven’t said the engine is all new or if it’s based on the 1750, but they did say it will be used by Chrysler as well as Alfa. I think they will reveal the engine in a month or two. It should be the cutting edge in turbo technology if Fiat Powertrain gets it right.
I’d be willing to bet that the other manufacturers will follow Fiat and Ford’s footsteps within the next few yearsThanks for the compliment, Trcustoms.
You know a turbocharged engine (with a lower “nominal” combustion ratio compared to a typical non boost engine) will create more combustion pressure under boost. So if you add boost, you increase the pressure and temperature of the charge, so you need higher octane and some enrichment of the mixture.
An engine’s compression ratio number is called “nominal” meaning that the number is merely a name. If I recall correctly, the actual compression ratio (and the resultant pressure/temperature) will change with RPM and with the cam profile. This is why a performance camshaft with greater duration and lift and overlap will benefit from an increase in the nominal compression ratio.
This is why I think the latest advances in direct fuel injection technology will lead to big improvements in turbocharged gasoline engines; smaller engines making the hp and or torque of bigger ones with lower fuel consumption and reduced emissions and CO2.
I have a 2004 Acura RSX with a 2 liter rated at 160 hp. The VTEC system yields 80 hp per liter on 87 octane gasoline, lots of hp per liter, but you would need more displacement or boost to raise the torque.Here’s a thought. One of the worst things you can do to reduce gas milage is move close to your place of work and shorten your commute. I have a 2004 Acura RSX. When I commute 15 miles to works (and 15 miles back home), I get 29-30 mpg. I had an assignment six miles from my home about a year ago and my mpg went to 26-27 mpg.
Years ago, old VWs with air cooled engines might get 29 mpg on long trips and less than 10 mpg on a short commute.“Premium” gasoline is of no higher quality than other gasoline. The difference is in octane rating, a measurement of the fuel’s resistance to combustion. Here’s a secret that few youngsters seem to understand. (As a substitute teacher, I teach high school auto shop sometimes, so I know this one baffles beginners.) Compression (or pressure) creates heat. Spark plugs (and glow plugs) are not necessary for combustion.
Yes, Virginia, there are gasoline engines that run without spark plugs (Homogeneous charge compression ignition or HCCI engines) and there are diesel engines that have no glow plugs (they are hard to start. Glow plugs assist in starting a Diesel, BTW. They shut down seconds after the Diesel engine starts.)
How much heat? In a diesel engine (with a typical compression ratio between 18 to 22 to one) the air entering the combustion chamber reaches over 800 degrees Fahrenheit on the compression stroke. Diesel fuel is injected into the combustion chamber on the power stroke and is ignited by that very hot air.In a gasoline engine, the fuel and air mixture (homogeneous charge) is superheated by pressure (the compression stroke) and is on the verge of combustion when the spark plug adds the additional heat needed for combustion.
This is why you have different fuels for different compression ratios. An engine with a high compression ratio will heat the charge to a higher temperature than an engine with a lower ratio. This means the gasoline for the high compression engine needs to have greater resistance to combustion. In other words, it needs to be capable of reaching a higher temperature without igniting by means of heat alone.
You need to match the fuel to the compression ratio. You need to match an engine which generates X amount of heat on the compression stroke to a fuel that can withstand that heat and “wait” for the spark plug to fire.Steebs, To answer your question, Do you have to use premium in a car when Premium is recommended? Yes… and no.
Back in the day before electronic sensors and controls, when cars had mechanical distributors and 4 barrel carburetors the size of toilets, you needed high octane fuel for high compression engines and if you didn’t use it, you would damage the engine. The engine would protest with noises variously called “knocking” or “pinging” which sounded like the same noise to some us, but the truly stuck-up among the grease monkeys insisted they could hear a difference. I recall I could tell the difference, but nowadays I can’t even remember which term applies to which condition. Anyway, the Bench Racers would smoke their Camels and jaw about red hot exhaust valves and pre-ignition and the young mechanics would commence with an actual diagnosis.
If you have an old gasoline vehicle and it sounds like an old diesel, something is not right; wrong octane fuel, ignition timing advanced too far, carbon deposits inside the chamber that heat up red hot, Communists under the bed…
New vehicles with high compression employ electronics that will detune the engine when you use fuel with low octane rating. There is even a Porsche (or was a couple years ago) that was intended to run fuels of different octane ratings. This was a normally aspirated flat six rated at well over 100 hp per liter, more horseponies per liter than anybody else got out of a liter! My Porsche enthusiast friend told me about it claiming Porsche engineering was superior to anybody else’s and he loaned me a car magazine with an article about the car. I read the article carefully. The Porsche was running compression of 13 or 14 to 1! You could obtain race gasoline at a track to match the high compression ratio, but Premium gasoline from a real world gas station could be used ordinarily as the car would sense it and de-tune. This means the horse ponies would disappear and the gas mileage would drop.
This is why you should run the recommended gasoline for your car if Premium is recommended. You will save no $ running cheaper lower octane. The engine will not run efficiently when your electronics take over and de-tune it behind your back.I have a little 12 volt compressor for airing tires. It has clips that attach to the battery. It works just fine and I’ve had it for several years. I bought it at Costco for $30, maybe $35. If you shop for something like this, check the amp rating for the cigarette lighter type versus the type that clips to the batt.
An adequate compressor will draw greater amperage and the lighter will not be up to supplying it, in my opinion.You’re doing this for the first time, so check your work after the you have finished tightening. Slip the feeler guage in again and see if the adjustment is off as a result of tightening. Too tight? Not good. Select a feeler gauge the next size up and see if it fits.
If your oil loss is that bad and it’s leaking, you’ll see oil under the vehicle on your driveway. If you don’t see it, you must be burning oil. A Chevy small block that old with over 250K miles on it will often burn oil past the valve guides and less often past the piston rings as well. If you remove a few spark plugs and find oil fouling, you know you’re burning oil.
Look at the drive way. Lots of fresh oil there? If there’s just a little, look at the spark plugs. If you find no oil fouling on four of them, then you need to look at all of them.
Go to Google images and enter “spark plugs”. You’ll find pics of oil fouled plugs.
If you have oil fouling, the next step would be a dry and wet compression test. Eric has a free video with perfect instructions on how to do this.
If the engine is toast, you may want to look into a Goodwrench 350 for your PU.