90 excel missfiring


Old 07-22-07, 07:31 AM
Rollie73's Avatar
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Join Date: Mar 2007
Location: Bras D'Or, Nova Scotia ,Canada
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90 excel missfiring

Hey all,
I have an old Hyundai Excel (1990) that I only use for beating back and forth to work. Normally the car works great but lately it devolped a miss under heavy loading conditions, like when going up hills or heavy acceleration. I have tried a complete tune up (new plugs, wires, distributor cap,rotor button,air filter and fuel filter. I have even tried advancing and retarding the timing by moving the dist. cap but to no avail. This is driving me crazy, if I dont get it fixed soon, I'm buying a new(new to me)car. Could this car need a timing belt/chain??
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Old 07-22-07, 12:51 PM
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How did the plugs look when you changed them?, and how do they look now?

I doubt it is fuel filter as you said nothing about lack of power - only a miss. Does the miss seem to be one-cylinder related?, or can't you tell?

Does this 1990 Hyundai have lots of emmissions control devices/computer controlled?, where every nuance of those affects gas mixture and timing? What type of carburetion does this have?

On the bad news side it is possible to have a worn cam lobe due to age of engine/bad oiling/bad metal on lobes and create condition of insufficient lift. During cruising, you require less mixture and bad lift won't matter so much. But during load condtions where all cylinders have to really 'work', and drink in and expell more mixture, one cylinder becomes way more imbalanced and can actually affect the flow pattern to all cylinders depending on which valve it is (intake or exhaust). Not that this IS your problem, but I am throwing it out there. Do valves clack a lot?

Does your car burn oil or drink anti-freeze?

Possible break down in coil. (if various cylinder missfiring) Is plug wires seated in distributor cap correctly (some can be a little tricky)

Number of things.
Old 07-22-07, 07:56 PM
Rollie73's Avatar
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Join Date: Mar 2007
Location: Bras D'Or, Nova Scotia ,Canada
Posts: 173
Car burns no major amounts of oil
small amount of smoke on first start of the morning then nothing

uses no antfreeze

plugs looked ok and still look good (slightly brown from the heat)

Changed the coil still no luck

Miss seems to be just one cylinder If it starts to miss and you let off the accelerator the car will settle down and work fine until u hit the accelerator again

no valve noise

Regular 2 barrell carb no serious emission controlls

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