1998 Buick LeSabre Won't Start

Hi,are the injectors working? I would check the earth connections on the block(on alternator bracket in particular) and the body (inner fenders behind battery?).

Could be a cam gear sheared manufactures and there infinite wizzdum of designed obsolescence liked to use plastic teeth on there cam gears.

A way would be to hold a rag over the exhaust pipe while engine is cranked too see if there is a suction pulse in the exhaust that may indicate a bent valve resulting from gear failure.If so then a Compression test to pinpoint cylinder with a leak down test to confirm.

GL

espically easy to damage if it overheats

As a quick and easy to check the valve timing, put your hand over the air intake in a manor that will block ALL air from entering the engine, Have an assistant Step on the throttle and turn the engine over.

If you have suction, you will also have compression, and the valve timing will be correct, or at least close enough to start.

I had one like that - sort of. My symptoms were that it wouldn't start on coolish damp mornings and all those things you mentioned being fine were also fine. Ya' know what? IF the computer thinks it's hot out when it's really kind of cold - it won't give enough fuel to fire. It'll be close - maybe sometimes 'puff' a little - but not fire enough to start up.

Check the temp. sensor.

Funny thing - if it was Minnesota cold - it started fine. Some sort of threshold thing where the sensor reading got low enough to bump the injecter command into 'cold start' mode, I reckon.

try this. Pour about 1/2 oz of gasoline into the intake manifold where it will run into the engine or lay in the manifold, then try to start it. If the problem is FUEL related, it will certainly fire and try to run until that fuel is exhausted. IF you do not get ANY response--it doesn't try to start and run--then ignition is the problem--timing most likely is way off or?

Does it fire at all? Any coughs, sputters, backfires? How do you know it has spark? Pull a plug or two; if they're wet and smell of gas, you have fuel and therefore it is an ignition problem. If they are dry, then it's an EFI problem. Unfortunately, on cars today everything is computer controlled, so you just about have to take it to a garage with the eqpt to troubleshoot. About all you can do is check for blown fuses and loose connectors.

Remove air cleaner duct from throttle body. Carefully spray starting fluid into the throttle body while assistance rotates engine and see if it fires. If engines starts you have a fuel filter, pump or regulator problem. If it does not start check the resistance on the crank and cam position sensors. If they are ok remove cam position sensor and rotate engine. Look at the end of the cam to see if is rotating. If no you have a broken cam shaft.

Good luck,

Tim H

If an engine is to run, it takes spark at the correct time, the proper amount of combustible fuel, the proper amount of compression, and air moving through the engine. For no starts, start your quest for knowledge by testing the spark. It should have a minimum of 25 KV potential at the spark plugs. This should be a nice blue thick spark jumping about 3/8" gap. You need to have fuel injection pulse, and fuel pressure. If you lack a lab scope to test the injection pulse, you can pull out a spark plug and look to see if the plug is wet, give the engine a crank and watch for fuel vapor to be blown out of the plug hole. If the plug is dry, after an extended crank, there is a pretty good indication that the engine is lacking fuel. If no fuel, you might try giving a few small shots of carburetor cleaner or propane into the intake while cranking, or you can use propane to run the engine on. I like propane, since it will not wash down the cylinder walls, and will not fowl the plugs if you get the mixture a little on the rich side. A static compression test is good, although it will not tell you if air is being pumped through the engine. If you want to know if air is being pumped, have someone crank the engine, while you burp the compression gauge, then observe what the needle does. If the needle comes back up to the pressure of the static test, then air is being pumped. If not, you will have an air restriction, which could be restricted exhaust, or a valve timing problem.

I see problems like this on a daily basis. Do the basics first, and most times you will come to a resolution of the problem.