i have a 1989 full size 4x4 jimmy. it has a 350 engine and 125,000kms {78,000miles}. truck has been working perfectly until yesterday morning. it turns over but doesn't catch. there is spark at the plug. nice blue glow. i can't tell if it's getting gas or not. but i've poured gas straight into the throttle body but still does not catch. it is cold here, 18c (0f). any help would be appreciated.

 

If you got fuel,and spark, Check your spark plugs.
Bad plugs dont like cold weather. Otherwise, you might have a mechanical problem.

 

You say there is spart "at" the plug! Is the "plug" firing? Pull a plug and re-attach the wire and ground plug. Turn over engine to see if the plugs are actually firing! If so, you may be able to clean, re-gap and re-install. If they are very old(miles) or carboned up, I would replace them!!

 

plugs have less than 5000kms on them. they are all a nice light grey in colour. no carbon on the tips at all.they look quite nice. the plugs are firing. a nice blueish strong spark.

thanks for your input, much appreciated.

 

Okay, when you say 'catch' are you saying you didn't even get a hint of it trying to to start? You might have flooded it.
I have had TBI's freeze up. Take the top off your air cleaner then crank the engine just a bit without pressing on the gas. Then get out and while looking down the throat of the carb, manually open the throttle. You should see some gas squirting out because there should be a little pressure on the TBI. If you don't see any squirt at all, it could be froze. I've thawed them out with hair dryers, heat guns and even a propane torch. BUT, if you use a torch, BE CAREFUL! Keep it 3-4 inches away, and pass it back and forth quickly. Don't keep it in one spot for more than a few seconds. Good Luck!!

 

thanks for the advice chuck. i'll soon check that. probably the weekend. we are preparing for a snow storm for the morning. of all times not to have my 4x4. we are suppose to get 12 inches of snow. i too am leaning towards a freeze up but haven't had a chance to really look at it. i work all day and it's dark and cold by the time i get home. much appreciated.

 

fooled around with the truck a bit. it is getting gas and spark. although i have no way of measuring either. i took the distributor cap off just because, and the rotor and cap were well worn, corroded. i replaced those but still won't start. i also took all the plugs out and check them. they are all burning the same and are not fouled or bad. any other help would be appreciated.

 

A freeze up is not likely to be the culprit this time, if it was when you poured gas in the throttle body the engine should run momentarly, then shut off. Pull the ignition coil wire from the coil and dist. looking for white corrosion on either end, I know it fires fine, out of the cylinder, but under compression it requires alot more voltage to get the job done. If you find any corrosion replace coil wire and, coil or dist. cap which ever is corroded. Other than that, does the engine sound normal when turning over? I have seen Chevys with slack timing chains drive up and be turned off, and not start again until timing chain was replaced. Is it turning over fast enough to start? If the battery is weak there wont be enough power to computer and ignition system for them to function properly. Just a few things to check.

 

thanks for the input. it does turn over fine and i've got a battery charger left on it. the cable on the coil looks fine, no corrosion. i did replace the dist. cap and rotor button. i may have to give up and take this to the garage. so frustrating. the strangest thing is that it work perfect, then all of a sudden wouldn't start. i've got most of my hair pulled out now..lol.

 

You can check for slack in the timing chain by:
1 remove dist cap
2 turn engine over with a socket and ratchet until the timimg mark is at TDC
3 turn engine the opposite direction while watching the dist. rotor, when it moves look to see where timing mark is
4 more than 16 to 18 degrees of crank rotation before the dist. moves could indicate excessive wear on timing chain.
Would not be the firs time I have seen this exact thing happen.

 

i haven't checked the timing yet, but i did check the coil wire on the coil side. it has white corrosion on it. is there any way to check the coil? i'll see if i can find a coil wire. i do know that the plug wires are decent.

 

If you have corrosion on the coil terminal just replace it, I do not know of any way to test it and have not heard of any body that has had any success in trying to clean it.

 

i've been trying to check my timing chain but when i bring the timing marks together i notice that the distributor does not point at number 1 but looks like number 3. is this the answer that i'm looking for? timing chain? thanks for the any help,

 

You may be at top dead center of the exhaust stroke for number 1 cyl. which would have the rotor pointing at the number 6 wire on the cap, try rotating the crankshaft one complete revolution then look at the rotor. What you are trying to find out is how far the crankshaft moves before the camshaft moves, this will show how much slack is in the timing chain.