89 full size jimmy wont start

i have a 1989 full size 4x4 jimmy with a 350 engine. it turns over but won't catch. there is spark at the plugs. the plugs are new. there is only 125000 kms on this vehicle. the fuel pump makes its usual hum when the key is turned on. i even poured gas straight into the throttle body but it still didn't catch. it's cold here -18c, but it's been colder. i did notice on sunday it did stumble a bit once but worked fine the rest of the day. it wasn't until this morning that it wouldn't start. this morning was -25c but again i've never had any issues before. i buy my gas at the same place all the time for all my vehicles. any help would be appreciated.

Have you ever changed cap, rotor and wires?
Have you checked for any codes?
Check for worn distributor shaft and gear.
Igntion module may be weak.
What does the spark look like color wise? I believe blue is good, orange is weak.

Just for the heck of it try disconnecting the left, (Drivers side), injector.
See if it will start.

Just for the heck of it try disconnecting the left, (Drivers side), injector.
See if it will start.

didn't see your message until this morning. what would that do, just curious. and how do i disconnect it?

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.

I had an early model 1/2 ton chevy with a 350. The injector was pouring fuel into the throttle body. So the vehicle would flood disconnected that injector and the vehicle would start. Customer decided not to persue that matter further so I did not get a chance to fully diagnose the problem.

This is A TBI injected vehicle ?

yes it is. now that you mentioned it, the driver side injector seems to be putting out more gas then the other. how can i disconnect it? it looks like i can just pull it of place. is that correct? thanks for the information. much appreciated.

Just for the heck of it try disconnecting the left, (Drivers side), injector.
See if it will start.

i tried what you mentioned. i pull the drivers side off first, but with no result. then for kicks i tried the other one, still nothing. i pulled the coil wire off at the coil side and it was corroded, so i cleaned it up. still nothing.

Is the battery still holding up after all this or does it need charging ?

Have you tried starting fluid instead of gas. Yea I know Pro's and Con's.

Have you done a compression test on the cyclinders just out of curiosty ?

Check to make sure you are getting a nice bright spark at the plugs. With the corrosion you mentioned the coil could be bad or going.

Do you have the HEI ignition system, Coil mounted on the top of the distributor cap ?

Is the battery still holding up after all this or does it need charging ?

Have you tried starting fluid instead of gas. Yea I know Pro's and Con's.

Have you done a compression test on the cyclinders just out of curiosty ?

Check to make sure you are getting a nice bright spark at the plugs. With the corrosion you mentioned the coil could be bad or going.

Do you have the HEI ignition system, Coil mounted on the top of the distributor cap ?

the battery is on a charger and has been cause i've been over zealous sometimes. my patience is growing thin...lol.

haven't done a compression test.

i am getting a nice bright blueish spark.

the coil is mounted next to the distributor.

Have you tried a fuel pressure test ?

Is there any hint that it is trying to fire, popping, sputter, etc. ?

If you are getting a bright spark it kind of rules out the ignition system.

Just for the heck of it pull the distributor cap and see if the rotor is rotating, may also want to bring it up on Top Dead Center and see where the rotor is pointing.

Hope something turns up.

Have you tried a fuel pressure test ?

Is there any hint that it is trying to fire, popping, sputter, etc. ?

If you are getting a bright spark it kind of rules out the ignition system.

Just for the heck of it pull the distributor cap and see if the rotor is rotating, may also want to bring it up on Top Dead Center and see where the rotor is pointing.

Hope something turns up.

thanks for the info. there is absolutely no hint of firing. it just turns over. i'm going to have to check for timing now and i will take the cap off and check that. i have to wait for the weather to clear up. it's sitting in the yard and the snow is piling up.
thanks again.

update. 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,

Hee is a thread explaing the distributor installation with pics, I am not sure where #3 is on the cap but this will show where the rotor should be at when on top dead center. Towards bottom of page it has a pic as to where the number 8 is stamped on the distributor housing is. This thread is in the How to/Techincal Info section of this form.

http://www.automotiveforums.com/vbulletin/showthread.php?t=881442

If the rotor does not line up within a degree or so I would first remove the distributor from engine and inspect the gear and rool pin to make sure the pin has not broken and the gear has turned a few degrees thus causing your problem. All looks well with distributor then I would take a better look at timing chain to make sure it has not jumped a few teeth.

good luck

Hee is a thread explaing the distributor installation with pics, I am not sure where #3 is on the cap but this will show where the rotor should be at when on top dead center. Towards bottom of page it has a pic as to where the number 8 is stamped on the distributor housing is. This thread is in the How to/Techincal Info section of this form.

http://www.automotiveforums.com/vbulletin/showthread.php?t=881442

If the rotor does not line up within a degree or so I would first remove the distributor from engine and inspect the gear and rool pin to make sure the pin has not broken and the gear has turned a few degrees thus causing your problem. All looks well with distributor then I would take a better look at timing chain to make sure it has not jumped a few teeth.

good luck

it's more than a degree or so. if the rotor was suppose to be on number 1 then it would be pointing at the passenger side headlight. but right now at tdc the rotor is pointing at the passenger seat. quite a difference. thanks for your information and time.

Have you taken the crankshaft dampner pulley off by chance?
Could it be possible that the woodruff key that holds the dampner and lower timing chain sprocket to the crankshaft has sheared and has thrown the timing off or the gear on distributor shaft has spun.

If I fiqured correctly by looking at the picture of the distributor in the tuitorial that the # 8 on the distributor housing should be pointing towards the drivers headlight which would mean that rotor is about 180 degrees off.

Just some more thoughts, I know its frustrating.