94 Blazer won't start, checked fuel pressure

Hello, i have a problem.

First time i noticed a problem is when i started it one day when it was below -15, started fine but was shaking like it wanted to stall, but after a couple seconds it smoothed out.

Next day, still cold, started up fine, but stumbled and died out. Wouldn't start again.

Pushed it into the garage, got the temp up to 20 plus for a few days now, won't start.

The cap, plugs and wires were replaced last winter, only 4000 miles since then. Wires still look new, not cracked.

Checked the fuel pressure just now, 62, but when i would crank it over the the pressure would jump around that 62 mark, maybe the injector was opening releiving the pressure.

I have an aftermarket tach too and when i am cranking the needle is jumping around, i am not sure if that means the spark is making it to the cylinders or not.

I put a little fuel in the the TB but still won't start, i am not sure how much to put in there though. Don't wanna burn the house down.

Any ideas?

You mentioned throttle body - but we need more clues!

When you have a moment sir, please post year, VIN engine code (8th digit in your VIN), and any other pertinent information, including any recent repairs/mods. I am sure someone here will be eager to help once those little tid-bits are in.

1994 4.3L W Vortec 4wd 4door,

last repair was the heater core about 3 weeks. Changed oil not too long ago. It has ran flawless beside this recent problem.

mpg is as low as 14 in town, and 19ish on highway.

Time for a CPI check. There are countless threads on the subject in this forum. However, I will shorten your quest for information a tad.

This may not prove reliable since you have poured gas into the intake and still did not get her to fire. Leave the intake tubing and filter off overnight, and give the truck plenty of air to breathe in. Tomorrow, go and pull the plastic Vortec cover off the top of your engine, then remove the round IMTV you will see exposed directly underneath it. Inspect the interior cavity with a flashlight - look for any parts that look golden in color. This would be a good indication that your CPI injector/regulator or both along with your "nut kit" has taken a permanent vacation on you.

If you do not see signs of washing, nor smell fuel - leaving the cover and IMTV off, turn the ignition to the "run" position - but do not crank or start it. Let it sit that way for about 15 seconds, then take the key out. Listen for hissing sounds, or the scent of gasoline from the hole that the IMTV came out of.

Using your fuel pressure gague, you can check for "bleed down" that would be indicative of a broken regulator or nut kit, but may not identify an injector problem.

*IF* it all checks out (No washing, no scent of raw fuel, no bleed down) then I would suspect the injector, or a faulty connection leading to the injector. Obtaining a "Noid" light and inserting that into the injector harness will at least show if you have a pulse.

If it flashes on engine cranking, then all of the electronics leading up to the injector are fine, it again has been narrowed down to the injector as being your most likely culprit. But here is the killer question for you:

When was the last time you changed your fuel filter? That too can cause a fuel starvation problem, rough running, total stall/dead engine condition. Also check your basics - how's the air? Are we getting Fuel? Is there a good spark when I crank the engine? So *check* and replace your fuel filter if you cannot remember when it was done - then start worrying about your CPI system as I described above after covering the basics. I am sure others will bring in some better insight than myself shortly. :)

EDIT: Last second thoughts. Hindsight and 20/20 vision seem to work well together...

I just changed the fuel filter now. No change. When cranking it sounds like it wants to start, like some of the cylinders are firing. I put more fuel in the tb, but no change.

After putting the key to 'on', the pressure hits 62 and stays, when i remove key the pump runs for a few seconds more, stops, then the pressure drops to 58 and stays there.

I'll look into the imtv next.

thanks for your help

Edit: I just pulled the spark plug from cylinder #4 and it was dripping with gas. Would this cause a no spark situation if all the plugs were like this? Checked the oil and it appears that i have gas in there now, level was higher then the lasttime i checked, and smells of gas, but after changing a fuel filter the smell of gas is getting harder to tell.

looking into the plenum through the imtv hole i saw no golden brown or smell of gas, saw no pools of gas on passenger or drivers side.

Checked for power to the injector, reads at 8 volts when in 'on' position, then drops to 6ish when cranking, needle didn't jump around much like i thought it would. i am goign to look for a noid light now atthe store.

I cleaned, dried and checked the gap on the wet plug, checked for spark, its there, replaced the plug. Cranked it over and it ran for a second, the best it has in a week.

Pulled the same plug out, wet with gas. Can i assume my coil is too weak? Looks old.

Or is this still an injector issue.

You are chasing a ghost. You said you put fuel in the throttle body and it did not even try to start and your fuel pressure is good to go. So look at a no spark problem.

I changed the plugs and got a new coil. Fired right up. Hopefully it will again in the morning.

The old plugs were pretty fouled up, only 4000 miles on them supposed to be new.

Don't know if this will help, as I have a 93 S-10, but I am now changing out my ignition module on my truck due to poor spark. If yours is similar to mine, it is at the base of distributor. If you can get it out OK you should be able to get NAPA or Advance to run a check on it. They do get weaker as time goes along. Would try that if it acts up some more, or gets hard to start when raining...

I changed the plugs and got a new coil. Fired right up. Hopefully it will again in the morning.

The old plugs were pretty fouled up, only 4000 miles on them supposed to be new.

Change that oil ASAP, it is destroying your bottom end bearings.

Change that oil ASAP, it is destroying your bottom end bearings.

I replaced the oil after i replaced the plugs but before i even thought about trying to start it.

I just hope that cranking it over a few times didn't give the gassy oil time to hurt the bearings.

Starts and runs like a champ now. Thanks for the help guys.

Nah, it wouldn't for short periods.