96 Safari Vortec V6 Will Not Start In Humid Weather

[dragbikebam]

hello all, i need help curing my 96 gmc safari vortec w problems. first of all about a year ago it would mis-fire a little sometimes when just cruising on the highway but as time passed it got worse, to the point now where it will not even start if it is humid outside.now though when it is cool and low humidity it will start right up and run so so.it will mis-fire bad when trying to accellerate from a stop to a low speed cruise in any type of weather..i know this has got to be just some sensor so i replaced the air mass and the temp. sensor on the manifold.after i changed the mass flo it ran great for a short time then went bad again so i thought it was a blem. part and traded it in for another one again it ran good for a few hours then it came back.im affraid it might be the ecm but i need some input from some pros. just trying to save myself any un needed expenses.

[jnpaddison]

I had an issue similiar to that - with a 90 Astro - 4.3 V6 ..

 

it would sometimes start ,, then driving - it would feel like it died - and then start up again ,, then get a huge back-fire ... thought it was fuel ,, fuel filter ,, i tried the quick fix's ,, took it in to a shop ,,

 

with it being sporatic - had a hard time diagnosing it - eventually showed itself as electical ...

i think it was just cheaper to replace the whole distributor assy - problem fixed

[dragbikebam]

I had an issue similiar to that - with a 90 Astro - 4.3 V6 ..

 

it would sometimes start ,, then driving - it would feel like it died - and then start up again ,, then get a huge back-fire ... thought it was fuel ,, fuel filter ,, i tried the quick fix's ,, took it in to a shop ,,

 

with it being sporatic - had a hard time diagnosing it - eventually showed itself as electical ...

i think it was just cheaper to replace the whole distributor assy - problem fixed

i know the fuel pressure is good and fire is good..it seems to be flooding itself out on start up and when trying to cruise under a load..i went ahead and ordered a ecm from napa ealier this afternoon, it was $222.00 with the flash program installed.im hoping this does the trick i cant think of any other component that could cause such havoc on the system as a whole..if it works i will be one happy motorhead...mike

[dragbikebam]

I had an issue similiar to that - with a 90 Astro - 4.3 V6 ..

 

it would sometimes start ,, then driving - it would feel like it died - and then start up again ,, then get a huge back-fire ... thought it was fuel ,, fuel filter ,, i tried the quick fix's ,, took it in to a shop ,,

 

with it being sporatic - had a hard time diagnosing it - eventually showed itself as electical ...

i think it was just cheaper to replace the whole distributor assy - problem fixed

i know the fuel pressure is good and fire is good..it seems to be flooding itself out on start up and when trying to cruise under a load..i went ahead and ordered a ecm from napa ealier this afternoon, it was $222.00 with the flash program installed.im hoping this does the trick i cant think of any other component that could cause such havoc on the system as a whole..if it works i will be one happy motorhead...mike

 

 

well it was not the ecm. still up to its old tricks...i got my $$$ back on the ecm thank goodness.now if i can just find my box of matches and some gas.....mike

[asilverblazer]

Plugs and wires condition?

[Mikeee]

Screens in the dizzy OK?

 

Have you tried....

http://astrosafarivans.org/bb2/

Nothing but Astros n Safaris

[dragbikebam]

well i installed a new coil, ignition module, and crank sensor...i installed the coil and ign. mod. first and no luck. then i put the crank sensor on and after a few tries it finally started.its running good so far but the engine light is on BUT IT STARTED...