wont start on certain days

[455_SS]

it seems my wifes bravada has its lazy days. it wont start then two days later it starts i figure it gets tired or something...its been 3 or 4 times this has happend and it just wont start for about 2 days then back to normal. We have like a on going bet on days it will act up,Just started this so called winter seems to be on rainy/drizzle days with a little cold. Please help luckly its always at the house when this happens.....

[ericn1300]

sounds like an ignition prob. water or condensation problem

more info please. what year and engine? does it crank and not start?

[455_SS]

sorry about late response road trip. 97 Olds Bravada the engine is a 4.3 ,when i try to start it just turns over,every few turns feels like its gonna start but doesent,step on the gas a little and it sounds harder to start. after the first few times this has happend i thought it could be condensation or water but where would it be forming????? the day i started the thread i put some HEET in the tank but really dont know if it worked due to road trip.

[MT-2500]

When it will not start check for good hot spark to plugs.
If you have that move on to a fuel pressure check.
Check it also when you have a no start.
Hard to start cold.
Check cold start fuel pressure.
Check engine running fuel pressure.
Check engine running on the road fuel pressure.
Then shut it off and watch for fast leak down.
Pinch off at rubber part or block off return line and check full pressure.
Later V6 and V8 gm engines should have 60-66 fuel pressure.
Cold start should be 64-65 lbs of pressure.
If you do not have full fuel pressure on a cold start the injectors will not squirt fuel.
Do not leave home without it.
Engine running should be 60-66 lbs pressure depending on engine load.
Full pressure with return pinched off should be 75-85 or more.
And if it has a fast leak down after shut off you have a leak.
Post back fuel pressure readings.
MT

[ericn1300]

i don't think it's a fuel problem. to intermintent. the only time i've heard of intermintent fuel problems is when the engine or fuel pump is hot and this is a cold start problem.

to check for spark is easy, pull a plug and lay it against the block and have someone crank the engine while you look for spark.

to check for a fuel problem is just as easy. pull the air supply hose off the manidold and shoot some starter fluid into the throttle body and see if it kicks over.

[MT-2500]

Originally Posted by ericn1300

i don't think it's a fuel problem. to intermintent. the only time i've heard of intermintent fuel problems is when the engine or fuel pump is hot and this is a cold start problem.

to check for spark is easy, pull a plug and lay it against the block and have someone crank the engine while you look for spark.

to check for a fuel problem is just as easy. pull the air supply hose off the manidold and shoot some starter fluid into the throttle body and see if it kicks over.

Go easy on that starting fluid. To much of that stuff and you can blow it up.
Never us anything stronger than carb cleaner.
The chev V6 MPI is a breed of it own on fuel pressure and cold start..
On a cold start it has to have full fuel pressure or the injectors will not squirt.
Even 2-3 lbs below specs will give cold start problems.
They will run and start all day with lower pressure but the next moring when cold you will have to have full pressure or it will not start.
And believe me I learned it the hard way.
MT

[Chris Stewart]

Give it up MT.....what did you blow up, and don't leave any of the juicy details out

[ericn1300]

Originally Posted by Chris Stewart

Give it up MT.....what did you blow up, and don't leave any of the juicy details out

He is right about being careful with the starting fluid. when i was a teenager i used a little to much on the tractor and got it to turn over backwards some how. man, Dad was pissed.

[MT-2500]

Originally Posted by Chris Stewart

Give it up MT.....what did you blow up, and don't leave any of the juicy details out

Well I did not do it.
But i have saw valve covers and oil pans blowed off and on this newer stuff the plastic intakes blow like a bomb.
You can always tell a starting fluid person by the burnt off eyebrows and singed hair and mustashes. And also a assortment of Band-aids in various places.
And that incitement expression on there face.
All telltale signs of starting fluid people.