blazer starting problems

[flame1234]

1998 with 4.3. starts most of the time. would not start one morning. had it towed to repair shop. sat overnight in heated building and started fine. couldn't find anything wrong with it. no codes in computer or nothing. had fuel pressure, spark etc.

week later started hard, but it started. ran kind of rough. took to dealer and they wanted to put a fuel pump in it for 850 dollars becasue it was down 5psi. could this really be the problem. it acts like its getting to much gas and it's flooding. another garage said it might be the coolant temp sensor, telling the computer the engine is cold and dumping to much fuel in it. changed that for 30 bucks.

had the truck since 17000 miles, now has 87000. has been a great truck. never any problems other that normal stuff...tune up, brakes etc. any help would be appreciated.

[Southern Comfort]

Welcome to the blazer forum. Sorry about a late reply to your post, I just found it. Have you look in the How TO's on this forum. Blazee has generated a really good post in the how To's. Here is the link to it, look it over and see if it relates to your blazers problem.
http://www.automotiveforums.com/vbul...d.php?t=450484
Lets us know if it does or not. Maybe we can explore other avenues. I apologize for the late reply.
SC

[MT-2500]

Get a fuel pressure gauge on it and check it out.
Even 1 lb under specs can give you a no start cold.

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

[flame1234]

if i remember...the mechanic said it had 60lbs. this was before it started. this was just after it came off the flatbed tow truck.

[flame1234]

Originally Posted by MT-2500

Get a fuel pressure gauge on it and check it out.
Even 1 lb under specs can give you a no start cold.

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

so when the dealer says that it is 5 lbs out of spec that more than likely the fuel pump is going bad? and that really is the root of my problem?

[MT-2500]

Originally Posted by flame1234

so when the dealer says that it is 5 lbs out of spec that more than likely the fuel pump is going bad? and that really is the root of my problem?

Yes and no on fuel pump being bad.
Yes 5 lbs low on fuel pressure will give you a no start when cold.
If the fuel pressure is 5 lbs low you need to run the full fuel pressure test I posted.
To see if it is the fuel pump or other things.
A bad fuel pressure regulater or internal leakage or bad wiring to fuel pump can also be a cause of low fuel pressure.
Pinch off fuel return line and check pressure and also check direct pressure at fuel filter and make sure fuel pump is getting full 12 volts and good ground.
MT

[534BC]

Your post stating that it acts like it's flooding could be the fuel is leaking into the intake system b-4 the injectors? The longer it sets the worse it gets until it sets for a few days.

To test turn key (and fuel pump) on every hour for a number of hours and then hold wide open and crank it like crazy noticing black smoke uot pipe until it finally starts.