96 blazer stalls when hot

[maxisp2000]

This is the same problem.

What makes you think that there has not been the proper testing?

The OP thought it was the same also.

Comparing notes helps us.

Splitting this thread does not help.

[maxisp2000]

I answered but someone moved my answers to a different thread.

[maxisp2000]

This is two years running for me and goes away in the winter.

Bought car 133, 000 then:

Fuel pump failed, replaced.
AC failed, rebuilt. Battery fails, replace. Replace HVAC fan, iductor control and dash panel. No high fan setting available in summer.
ICM failed, replaced. While there changed coil, cap, rotor, wires, s plugs, PVC. Drove 1000 miles in the southwest summer, no problems. Test EGR OK.
Torque converter lockup solenoid failed, replaced.
Car fails when temp gets up to 80 degrees.
Automatic tensioner, alternator bearings failed, water pump bearings, idle pulley. Replace.
Change engine coolant temperature sensor.
Hit object (rock?), radiator fan explodes. Replace all belts hoses, radiator fan, thermostat and radiator.
Intake manifold gasket blew. Peanut butter in engine. Cleaned and replaced gaskets, seals and o-rings. Replaced fuel regulator. Discover vapor scavenge not connect to back of car. Connect. Replace all vacuum lines. Original light whistle on acceleration disappears.
Check engine light. Bad fuel cap.
Air temperature damper door actuator fails. High heat on full time. Remove dash and replace.
Car runs 2000 miles after intake manifold gasket repair no codes, no problems 20 miles a gallon, up from 17.
Ambient temp 80 and car fails after 25 miles on the freeway. Just get off the freeway safely and coast into parking lot. Cool off 10 minutes, then go 6 miles home with no problem.

Hey! They change the gas here in the spring for the summer, by adding or taking away alcohol and back in the winter. Do they do that in other states?

[MT-2500]

Originally Posted by maxisp2000

This is the same problem.

What makes you think that there has not been the proper testing?

The OP thought it was the same also.

Comparing notes helps us.

Splitting this thread does not help.

Looks like it has done been split to a new thread.
Not by me.
But thanks to someone.
Good deal.
Now
If you want help give us less head and some answers to post 2.

[maxisp2000]

Fuel pressure 58 changes with accel or idle speed.

This problem is two years running for me and goes away in the winter.

What I have done. Bought car 133, 000 then:

Fuel pump failed, replaced.
AC failed, rebuilt. Battery fails, replace. Replace HVAC fan, iductor control and dash panel. No high fan setting available in summer.
ICM failed, replaced. While there changed coil, cap, rotor, wires, s plugs, PVC. Drove 1000 miles in the southwest summer, no problems. Test EGR OK.
Torque converter lockup solenoid failed, replaced.
One month later, car fails when temp gets past 80 degrees.
Automatic tensioner, alternator bearings failed, water pump bearings, idle pulley. Replace.

Change engine coolant temperature sensor.
Hit object (rock?), radiator fan explodes. Replace all belts hoses, radiator fan, thermostat and radiator.
Intake manifold gasket blew. Peanut butter in engine. Cleaned and replaced gaskets, seals and o-rings. Replaced fuel regulator. Discover vapor scavenge not connect to back of car. Connect. Replace all vacuum lines. Original light whistle on acceleration disappears.
Check engine light. Bad fuel cap.
Air temperature damper door actuator fails, because they fail when they are this old and you take the battery on and off. High heat on full time. Remove dash and replace.

Car runs 2000 miles after intake manifold gasket repair no codes, no problems 20 miles a gallon, up from 17.

Ambient temp 80 and car fails after 25 miles on the freeway. Just get off the freeway safely and coast into parking lot. Cool off 10 minutes, then go 6 miles home with no problem.

I cannot test something acting up because nothing is acting up until it gets hot. No codes. no codes in memory.

Hey! They change the gas here in the spring for the summer, by adding or taking away alcohol and back in the winter. Do they do that in other states?

[mcdon26]

Originally Posted by maxisp2000

This is two years running for me and goes away in the winter.

Bought car 133, 000 then:

Fuel pump failed, replaced.
AC failed, rebuilt. Battery fails, replace. Replace HVAC fan, iductor control and dash panel. No high fan setting available in summer.
ICM failed, replaced. While there changed coil, cap, rotor, wires, s plugs, PVC. Drove 1000 miles in the southwest summer, no problems. Test EGR OK.
Torque converter lockup solenoid failed, replaced.
Car fails when temp gets up to 80 degrees.
Automatic tensioner, alternator bearings failed, water pump bearings, idle pulley. Replace.
Change engine coolant temperature sensor.
Hit object (rock?), radiator fan explodes. Replace all belts hoses, radiator fan, thermostat and radiator.
Intake manifold gasket blew. Peanut butter in engine. Cleaned and replaced gaskets, seals and o-rings. Replaced fuel regulator. Discover vapor scavenge not connect to back of car. Connect. Replace all vacuum lines. Original light whistle on acceleration disappears.
Check engine light. Bad fuel cap.
Air temperature damper door actuator fails. High heat on full time. Remove dash and replace.
Car runs 2000 miles after intake manifold gasket repair no codes, no problems 20 miles a gallon, up from 17.
Ambient temp 80 and car fails after 25 miles on the freeway. Just get off the freeway safely and coast into parking lot. Cool off 10 minutes, then go 6 miles home with no problem.

Hey! They change the gas here in the spring for the summer, by adding or taking away alcohol and back in the winter. Do they do that in other states?

yes, they adjust the gas here well, I don't think it has much to do with this though. One thing I did want to ask you though is you said you get the evap small leak code. Have you replaced the gas cap and has that code still come up? Mine just shot that code off again today and as usual I was low on fuel. I'm thinking there may be something to this. when you replaced your vacuum lines, did you replace the one that went to fuel pump? I believe there is one there.

Anyway, I purchased a fuel pressure test gauge today and hooked it up to see what's going on with the fuel pressure. So far, key turned on it jumps up above 60psi then immediately goes to 55psi. Start the motor and it jumps up over 60 and immediately down to 55 again. At idle the needle jiggles at 55psi. I brought the RPMs up to 3000 and as soon as I press on the gas pedal it jump up to at least 65psi then immediately down to 55psi while holding at 3000rpms. I let off the gas and the pressure drops below 50psi then immediately back up to 55. Now, when I turn the key off, then pressure drops down to 43-44psi. If I turn the ignition on, but not start the vehicle it comes back up above 60 then drops back down to 55. Go through the same cycle, turn off the ignition and pressure drops to 43-44psi. I'm currently doing a leak down test on it so we'll see what happens next. I've hooked it up temporarily so I can watch it while driving.

[MT-2500]

Originally Posted by maxisp2000

Fuel pressure 58 changes with accel or idle speed.

This problem is two years running for me and goes away in the winter.

What I have done. Bought car 133, 000 then:

Fuel pump failed, replaced.
AC failed, rebuilt. Battery fails, replace. Replace HVAC fan, iductor control and dash panel. No high fan setting available in summer.
ICM failed, replaced. While there changed coil, cap, rotor, wires, s plugs, PVC. Drove 1000 miles in the southwest summer, no problems. Test EGR OK.
Torque converter lockup solenoid failed, replaced.
One month later, car fails when temp gets past 80 degrees.
Automatic tensioner, alternator bearings failed, water pump bearings, idle pulley. Replace.

Change engine coolant temperature sensor.
Hit object (rock?), radiator fan explodes. Replace all belts hoses, radiator fan, thermostat and radiator.
Intake manifold gasket blew. Peanut butter in engine. Cleaned and replaced gaskets, seals and o-rings. Replaced fuel regulator. Discover vapor scavenge not connect to back of car. Connect. Replace all vacuum lines. Original light whistle on acceleration disappears.
Check engine light. Bad fuel cap.
Air temperature damper door actuator fails, because they fail when they are this old and you take the battery on and off. High heat on full time. Remove dash and replace.

Car runs 2000 miles after intake manifold gasket repair no codes, no problems 20 miles a gallon, up from 17.

Ambient temp 80 and car fails after 25 miles on the freeway. Just get off the freeway safely and coast into parking lot. Cool off 10 minutes, then go 6 miles home with no problem.

I cannot test something acting up because nothing is acting up until it gets hot. No codes. no codes in memory.

Hey! They change the gas here in the spring for the summer, by adding or taking away alcohol and back in the winter. Do they do that in other states?

Yes they go from a winter to a summer blend.
Your fuel pressure is low.
4.3 V6 specs are 60/66 lbs.
You should see 64-65 cold start and 62-64 running on road.

If you did not replace the fuel pump with a Delphi pump you may be in bad shap there.
Airtex and other aftermarket fuel pumps are junk.
Very high fail rate and almost all are low on pressure.

Needs to be tested when it quits or acts up.

I would hook up a fuel pressure gauge and tape it to outside windshield or out side mirrow and watch fuel pressure on the road and see if it drops below specs when it quits or acts up.

If not you need to check for loss of spark to plugs when it quits.

Also with a light whistle you need to check back pressure on exhaust.

If it is acting up that bad it should have some stored or past or present code or data reading out of range..
Is fuel trim data holding good or going high or low.
What is the camshaft retart setting reading?

[maxisp2000]

I have put on three gas caps since I got the car. The caps have a space above the seal that allows the seal to be pushed up higher and higher when you tighten it. Lately I just push the seal back down until I get gas again. It goes away.

My scavenge solenoid was connected to a line that went down under the firewall bulge, but I found it wasn't connected. That solenoid opens to pull the vapor for a few seconds after you turn off the key.

My fuel pressure behavior is very similar. It starts at 58 and varies like you stated.

I was wondering if the alcohol dis-associates from the gas at high temp and causes a vapor lock type situation.

At one time, I thought it was a fuel pump motor overheating and shutting off problem, so I kept the tank full to make sure there was enough heatsink (the reason it's in the tank) to cool the motor, but that didn't work last year.

I do have a problem with the vacuum switch on the transfer case needs to be replaced. That's the shift assist for 4WD low.

I would like to know if someone with a similar problem of the car stalling at hot ambient temperatures tracked it back to the fuel injector, spider or VCM.

There are thousands of this type of problem for the engine in every application with the same problem when Googled. None show solved.

[maxisp2000]

OK,
I am waiting for it to warm up again.

Fuel pressure at 58 idle, ~65 @ 3000 rpm. Will check driving around.

Whistle I had since bought the car was leaking intake manifold seal in back. Fixed.

What's a good way to check spark when you have to start the car too?

Once, I got ICM voltage high code. That indicated floating grounds to me so I went through all cables and ground connections and cleaned them and polished them and that went away. They were untouched since the factory installed them.

No other codes stored. I drove around with an engine status monitor for awhile and got no out of spec readings on any sensor. Fuel trim was unremarkable.

I don't know about any change in the camshaft that would run cold and stop the engine hot. I would be interested to know how that would work.

[MT-2500]

Originally Posted by maxisp2000

OK,
I am waiting for it to warm up again.

Fuel pressure at 58 idle, ~65 @ 3000 rpm. Will check driving around.

Whistle I had since bought the car was leaking intake manifold seal in back. Fixed.

What's a good way to check spark when you have to start the car too?

Once, I got ICM voltage high code. That indicated floating grounds to me so I went through all cables and ground connections and cleaned them and polished them and that went away. They were untouched since the factory installed them.

No other codes stored. I drove around with an engine status monitor for awhile and got no out of spec readings on any sensor. Fuel trim was unremarkable.

I don't know about any change in the camshaft that would run cold and stop the engine hot. I would be interested to know how that would work.

You need to get the fuel pressure up to par and make sure it is not dropping off when it acts up.
After you get that fixed then check for lose of spark if still acting up.

To check spark I hook up a push button starter button to starter system.
Make sure it is in park before pushing button and pull coil wire or wire off of spark plug and key on and crank engine over.
You can use a screw drive in end of wire or a spark jumper tester to see if you have good hot blue loud spark.

Spark should jump 1 1/4 in or more and snap a good blue spark.

Camshaft retard setting is the position of rotor to plug wires terminals.
Should read out as close to - or plus 0 degrees as you can get it.
Not over 1 or 2 degrees - or plus.

If reading 25 degrees you have sensor problem.

If over 3 degrees off it increase the spark to much and overloads coil and ign system.

[mcdon26]

Originally Posted by mcdon26

yes, they adjust the gas here well, I don't think it has much to do with this though. One thing I did want to ask you though is you said you get the evap small leak code. Have you replaced the gas cap and has that code still come up? Mine just shot that code off again today and as usual I was low on fuel. I'm thinking there may be something to this. when you replaced your vacuum lines, did you replace the one that went to fuel pump? I believe there is one there.

Anyway, I purchased a fuel pressure test gauge today and hooked it up to see what's going on with the fuel pressure. So far, key turned on it jumps up above 60psi then immediately goes to 55psi. Start the motor and it jumps up over 60 and immediately down to 55 again. At idle the needle jiggles at 55psi. I brought the RPMs up to 3000 and as soon as I press on the gas pedal it jump up to at least 65psi then immediately down to 55psi while holding at 3000rpms. I let off the gas and the pressure drops below 50psi then immediately back up to 55. Now, when I turn the key off, then pressure drops down to 43-44psi. If I turn the ignition on, but not start the vehicle it comes back up above 60 then drops back down to 55. Go through the same cycle, turn off the ignition and pressure drops to 43-44psi. I'm currently doing a leak down test on it so we'll see what happens next. I've hooked it up temporarily so I can watch it while driving.

Alright, no pressure reading on the gauge this morning. turned the key over started right away. Cold start 58psi with ambient air temp at 45 degrees. While driving within the first 15 minutes, under acceleration, the pressure would increase from 58 to 67psi. 67psi under acceleration, 58 at cruising, and 58 at idle. By the time I reached worked, 20 or so miles away, acceleration pressure was about 64, cruising was 55 and idle was 55psi.

Occasionally under accelleration, I would get a split second massive spike that I couldn't even tell you how high it got because it happens way to fast. All I can say is massive spike for a fraction of a second.

Reach work, turn the motor off and pressure dropped to 42psi. turned the key on, pressure went up to 62psi.

The fuel pressure gauge wasn't the esiest of things to line up and get on for some reason and is only finger tight based on instructions. I did not feel any leaks from the connection so I hope the leak down is accurate. This evening I plan on removing the gauge and reseating it and redoing the leak down test to be sure.

[MT-2500]

Originally Posted by mcdon26

Alright, no pressure reading on the gauge this morning. turned the key over started right away. Cold start 58psi with ambient air temp at 45 degrees. While driving within the first 15 minutes, under acceleration, the pressure would increase from 58 to 67psi. 67psi under acceleration, 58 at cruising, and 58 at idle. By the time I reached worked, 20 or so miles away, acceleration pressure was about 64, cruising was 55 and idle was 55psi.

Occasionally under accelleration, I would get a split second massive spike that I couldn't even tell you how high it got because it happens way to fast. All I can say is massive spike for a fraction of a second.

Reach work, turn the motor off and pressure dropped to 42psi. turned the key on, pressure went up to 62psi.

The fuel pressure gauge wasn't the esiest of things to line up and get on for some reason and is only finger tight based on instructions. I did not feel any leaks from the connection so I hope the leak down is accurate. This evening I plan on removing the gauge and reseating it and redoing the leak down test to be sure.

Fuel pressure is a little low.
You should be seeing 62 t0 64 normal speed crusing.

Make sure direct full pressure or with return luine blocked/pluged is 95-105 lbs.

If good full pressure the fuel pressure regulator may be off.

But you need to drive it long enought for it to act up or quit and check fuel pressure then.

If it holds good then go for a spark / test when no start.

Let us know how it goes.

[mcdon26]

alright, looks like I definately have a leak down prob. Assuming this is most likely caused by the spider assembly/cpi nut kit/fuel regulator leaking. Correct? Is it possible this could be caused by the fuel pump?

Last question, could this also be causing the stall issue on hot days. Leak possible getting worse on hotter days and flooding the intake? I couldn't imagine all the cylinders getting too much fuel. Any thoughts? I guess I could also take out the spark plugs to see if I had fouled out any. it's only been about 3 weeks since the motor was replaced and spark plugs were replaced at that time. I just don't readily see how the issue could be related.

[MT-2500]

Originally Posted by mcdon26

alright, looks like I definately have a leak down prob. Assuming this is most likely caused by the spider assembly/cpi nut kit/fuel regulator leaking. Correct? Is it possible this could be caused by the fuel pump?

Last question, could this also be causing the stall issue on hot days. Leak possible getting worse on hotter days and flooding the intake? I couldn't imagine all the cylinders getting too much fuel. Any thoughts? I guess I could also take out the spark plugs to see if I had fouled out any. it's only been about 3 weeks since the motor was replaced and spark plugs were replaced at that time. I just don't readily see how the issue could be related.

leak down can be fuel pump check valve or hose or line or nut kit or fuel pressure regulator.

Stall can be cause by low or no fuel pump pressure.
Leak inside intake or leaking pressure regulator can cause a hard or flooded restart.

First thing confirm good strong fuel pump pressure at all times.
And then go from there.
Get a fuel pump pressure gauge on it and drive it 30 or more minutes watching pressure untill it quits or acts up.
A good pump will deliver 95-105 lbs of direct fuel pressur.

[maxisp2000]

That sounds right. When it gets too hot outside, maybe the pintles or injector leak and the car floods hot.
But I would think that there is a code for too rich, beyond tolerances.
When my fuel pump went out the code set was for one bank too lean, it was symptom of low fuel pressure.