YACT: Startin' & Stallin'

[VTEC01EX]

I'm borrowing my parents' 97 Blazer 4WD 4-dr for the next few weeks. 66K miles. Unfortunately, it seems to have developed an interesting quirk. It takes rather long to start (compared to how it always used to start) - maybe 6 seconds of cranking compared to the usual 1 to 2. That's a slow count to 6, too. So you get it going, and start driving, and maybe 1 out of 10 times, at some point during the drive the motor will just stall. No warning, no running rough, you just look down and the cluster is lit up like a christmas tree and you're not going anywhere. Usually this happens while either accelerating from or slowing down approaching a light/stop sign. Right before I started driving it, they had the plugs, wires, and distributor replaced to "solve" this problem. What else could it be? The truck runs great otherwise.

 

[Jeff7181]

Could be multiple leaking injectors loading up the cylinders... any smoke when you accelerate or decelerate? Could be carbon build up in the throttle body. Could be a malfunctioning throttle position sensor. Could be a bad coil. Could be a clogged CAT. Could be bad oxygen sensor. The sensors would normally set a code, so if the check engine light isn't on, it's probably not those. Those are just basic things that could be wrong... I don't know about any possible vehicle specific problems.

 

[VTEC01EX]

Jeff - Bad coil... duh, that never even occured to me. It really feels like it's something spark-related just because the truck runs well, it just gets fussy when starting. I'll have to check that out. Thanks!

 

[Quixfire]

It most likely a fuel pressure problem. Sounds like it's running lean at start up and when accelerating. I would have a shop, or yourself, check the fuel pump pressure and volume.

 

[Pepsi90919]

a new fuel filter may be in your near future.

 

[moonshinemadness]

Originally posted by: Pepsi90919
a new fuel filter may be in your near future.

Agreed, especially if you start noticing random drops in power even if for a split second.

 

[Crucial]

My fuel pump was going bad when I had these symptoms. My wifes car nad the same problem and the fuel pressure regulator was the culprit. The fuel filter should be the cheapest place to start.

Does it take a long time to start all the time or just after it's been sitting for a long time. I would test the fuel pressure to make sure it's up to spec.

If the long start only happens after it sits I would leave the pressure gauge on overnight and see if the pressure bleeds down. More than likely the pressure is bleeding off and it is taking 4 more seconds to bring the pressure up when you start it.

Edit:
When you start it, try turning the key to the run position and leaving it for 5 seconds then back off then back to run for 5 seconds. Then try and crank it. Does it start right away then? If it does it may point to a fuel problem other than electrical like coil, plugs, an so on.

 

[Eli]

If it was a spark problem it would most likely manifest itself all the time, not just when starting.

I agree with the fuel system diagnosis.

 

[Zenmervolt]

EDIT: What the? I hit "reply" in the quick reply box instead of hitting the link below it back to Off Topic and it posted a blank reply.

 

[Jeff7181]

If the long start only happens after it sits I would leave the pressure gauge on overnight and see if the pressure bleeds down. More than likely the pressure is bleeding off and it is taking 4 more seconds to bring the pressure up when you start it.

One way to test that if you don't have a fuel pressure guage is to just turn the ignition on, don't start it, you'll be able to hear the fuel pump run, and then shut off... then try to start the engine... if it fires up, then it's bleeding off pressure overnight. If it still takes 6 seconds to start, the cause is not pressure being bled off overnight, but still can be fuel pressure related. (bad pump, clogged filter, clogged pickup, bad regulator) I think those bottles of fuel injector cleaner you can buy at any gas station or the auto section of most any store are underrated. I run a bottle through my cars at every oil change. Be warned though... fuel injector cleaner will ruin seals in a carburetor... so buy stuff that says carb cleaner for use in a carbureted engine.

 

[Eli]

Originally posted by: Jeff7181

If the long start only happens after it sits I would leave the pressure gauge on overnight and see if the pressure bleeds down. More than likely the pressure is bleeding off and it is taking 4 more seconds to bring the pressure up when you start it.

One way to test that if you don't have a fuel pressure guage is to just turn the ignition on, don't start it, you'll be able to hear the fuel pump run, and then shut off... then try to start the engine... if it fires up, then it's bleeding off pressure overnight. If it still takes 6 seconds to start, the cause is not pressure being bled off overnight, but still can be fuel pressure related. (bad pump, clogged filter, clogged pickup, bad regulator) I think those bottles of fuel injector cleaner you can buy at any gas station or the auto section of most any store are underrated. I run a bottle through my cars at every oil change. Be warned though... fuel injector cleaner will ruin seals in a carburetor... so buy stuff that says carb cleaner for use in a carbureted engine.

ooh. Thanks for the heads up. Going to pick some up for my dads truck today, glad I saw this.

 

[Jeff7181]

You won't have gas spraying out instantly... but it will break down seals over time and I'm sure rebuilding a carburetor isn't near the top of your "list of fun things to do on the weekend."

 

[desertdweller]

Sounds like the fuel pump is going.

Unless you know how and have the tools to test the fuel system, I'd take it in and
have it looked at.

DD

 

[desertdweller]

Originally posted by: Eli
If it was a spark problem it would most likely manifest itself all the time, not just when starting.

I agree with the fuel system diagnosis.

It depends on what the problem is. Dodge used to have a problem with thier V-8s dying
with no warning. The problem was the distributor rotor was not balanced and it caused the
bearings in the distributor to wear out and wore out the gear enough to cause the timing
to jump around enough to stall the engine. The problem was anything but consistant.


DD

 

[Jeff7181]

Originally posted by: desertdweller
Sounds like the fuel pump is going.

Unless you know how and have the tools to test the fuel system, I'd take it in and
have it looked at.

DD

True... you don't want to mess with a fuel system with 40+ PSI of pressure in it if you don't know what you're doing... break open a line and a mist of gas sprays out onto a hot exhaust manifold... not good. I've seen it happen at a drag strip... guy tryin to change out an inline filter and forgot the fuel system was still under pressure... he had moved the inline filter to the engine compartment... cracked it open, sprayed a fine mist of fuel onto the headers and his face. Started a small fire on the headers, but it was put out quick, and he didn't get burned... probably because it was 112 octane racing gas that doesn't ignite as easily as pump gas.

 

[Crucial]

Originally posted by: Jeff7181
I'm sure rebuilding a carburetor isn't near the top of your "list of fun things to do on the weekend."

<looks around> Am I the only one who disagreed with that?

 

[Jeff7181]

Originally posted by: csaddict

Originally posted by: Jeff7181
I'm sure rebuilding a carburetor isn't near the top of your "list of fun things to do on the weekend."

<looks around> Am I the only one who disagreed with that?

Well I don't mind doing it either... but I'd rather do it on my schedule, not HAVE to do it to be able to drive my car =)

 

[LAUST]

Sounds like a fuel delivery problem, how long ago was the fuel filter changed?

 

[VTEC01EX]

UPDATE: The problem didn't exist today. I seriously started the car no fewer than 6 times today, and even this morning when it had sat for 12 hours, it started right up. However, I'm going to have to investigate the fuel issues. Chances are the fuel filter has never been changed - if it has, it was a long time ago. This is why I don't like borrowing my parents cars for extended periods of time, I always get stuck figuring what's wrong with them! Can't wait to get my reliable car back.