Starting Problem---again

Gems · 08-07-2006, 08:43 PM

About 3 months ago my wife had a problem re-starting the car... After driving around on a hot day, with the A/C, she had it parked for a few minutes and then had trouble re-starting... It would fire, stumble, and stall... Did this about 6 times... Waited a few more minutes and then it started right up... It's been perfect for 3 months now (including the horrible heat wave we had last week) until today... Drove home from work, with A/C running... Stopped at a store for a few minutes... Started again just fine... Stopped for gas... Had trouble re-starting... It would fire, stumble, stall... After about 4 tries it fired up and ran perfectly... In the old days I would call this vapor lock... What do you think???... It's a 2001 LS with the 3.8L motor, 53,000 miles...

BNaylor · 08-08-2006, 04:45 PM

Did you ever get around to checking fuel pressure to see if in specs when you had the prior problems?

I had a similar problem with bad gas one time.

Gems · 08-08-2006, 09:15 PM

No I have not checked for proper fuel pressure...

I guess I'd have to buy a fuel pressure gage to do that?
Connect it to the schrader type valve right below the fuel pressure regulator?
Maybe just replace the fuel pressure regulator? (I think it's a $50 part?)

bigrod118 · 08-08-2006, 09:17 PM

Yes you would have to buy a fuel pressure tester, I got an actron one, works great, I think it was like $40 or so.

and the last time I looked at a FPR from autozone, it was $70.

Gems · 08-08-2006, 09:25 PM

Is checking the pressure as easy as hooking the gage to the schrader valve just below the fuel pressure regulator and cranking the motor?

BNaylor · 08-08-2006, 10:37 PM

Go with the Actron fuel pressure gauge. Also, it has purge valve so it is easy to discharge or relieve fuel system pressure.

I'd hold off on the fuel pressure regulator. Very seldom fixes the problem and turns out to be a waste of money but the fuel pressure test will determine whether it is flaky.

On the FPR, remove it from the fuel injector rail and inspect from the inside. One simple C-clip holds in on. Remove the vacuum line and look for fuel maybe indicating a ruptured diaphragm.

BTW - There are about 3 phases of checking fuel pressure. Initial check is at ignition to on engine off (fuel pump prime mode). Rest are with the engine running at idle and by removing the vacuum line to the FPR. You'll compare readings and see if within GM specs.

Actron Hooked Up to GM 3.4L V6

Gems · 08-09-2006, 05:46 AM

OK, thanks for the good info... Yesterday the car started and re-started perfectly many times... Both with a cold and hot engine... I sure do hate intermittant problems!!

BNaylor · 08-09-2006, 04:54 PM

Quote:

Originally Posted by Gems

OK, thanks for the good info... Yesterday the car started and re-started perfectly many times... Both with a cold and hot engine... I sure do hate intermittant problems!!

Yeah Gems those intermittent problems sure are a PITA. The fuel pressure tester, although a great tool, may not do any good for now. You'd probably have to hook it up and tape it to the driver's side wiper so you can monitor it while driving. But if nothing else you will be able to confirm what fuel pressure you do have and use it as a reference. I've got the readings on all of mine written down.

Gems · 08-09-2006, 09:09 PM

LOL, you are a fanatic bnaylor!... I mean that in a good way!... You've got the pressure readings on all your vehicles!... Amazing!...

Today, all day and night, my car started and re-started perfectly... Both with the A/C on at times and with it off... I still am considering buying that pressure gage... And when my wife's not looking tape it to the windshield and drive around town!...

BNaylor · 08-10-2006, 11:11 AM

Quote:

Originally Posted by Gems

LOL, you are a fanatic bnaylor!... I mean that in a good way!... You've got the pressure readings on all your vehicles!... Amazing!...

Today, all day and night, my car started and re-started perfectly... Both with the A/C on at times and with it off... I still am considering buying that pressure gage... And when my wife's not looking tape it to the windshield and drive around town!...

Have fun Gems!

While we are on the subject of useful tools and gauges I found an automotive vacuum gauge (0 - 30 hg) comes in handy. I used one to convince the GM dealer our CAT in my wife's Impala LS (rip) was bad.

I've got all the vacuum readings from all of my GM cars recorded too. Easy test to run at idle and 2000 rpms.

Just food for thought. These gauges really do not cost that much but I have fun playing with them when I'm bored.

Back in the old days I used a vacuum gauge to check the advance and timing out on my old Mopar '70 Dodge Challenger R/T (440 Magnum).

Gems · 08-10-2006, 04:58 PM

The car again started and re-started without a hitch today... So whatever was the problem is VERY intermittent... At your suggestion, a few minutes after driving home from work, I pulled the vacuum line off the FPR to see if there was any gas from a ruptured diaphragm... Looks and smells dry as a bone (see photo)... So I guess I chaulk this up as a no-problem at the moment until it happens again??

richtazz · 08-14-2006, 03:42 PM

do you remember if the security light ever came on when the car wouldn't stay running? It could need a key-relearn done if it did.

BNaylor · 08-14-2006, 04:25 PM

Quote:

Originally Posted by richtazz

do you remember if the security light ever came on when the car wouldn't stay running? It could need a key-relearn done if it did.

In my experiences with Passlock the car will not start when the SECURITY light comes on so it will not run. Passlock/VATS will disable the fuel injectors. One thing it does is send a pulse width modulated signal to the PCM module via the BCM to enable the fuel injectors.

Either way, 99% of those problems are a defective key cylinder or ignition switch.

Gems · 08-14-2006, 04:38 PM

No, my security light has never come on... Plus, the car did start, it just wouldn't continue running... It would start, stumble and die... Start, stumble and die... After 4 tries it started and ran perfectly... And now over a week has gone by and it hasn't happened again... Also, I have an '01 LS.... I don't think there is a chip in the key...

BNaylor · 08-14-2006, 04:42 PM

Quote:

Originally Posted by Gems

No, my security light has never come on... Plus, the car did start, it just wouldn't continue running... It would start, stumble and die... Start, stumble and die... After 4 tries it started and ran perfectly... And now over a week has gone by and it hasn't happened again... Also, I have an '01 LS.... I don't think there is a chip in the key...

Thats because you have Passlock. Only Passkey I/II has the resistor pellet.

Did you have crank position sensor problems in the past?

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