Starting Problem---again

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...

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.

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?)

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.

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

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.


http://i5.photobucket.com/albums/y186/lizzywiz/alerofp.jpg
Actron Hooked Up to GM 3.4L V6

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!!

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.

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

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!...

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

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).

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??

http://i70.photobucket.com/albums/i85/gemstonian/FPR.jpg

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.

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.

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...

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?

Did you have crank position sensor problems in the past?

Not that I'm aware of....

Can the crank or cam position sensors be intermittent? (Like 98% of the time OK and 2% of the time flakey)

Not that I'm aware of....

Can the crank or cam position sensors be intermittent? (Like 98% of the time OK and 2% of the time flakey)

I'm not saying it is your problem but it is just one item that can cause a similar problem. Those Hall Effects sensors are heat sensitive. Symptoms are hard starting or stalling when driving down the road. And yes they can be intermittent along with no SES/CEL light or any odb-ii codes.

It always the basics, either ignition or fuel.

One other item, the MAF sensor.

OK... I'm going away on a business trip for the next 4 days... The Impala will be under the custody and care of my wife :rolleyes: ... If there is a intermittant problem she will be sure to find it! :grinyes:

The crankshaft position sensor can cause intermittent starting problems, but it'd also cause intermittent stalling. The fuel pressure regulator can cause intermittent starting problems if it's going bad. Usually, it will be if you start the car once it is warmed up. It will crank, start for a second, but not get up to idle rpm, then fail. You might get this once in a month's time.

The crankshaft position sensor can cause intermittent starting problems, but it'd also cause intermittent stalling. The fuel pressure regulator can cause intermittent starting problems if it's going bad. Usually, it will be if you start the car once it is warmed up. It will crank, start for a second, but not get up to idle rpm, then fail. You might get this once in a month's time.

OK... I've been away on business all this week (I still am)... My wife just called me and it happened again... She was running local errands, starting and shutting the car a few times inbetween local stores... Finally, at the post office, she had starting problems... It would start, stumble and die... She tried a few times with no luck... Then waited a few minutes and it started right up and ran fine... It has never stalled after running... You are one of several who have mentioned the FPR, but "bnaylor" has said in this thread it is rarely the cause of this problem... Any comments??... I'll be back to my home tomorrow as long as I get thru the airport security with a carry-on bag full of electronics!!

Based on my experiences the FPR is very seldom the problem but there may be exceptions. However, proper troubleshooting is required. I had recommended running a fuel pressure test so you could make a determination. The fuel pressure check tests the FPR and as to whether it is functioning properly. Based on the reading with vacuum connected and disconnected at the FPR, if the reading on the gauge deviates by 7 psi or more than the FPR should be replaced. Based on your symptoms you could have a problem any place in the fuel circuits. It could be the fuel pump or the fuel pump relay. An ignition related problem can cause it. A bad MAF sensor gives similar symptoms.

OK... When I'm home this weekend I'll probably buy the fuel pressure gage and take some readings... I'll keep you all posted and thanks for the continued help and support!!

OK, I'm back again with this problem...

First of all, I must say to 'bnaylor', that I'm an idiot... Instead of exactly taking your prior advice I bought a new fuel pressure regulator last weekend and installed it... Several guys on the "naioa" forum told me they had the exact same problem and it was a bad FPR... So I replaced it last saturday and the car has been good until tonight...

Once again my wife was running local errands, with the A/C running, and after a few starts and stops between stores the car again would not restart... It would fire, and die in about 1 second... She then let the car sit for 5-10 minutes and it restarted and ran perfectly... During the restarts she had the A/C off... I just restarted the car in the driveway a few times and it seems fine...

So consider me STUPID and give me some advice again as to where I should start to troubleshoot this intermittent problem...

Thanks in advance...

Sorry to hear the problem is still there.

What problem one Impala owner has may not be applicable to the other so it is really hard to say. The problem with intermittent problems such as yours items like the FPR winds up getting replaced in the course of troubleshooting. At least you can rule it out. Also, it doesn't help when no DTC error codes are triggered with a SES/CEL light.

Back to the basics. It is either fuel or ignition. Based on my experience with the SII 3800 engine which is over 8 years and various GM makes I would say taking an educated guess that for fuel - possible fuel pump. For ignition - the crank position sensor. But based on your symptoms I would put emphasis on fuel first.

Thanks 'bnaylor'... In one of your prior responses you did mention the fuel pump relay as a possibility... Where is that relay located and is there a test (voltage or current or resistance) that I can do on it?...

Also, I did clean the MAF sensor a couple of months ago with electrical contact cleaner... Of course, that wouldn't fix a flaky MAF sensor, it would just make it a clean and flaky MAF sensor... :screwy:

By the way... When I replaced the FPR I pressed on the schrader valve to release the fuel pressure... Very little gas dribbled out, only about a teaspoon, or less... Is that normal?... I thought I'd get more gas under some pressure to come out... The car had been off for about 2 hours prior to me pressing on the valve...

Thanks 'bnaylor'... In one of your prior responses you did mention the fuel pump relay as a possibility... Where is that relay located and is there a test (voltage or current or resistance) that I can do on it?...

The fuel pump relay should be located in the engine compartment fuse box. On the back of the lid is a diagram of all fuses and relays located there. With ignition to on there is always 12 volts DC on one side the the relay coil. The PCM module provides a low/ground to energize the relay. The output from the relay to input of the fuel pump will be around 12 volts.

Also, I did clean the MAF sensor a couple of months ago with electrical contact cleaner... Of course, that wouldn't fix a flaky MAF sensor, it would just make it a clean and flaky MAF sensor... :screwy:

Yeah, thats true. On the MAF sensor you could try this test. Just remove the electrical connector to it. All you will get is an erratic idle until the engine warms up. You will have normal driveability. I've driven with a MAF sensor disconnected for a week until my part arrived. The PCM will detect the MAF sensor signal missing and use pre-programmed MAF/VAF tables along with a few other sensors. Your problem doesn't sound like a flaky MAF but it won't hurt to rule it out.

By the way... When I replaced the FPR I pressed on the schrader valve to release the fuel pressure... Very little gas dribbled out, only about a teaspoon, or less... Is that normal?... I thought I'd get more gas under some pressure to come out... The car had been off for about 2 hours prior to me pressing on the valve...

After about 2 hours or more that sounds normal. What counts is when the fuel pump primes for the two seconds at ignition on where pressure will be back up, hopefully in spec. Only way to tell is to connect the fuel pressure gauge.

Hope the info helps.

"Just in case", I called my local Chevy dealer to see if he had the fuel pump relays in stock, and what they cost... He tells me they have them in stock but there are two types... One cost $12 and one cost $30... He didn't know the difference, or why, but it depended on what code number was marked on top of the relay... Does that make any sense??

(The relay in my car is marked with two numbers: 7866 and 12077866... It is BLACK in color...)

I would go with the advice from the dealer. Part number 12077866 is correct and the GM list price is around $29.98.

Well I'm thinking for 30 bucks I should just buy that relay and put it in...

BTW, I just received my ACTRON code reader today... I plugged it into the ODB port, turned the ignition to "ON" and it scanned and came up with zero codes... No surprise since the SES/CEL light has never come on (why don't they call it an OBD light??)...

Thanks for the info 'ysteve'... But my car cranks just fine (I have a 1 year old Optima Red Top battery) and it starts... When this problem happens it starts and dies in about 1 to 2 seconds... Then when it starts and continues running it's perfect... And this problem only happens VERY rarely...

Try that for now. Maybe you have somewhere poor wire connection, because you saying its not happening at all the time. I am gonna look for something else. Good luck.

It's been 3 days now and the car's been perfect... Starts and restarts with no problem over these past 3 days... The only common denominator I can think of is that each time I've had this re-starting problem it's been a hot day with the A/C running... I know this should not be a factor but I'm just looking for something to point me in the right direction... I haven't bought the fuel pump relay yet as I don't like to randomly change parts and "wish" the problem away... If it stops raining over this weekend I'll try some of the troubleshooting suggestions 'bnaylor' and 'ysteve' have posted here first...

You can get it at Camp chevrolet, Spokane,WA, 18007769979 $3.92. Good luck. BTW i am looking for original GM gas cap, do you have some info mod# etc.
Have good LABOR DAY

You can get it at Camp chevrolet, Spokane,WA, 18007769979 $3.92. Good luck. BTW i am looking for original GM gas cap, do you have some info mod# etc.
Have good LABOR DAY

Interesting information... I'll check that out if I can locate the A/C accumulator... Does anyone know where in the engine bay it's located?...

As far as your gas cap is concerned, rockauto.com has ACDelco gas caps for the Impala...

Thanks for the Labor Day wishes, same to you... I wish it wasn't going to rain like crazy tomorrow because I have concert tickets at Jones Beach for Saturday! :frown:

On 3.4 its between engine and radiator Air filter compartment area. Its round cilinder aproxim. 3" by 6" alluminum you cant miss it. Easy words look around 2 feet before wires going to PCM. Really i dont had this problem but i saw posts on it.
Go take a look i am not sleeping yet any problems just tell me.

Btw i am sorry about the picture. The moderator of this forum is not loud to post me the picture and its keep changing the way it want it. Ijust erased it. i dont know maybe i am wrong but this picture driving nuts. ijust copy it from ALLDATA and paste it but it playing around i have no clue why.

OK... I have the 3.8L engine... If it ever stops raining today I'll poke my head under the hood and take a look...

ysteve,

You'll need to be careful posting copyrighted material such as from GM TSBs and AllDataDIY/Autozone unless you have expressed authorization to do so from those entities. It is called copyright infringement. Also, it violates AF copyright rules and we do want any liability.

Just FYI.

DAMN!! My wife just called and it happened again... Took 3 tries to restart after a short visit to a store... And she was running the A/C again, although everyone tells me it has nothing to do with the A/C... This is driving me crazy!

Gems, did you check those wires around A/c acumulator. Are they in good shape?

Gems, did you check those wires around A/c acumulator. Are they in good shape?

Yes, they look fine and are not nearly as close to the accumulator as your first picture indicated...

I'm back!! Well after nearly 2 weeks of no troubles with this hot restart problem happened again :banghead: ... Once again the only common factor is the fact that today we ran the A/C in the car... And sure enough, the hot engine restart problem occured again... For the past 2 weeks I have not run the A/C and had no troubles... Today we ran the A/C for a little while and damn!! it happened again... What the heck could running the A/C have to do with this?!?!

GM TSB # 00-06-04-049b referes to a problem with the wiring harness chafing against the A/C accumulator mount ring that would cause your no-start issue. Since it only happens when the A/C is on, I'd bet there is a bare wire near the A/C accumulator that is shorting out when the accumulator starts to condensate. This problem applies the following vehicles:

1997-2003 Buick Century, Regal Built Prior to 2/03
2000-2003 Chevrolet Impala, Monte Carlo Built Prior to 2/03
1999-2001 Pontiac Grand Prix Built Prior to 10/1/00 -- VIN Breakpoint 1F136536

It could cause any of the following symptoms:

Anti-Lock Brake System Warning Light illuminated
Intermittent MIL/Service Engine Soon indicator illuminated
Engine will not start
Engine stalls after start up
Various electrical system failures
Various driveability concerns

Gems i told you before about bunch of wires around A/c accumulator. Did you chekd them?

Gems i told you before about bunch of wires around A/c accumulator. Did you chekd them?

Yeah I did check them but I'm gonna check them again today... Maybe my eyes are not seeing too good these days... By the way... Does the TSB refer to the 3.4L or the 3.8L??? I have the 3.8L engine...

Thanks guys...

On the 3.8L engine, is the A/C accumulator the round silver cylinder located under the intake air filter box on the drivers side of the engine??

If it is I really have to remove the plastic air filter box to see everything down there around the A/C accumulator...

I dont know about 3.8, but i think you dont have to go to dealer they gonna f$^&%$ you. You can do that your self with electrical tape. Just find damaged wires and tape them.
Keep us posted. Good luck.

I took the air box out and checked the wires in that area... Everything looks perfect... There is one cable that is slightly against the mounting bracket of the accumulator but, like all the other harness cables, it has that heavy plastic wrap around it and there wasn't any chafing... I wrapped it with electrical tape anyway...

This is only thing what i can think of right now. Yuo not gonna use ac now. So look if its gonna happen again. SEnd us your investigation. If this sh#%^&t gonna happen again whithout A/c we gonna find somethig else.
Good luck. Respond if everything is fine.

my '02 Imp has had the hard start problem for several months now, start-stumble and die cold or hot, intermittantly. Today I check the fuel pressure with the key on. It came up to 8psi. I then cycled the key several more times and it finally got up to 44psi. I then checked to see how quickly the pressure dropped off. It fell a little to quickly according to my manual about 25psi drop in and hour or so. Next, I pulled the regulator apart and found the screen dirty and the "O" ring slightly out of place and fuel in the vacuume hose. I proceeded to clean out the regulator and and screen and carefully reassembled it. I again checked to see how quickly the pressure would come up. First toggle of the key took the pressure from 0 to 25 the second toggle of the key took it all the way to 45psi. This was a big improvement from before cleaning to regulator. Next I checked to see how quickly the pressure dropped back off. The pressure receeded even faster then before the cleaning(kinda unnerving). I then started the engine with no problem. Now I relieved all the pressure in the system and again started the engine immediately with no issues. I also cleaned the Idle air control pintle and its well and also cleaned the throttle blades because the buid up of carbon residue on them has been known to cause idle problems. This morning I started the engine with no issues. This afternoon I again started the engine with no issues and let it warm up and then I let it sit for 15-20 minutes and again I stearted the engine with no issues. I have no driven the car yet but if the problems returns when I drive it I will most likely replace the regulator.

well the sketchy starting problem persisted for several more days after everything I did (as outlined previously) so I replaced the fuel pressure regulator last week and the engine has started fine ever since.:grinyes:

One of the first thongs I did was to replace the FPR... That didn't fix the problem for me... Since I have not been running the A/C and I taped off the wires near the accumulator the problem has not occured again... Hmmmmm???

Guess what guys, I'm back with this damn problem... After 2-3 months of no re-starting problem, out of the blue it is happening again today... Exact same symptoms as before except we are NOT running the A/C (or defroster)... After running for awhile, then stop for a short time it doesn't want to restart... It fires, stumbles, stalls... Wait about 15 more minutes and it starts up just fine... Right now it's in the driveway and doesn't want to start... So I'm gonna wait 15 minutes and try again... Oh yeah, I have a DTC reader and it shows no codes... Damn!!!!!!!!!!!!!!!!

OK I waited the magical 15 minutes and it started right up again... What the hell is this problem???? Flaky fuel pump maybe???

you're gonna need a new ignition lock. It has an anti theft feature that, as with any electro-mechanical part, is susceptible to premature failure.

you're gonna need a new ignition lock. It has an anti theft feature that, as with any electro-mechanical part, is susceptible to premature failure.

I thought the ignition lock problem caused the engine to NOT crank when the key was turned... In my case the engine cranks and starts but then stumbles and dies about 1 second later...

Bob, did you ever get that fuel pressure gauge we recommended. Starting to sound like a fuel system problem to me. Fuel pump is the most likely part. I recall you had replaced the fuel pressure regulator.

Bob, did you ever get that fuel pressure gauge we recommended. Starting to sound like a fuel system problem to me. Fuel pump is the most likely part. I recall you had replaced the fuel pressure regulator.

Yes, I bought a fuel pressure gauge... Last time I checked the pressure readings it was starting normally and I sent the pressure numbers to you... You said the numbers looked good... Yesterday, when it was not starting, I should have hooked the gauge up and took pressure readings... But it was at night and I was pissed off!!... Then 15 minutes later all was good again... And yes again on the FPR... I replaced the FPR about 3 months ago...

Yes, I bought a fuel pressure gauge... Last time I checked the pressure readings it was starting normally and I sent the pressure numbers to you... You said the numbers looked good... Yesterday, when it was not starting, I should have hooked the gauge up and took pressure readings... But it was at night and I was pissed off!!... Then 15 minutes later all was good again... And yes again on the FPR... I replaced the FPR about 3 months ago...

It has been so long I couldn't remember. "I should have hooked the gauge up and took pressure readings" <-- Good idea.

Keep the gauge in the trunk. Good luck.