Strange things happening with fuel pressure…

[Dwayne]

I’m currently working on a car for a customer, that has strange things happening with fuel pressure…

Vehicle is a 2004 Chevrolet Cavalier with Ecotec 2.2 automatic 117,000 ish miles

I have repaired numerous issues with this car over the last few monthe, and now there is another issue that need to be resolved. I’m no professional auto tech, but I Lovetowrenchit!, So here we go…

Complaint
1. engine will run rough at idle sometimes, engine will run smooth sometimes, engine will be hard to start sometimes, engine will quit running sometimes, engine will shut off sometimes when cornering, leaning ect.

2. CEL comes on sometimes.

3. I take a chance on driving the car, never know when it will quit running, and if it does…It will be hard to restart, but it can be restarted, and will run

What I have done after work hours, and what my finding are. I’m suspecting a fuel issue of some sort

1. Pulled trouble stored trouble code, cam back P0300..YUCK!! I know I’m in for a real fun time with this one Lol

2. Hooked up my fuel pressure tester, tested fuel pump for pressure KOEO got 60psi, Okay, good!

3. I decided to see if she will have a problem starting and running, fired right up, and ran smooth and without any misfire…Good:) while running fuel pressure dropped down to 57psi Good!…

4. After about 20 minute of no evidence of the initial complaint. I shut the engine down, and watched the fuel pressure needle. It dropped from 57psi down into low 50’s, but over a period of time, about 1 hour the pressure was down to low 40’S, after several more hours, pressure down to the 30″s, let the car sit over night, got up to go to work the next morning, checked the pressure gauge…it was ” 0 ” psi.

This is where it gets weird. I went to work that day, came home 12 hours later, looked at the fuel pressure gauge, and somehow the pressure went back up to the 30 ish psi range. Well i didn’t expect that Lol..now I’m scratching my head trying to figure out what is going on…

5. I decided to do a fuel pump volume test KOEO and got around 1 Qt in about 40sec..Good!
don’t think the fuel volume is a problem…maybe the fuel pump check ball is leaking, slowly…still a possibility

6. I got to thinking maybe a vacuum leak, fuel pump pressure regulator issue, leaking injector, or injectors. Well before I could start figuring out which way to go with my troubleshooting, I smelled fuel. I spotted some fuel on the outside of the fuel pressure regulator where it is mated together, and thought how could that be happening??

Well, I don’t have any fuel in the vacuum line, and the vacuum line is hooked to the intake boot, and not on the manifold, so no vacuum at idle on that hose. I’m not sure if if it has any vacuum at all on that hose. I pulled that line off the fuel pressure regulator while engine was running, for about 10 minutes or so, and no fuel pushed out of the regulator.

7. I’m going to purchase a new fuel pump regulator tomorrow, not sure if it is causing the pressure bleed off, because when I pinch the return hose I get pressure increase of 10 psi or so, that seems normal to me from what I know.

I am purchasing the regulator tomorrow to take away a fire hazard, and hoping that the diagram inside has a small rupture, and all this troubleshooting will end, without me going to troubleshoot the fuel pump…

I would appreciate any help/direction on which way to go. I don’t want to drop the tank unless I need to, and want to keep the cost as low as possible, for my buddy

thanks for taking the time to read this, I appreciate it:)

Topic

[Dwayne]

[quote=”Tedybear315″ post=110214]I’m going to go out on a limb–as this issue is one that the VW’s I work with also share.

It’s caused a lot on those cars by a defective crank sensor. Could also be a cam sensor as well on some engines. I’m not sure on yours, just floating it as a possible issue.

I’d check the grounds–as that’s very possible– And I’d also look into testing the crank and/or cam sensor- Which ever one this car uses for the engine RPM. If the sensor is easy to get to? Maybe having the car just sit there at idle and give the sensor a very light ‘tap’ with the butt end of a screw driver?

S-

edit: at times if the sensor is vibrated just right it can drop the signal to the computer. If the computer sees the engine has no RPM? Then it will throw the system into ‘shut down’. as in–no fuel pump or ignition. It thinks the engine stalled out. Tapping the sensor with a screwdriver handle can cause the issue to happen on ‘command’ if it’s bad enough.

I’m only throwing it out there, as I am not sure about your system.[/quote]

Thanks for the input:) have thought this, because it too me seems like a crank sensor, and this crank sensor is built into the ECU. It uses some sort of different type of signal built in, so i’m off to search that.
thanks again…several more options to check into
it sucks to have to do this diagnosis the old school way, I have no diagnosis equipment, except for a code reader with live data, but the live data is limited, and hard to understand some of it without a technical course

[EricTheCarGuy]

A crank sensor problem doesn’t explain the fuel pressure changes you described in your OP. I’m not saying rule it out, but if the stalling issue is caused by a lack of fuel pressure, perhaps we should keep our focus there. You might even consider test driving with the gauge hooked up so you can monitor it when the problem occurs. That said, does this vehicle have a fuel filter? If so I’d recommend changing it. A partially clogged fuel filter may cause the symptoms you describe. BTW the check ball in the fuel pump would cause the pressure to bleed off when it’s bad.

Keep us posted on your progress.

[Dwayne]

[quote=”EricTheCarGuy” post=110323]A crank sensor problem doesn’t explain the fuel pressure changes you described in your OP. I’m not saying rule it out, but if the stalling issue is caused by a lack of fuel pressure, perhaps we should keep our focus there. You might even consider test driving with the gauge hooked up so you can monitor it when the problem occurs. That said, does this vehicle have a fuel filter? If so I’d recommend changing it. A partially clogged fuel filter may cause the symptoms you describe. BTW the check ball in the fuel pump would cause the pressure to bleed off when it’s bad.

Keep us posted on your progress.[/quote]
Eric, thanks for your input:) I agree with what your saying. I have been doing my current testing in my back yard under a huge shade tree:), I don’t have a garage anymore:(. The testing I’m currently doing, is being done with the fuel pump pressure gauge hooked up, and the engine running at idle,and when It quits suddenly, I look at the fuel pressure gauge, and the pressure is within specs.

When the engine quits, I have no shaking or weird noises from the engine, almost like the electrical is cut to the engine, it’s a quiet, quick sudden shut down. I do here the fuel pump relay click, when the engine quits, maybe it’s resetting?

The fuel pump relay temperature is 106* when the engine quits, I wonder if it’s overheating from the fuel pump? idk…This fuel system is a different setup than what I’m use to messing with. The pump is energized with the key on, then after start the computer takes over the operation of the fuel pump.

If the computer controls the operation of the pump,after initial start, what is shutting down the engine, thus tripping the relay? maybe the pump is overheating at idle, but not at higher RPMS?

More testing is needed. I just hope I have the skills to find this issue…and I’m ” Staying Dirty ” on this one…

I’m going see if I can get my stethoscope somewhere on that fuel tank while the engine is running, and maybe I can hear some sort of clue that the pump is starting to fail

fuel filter? I’ll have to check into that. I think it is on the bottom of the pump

[Stephen Bowen]

Fuel Filter is a can type. Runs about $10 bucks from RockAuto. If that’s never been changed before? Let me put it this way. Designers ‘claim’ these are lifetime filters. Last time I changed one on a car with over 100k on it? The filter, when turned upside-down was pouring out black sludge. Totally putrid and plugged up.

The filter at the pump itself, that’s the filter ‘sock’. Yes that can be plugged up with dirt and ‘tank gunk’. I’d personally chase after the can type fuel filter–it’s just in front of the fuel tank under the car.

Question: Where is the fuel filter located on a Chevy Cavalier?

Answer:

On my 2004 Cavalier it is in front of the gas tank under the body. If you put the car up on ramps or stands and get under it from the back it is easily visable.
AnswerI just changed one today (5/28/05) on a 2002 Cavalier. A few feet from the end of the car, located in the middle (basically right after the trunk). To change it is pretty easy if you take the plastic clips sort of off (this gave me LOTS of trouble but now I can take off this end in 2 seconds). Just pinch the plastic clip (green on my car) & then push the platic clip almost out. Then pull that side out (watch out – you will have gas come out). Then unscrew the other side. I had to take off another part to unscrew this side because of little room. Also – BEFORE you start – take off the gas cap, jackstand the car & I also removed the fuel pump fuse (located in the engine, driver side).

Found this as well:

http://www.ipatools.com/products/index.php/ipa-9038.html

It plugs into the relay socket and just has a ‘toggle’ switch. It bypasses the computer control over the relay and forces the pump to always ‘run’. If the computer is commanding the fuel pump to shut down–thus causing the car to stall/quit? Install this and flip the switch ‘on’. You can probably make one of these yourself using a set of lug terminals, heavy gauge wire and a toggle switch.

S-

[Dwayne]

[quote=”Tedybear315″ post=110420]Fuel Filter is a can type. Runs about $10 bucks from RockAuto. If that’s never been changed before? Let me put it this way. Designers ‘claim’ these are lifetime filters. Last time I changed one on a car with over 100k on it? The filter, when turned upside-down was pouring out black sludge. Totally putrid and plugged up.

The filter at the pump itself, that’s the filter ‘sock’. Yes that can be plugged up with dirt and ‘tank gunk’. I’d personally chase after the can type fuel filter–it’s just in front of the fuel tank under the car.

Question: Where is the fuel filter located on a Chevy Cavalier?

Answer:

On my 2004 Cavalier it is in front of the gas tank under the body. If you put the car up on ramps or stands and get under it from the back it is easily visable.
AnswerI just changed one today (5/28/05) on a 2002 Cavalier. A few feet from the end of the car, located in the middle (basically right after the trunk). To change it is pretty easy if you take the plastic clips sort of off (this gave me LOTS of trouble but now I can take off this end in 2 seconds). Just pinch the plastic clip (green on my car) & then push the platic clip almost out. Then pull that side out (watch out – you will have gas come out). Then unscrew the other side. I had to take off another part to unscrew this side because of little room. Also – BEFORE you start – take off the gas cap, jackstand the car & I also removed the fuel pump fuse (located in the engine, driver side).

Found this as well:

http://www.ipatools.com/products/index.php/ipa-9038.html

It plugs into the relay socket and just has a ‘toggle’ switch. It bypasses the computer control over the relay and forces the pump to always ‘run’. If the computer is commanding the fuel pump to shut down–thus causing the car to stall/quit? Install this and flip the switch ‘on’. You can probably make one of these yourself using a set of lug terminals, heavy gauge wire and a toggle switch.

S-[/quote]
Tedybear315
Thanks for your input and time,and the info. I appreciate it:)
I will ask the owner to get a quality external fuel filter today ( he is a Co worker/close friend, and buys the parts I need, when needed). I don’t know if it has ever been changed, but will get changed, and I’ll put a changed date on the filter for future referance.
I will update after that filter change

Now if that doesn’t solve the issue. I will continue to troubleshooting of the pump and electrical.
I think I’m in testing in the right areas

Btw the ignition system on this car is called CSI…compression sense ignition, which there is no information in my cheep repair manual for testing.
It took me days of searching on the net to find something about this type of ignition system, but I haven’t found how to test it without expensive equipment
If you come across any testing info on this system without expensive equipment. I would appreciate see that

Thanks again

[Stephen Bowen]

http://facultyfiles.deanza.edu/gems/waltonjohn/Theftdeterentapplicationupda.pdf

http://www.motor.com/article.asp?article_ID=853

http://www.flatrater.com/Friends/CS1/CompSense.htm

http://www.greatautohelp.com/auto_basics/Ecotec-2200-4-Cylinder-Ignition.html

Consider that everyone’s homework assignment. (Just kidding)

Good lord’n butter Mort!! I think I got a headache just reading up on how this thing functions. Where’s Scanner Danner when you need him!!??

Okay, panic mode aside. This is a whole lot of new tech that I’ve no clue about. (At least I’ll admit it) I’d start by finishing up the fuel angle and getting that system down pat, so that is removed as a variable.

The “Flatrater” page is excellent. It explains a lot about the theory of operation on this. Hopefully the fuel issues are the cause of the problems. If not? Then the theory behind how this pig works should be helpful.

S-

[Dwayne]

[quote=”Tedybear315″ post=110425]http://facultyfiles.deanza.edu/gems/waltonjohn/Theftdeterentapplicationupda.pdf

http://www.motor.com/article.asp?article_ID=853

http://www.flatrater.com/Friends/CS1/CompSense.htm

http://www.greatautohelp.com/auto_basics/Ecotec-2200-4-Cylinder-Ignition.html

Consider that everyone’s homework assignment. (Just kidding)

Good lord’n butter Mort!! I think I got a headache just reading up on how this thing functions. Where’s Scanner Danner when you need him!!??

Okay, panic mode aside. This is a whole lot of new tech that I’ve no clue about. (At least I’ll admit it) I’d start by finishing up the fuel angle and getting that system down pat, so that is removed as a variable.

The “Flatrater” page is excellent. It explains a lot about the theory of operation on this. Hopefully the fuel issues are the cause of the problems. If not? Then the theory behind how this pig works should be helpful.

S-[/quote]
Yep, I was thing the same thing lol
ScannerDanner…is cool

[Dwayne]

Maybe EricTheCarGuy
Can make a video of how to test this type of ignition system,using basic tools, and upload it in a couple of days, so if I don’t have a fuel issue, I can go straight to that video lol

What you think Eric?

[EricTheCarGuy]

[quote=”lovetowrenchit” post=110437]Maybe EricTheCarGuy
Can make a video of how to test this type of ignition system,using basic tools, and upload it in a couple of days, so if I don’t have a fuel issue, I can go straight to that video lol

What you think Eric?[/quote]

Not likely. I’d need the same vehicle in and time to shoot the video. That said, I’ve also got videos already planned out for the rest of the year. So to answer your question, not likely anytime soon.

I still think it’s a good idea to check the fuel filter if you haven’t already.

[Dwayne]

[quote=”EricTheCarGuy” post=110469][quote=”lovetowrenchit” post=110437]Maybe EricTheCarGuy
Can make a video of how to test this type of ignition system,using basic tools, and upload it in a couple of days, so if I don’t have a fuel issue, I can go straight to that video lol

What you think Eric?[/quote]

Not likely. I’d need the same vehicle in and time to shoot the video. That said, I’ve also got videos already planned out for the rest of the year. So to answer your question, not likely anytime soon.

I still think it’s a good idea to check the fuel filter if you haven’t already.[/quote]
Shoot! , hope ya know i was just messing with ya…Thanks for the reply. I appreciate it.
I have asked the owner to pick up a quality fuel filter, and any special tool that maybe required to remove the connections

I’ll post my results when filter is replaced

[Lorrin Barth]

This is from the “J Body Organization” and while for manual transmission cars only, from reading around, I find this is happening to automatic transmission cars too. I’d suggest checking with the dealer for any available reflashes.

“Idle Flare or Decel Stall
This condition may affect 2002-04 vehicles with 4 cylinder 2.2L engine
(VIN F – RPO L61) (Chevrolet Malibu, Cavalier, and Classic, Oldsmobile Alero, Pontiac Grand Am and Sunfire).
Some owners may comment about an engine idle flare when the clutch is depressed. Also, some owners may comment about a low speed engine decel stall when coming to a stop.
The flare is caused by the vehicle entering stall-saver mode when the clutch is depressed. The low speed engine decel stall is produced by an interaction between the engine control software and the IAC motor.
Reprogram the PCM with the latest calibration available. The new calibration was released beginning with TIS satellite data update version 6.0 for 2004 available June 2004. As always make sure your Tech 2 is updated with the latest software version.”http://www.j-body.org/forums/read.php?f=11&i=99416&t=99225#99416

[Stephen Bowen]

[quote=”barneyb” post=110508]This is from the “J Body Organization”

“Idle Flare or Decel Stall
This condition may affect 2002-04 vehicles with 4 cylinder 2.2L engine
(VIN F – RPO L61) (Chevrolet Malibu, Cavalier, and Classic, Oldsmobile Alero, Pontiac Grand Am and Sunfire).
Some owners may comment about an engine idle flare when the clutch is depressed. Also, some owners may comment about a low speed engine decel stall when coming to a stop.
The flare is caused by the vehicle entering stall-saver mode when the clutch is depressed. The low speed engine decel stall is produced by an interaction between the engine control software and the IAC motor.
Reprogram the PCM with the latest calibration available. The new calibration was released beginning with TIS satellite data update version 6.0 for 2004 available June 2004. As always make sure your Tech 2 is updated with the latest software version.”http://www.j-body.org/forums/read.php?f=11&i=99416&t=99225#99416%5B/quote%5D

barneyb: Would that software update be provided for free of charge from the dealership? Maybe in the form of a ‘Recall’? That makes a lot of sense as being a possible issue with the OP’s mystery.

These things are toooo complex at times.

S-

[Lorrin Barth]

Hard to say if free or not. The thing is with the VIN you could at least find out what reflashes are available if any, what they are supposed to correct and if any have been done to the vehicle.

[Dwayne]

[quote=”barneyb” post=110508]This is from the “J Body Organization” and while for manual transmission cars only, from reading around, I find this is happening to automatic transmission cars too. I’d suggest checking with the dealer for any available reflashes.

“Idle Flare or Decel Stall
This condition may affect 2002-04 vehicles with 4 cylinder 2.2L engine
(VIN F – RPO L61) (Chevrolet Malibu, Cavalier, and Classic, Oldsmobile Alero, Pontiac Grand Am and Sunfire).
Some owners may comment about an engine idle flare when the clutch is depressed. Also, some owners may comment about a low speed engine decel stall when coming to a stop.
The flare is caused by the vehicle entering stall-saver mode when the clutch is depressed. The low speed engine decel stall is produced by an interaction between the engine control software and the IAC motor.
Reprogram the PCM with the latest calibration available. The new calibration was released beginning with TIS satellite data update version 6.0 for 2004 available June 2004. As always make sure your Tech 2 is updated with the latest software version.”http://www.j-body.org/forums/read.php?f=11&i=99416&t=99225#99416%5B/quote%5D
thanks barneyb! for your input and research. I will call my buddy who owns a Chevrolet Dealership in barnesville, and ask him if that is specific to a month of manufacturer.
sounds like something to check into…thanks again I appreciate it.

I did get that filter from the owner last night. I plan on installing that on Saturday

[Dwayne]

Well, I’m tired. I work 12 hours a day and can only do work on vehicles after I get home, and on weekends.

This has been a real head scratchier for me, an I’m sure confusing for others trying to help.

I have troubleshooted to to the point my brain is fried!…I have come to the conclusion that, with the symptoms this car is experiencing, I have tracked the issue down to two items.

I’m not 100% positive on one of these items being the cause of complaint, UNTIL I TEST THEM FIRST:)…cross my fingers and toes that one of these is the culprit….maybe y’all can figure out what I zeroed in on?…. remember I could be wrong in my diagnosis….but I hope not…

[Author]

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