How JustAnswer Works:

  • Ask an Expert
    Experts are full of valuable knowledge and are ready to help with any question. Credentials confirmed by a Fortune 500 verification firm.
  • Get a Professional Answer
    Via email, text message, or notification as you wait on our site.
    Ask follow up questions if you need to.
  • 100% Satisfaction Guarantee
    Rate the answer you receive.

Ask BigBob Your Own Question

BigBob
BigBob, Shop manager/technician
Category: Chevy
Satisfied Customers: 4836
Experience:  Shop Manager with 25 years experience
Type Your Chevy Question Here...
BigBob is online now
A new question is answered every 9 seconds

diagnosing a fuel pump problem. On a 1999 Cevy Cavelier with a 2.2.

Resolved Question:

Need help diagnosing a fuel pump problem. On a 1999 Cevy Cavelier with a 2.2.
Submitted: 2 years ago.
Category: Chevy
Expert:  BigBob replied 2 years ago.
Greetings and welcome to just answer!!!!!!!!!!!!



That is normal. The pcm shuts it off after about 2 seconds.

graphic

graphic

graphic
graphic

Bob
Customer: replied 2 years ago.
With out having to go through all of the steps indicated. What would your experience tell my about this car and why it will not maintain fuel presure at start up?

Fuel presure regulator, bad ground, good testing points?

I do not have a fuel presure tool and do not want to buy one for a one...... time issue I hope. Is this the only way to find a bad part or ground or connection point problem.?

Thank you for the diagnostic table but I just need help with what would cause it to shut off even after 2 seconds if there is no presure in the line would it not have to stay on longer until it meets desired start up presure?
Expert:  BigBob replied 2 years ago.
How do you know it is losing fuel pressure?




Bob
Customer: replied 2 years ago.
Car quit running. This is my second fuel pump. Both new. Bad assumption..... I have tank out with both conectors hooked up I can not get fuel to pump in two seconds. When I apply power from battery I can pump until I disconnect.

Expert:  BigBob replied 2 years ago.
Have you checked the fuel pump relay? Did the car stop running because of spark? Are you cranking to get fuel past the 2 seconds?

While cranking the engine,make a second pin of the relay is getting 12 volts coming from the Powertrain Control Module. This should be the Dark Green/White wire. If the circuits are good then at the fuel pump relay jumper the 12 volt supply wire to the Gray wire and see if the fuel pump runs. If the pump still does not come on then check the Gray wire from the relay to the tank and see if the wire is broken. If there is power on the Gray wire at the tank but the pump does not run then verify the ground to the fuel pump is good and replace the fuel pump.


Bob
Customer: replied 2 years ago.
Yes I swapped it with the relay next to it. Yes the car did stop running. I blew in staring fuid and it runs. I am confident that I have a bad electrical connection, bad ground or a fuel presure regulator control problem.

Can you help me with specifict locations and what kind of power to check on specific wires. I am working against time.

I am very appreciative of your quick response. I will loose some good day light soon.

THANKS......
Expert:  BigBob replied 2 years ago.
The fuel pump grounds at G304, which is also the ground for most of the lighting, so if they are all working probably not a ground issue. Maybe the computer is losing supply? Check the green/white wire from the pcm to make sure you the pcm is dropping signal.



Bob
Expert:  BigBob replied 2 years ago.
Also is did the check engine light come on? Does the security or anti theft light stay on while cranking?


Bob
Customer: replied 2 years ago.
Ok good stuff we might be getting close. The car does have lighting problems. We had to jump from one Sid to the other to get a light to work and day time lights flicker unless lights are turned on.

Where is G304.

I will check dashboard lights and get back to you as you respond to my response above.
Expert:  BigBob replied 2 years ago.
At the left front of the passenger compartment.


graphic



Bob
Customer: replied 2 years ago.
Yes the anti theft light stay on while cranking, my current codes are P0452 listed twice. They have been cleared since I started working on car.
Expert:  BigBob replied 2 years ago.
Does your scanner look at body codes?




Bob
Customer: replied 2 years ago.
Not sure Can OBD2 Innova from Oriely
Expert:  BigBob replied 2 years ago.
It has to be able to scan the body control module? Does it start and stall or not at all?
I'm thinking this may be a security issue, which is very common on GM cars. Try this:

1. Turn ON the ignition, with the engine OFF.
2. Attempt to start the engine, then release the key to ON. The vehicle should start and stall instantly.
3. Observe the SECURITY telltale. After approximately 10 minutes, the telltale will change its state.
4. Turn OFF the ignition and wait 5 seconds.
5. Repeat steps 1 through 4 two more times for a total of 3 cycles/30 minutes. The vehicle is now ready to relearn the security system on the 4th attempt to start the engine




Bob
Customer: replied 2 years ago.
Ok this sound worth trying.

Couple things while I am working through this cycle.

1. Note I do not have the tank in car or hooked up do I need to do that?

My concern is that it is easy for my to test fuel delivery when it it out and I can see and control the fuel as it pumps. It is not pumping any fuel as I try to start / crank. This seams to make sence for why it will not start and or even start and stall?

I just talkednto my Son it is his car. He did confirm as this developed into a perminate problem. Over the past 6 month this car has had three or four times when it would not start. He said it would start and then quit. Then after about a hour or so and maybe the next morning itnwould run normal for a couple weeks to a month.

I have replaced the fuel pump about a month ago with no problems and now back to the same problem. I thought I had a defective pump because I seen power at the pump. But may not have taken the time to see the power disappear after 2 sec. Which does not give it enough time to get fuel up on a newly changed fuel pump.

With all of the said. What are you thoughts?

Thank you for you time and quick response.

I will do my best to compensate you accordingly. I am loosing light and we may need to go into another day if this goes deeper long.

Expert:  BigBob replied 2 years ago.
Definitely try the relearn i gave you, this could be the issue. The problem is that if it is anti theft it will probably need new passlock sensor to fix correctly. At this point I do not think the fuel pump is the issue. If you have power there and the ground is good then the pump should run shortly. If it does not then the pump is bad, that's where we need a fuel pressure guage. Every time you cycle the pump it should run shortly. I feel pretty confident your issue is not in the pump. I will be on again tomorrow some time as I am home with an injury, so let me know.


Please let me know if I can help further,
Bob
Customer: replied 2 years ago.
Ok but here is my issue before I put the tank back in.

Should it not pump fluid.

I just checked with the switch in the run position I get 2sec of power then in the crank I get power till I let off then no power on the gray and solid black which I was told from pump tech Suport is the source for the pump.

When I connect why can't I get fund to pump. If I put 12 on the gray and black I get fluid in less than 2sec.

I just ran another test. Battery a little low. Only getting 7 to 10 volts for two seconds then 5 volts when cranking. So I hooked up the boat battery that I have been using to apply 12 volts to the pump directly as a jumper to the existing in car battery and got the same result.

I have put battery on charger for now.

What are you now thoughts.

ps the "theft system" light does not go off after 10 min. As the procedure indicates??




Ps the
Expert:  BigBob replied 2 years ago.
When the ignition switch is turned to the ON position, the PCM energizes the fuel pump relay for 2 seconds allowing the fuel pump to pressurize the fuel system. If the PCM does not receive any ignition reference pulses (engine cranking or running) within 2 seconds , the PCM de-energizes the fuel pump relay; this causes the fuel pump to stop. Yes the gray wire is the power, but if you are losing ignition reference pulses then it shuts off. You are going to have to check the cam and crank signals next. You will need a scanner to check for these signals.



Bob
Customer: replied 2 years ago.
Good morning and welcome back. I hope to have another shot at repairing car today this evening.

I hope we can work together and get me pointed in the right direction. I run a business and do not have a lot of time getting the the right area to solve my problem so diagnosing based on symptoms and knows will be my best approch. I have two years of old time auto mechanic school in my back pocket. Dangerous I know..........

I hope your recovery is going well.

Hear are my current morning digested thoughts from some more testing after we last chatted.

Befor I put the tank back in ( which gives me the opportunity to visualize and apply voltage tests to the end result ) I have the following symptoms that I hope point to something.

Most recent Facts:

When I apply 12 volts from a boat battery to the Gary and Blk wire I can hear the pump and get instant fuel out of the output.

When I monitor the voltage at the conectors that connects to the pump. In the on position I get between 5 and 8 volts. Then it shuts off like I think it should. As we continue the normal process and turn the key to crank I get the gray and the black to show me the same 5 to 8 volts as long as I am cranking. Which leads me to belieive I may have a bad ground. Could it be that 8 volts is not enogh to power the pump.

A piece of info that I have not shared with you from the past that when you said something about light issues, is that a past just answer mechanic helped me repair a front head light by jumping a wire from the good one to the one that would not work because it was a easier solon that finding a common problem with a junction box under the battery??????

I forget to mention I also have a electrical background that leads me to this. Is it possible that I am looking for a bad ground. Is their a historical spot I should look at that would be common to light and fuel pump?

It is my hope that you and I can go back and forth today in and out of my appointments so that when I get home tonight I can go to the spot that makes me feel most confident with seeing the pump produce fuel while the tank is out and easily visible.

I will look forward to your response.

Expert:  BigBob replied 2 years ago.
The easiest thing to do at this point would be to run a new ground wire at the gray wire at the pump, there has been some problems with these plugs. You have to have 12 v at the pump. If you don't then there is a problem. How many volts are in the battery? This is the voltage that you should be getting at the pump. This system is :

The pcm commands the fuel pump relay on then the relay pulls in and energizes the gray wire to the injectors and the fuel pump. At this point you should get battery voltage at the pump for 2 seconds or while cranking. If you have this scenario then the ground or plug would have to be the culprit. Run a new ground if you have this and it should run.

I will be on and off all day so talk to then,
Bob
Customer: replied 2 years ago.
Ok I think we are getting close.

I have less than 200 ohm resistance from connector at pump to battery.

So I now must look to the B+ side to see where I am loosing power.

Can you please get me the schematic for this circuit and the connector locations?

Thanks

I hope to have another shot at it tonight.

Thanks for hanging with me
.

Rick
Expert:  BigBob replied 2 years ago.
graphic


splice s121 is In the engine harness, front of the engine, approximately 27 cm (11 in) from C100


graphic




graphic

(16 cavities) On the fuel tank





Bob
Customer: replied 2 years ago.
Bob, I hope to finish the car today. Thanks for the connection points and electrical diagram.

I hope to be successful and would love to move on to other projects that seem to be stacking up.

Have a great day and thanks for the quick responses.

Rick

Expert:  BigBob replied 2 years ago.
No problem let me know how it goes!!!!


Bob
Customer: replied 2 years ago.
Bob, thank you for your time on this issue.

I would like to close this for I now know what the problem is. It is one of two connectors and to be specific the B+. side of the equation. Under the dash board or the one by the tank.

Having twenty twenty vision on this issue. That has taken approx 5 to 6 different attempts to find this problem if wish you would have told me to run a external ground from the battery to black at tank that would have and proved the ground to prove not to be the problem. I then needed and did start checking the B+ points coming from battery to the tank at all of the connection points until I found my voltage drop from 12 to the 5 / 8 volts that I expressed in a early on symptom. Which also proved to be the right path to solve this problem with out having to go through all off guessing at what it could be.

With all of that said for your future reference.

I have had much success with just answer and this experience was another positive one. My feedback to you would be. Knowing that these cars have connector issues I feel that as back yard mechanics that do not have access to your experiences and the tools like body scanners and schematics and your ability to navigate through them quickly and much more efficiently. I would have and will continue to hope and expect as I use you again and or another expert is that with all of the above skills that you all have is to help us quickly get to the problem with our old fashion and simple tools that most of us possess. I wish you would have taken me down the path of checking certain points that you directed me to for power and to have ran jumper wire from battery to black at tank. This would have saved us slot of speculative guessing.

You were quick to respond and always gave me what I wanted when I asked for a specific want and this was your value in the process. I just wish because most of us are looking for assistance in getting to the specific problem with simple tools like volt / ohm meters, jumper wires and by asking questions led from experience and knowledge most problems can or could be simply identified and would give you much more value.

I do not want to come off as all knowing and or unappreciated just......think you guys have a good thing going and would like to use you and the just answer team more effective and efficient at assisting us get to the problem. Asking us questions the would then guide us to the area or specific problem and the ultimate value that we and you are looking for and willing to pay for.

I hope you find this helpful feedback.

I hope you are ok with $50 for your quick responses in this back and forth problem solving. I quicker and simplified approach to solving this problem would have this value to me worth $100. I have spent $400 on two pumps now and would like to find a great mechanic that can help me not make these kinds of mistakes in today's times with today's vehicles.

I will wait for your response before I make my final decision about fair compensation based on time and results and your side of fair compensation.

Thank you once again and I hope you have and or are recovering well.

Rick
Expert:  BigBob replied 2 years ago.
Thanks for the follow up. Most importantly you have narrowed it down. I do appreciate your feedback and it is well taken. Let me explain a little what i was thinking. You did mention that you were losing voltage, but you also said in an earlier post that you could spray carb spray and it would run. Also on the same post about the relay : While cranking the engine,make a second pin of the relay is getting 12 volts coming from the Powertrain Control Module. This should be the Dark Green/White wire. If the circuits are good then at the fuel pump relay jumper the 12 volt supply wire to the Gray wire and see if the fuel pump runs. If the pump still does not come on then check the Gray wire from the relay to the tank and see if the wire is broken. If there is power on the Gray wire at the tank but the pump does not run then verify the ground to the fuel pump is good and replace the fuel pump. This test would have shown us if you were losing power, but in your response you said you checked the relay, which I assumed you did my test, so then we moved on to other possibilities, like grounds and connections. At this point as long as you have narrowed it down I have very happy and I hope you are also. If you are not satisfied or do not feel comfortable leaving positive feedback please do not hit the accept button. I am constantly learning just like every Tech on here so next time I will be more precise in my answers. Thanks for the kind responses and honesty, that is priceless these days.



Please let me know if I can help further,
Bob
Customer: replied 2 years ago.
Bob, I am sorry but I I closed out on this some how I did not get or over looked the opportunity to add the tip to bring this to a value of $50. Can you reopen ticket.

I am also not sure if you received me full response.

I was very pleased with you acceptance off my feed back. I am sure that much of the time it took me to get right to the problem as quick and easy, and as cheap as I wanted it to be is on me and my fast paced life. I loose track of the past often and seem to only look at my present and the further. Which get me in trouble. so much of the blame for my $400 worth of pumps and lots of extra time could have been reduced significantly by not assuming and doing a better job of testing in order to verify the actual problem. Your part in my future needs to help me quickly get to the source if the problem with simplest test with our simple tools. Many time I will find myself traveling and or at a friends house and or a dansel in distress (you ....me....and detirmination) and would love to count on you as a quick resource with limited time and resouces (the story of my life.......)

It want you to know that you were quick to respond which is HUGE...... You ability to get me the right to the diagrams that I need are huge......but most importantly I count on you to asking me specific questions and instructions that should help me / us get to the problem as quickly and inexpensively as possible. This is where I think the value is when it comes to us seeking assistance from you profesionals.

I wish you the very best in your venture with Just Answer. I would like to you you as my go to Chevy. mechanic. I will refer you also because of your response that you took constructively.

I would value fir the sake of future compensations, to know you honest feelings about my assessment of $50 on this and the time and energy that it took you along with our results.

I will look forward to you your response.

I hope you have a blessed day and have fully recovered from you needed time at home.

Rick Nelson





Expert:  BigBob replied 2 years ago.
Thanks for the follow up Rick. I think the amount you are suggesting is more than fair, I was not expecting that at all. Again I appreciate your honest answers and I hope to be talking to you in the future. Anytime I can help you just request me and I will get back to you ASAP.


God bless,
Bob
Expert:  BigBob replied 2 years ago.
Hopefully you received my last reply!!!



Thanks again!!!
Bob
Customer: replied 2 years ago.
Sorry about the late repines. Busy with spring and the business.

I will open another ticket for you on this same car. You are my man. I will give you the details when I am ready to proceed with the repair.

I will look forward to your services in the future.

Please remember to ask me specific questions that will allow me with simple tools to get to the most likely source of the problem with simple testing points. This will be the most valuable for us both.

It has been a pleasure to work with you and your passion to be helpful first and then compensated vs.the opposite.

Have a God Blessed Day.

No need to reply. I will chat with you on a new ticket in the next couple of weeks.
Expert:  BigBob replied 2 years ago.
I will do my best for you Rick. We will figure it out. Sometimes electrical is a pain to figure out, but process of elimination we will get there. Have a great and God Bless.


Talk to you soon,
Bob




BigBob, Shop manager/technician
Category: Chevy
Satisfied Customers: 4836
Experience: Shop Manager with 25 years experience
BigBob and 3 other Chevy Specialists are ready to help you

JustAnswer in the News:

 
 
 
Ask-a-doc Web sites: If you've got a quick question, you can try to get an answer from sites that say they have various specialists on hand to give quick answers... Justanswer.com.
JustAnswer.com...has seen a spike since October in legal questions from readers about layoffs, unemployment and severance.
Web sites like justanswer.com/legal
...leave nothing to chance.
Traffic on JustAnswer rose 14 percent...and had nearly 400,000 page views in 30 days...inquiries related to stress, high blood pressure, drinking and heart pain jumped 33 percent.
Tory Johnson, GMA Workplace Contributor, discusses work-from-home jobs, such as JustAnswer in which verified Experts answer people’s questions.
I will tell you that...the things you have to go through to be an Expert are quite rigorous.
 
 
 

What Customers are Saying:

 
 
 
  • I was having a terrible problem with the wheel bearings on my 98 Chevy Cavalier and I suspect that using this website saved me plenty of time and money. Todd L Rochester NY
< Last | Next >
  • I was having a terrible problem with the wheel bearings on my 98 Chevy Cavalier and I suspect that using this website saved me plenty of time and money. Todd L Rochester NY
  • Wonderful service, prompt, efficient, and accurate. Couldn't have asked for more. I cannot thank you enough for your help. Mary C. Freshfield, Liverpool, UK
  • This expert is wonderful. They truly know what they are talking about, and they actually care about you. They really helped put my nerves at ease. Thank you so much!!!! Alex Los Angeles, CA
  • Thank you for all your help. It is nice to know that this service is here for people like myself, who need answers fast and are not sure who to consult. GP Hesperia, CA
  • I couldn't be more satisfied! This is the site I will always come to when I need a second opinion. Justin Kernersville, NC
  • Just let me say that this encounter has been entirely professional and most helpful. I liked that I could ask additional questions and get answered in a very short turn around. Esther Woodstock, NY
  • Thank you so much for taking your time and knowledge to support my concerns. Not only did you answer my questions, you even took it a step further with replying with more pertinent information I needed to know. Robin Elkton, Maryland
 
 
 

Meet The Experts:

 
 
 
  • Tim's Auto Repair

    mechanic

    Satisfied Customers:

    7641
    Have owned a repair shop for 25 yrs.
< Last | Next >
  • http://ww2.justanswer.com/uploads/TI/tim37857/2011-10-28_23053_S6301814.64x64.JPG Tim's Auto Repair's Avatar

    Tim's Auto Repair

    mechanic

    Satisfied Customers:

    7641
    Have owned a repair shop for 25 yrs.
  • http://ww2.justanswer.com/uploads/DT/dt69nova/2012-6-15_234154_pic1.64x64.jpg Dave Nova's Avatar

    Dave Nova

    Chevrolet Technician

    Satisfied Customers:

    6870
    ASE Master Certification. GM World Class Certification
  • http://ww2.justanswer.com/uploads/ggrote1/2009-06-27_031011_me.jpg Gary's Avatar

    Gary

    Chevy Technician

    Satisfied Customers:

    5404
    15 years GM master tech
  • http://ww2.justanswer.com/uploads/testedtuff/2009-09-26_170108_pictures.jpg John's Avatar

    John

    Master A.S.E Automotive technician

    Satisfied Customers:

    4071
    A.S.E MasterTechnician A1-A8 w/L1,38 years experience General Motors Master Technician
  • http://ww2.justanswer.com/uploads/RO/rodcuda/2011-7-25_224114_Donhoff1.64x64.JPG Neal's Avatar

    Neal

    Chevy Mechanic

    Satisfied Customers:

    2306
    Shop Owner and Mechanic on multiple makes.
  • http://ww2.justanswer.com/uploads/goodwrench9124/2008-11-09_220838_dscf0007.jpg goodwrench9124's Avatar

    goodwrench9124

    ASE Certified Technician

    Satisfied Customers:

    2041
    Ase Master Certified, GM Master Certified Tech. Awarded GM Top performer, Hybrid certified
  • http://ww2.justanswer.com/uploads/DR/drivefast1971/2012-1-12_172422_0009051tQKh.64x64.jpg Ron Z.'s Avatar

    Ron Z.

    - Chevy Tech -

    Satisfied Customers:

    1912
    18+yrs experience. State Inspector and Chevy Diagnostics