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 Car expert Your Own Question

Car expert
Car expert, ASE Certified Technician
Category: Car
Satisfied Customers: 10370
Experience:  ASE MASTER TECHNICIAN,30 YRS EXPERIENCE
22989858
Type Your Car Question Here...
Car expert is online now
A new question is answered every 9 seconds

infinity QX4: it stop at stop sign and red light

Resolved Question:

my car infinity QX4, when it stop at stop sign and red light . some time the engine it stop ,I must retart let it go.why?
Submitted: 5 years ago.
Category: Car
Expert:  Car expert replied 5 years ago.

HI I CAN HELP, THIS IS MOST LIKELY A BAD DISTRIBUTOR BUT HERE ARE A FEW TESTS WE SHOULD DO FIRST,

 

Customer Concern:The engine idles fine but touch the throttle and it dies. Has good fuel pressure.
Tests/Procedures:1. Check the strength of the spark at the spark plugs with a round blade screwdriver. Look for a good 1/2 inch minimum nice strong blue spark.

2. Put a timing light on it and verify ignition is firing consistently in time Specification is 15 degrees Before Top Dead Center (BTDC) at warm idle with the brown connector of the Throttle Position Sensor (TPS) disconnected.

3. See if the engine responds to supplemental fuel.

4. Check long and short term fuel trims on the scanner to see if the system is in proper fuel control - look for 0% plus or minus 5% to be normal.

5. Check the Mass Airflow (MAF) sensor grams/second - specification is 3.3-4.8 grams at warm idle and 12.0-14.9 grams at 2500 RPM no load.

6. Check calculated engine load - specification is 18.5-26.0% at warm idle and 18.0-21.0% at 2500 RPM no load.

7. Check engine vacuum.

8. Check camshaft timing/timing belt as necessary.

9. Check for a clear exhaust.

10. Check the scanner for throttle %. Specification is 0% closed throttle and 80% at Wide Open Throttle (WOT).

11. Check the Throttle Position Sensor (TPS) sweep voltage on the White wire in the brown connector with the connector plugged in and back probing. Look for about 0.3-0.5 volts closed throttle and about 4.0 volts at WOT.

12. Check the idle switch voltage on the Orange/White wire in the gray connector at the TPS. Look for 12 volts (battery voltage) closed throttle and near 0 volts just off idle.
Potential Causes:Distributor
Exhaust System
Mass Air Flow (MAF) Sensor
Weak Spark
Timing Belt

Car expert, ASE Certified Technician
Category: Car
Satisfied Customers: 10370
Experience: ASE MASTER TECHNICIAN,30 YRS EXPERIENCE
Car expert and 11 other Car 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 would (and have) recommend your site to others I was quite satisfied with the quality of the information received, the professional with whom I interacted, and the quick response time. Thanks, and be sure that I'll be back whenever I need a question answered in a hurry. Stephanie P Elm City, NC
< Last | Next >
  • I would (and have) recommend your site to others I was quite satisfied with the quality of the information received, the professional with whom I interacted, and the quick response time. Thanks, and be sure that I'll be back whenever I need a question answered in a hurry. Stephanie P Elm City, NC
  • used your service this weekend with "Trecers" help. thank you ,thank you, thank you. replaced an A/C fan motor. Local Auto Zone had part. $15.00 "tracer" fee and $40.00 for parts, I saved several hundreds of dollers at a shop. i will recommend you and use you in the future. David L. Richmond, TX
  • 9 dollars, 2 hours of my time, and I drove away. Your diagnosis was right on the mark. Thank you so much. Phil Marysville, CA
  • Lurch. Thank you very much. I had real doubts about this website but your promptness of response, quick followup and to the point answer with picture was incredible. Charles Walnut Creek, CA
  • As a single woman, I really appreciate an excellent and affordable opinion.
    Thank you Geordie, I will not hesitate to contact justanswer in the future!
    Sue Charleston, WV
  • Another great insight to what may be the problem. I will have my mechanic take a look at it tomorrow. Thanks again, Frank...you do indeed know your stuff. Jim Castleberry, FL
  • Excellent reply, and also very quick. Really sounds like the Expert knows what he is talking about. I will be back to use your service when I need more help with my RV. Dutch USA
 
 
 

Meet The Experts:

 
 
 
  • Chris (aka-Moose)

    Technician

    Satisfied Customers:

    846
    16 years of experience
< Last | Next >
  • http://ww2.justanswer.com/uploads/MU/muddyford/2012-6-13_1204_1.64x64.png Chris (aka-Moose)'s Avatar

    Chris (aka-Moose)

    Technician

    Satisfied Customers:

    846
    16 years of experience
  • http://ww2.justanswer.com/uploads/TE/TedG/2012-6-15_14759_avaLarge.64x64.jpg Ted G.'s Avatar

    Ted G.

    ASE Certified Technician

    Satisfied Customers:

    1596
    20 years auto repair experience, ASE Master Tech, Mechanical Failure consultant, Expert Witness
  • http://ww2.justanswer.com/uploads/joecamel90/2008-11-13_03615_head_shot.jpg George H.'s Avatar

    George H.

    ASE Certified Technician

    Satisfied Customers:

    1311
    ASE Master Tech 15+ yrs, AAS Automotive Technology, Factory trained Asian specialist
  • http://ww2.justanswer.com/uploads/AM/amedee/2013-10-24_23656_Amedee1.64x64.jpg Amedee's Avatar

    Amedee

    ASE Master Tech

    Satisfied Customers:

    2367
    ASE Master Tech advanced level specialist
  • http://ww2.justanswer.com/uploads/SU/supermechanic/2013-8-23_03546_500.64x64.jpg Jerry's Avatar

    Jerry

    Master Mechanic

    Satisfied Customers:

    1906
    ASE master, 30+ years. All makes and models. Trouble shooter, shop forman, service manager
  • http://ww2.justanswer.com/uploads/CR/crzydrvr00/2013-11-3_12123_246347.64x64.jpg Richard's Avatar

    Richard

    ASE Certified Technician

    Satisfied Customers:

    942
    12 years Ford Lincoln/Mercury Jaguar dealership as a technician and shop foreman reparing all makes
  • http://ww2.justanswer.com/uploads/ST/Steve7654/2012-6-5_215929_japic800x660.64x64.jpg Steve's Avatar

    Steve

    Auto Service Technician

    Satisfied Customers:

    1980
    25+ yrs experience as a professional working technician; ASE L1 master technician
 
 
 
Chat Now With An Auto Mechanic
Car expert
Car expert
631 Satisfied Customers
ASE MASTER TECHNICIAN,30 YRS EXPERIENCE