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 Steve Your Own Question
Steve
Steve, Auto Service Technician
Category: Car
Satisfied Customers: 5494
Experience:  25+ yrs experience as a professional working technician; ASE L1 master technician
157173
Type Your Car Question Here...
Steve is online now
A new question is answered every 9 seconds

Spark..ther are2 amps reading at the injectors..plug.

Customer Question

My engine light is on when switch is on. There is spark at the plugs. ther are2 amps reading at the injectors plug. I have been unable to do a pulse resistance test as of yet. The single wire from the ignition module spoken about is yellow, I replaced the connector with a new one. I have a black/Brown wire coming from the relay with an unpluged end that i am unable to find have another smaller unplugedblk/brown wire from undetermined orgin. Puzzled?
Submitted: 11 years ago.
Category: Car
Expert:  Steve replied 11 years ago.

As I understand the question, the injectors are not spraying fuel.


Step #1 with any fuel system problem: Measure fuel pressure. If there is little or no fuel pressure, the injectors will not spray any fuel... The injection system used on this model is extremely reliable and very rarely develops any sort of electrical problem; more often it turns out to be a failed fuel pump or fuel pump relay.


Not sure what you mean b a pulse resistance test... but it is an extremely bad idea to connect an ohmmeter across the injector plug, or to crank the engine with the plug disconnected. Either procedure can result in damage to the switching transistors in the engine controller. If you want to check for injector circuit pulse, the recommended tool to use is either a noid light (available at any auto parts store) or a computer logic probe (available at radio shack); do NOT use a 12volt test light. The noid light and the logic probe do not load the circuit during testing, so they will not cause any electronic damage.


If you can measure your fuel pressure, let me know the results and I would be glad to give you some idea what direction to take with your testing...





  1. Check electric fuel pump operation as follows:



    1. Connect pressure gauge T80L-9974-A or equivalent to fuel diagnostic valve on fuel rail.
    2. Turn ignition key to On position and ensure gauge indicates 30---40 psi pressure.
    3. Carefully disconnect fuel return line from fuel rail and position the fuel line in a calibrated container with a capacity of at least one quart.
    4. Locate fuel pump relay and replace with a modified relay, Fig. 14.
    5. Energize fuel pump for ten seconds, then allow fuel to drain into container.
    6. The fuel pump is operating properly if; fuel pressure reaches 35---45 psi; the fuel flow is a minimum of 5.6 ounces in ten seconds and; fuel remains at a minimum of 30 psi immediately after shutdown.
    7. If all three conditions are met, the fuel pump is operating properly. Check for engine and/or electrical malfunctions.
    8. If pressure condition is met, but flow is not, inspect filters and fuel lines for obstructions and correct as necessary. If, after making necessary repairs, flow conditions are still not met, replace fuel pump.
    9. If both flow and pressure conditions are met, but pressure drops off immediately after shutdown, check for leaking injectors or regulator. If injectors and regulator are satisfactory, replace fuel pump.
    10. If no fuel flow or pressure is observed, repeat step 4h. If no trouble is found, replace fuel pump.
    11. Replace modified fuel pump relay with original relay
Steve, Auto Service Technician
Category: Car
Satisfied Customers: 5494
Experience: 25+ yrs experience as a professional working technician; ASE L1 master technician
Steve and 6 other Car Specialists are ready to help you
Expert:  Steve replied 11 years ago.

Note: If you are measuring a 2 amp draw at the injectors, then obviously there is current flowing in the circuit and the injectors are operating (drawing 2 amps of current), another indication that the problem is less likely to be electrical than it is to be on the pressure side of the system...


If the injectors were not operating, or if they were not receiving any on-time from the powertrain controller, then there would be no current flow in the circuit, hence zero amp draw is what would be the expected reading if there was no injector signal from the PCM...

Steve, Auto Service Technician
Category: Car
Satisfied Customers: 5494
Experience: 25+ yrs experience as a professional working technician; ASE L1 master technician
Steve and 6 other Car Specialists are ready to help you
Customer: replied 11 years ago.
Reply to Steve7654's Post: i am getting fuel through the pressure relief valve but i havent did pressure test. does that matter
Expert:  Steve replied 11 years ago.

It might matter if the pressure is way down; I would suggest measuring the pressure with a gauge and making sure that it is within specs before attempting any electrical diagnosis. If you ahve, for example, a pressure regulator that is stuck open and returning most of the fuel back to the tank, or a fuel pump only generating 3 psi ther will be some fuel present at teh test port but not enough to force through the tiny injector openings to atomize and start the engine.


there very well may be some other cause here, but with any fuel system problem you have to make sure that there is sufficient fuel present at the injector first; if not, you can spend days testing and checking other things and get nowhere...

Steve, Auto Service Technician
Category: Car
Satisfied Customers: 5494
Experience: 25+ yrs experience as a professional working technician; ASE L1 master technician
Steve and 6 other Car Specialists are ready to help you
Customer: replied 11 years ago.
Reply to Steve7654's Post: I have checked all the 4 questions asked ie engine light is on getting spark fuel pressure positive resistancce positive but there is still a problem. The brn wire on the injectors are not working ex supply power from battery to brn ground will cause injectors to spray + the single blk/org from Engine control module at no 1 is not connected to anything and i cant find a plug fore it. I reads postive on ohm meter.I appears that it should connect to the red/lt blue wire going back to the ignition modgule. I am really stumped. give me some [email protected]

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
< Previous | 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)

    Chris (aka-Moose)

    Technician

    Satisfied Customers:

    1006
    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:

    1006
    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:

    1694
    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:

    1447
    ASE Master Tech 15+ yrs, AAS Automotive Technology, Factory trained Asian specialist
  • http://ww2.justanswer.com/uploads/BL/Bluegorilla/2012-6-21_16298_cam.64x64.JPG GM Tech (Cam)'s Avatar

    GM Tech (Cam)

    Auto Service Tech

    Satisfied Customers:

    669
    GM Grand Master Technician 2007. 14 years experience.
  • http://ww2.justanswer.com/uploads/AM/amedee/2013-10-24_23656_Amedee1.64x64.jpg Amedee's Avatar

    Amedee

    Former ASE Master Tech

    Satisfied Customers:

    2406
    ASE certified tech advanced level specialist. Wisconsin certified emissions state inspector
  • http://ww2.justanswer.com/uploads/SU/supermechanic/2013-8-23_03546_500.64x64.jpg Jerry's Avatar

    Jerry

    Master Mechanic

    Satisfied Customers:

    2123
    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:

    992
    12 years Ford Lincoln/Mercury Jaguar dealership as a technician and shop foreman reparing all makes