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 Bob Your Own Question

Bob
Bob, Auto Tech
Category: Chevy
Satisfied Customers: 4087
Experience:  Plus 40 years GM, over 30 certified with Chevrolet, ASE certified Master Tech. (Expired, Retired)
2210118
Type Your Chevy Question Here...
Bob is online now
A new question is answered every 9 seconds

did a complete tune up on chevy 350 hei charged ...

Customer Question

did a complete tune up on chevy 350 hei charged battery but still have weak spark
Submitted: 6 years ago.
Category: Chevy
Expert:  Bob replied 6 years ago.
The spark to the ignition system is regulated by the HEI system, not the battery. Some of the components can be tested separately to see if they are with in specs or not. The items that cause the most problems are the module, the coil and the pick up coil. What year is the car?
Customer: replied 6 years ago.
Reply to Bob's Post: 41 chevy pickup not sure of engine yr best guess   early to mid 70"s set up for 2yrs alot of old wiring ran fine before setting up
Expert:  Bob replied 6 years ago.

I am sending you the test procedure for the HEI, all you need is a volt meter and an ohm meter. This is out of the factory service manual and should help you find the problem. Even if the battery was dead, as long as the car will run, the battery has no say so as to how hot the spark is. All it does is supply a 12 volt source for the distributor. Let me know what you find. Thanks, XXXXX XXXXX May take more than one post. Just follow the instructions.

 

graphic
Bob, Auto Tech
Category: Chevy
Satisfied Customers: 4087
Experience: Plus 40 years GM, over 30 certified with Chevrolet, ASE certified Master Tech. (Expired, Retired)
Bob and 4 other Chevy Specialists are ready to help you
Expert:  Bob replied 6 years ago.
graphic
Customer: replied 6 years ago.
whats number 5. get spark at plug very weak new coil cap rotor and module could poor ground or bad wire to dist
Expert:  Bob replied 6 years ago.
I would suspect the wire before the ground, only because if the ground were bad, it should affect all of the cylinders. You could try a wire from a different cylinder, just swap them and see if it changes.
Customer: replied 6 years ago.
new super stock 8mm wire all have weak spark would poor groud connection or low volts to ignition reason really old wiring
Expert:  Bob replied 6 years ago.
It is possible. Have you checked the voltage going into the distributor? It needs 12 volts. A ground also may cause that. Have you run the chart that I sent you to eliminate the coil and module and pick up coil? The module can be tested out of the car by most parts stores. Also be sure there is no resistor in the power line to the distributor. It needs 12 volts
Customer: replied 6 years ago.
the ground from battery is bolted to trans is that best place also replaced weights and springs old cap had crack they were rusted up     could rust affect pickup coil
Expert:  Bob replied 6 years ago.
If it is an aluminum trans, you would be better off having it grounded to the motor. Aluminum is not a great conducter. And yes, rust could change the resistance values on anything electrical. Have you checked the voltage supply going into the distributor yet? I will be off line for a couple of hours, but will check my mail as soon as I sign back on. Thanks
Customer: replied 6 years ago.
one last thing do you have picture diagram of plugwires from dist to plugs bad memory
Expert:  Bob replied 6 years ago.

Sure, here you go.

 

Click image to see an enlarged view
Fig. 4: V8 firing order-1967-74 engines

Customer: replied 6 years ago.
thank you
Expert:  Bob replied 6 years ago.
You are most welcome. Thanks for the accept and feedback and for using JA

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