Ford

Have Ford Questions? Ask a Mechanic for Answers ASAP

Ask an Expert,
Get an Answer ASAP!

Ford

I have a ford mustang gt. 89. I'm only getting 5 volts tops

Customer Question
at the coil when measured...
I have a ford mustang gt. 89. I'm only getting 5 volts tops at the coil when measured across the 2 terminals that go to the coil but if I use the battery ground I get 14 with the engine running. it hunts and will stall after the volts get under 2. replaced the distributor, coil, tps and iac sensor.
Submitted: 1 year ago.Category: Ford
Show More
Show Less
Ask Your Own Ford Question
Customer reply replied 1 year ago
if I jump a ground to the neg. side of the coil it will stall like right now as well.. really noticed stalling and voltage drop when the ac or head lights are on. this problem seems to show up after running it for 15 min or so
Answered in 20 minutes by:
6/29/2016
Ford Mechanic: Juan Crespo, Tech Trainer replied 1 year ago
Juan Crespo
Juan Crespo, Tech Trainer
Category: Ford
Satisfied Customers: 1,526
Experience: A.S.E. Master Technician, Advanced Level, Emissions - Asian, Domestic, & European
Verified

Hi there.

Let me see if I have it right: the engine will start and run; then stalls when the A/C or head lamps are turned on. Is that correct?

If yes, is your battery showing more than 13 volts at idle with no accessories on? Does voltage drop after 15 minutes?

Ask Your Own Ford Question
Customer reply replied 1 year ago
batter is 14 with all the stuff on and if I go pos. on the coil to neg on the battery I get 13/14
Customer reply replied 1 year ago
but pos. to neg on the coil I get 5 tops
Ford Mechanic: Juan Crespo, Tech Trainer replied 1 year ago

OK. Let's not worry about voltage at the coil - if there is 14 volts at the positive side with the engine running, then we're good to go.

Let's put our attention on the battery. Does voltage go down once the A/C and the headlamps are turned on? Does it affect the brightness of the headlamps or the speed of the A/C blower?

Ask Your Own Ford Question
Customer reply replied 1 year ago
doesn't seem to... nothing dims or slows down... I just need to know were the coil gets its positive and ground from
Customer reply replied 1 year ago
I jumped from the battery pos and neg to the coil and it wouldn't start
Ford Mechanic: Juan Crespo, Tech Trainer replied 1 year ago

The coil gets steady positive voltage from the ignition switch. Ground to it is applied intermittently by the onboard computer to match engine firing order - if you were to touch the coil negative terminal with a grounded LED test light, you would see it flash rapidly, similar to how the injectors are pulsed open.

Would it help you if I uploaded the factory wiring diagram?

Ask Your Own Ford Question
Ford Mechanic: Juan Crespo, Tech Trainer replied 1 year ago

Please do not ground the coil negative terminal. Doing so will burn the driver inside the onboard computer.

Ask Your Own Ford Question
Ford Mechanic: Juan Crespo, Tech Trainer replied 1 year ago

I'm sorry, but seeing that you disregarded my advice to leave the coil alone, I have no option but to opt out of this question. Please do not reply until another expert responds or the site will cycle it back to me.

Ask Your Own Ford Question
Ask Juan Crespo Your Own Question
Juan Crespo
Juan Crespo
Juan Crespo, Tech Trainer
Category: Ford
Satisfied Customers: 1,526
1,526 Satisfied Customers
Experience: A.S.E. Master Technician, Advanced Level, Emissions - Asian, Domestic, & European

Juan Crespo is online now

A new question is answered every 9 seconds

How JustAnswer works:

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

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:

AlvinC answered a question about my Ford truck that only someone with an in-depth knowledge of his subject would have known what was going on.

Rich DUSA

Because of your expertise, you armed me with enough ammunition to win the battle with the dealer. They are installing a fuel filter and fuel pump at no charge to me.

MollyUSA

I needed help with my car on Saturday morning....got a response in 5 minutes, and it was the perfect solution. Thanks again to your service.

Jason V.Kirkland, WA

I do know, after going though this with JustAnswer, that I can somewhat trust my mechanic but I will always contact you prior to going there.

BRNew Jersey

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 PElm 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.

PhilMarysville, CA

< Previous | Next >

Meet the Experts:

Ron

Ron

ASE Certified Technician

24,155 satisfied customers

23 years with Ford specializing in drivability and electrical and AC. Ford certs and ASE Certs

Chris (aka- Moose)

Chris (aka- Moose)

Technician

27,937 satisfied customers

16 years experience

John Mc

John Mc

Ford Technician

5,495 satisfied customers

19 years Ford Lincoln Mercury experience

Chuck

Chuck

ASE Certified Technician

1,685 satisfied customers

33 Years Experience,Ford Senior Master,ASE Master,L1 Advanced Engine Performance

Cam

Cam

Journeyman Automotive Technician

10 satisfied customers

GM Grand Master Technician 2007. 14 years Automotive experience.

Richard

Richard

ASE Certified Technician

1,524 satisfied customers

12 years at a Ford Lincoln/Mercury and Jaguar dealer as a technician and shop foreman.

Mike V.

Mike V.

Auto Service Technician

1,335 satisfied customers

25 years experience on all makes and models, Licensed NYS Inspector.

< Previous | Next >

Related Ford Questions
Engine does not start. replaced the coil but there is no
Engine does not start. replaced the coil but there is no spark … read more
Jaybird61
Jaybird61
Master Automotive Mechanic
1,900 satisfied customers
The engine will crank but will not start. The wait to start
The engine will crank but will not start. The wait to start light does not come on when the key is in the start position. I've read Sean's post above, but am unable to remove the cover of the fuse box… read more
Chris (aka- Moose)
Chris (aka- Moose)
Technician
Vocational, Technical or Trade School
27,937 satisfied customers
2002 Ford Escape. How to change the bulb for the engine
2002 Ford Escape. How to change the bulb for the engine light. It seems stuck. Does it come off?… read more
Matt
Matt
Engineer
Bachelor\u0027s Degree
5 satisfied customers
2007 ford ranger. Check engine light on/tachometer to
2007 ford ranger. Check engine light on/tachometer to zero/speedometer to zero. everythingelse is normal. when shut down cannot restart. to restart have to disconnect the battery for a period of time … read more
eauto
eauto
self employed
High School or GED
74 satisfied customers
Car runs well, engine purrs, so don't think it's an engine
Car runs well, engine purrs, so don't think it's an engine efficiency issue. Odometer typically always showed approximately 390-410 miles to empty when gas tank was filled up. All of a sudden, it only… read more
Chris (aka- Moose)
Chris (aka- Moose)
Technician
Vocational, Technical or Trade School
27,937 satisfied customers
I believe that i need to replace the engine coolent
i believe that i need to replace the engine coolent temperature switch on a 2008 f-250 6.4 powerstroke and need to know where it is and how to get to it … read more
Ron
Ron
ASE Certified Technician
Vocational, Technical or Trade Scho
24,155 satisfied customers
My engine is a 70 302, was a 2bbl carb, now a 4bbl. engine
my engine is a 70 302, was a 2bbl carb, now a 4bbl. engine fires great, but after driving awhile, it wants to stall at idle slow braked … read more
heavy_chevy_396
heavy_chevy_396
Vocational, Technical or Trade Scho
2,518 satisfied customers
Are you able to provide quick help for engine not turning
Hi, are you able to provide quick help for engine not turning over? … read more
Chris (aka- Moose)
Chris (aka- Moose)
Technician
Vocational, Technical or Trade School
27,937 satisfied customers
Service engine light just came on and engine stalls at an
Service engine light just came on and engine stalls at an idle … read more
Dan
Dan
Automotive Technician
Vocational, Technical or Trade Scho
25 satisfied customers
Engine will spin but it won't start. No there's no
engine will spin but it won't start JA: Have you checked the battery, particularly the terminal connections? Are they corroded? Customer: no there's no corrodison JA: What is the model/year of your Fo… read more
Kenny Z
Kenny Z
Ford Senior Master Technician
High School or GED
16 satisfied customers
2006 f 350 have to rev engine high to keep engine from
2006 f 350 have to rev engine high to keep engine from stalling when engaging clutch. Clutch does not engage smooth … read more
Chris (aka- Moose)
Chris (aka- Moose)
Technician
Vocational, Technical or Trade School
27,937 satisfied customers
2012 FordFusion - start engine in park horrible jet engine
2012 FordFusion - start engine in park horrible jet engine roar starts I'm so scared I turn off car. Checked at ford dealer. No history found. I can't drive it from my terror. Husband has driven it wi… read more
eauto
eauto
self employed
High School or GED
74 satisfied customers
Replace the gas engine on a 2004 ford escape hybrid. Engine
replace the gas engine on a 2004 ford escape hybrid … read more
Eric
Eric
Retired
N/A
14,436 satisfied customers
The check engine light came on, It stays on. It was on at
We have gone to a service centre and told they could not look at it until probably Tuesday next week. We are travelling and away from home. … read more
Ron Z.
Ron Z.
Vocational, Technical or Trade Scho
2 satisfied customers
Coolant leaks at rear of engine. Engine not run for last
coolant leaks at rear of engine. Engine not run for last several days so no pressure in engine. … read more
heavy_chevy_396
heavy_chevy_396
Vocational, Technical or Trade Scho
2,518 satisfied customers
6 Bucs 2012 f250 6.7 engine. truck has the check engine on,
6 Bucs 2012 f250 6.7 engine. truck has the check engine on, and the following codes. P20BA, P026A, P0087. I changed fuel filters and drove the truck from 0 to 70mph it picks up and works fine, let spe… read more
Chris (aka- Moose)
Chris (aka- Moose)
Technician
Vocational, Technical or Trade School
27,937 satisfied customers
2011 F150, rebuilding engine 3.5 ecoboost. Engine started
2011 F150 , rebuilding engine 3.5 ecoboost. Engine started well and ran very smooth. After several minutes run, oil pressure dropped off at idle. Low oil pressure warning comes on, If RPM's increase, … read more
HDGENE
HDGENE
Master Technician/Lead Technician
Associate Degree
2,835 satisfied customers
Stopped for gas, when i started the engine the check engine
stopped for gas, when i started the engine the check engine light came on and the air conditioning stopped cooling. Noticed that the engine idled rough and slower, stalled a couple of times. suspect t… read more
Pete
Pete
Independent Auto Technician
Vocational, Technical or Trade Scho
138 satisfied customers
Disclaimer: Information in questions, answers, and other posts on this site ("Posts") comes from individual users, not JustAnswer; JustAnswer is not responsible for Posts. Posts are for general information, are not intended to substitute for informed professional advice (medical, legal, veterinary, financial, etc.), or to establish a professional-client relationship. The site and services are provided "as is" with no warranty or representations by JustAnswer regarding the qualifications of Experts. To see what credentials have been verified by a third-party service, please click on the "Verified" symbol in some Experts' profiles. JustAnswer is not intended or designed for EMERGENCY questions which should be directed immediately by telephone or in-person to qualified professionals.

Disclaimer: Information in questions, answers, and other posts on this site ("Posts") comes from individual users, not JustAnswer; JustAnswer is not responsible for Posts. Posts are for general information, are not intended to substitute for informed professional advice (medical, legal, veterinary, financial, etc.), or to establish a professional-client relationship. The site and services are provided "as is" with no warranty or representations by JustAnswer regarding the qualifications of Experts. To see what credentials have been verified by a third-party service, please click on the "Verified" symbol in some Experts' profiles. JustAnswer is not intended or designed for EMERGENCY questions which should be directed immediately by telephone or in-person to qualified professionals.

Show MoreShow Less

Ask Your Question

x