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Car dies at low RPM's - New battery - Alternator tested OK.

Sent to Car Experts July 07, 2006 12:01 p.m.

My 1994 Mustang V6 has had problems starting twice in the past month. The battery seemed fine because when we hooked up jumper cables and touched them together, it would throw out sparks. A Jump worked like a charm the first time. The second time, I noticed it would die while driving only when coming to a stop and I let the RPM's drop. I had to turn the key to start it again and hope I could keep the RPM's up. It was more difficult to jump this time. I had a new battery put in and my alternator test from Auto Zone came back fine... I thought it was fixed. The very next day, I noticed that the car was doing the same thing while driving. I was more careful not to let the RPM's drop so I didn't have to restart it again. It had problems starting so I sat there while it warmed up, keeping the engine reved and watching the battery guage. Whenever the RPM's would get real low, the battery meter would fall. After a long warmming up, I made it home fine. The next morning it started as normal with no work. I was thinking of increasing the idle rpm's but don't want it to be a serious problem that I am just patching.

Optional Information:
1994 Ford Mustang V6 - 3.8

Already Tried:
New Battery, Alternator checked.

Customer (name blocked for privacy)

Status: Closed Value: $15

Answer
July 07, 2006 12:40 p.m. (39 minutes and 34 seconds later)

REPLIED

Hope this helps. Please click accept for me. ThanksImages available only to Customers.

The voltage will drop with the rpm the alt. must be spinning at normal idle to produce the proper voltage. The car sounds like it has an IAC(idle air control) motor fault. We have a tester that can actuate the IAC to see if it is the problem. Without being there to test it for you and going by the symptoms I would say it does not seem serious. I would replace the IAC valve and clean the throttle blade good.

This is a fairly easy repair. First you should check all the vacuum line for a leak (which I doubt you will find one). The most likely cause for this is that the IAC (idle air control) motor is slow to respond. Replace the IAC valve to fix this problem, it may start to work but will get worse until the car will not run unless you press the gas pedal all the time.

The valve can be obtained from most parts stores for about 50.00 -100.00 depending on engine size.

Images available only to Customers.

This is very common. They are very easy to replace, just two bolts and 1 connector. This IAC motor is located on the throttle body or intake when you get the new part you will see how easy it is to replace. This IAC motor is what the computer uses to control the engine Idle when it goes bad you have to hold the gas to make the car run.

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Reply to Danny
Sent July 07, 2006 1:35 p.m. (55 minutes and 17 seconds later)

Thanks for the reply. Do I have to replace the part or can it just be cleaned as outlined at: http://www.muscularmustangs.com/iac.php

Thanks!
Steve

Customer (name blocked for privacy)

Answer
July 07, 2006 1:39 p.m. (3 minutes and 26 seconds later)

ACCEPTED

I have not had much luck in cleaning them, but you can try it first. Make sure however that you clean the throttle blade and body.

__________________
PLEASE -Remember that your Expert will not be paid until you accept an answer and complete the process. Please leave "FEED BACK".

Danny -- Shop foreman -- 99% Positive Feedback on 331 Car Accepts
Senior Master Subaru, G.M.Cert.,Honda cert., Dodge Cert., Ford Cert., 2 ASE Master cert.15 yrs exp.

Reply to Danny
Sent July 07, 2006 2:44 p.m. (1 hour and 5 minutes later)

OK, I just got the part and got the car home to look at it. This is what I got:
http://img424.imageshack.us/my.php?image=10014024cy.jpg

I don't want to replace the wrong part and do something horrible to the car. This is what 'I think' I need to replace. It does not look exactly the same as my new part:

http://img251.imageshack.us/my.php?image=10013963pj.jpg
...this part is on the very top of the engine and looks easy to replace, I hope it's right... the sticker on it says "Service Procedure: Do not clean inside the throttle body or adjust throttle set screw in a CCW direction, See service manual."

I checked the wire that was connected to the part in the car, and it fits... but my new part came with another wire... I don't see any way that this new wire can be installed.

Once again, your help is most apprieciated. Once I get this part in, I will click accept for you!

Thanks!!

Steve

Customer (name blocked for privacy)

Info Request
July 07, 2006 5:05 p.m. (2 hours and 20 minutes later)

REPLIED to Info Request

Do you still need help? did you figure hoe to install?

Sorry about the delay its been busy at work today.

__________________
PLEASE -Remember that your Expert will not be paid until you accept an answer and complete the process. Please leave "FEED BACK".

Danny -- Shop foreman -- 99% Positive Feedback on 331 Car Accepts
Senior Master Subaru, G.M.Cert.,Honda cert., Dodge Cert., Ford Cert., 2 ASE Master cert.15 yrs exp.

Reply to Danny
Sent July 07, 2006 5:13 p.m. (8 minutes and 13 seconds later)

I installed it, and it worked fine!

The part looked different than the original one. But when I was going back to work from my lunch break... the car did it again.. grr... so, I installed it... I was reassured that it was the right part when I saw the shape of the gasket... This particular model I got (Wells p/n TV206) wanted me to put it on backwards from the original... so I did it...... and it started like a champ!!! Thanks so much for your help!

A little more mechanically inclined,
Steve.

Customer (name blocked for privacy)

Info Request
July 07, 2006 5:18 p.m. (4 minutes and 36 seconds later)

You are welcome. If you need any more help please just request me. Thanks for using JA.

__________________
PLEASE -Remember that your Expert will not be paid until you accept an answer and complete the process. Please leave "FEED BACK".

Danny -- Shop foreman -- 99% Positive Feedback on 331 Car Accepts
Senior Master Subaru, G.M.Cert.,Honda cert., Dodge Cert., Ford Cert., 2 ASE Master cert.15 yrs exp.

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