1988 Ford mustang gt Altinator Problem

1988 FORD F-150
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DJ-TAINO
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My problem is driving me crazy! My mustang when running on idle about 750-850 RPM my meter in the dash shows that the car is not charging. I replaced the altinator 3 times thinking it was a bad altinator, I also replaced the battery,and i traced the wires from altinator to see if any were bad,every thing ok.I replaced battery cables,i replaced starter,and i still am having a problem. the altinator charges when i accelerate the car passed 1500 RPM then it is charging ok. But at idle it does not charge completly.The altinator is a 75 AMP-They make a 80AMP but i do not want to buy and still have the same problem.It is exspensive.Please help! Also when lights not on and thier is no power load.It is charging ok but when lights on wipers on fog lights it does not charge at all.
Jan 12, 2006 at 11:21 AM

What to check next

Diagnostic guidance. Suggested checks and possible repairs are separate from the owner's reported results.

Document the owner's pulley finding and verify charging performance under load after any pulley or belt-drive change.

Guidance references and applicability

Source: Original question and visible replies. Owner outcomes are attributed; other participants' experiences are not treated as this owner's repair. Next steps are editorial guidance, not a confirmed diagnosis. DENSO: Alternator troubleshooting. General charging-system checks; no vehicle-specific diagnosis. https://www.denso-am.eu/news/alternator-troubleshooting

Read the replies · Discussion summary and reported outcome

AI-ASSISTED GUIDANCE · REVIEWED BY 2CARPROS
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DJ-TAINO
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I solved the problem my self this weekend. Just in case any one runs in to this problem. If you change you pully to aftermarkit pullys make sure it is a good set not cheap ones. That was my problem the altinator pully was to big that is why the altinator was not charging right.
Jan 15, 2006 at 4:39 PM

Discussion summary

1988 Ford mustang gt Altinator Problem

A 1988 Mustang GT appeared to charge poorly at idle under accessory load but improved above about 1,500 rpm. Repeated alternator replacement and other electrical parts had not resolved the complaint.

Reported outcome: The original owner reported resolving the problem and attributed it to an oversized aftermarket alternator pulley.

No pulley dimensions or before-and-after charging measurements were posted. This account does not justify changing pulley sizes on another vehicle without checking compatibility.

Read the original discussion

AI-ASSISTED SUMMARY · REVIEWED BY 2CARPROS
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