Losing HP

B.A.M302 · March 20th, 2007, 09:49 AM

My 87 5.0 is losing hp at 4000 rpms and higher when i stomp on it. The amp light comes on at that range of rpms and higher and the car just stops accelerating but the rpms still go up very slow at that point. I put in a new alternator ... still didn't fix the problem do i need a alternator that pushes more amps or is there another issue that needs to be addressed here thanks.

mikebert · March 20th, 2007, 10:12 AM

Sounds like a different problem. Even if the alternator wasn't working very well, you would still run off the battery. Besides, even if the alternator was dying, it either wouldn't work the whole time or if it had reduced output, it would still make more power at higher rpms.

B.A.M302 · March 20th, 2007, 10:18 AM

When i drive the car when its cold it doesn't do it. When it warms up it starts to lose the hp. Do you think it could be my cats then.

Stangzilla · March 20th, 2007, 10:54 AM

Originally Posted by B.A.M302

When i drive the car when its cold it doesn't do it. When it warms up it starts to lose the hp. Do you think it could be my cats then.

Cats? What are those?!! LOL

TurboLX · March 20th, 2007, 11:02 AM

sounds like a vaccumm leak???

mikebert · March 20th, 2007, 11:06 AM

I don't even know where to begin.

How long has it done that? Did you change anything? What all has been done to it?

GTXRacing · March 20th, 2007, 12:47 PM

Originally Posted by Stangzilla

Originally Posted by B.A.M302

When i drive the car when its cold it doesn't do it. When it warms up it starts to lose the hp. Do you think it could be my cats then.

Cats? What are those?!! LOL

+1. To be honest I might ask myself soon..."What's muffler pipes?" Might go full open header all day night long

dr.gonzo · March 20th, 2007, 05:56 PM

buy a haynes and go throgh the trouble shooting. good tune up (plugs/cap/roter/fuel filter) a fuel pressure reg. carb build up? you got that oil sludge castrol gtx is talking about? seafoam engine cleaner and change oil+filter. I dont know if o2 sen matters but if you did all the above with no gain and your still on the stock ones...cant hurt. if you really want to have fun get some exhaust cut outs put ahead of the cats. warm it up and try it. loud is fun.

Stangzilla · March 20th, 2007, 06:30 PM

Originally Posted by GTXRacing

Originally Posted by Stangzilla

Originally Posted by B.A.M302

When i drive the car when its cold it doesn't do it. When it warms up it starts to lose the hp. Do you think it could be my cats then.

Cats? What are those?!! LOL

+1. To be honest I might ask myself soon..."What's muffler pipes?" Might go full open header all day night long

When i was building my car I have longtubes on it and took it for a ride before I put the exhaust on and honestly I did not like how it sounded at all.. I have a 347 with 10.5:1 compression.. Sounded way to loud and raspy.. hated it...

dr.gonzo · March 20th, 2007, 06:31 PM

aod or manual? 3.73 for manual 4.10 for the aod. also a step up to after market heads. not sure on the spec of your cam either. aod stall converter?

Tony_90fox · March 20th, 2007, 06:46 PM

i really think the 3:73 for this and 4:10 for this is retarded. I know people with manuals running 4:56s, and others who run 4:10s no problem in there manual, and the gas isnt bad unless you get on it every stop light.....It is really what you want to do with your car and base it around your setup.

Stangzilla · March 20th, 2007, 07:14 PM

Yeah you can run 4.56 gears with a manual if you want to spin 3500+ rpm at 70 mph.. To many rpm's for me..

stang fanatic · March 20th, 2007, 09:21 PM

you can run 4.56 gears with a manual if you want to spin 3500+ rpm at 70 mph

Its not that high unless your running midget tires or something. I run 4.56's with a 25" tire and turn around 2700-2800 for 70 mph.

Stangzilla · March 20th, 2007, 09:55 PM

See I run 275\40\17's and with a Tremec trans and 3.73 gears I turn 2900 at 70mph in 5th.. If I ran that gear with my tire I would turn prob 34-3500rpm. Like I said to much for me.. Fanatic are you runnin a 15 inch rim or a 16?

Tony_90fox · March 20th, 2007, 10:02 PM

See, it just depends on your setup and how you want the car to run. Track time and high way time will have a deciding factor, but i know people who run 4:56s as their dd and commutes about 65 miles a day. i think he is in the low 3000 rpm range but he is young and can take the noise.

You are getting too old stangzilla, that is it isnt it?

Stangzilla · March 20th, 2007, 10:17 PM

Originally Posted by Tony_90fox

See, it just depends on your setup and how you want the car to run. Track time and high way time will have a deciding factor, but i know people who run 4:56s as their dd and commutes about 65 miles a day. i think he is in the low 3000 rpm range but he is young and can take the noise.

You are getting too old stangzilla, that is it isnt it?

That may be part of it and another part is the fact that I have a almost $7000 motor and dont want to put extra strain on it by spinning that much rpm on the highway when I am crusing long distances. I drive about 100 miles each way when I go to the track.. + when you are pushin 400+ hp without No2 like I am it really is not needed to have a gear that low because I have enough power to rip it up... If I had 4.56's in my car 1st and 2nd gear would be virtually useless.. its a good gear for a total drag car and for cars that are stock or mildly modded...

Tony_90fox · March 20th, 2007, 10:21 PM

Shoot, that is why you need to get a trailor! LOL, just kidding man, I bet your 3:73s suit your setup well.

You think your block will hold just fine when the gas comes?

I got it made, the track is 10 minutes from campus, and the only long commutes i make is home about once a month or so...about 280 round trip.

Stangzilla · March 20th, 2007, 10:24 PM

Yeah its fine I run a 175-200hp wet shot... But I have a stud girdle and a lifter valley girdle.. Good to 650hp.. Not gonna change my block until 4 or 5 years from now when my crate motor starts to get tired and I build my twin hair-dryer motor.. Then look out 9's here I come...!!!

Darrell · March 20th, 2007, 10:28 PM

Possible causes are plugged cats, bad valve springs, retarded ignition timing, jumped timing chain, etc. The amp light coming on is odd. Is the belt slipping? Is there belt dust on the alternator fan/pulley?

95opal · March 20th, 2007, 11:39 PM

A slipping belt came to mind first, but i didnt see if you checked your coil that would be my next guess.

March 20th, 2007, 09:49 AM	#1
B.A.M302 Regular Join Date: Jan 2007 Location: maryland Posts: 89	Losing HP My 87 5.0 is losing hp at 4000 rpms and higher when i stomp on it. The amp light comes on at that range of rpms and higher and the car just stops accelerating but the rpms still go up very slow at that point. I put in a new alternator ... still didn't fix the problem do i need a alternator that pushes more amps or is there another issue that needs to be addressed here thanks. __________________ Crate 302, Trick Flow Intake R, 75mm MAF, bbk 75mm throttle body, bbk 76mm EGR spacer, 351 Winsor heads ported and polished by Bennet Racing, Lunati cam, 30 pd. Injectors, TKO 500, aluminum drive shaft, bbk mid length headers, bbk off road H pipe, 3:55,

March 20th, 2007, 10:18 AM	#3
B.A.M302 Regular Join Date: Jan 2007 Location: maryland Posts: 89	When i drive the car when its cold it doesn't do it. When it warms up it starts to lose the hp. Do you think it could be my cats then. __________________ Crate 302, Trick Flow Intake R, 75mm MAF, bbk 75mm throttle body, bbk 76mm EGR spacer, 351 Winsor heads ported and polished by Bennet Racing, Lunati cam, 30 pd. Injectors, TKO 500, aluminum drive shaft, bbk mid length headers, bbk off road H pipe, 3:55,

March 20th, 2007, 11:02 AM	#5
TurboLX IT'S TURBO TIME 1990 Mustang LX Turbo Join Date: Oct 2006 Location: NY Posts: 8,643	sounds like a vaccumm leak??? __________________ *Put up, Shut up, Line Up And Get Beat Up!!!*

March 20th, 2007, 05:56 PM	#8
dr.gonzo Enthusiast Join Date: Oct 2006 Location: kc mo Posts: 790	buy a haynes and go throgh the trouble shooting. good tune up (plugs/cap/roter/fuel filter) a fuel pressure reg. carb build up? you got that oil sludge castrol gtx is talking about? seafoam engine cleaner and change oil+filter. I dont know if o2 sen matters but if you did all the above with no gain and your still on the stock ones...cant hurt. if you really want to have fun get some exhaust cut outs put ahead of the cats. warm it up and try it. loud is fun. __________________ FREE LUNCH, FINAL WISDOM, TOTAL COVERAGE... WHY NOT?

March 20th, 2007, 06:31 PM	#10
dr.gonzo Enthusiast Join Date: Oct 2006 Location: kc mo Posts: 790	aod or manual? 3.73 for manual 4.10 for the aod. also a step up to after market heads. not sure on the spec of your cam either. aod stall converter? __________________ FREE LUNCH, FINAL WISDOM, TOTAL COVERAGE... WHY NOT?

March 20th, 2007, 10:12 AM	#2
mikebert Enthusiast Join Date: Oct 2006 Location: Augusta, GA Posts: 906	Sounds like a different problem. Even if the alternator wasn't working very well, you would still run off the battery. Besides, even if the alternator was dying, it either wouldn't work the whole time or if it had reduced output, it would still make more power at higher rpms.

March 20th, 2007, 11:06 AM	#6
mikebert Enthusiast Join Date: Oct 2006 Location: Augusta, GA Posts: 906	I don't even know where to begin. How long has it done that? Did you change anything? What all has been done to it?

March 20th, 2007, 06:46 PM	#11
Tony_90fox MM Fanatic Join Date: Jun 2006 Location: Bowling Green, KY Posts: 3,593	i really think the 3:73 for this and 4:10 for this is retarded. I know people with manuals running 4:56s, and others who run 4:10s no problem in there manual, and the gas isnt bad unless you get on it every stop light.....It is really what you want to do with your car and base it around your setup. __________________ 393 dropping in a foxbody near you, very very soon Military Crew E-3 Combat Engineer

March 20th, 2007, 07:14 PM	#12
Stangzilla MM Fanatic Join Date: Aug 2006 Location: On my way to Baines's house!! Posts: 3,008	Yeah you can run 4.56 gears with a manual if you want to spin 3500+ rpm at 70 mph.. To many rpm's for me.. __________________ Rotating The Earth 1320 Feet At A Time!! The very existence of flamethrowers proves that sometime, somewhere, someone said to themselves, “You know, I want to set those people over there on fire, but I’m just not close enough to get the job done.”

March 20th, 2007, 09:55 PM	#14
Stangzilla MM Fanatic Join Date: Aug 2006 Location: On my way to Baines's house!! Posts: 3,008	See I run 275\40\17's and with a Tremec trans and 3.73 gears I turn 2900 at 70mph in 5th.. If I ran that gear with my tire I would turn prob 34-3500rpm. Like I said to much for me.. Fanatic are you runnin a 15 inch rim or a 16? __________________ Rotating The Earth 1320 Feet At A Time!! The very existence of flamethrowers proves that sometime, somewhere, someone said to themselves, “You know, I want to set those people over there on fire, but I’m just not close enough to get the job done.”

March 20th, 2007, 10:02 PM	#15
Tony_90fox MM Fanatic Join Date: Jun 2006 Location: Bowling Green, KY Posts: 3,593	See, it just depends on your setup and how you want the car to run. Track time and high way time will have a deciding factor, but i know people who run 4:56s as their dd and commutes about 65 miles a day. i think he is in the low 3000 rpm range but he is young and can take the noise. You are getting too old stangzilla, that is it isnt it? __________________ 393 dropping in a foxbody near you, very very soon Military Crew E-3 Combat Engineer

March 20th, 2007, 10:21 PM	#17
Tony_90fox MM Fanatic Join Date: Jun 2006 Location: Bowling Green, KY Posts: 3,593	Shoot, that is why you need to get a trailor! LOL, just kidding man, I bet your 3:73s suit your setup well. You think your block will hold just fine when the gas comes? I got it made, the track is 10 minutes from campus, and the only long commutes i make is home about once a month or so...about 280 round trip. __________________ 393 dropping in a foxbody near you, very very soon Military Crew E-3 Combat Engineer

March 20th, 2007, 10:24 PM	#18
Stangzilla MM Fanatic Join Date: Aug 2006 Location: On my way to Baines's house!! Posts: 3,008	Yeah its fine I run a 175-200hp wet shot... But I have a stud girdle and a lifter valley girdle.. Good to 650hp.. Not gonna change my block until 4 or 5 years from now when my crate motor starts to get tired and I build my twin hair-dryer motor.. Then look out 9's here I come...!!! __________________ Rotating The Earth 1320 Feet At A Time!! The very existence of flamethrowers proves that sometime, somewhere, someone said to themselves, “You know, I want to set those people over there on fire, but I’m just not close enough to get the job done.”

March 20th, 2007, 10:28 PM	#19
Darrell Feb 08 ROTM 1990 Mustang LX 9.36@143 mph Join Date: Jan 2006 Location: Fond du Lac, Wisconsin Posts: 7,026	Possible causes are plugged cats, bad valve springs, retarded ignition timing, jumped timing chain, etc. The amp light coming on is odd. Is the belt slipping? Is there belt dust on the alternator fan/pulley? __________________ Racing in memory of Dave Bandt 11/19/69 - 3/23/08 "he's traded his wheels for wings" Professor of Natural Aspiration Thanks to: Artie at Trick Flow, Dave at Team Z Motorsports, Brian at Total Engine Airflow and Harold at Furo Racecraft

March 20th, 2007, 11:39 PM	#20
95opal Enthusiast 95 opalfrost gt Join Date: Nov 2006 Location: Connecticut Posts: 988	A slipping belt came to mind first, but i didnt see if you checked your coil that would be my next guess. __________________

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