High Reving?

PowerSlideGT · 06-01-2005, 07:04 PM

Hey guys,

Okay here is my question. I just rebuilt a 5.0 ho motor i put svo heads on it, roller rockers, stock intake and E303 cam. The problem is when i started it it reved fine at first at low idel, then it High reved as it was going in to the warming up stage, reving at 1500 rpms, and it never went down, it stays there, What may be the problem?

06-01-2005, 07:20 PM

Sounds like you could have a vacuum leak somewhere. Check all of the vacuum lines leading to the upper intake. If it still happens then you could go buy a vacuum tester from your local autoparts store and test your vacuum at the manifold. Or, you could always take the car somewhere to get a vacuum test done on it.

FYI - that stock intake manifold is going to really restrict the air going into your motor, therefore choking your power down. The heads & cam want more air...but that stock intake will not give it to them.
I have an Edelbrock Performer manifold for sale right now in the classified section of this site. Upper & lower manifold plus 1/2" plenum spacer for $300 + shipping.

NOTCH306 · 06-01-2005, 08:16 PM

yea a vaccuum leak sounds like a good possiblity

PowerSlideGT · 06-02-2005, 03:12 PM

I checked my engine, turned it on and i deffently hear a air suction but i cant fine the place its comming from, Deffently from the upper intake or some wheres like that. But i checked the three upper hoses on the back and the one upper hose on the front and there not leeking, i Pinched the hoses and the noise didnt stop. This car also isnt mass air. Could this be another problem?

mustangII460 · 06-02-2005, 05:23 PM

Seems like ive been saying this alot lately. Check your TPS voltage.

PowerSlideGT · 06-02-2005, 06:31 PM

And a TPS is what? and how do u check it

NOTCH306 · 06-02-2005, 06:43 PM

TPS is your throttle postion sensor. its the little guy on top of you throttle body. One wire is ground, one is 5v refernece wire from the computer and the other is the signal wire back to the computer. at idle you are probably looking for anywhere from .8 to 1 volt and a WOT around 4.5 or more volts. do not try to check voltage at WOT with the engine running. It can be done with the key on.

06-01-2005, 07:04 PM	#1
PowerSlideGT Registered Member Join Date: Apr 2004 Location: Tecumseh Posts: 165	High Reving? Hey guys, Okay here is my question. I just rebuilt a 5.0 ho motor i put svo heads on it, roller rockers, stock intake and E303 cam. The problem is when i started it it reved fine at first at low idel, then it High reved as it was going in to the warming up stage, reving at 1500 rpms, and it never went down, it stays there, What may be the problem? __________________ 1988 mustang gt t-top svo alum. Heads, comp cam rockers, e303 cam, Mass air, BBK cold air induction, BBK throttle body, gt-40 intake 1 inch spacer, Alum. drive shaft, world class 5 speed, 3.55 gear rear end, drag front springs.

06-01-2005, 07:20 PM	#2
Simi Stang Guest Posts: n/a	Re: High Reving? Sounds like you could have a vacuum leak somewhere. Check all of the vacuum lines leading to the upper intake. If it still happens then you could go buy a vacuum tester from your local autoparts store and test your vacuum at the manifold. Or, you could always take the car somewhere to get a vacuum test done on it. FYI - that stock intake manifold is going to really restrict the air going into your motor, therefore choking your power down. The heads & cam want more air...but that stock intake will not give it to them. I have an Edelbrock Performer manifold for sale right now in the classified section of this site. Upper & lower manifold plus 1/2" plenum spacer for $300 + shipping.

06-01-2005, 08:16 PM	#3
NOTCH306 Registered Member Join Date: May 2005 Location: York, PA Posts: 46	Re: High Reving? yea a vaccuum leak sounds like a good possiblity __________________ 1990 Notch, 306, T-56 trans, 3:73 gears, zex 100 shot, gt-40,z-303 cam, roush 200 heads, powerdyne on the way

06-02-2005, 03:12 PM	#4
PowerSlideGT Registered Member Join Date: Apr 2004 Location: Tecumseh Posts: 165	Re: High Reving? I checked my engine, turned it on and i deffently hear a air suction but i cant fine the place its comming from, Deffently from the upper intake or some wheres like that. But i checked the three upper hoses on the back and the one upper hose on the front and there not leeking, i Pinched the hoses and the noise didnt stop. This car also isnt mass air. Could this be another problem? __________________ 1988 mustang gt t-top svo alum. Heads, comp cam rockers, e303 cam, Mass air, BBK cold air induction, BBK throttle body, gt-40 intake 1 inch spacer, Alum. drive shaft, world class 5 speed, 3.55 gear rear end, drag front springs.

06-02-2005, 05:23 PM	#5
mustangII460 Factoy Five Roadster Join Date: May 2000 Location: Sevier Co,Tennessee Posts: 1,681	Re: High Reving? Seems like ive been saying this alot lately. Check your TPS voltage. __________________ Frank

06-02-2005, 06:31 PM	#6
PowerSlideGT Registered Member Join Date: Apr 2004 Location: Tecumseh Posts: 165	Re: High Reving? And a TPS is what? and how do u check it __________________ 1988 mustang gt t-top svo alum. Heads, comp cam rockers, e303 cam, Mass air, BBK cold air induction, BBK throttle body, gt-40 intake 1 inch spacer, Alum. drive shaft, world class 5 speed, 3.55 gear rear end, drag front springs.

06-02-2005, 06:43 PM	#7
NOTCH306 Registered Member Join Date: May 2005 Location: York, PA Posts: 46	Re: High Reving? TPS is your throttle postion sensor. its the little guy on top of you throttle body. One wire is ground, one is 5v refernece wire from the computer and the other is the signal wire back to the computer. at idle you are probably looking for anywhere from .8 to 1 volt and a WOT around 4.5 or more volts. do not try to check voltage at WOT with the engine running. It can be done with the key on. __________________ 1990 Notch, 306, T-56 trans, 3:73 gears, zex 100 shot, gt-40,z-303 cam, roush 200 heads, powerdyne on the way

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