No power in 5.0 Mustang
08-31-2003, 01:47 AM
#1
Thread Starter
Join Date: Aug 2003
Location: United States
Posts: 15
No power in 5.0 Mustang
I have a weird problem with my '91 Mustang GT. I am hoping someone can help. I recently rebuilt the engine. It is a 347 with twisted wedge heads, 1.7 roller rockers, BBK long tube headers, GT40 intake MAC 70 TB & spacer and it formerly had a Trick Flow Stage I cam. I found that I had no power below 2000 RPMs (lots above though) so I put the stock cam back in. At the same time, I installed 24lb injectors and replaced the MAF with a 76mm C&L for 24lb injectors (blue tube).
After setting the timing to about 12 BTDC, the thing idles pretty well. But there is no power at all. I can back up into mu driveway, but I cannot get up the small slope to the street. I seem to be getting only 11 in of vacuum at idle, and occasionaly, something happens in the engine and I get 15 in for a couple seconds, and then it goes back to 11.
I have checked for vacuum leaks and I cannot find any. I have tried plugging all 4 openings on the GT40 intake with no luck.
Given my stock cam and 1.7 rockers, what kind of vacuum should I get at idle?
Any thoughts would be appreciated.
Bill Temple
After setting the timing to about 12 BTDC, the thing idles pretty well. But there is no power at all. I can back up into mu driveway, but I cannot get up the small slope to the street. I seem to be getting only 11 in of vacuum at idle, and occasionaly, something happens in the engine and I get 15 in for a couple seconds, and then it goes back to 11.
I have checked for vacuum leaks and I cannot find any. I have tried plugging all 4 openings on the GT40 intake with no luck.
Given my stock cam and 1.7 rockers, what kind of vacuum should I get at idle?
Any thoughts would be appreciated.
Bill Temple
08-31-2003, 08:46 PM
#2
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Join Date: Jul 2003
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No power in 5.0 Mustang
well how was the cams installed..also do a compression test..due you have the pcv valve installed?...what is the time set at?</P>
lots of things..one would guess you might have a valve set to tight..go over the valves again 0 lash</P>
08-31-2003, 10:17 PM
#3
Thread Starter
Join Date: Aug 2003
Location: United States
Posts: 15
No power in 5.0 Mustang
I installed the cam by the following procedure:
1] I rotated the engine to TDC on #1. I know it was #1 because I made sure the distributor was pointing at #1.
2] I took off the timing cover (along with the intake manifold, lifters, rocker arms and a bunch of other stuff) and made sure the circle marks on my cloyes timing chain were properly aligned.
3] I pulled out the old (trick flow) cam and put the new (stock) cam back in. I made sure that the circle mark on the cam gear was aligned with the mark on the crank gear ,which had not moved.
4]I then buttoned up the timing cover and moved on to the valve train.
5]I verified that the lifters for #1 were both on the heel of the cam. I adjusted the rocker for both lifters to half a turn past 0 lash. I then turned the crank 90 degress and repeated the process for each cylinder in order of the firing order. In each case I verified (visaully) that the lifters were on the heel of the cam lobes.
6] I buttoned up the engine, putting in new, blue 24lb injectors and substituting the 24lb C&L maf along the way.
7] I put the distributor back in and set the static timing by rotating the engine to 10 degrees btdc and then (with the ignition on)turnning the distributor until the #1 spark plug fired. Generally, this method gets me pretty close.
8] When I tried to start the engine, it would come close to starting but would not start. I advanced the distributor by hand. Then the engine started, but it would barely idle. I set the timing with a timing light. The little plug next to the distributor was removed when I did this. It did seem to me that I had to advance the timing quite a bit to get to 12 degrees btdc. This did seem odd.
Other items of interest:
A] I have a fluidampr harmonic balancer. It has two sets of timing marks that are 90 degrees apart. This has caused confusion in the past so I marjked the correct set with a piece of tape. Writing this out makes me wonder if I my timing is not off by some wide margin.
B] I have an Auto XRay scanner. I ran the KOEO (key on engine off) scan, and it came back with no codes. I tried to run the KOER (key on engine running) scan and it kept telling me that the vehicle was not responding.
What the heck?
By the way, thanks for the help.
Bill Temple
1] I rotated the engine to TDC on #1. I know it was #1 because I made sure the distributor was pointing at #1.
2] I took off the timing cover (along with the intake manifold, lifters, rocker arms and a bunch of other stuff) and made sure the circle marks on my cloyes timing chain were properly aligned.
3] I pulled out the old (trick flow) cam and put the new (stock) cam back in. I made sure that the circle mark on the cam gear was aligned with the mark on the crank gear ,which had not moved.
4]I then buttoned up the timing cover and moved on to the valve train.
5]I verified that the lifters for #1 were both on the heel of the cam. I adjusted the rocker for both lifters to half a turn past 0 lash. I then turned the crank 90 degress and repeated the process for each cylinder in order of the firing order. In each case I verified (visaully) that the lifters were on the heel of the cam lobes.
6] I buttoned up the engine, putting in new, blue 24lb injectors and substituting the 24lb C&L maf along the way.
7] I put the distributor back in and set the static timing by rotating the engine to 10 degrees btdc and then (with the ignition on)turnning the distributor until the #1 spark plug fired. Generally, this method gets me pretty close.
8] When I tried to start the engine, it would come close to starting but would not start. I advanced the distributor by hand. Then the engine started, but it would barely idle. I set the timing with a timing light. The little plug next to the distributor was removed when I did this. It did seem to me that I had to advance the timing quite a bit to get to 12 degrees btdc. This did seem odd.
Other items of interest:
A] I have a fluidampr harmonic balancer. It has two sets of timing marks that are 90 degrees apart. This has caused confusion in the past so I marjked the correct set with a piece of tape. Writing this out makes me wonder if I my timing is not off by some wide margin.
B] I have an Auto XRay scanner. I ran the KOEO (key on engine off) scan, and it came back with no codes. I tried to run the KOER (key on engine running) scan and it kept telling me that the vehicle was not responding.
What the heck?
By the way, thanks for the help.
Bill Temple
08-31-2003, 10:42 PM
#4
I ♥ Acer
Join Date: Jul 2003
Location:
Posts: 11,394
No power in 5.0 Mustang
one thing leads me to you are off aleast 1 tooth on the dist....I can't be 100% sure not seeing'in person but would lead to believe with you saying you have to really move the dist alotto get the advance..you can move your plug wires around 1 to see it correct with out pulling the dist...let me know what you find
05-15-2009, 03:19 AM
#5
Join Date: May 2009
Location: ct
Posts: 4
yea i have a 87 mustang gt i bought it stock and had a friend put a different 5.0 in with a lot more power but i have no power when the motor was in his car it was fast i put it in mine it does nothing i dont no whats rong with it, it sounds good and reves up but doesent go fast its really slow
