Just rebuilt 5.0 - why so slow - LOST power

bsedwebt70-5.0 · Mar 19, 2006

Just installed the rebuilt 5.0 FI in my 1993 GT - now it is slower - feels like 100 hp vs 250hp - all this is new - Cold air intake, 76mm C&L MAF w/ 19lb calibrated tube - stock 19lb injectors, MAC 70mm T/body & EGR spacer with water lines hooked up, Edelebrock Performer 5.0 upper/lower intake, E303 cam, Crane performance roller lifters, Crane high performance springs 110 seat pressure w/ apx. 350lbs open (recommended by Summit for this combo), Motorsport 1.7 roller rockers, MAC equal length shorties, flowmaster dual exhaust - cat back, MAC underdrives, 200amp 3g alternator,new starter, new water pump, all new hoses, new belt, 3.8 Taurus electric fan, 192* thermostat (factory type), stock oil pump, stock pistons and rods, stock bore with new rings - just honed out, New stock crank, mild porting done to exhaust side of E7 factory heads, timing 14* w/ spout out and plugged back in after setting it, Adjustable fuel pressure regulator set to 34lbs with vacuum on and 42lbs with it off, all vacuum pipes/fittings accounted for and hooked up properly - no vacuum leaks found, 3.27 gear (soon to be 3.73) ... I thought I did everything right - replace everything while in there and do it once. Checked orange O2 sensor ground wire, Engine ground wire, electrical connectors.... The gas is 87 octane purchased on 2/01/06 when the car was taken off the road for this rebuild, the plugs are autolite 1's (looked good so re-used) wires are 8mm gray high temp silicone style (looked good so re-used) cap and rotor looked good so I re-used.... Have I exceeded the capacity of the stock A9P computer? Do I need to burn a chip? Could plugs be causing this? The next things I am going to do are plugs (autolite 25's) fuel injector cleaner (BG 44k) since the injectors are stock with new o rings and plastic tips from Federated Auto Parts (they did not look dirty but who knows) -- any other ideas..... HELP PLEASE -

bryce93lx · Mar 19, 2006

Trouble mainly with bottom end power??? according to my engine builder if so you rocker ratio is to big, he just did a dart head, install on my 5.0 i wanted to go with 1.7's but he said they would steal bottom end power and with my combo and that same e303 cam that i did not need the added lift. have not ran it yet so this is just his .02 good luck

ninety15.0 · Mar 19, 2006

how many miles on the rebuild so far? it might be a little tight....but the way you are explaining it makes me think you might be missing something crucial

1SLO306 · Mar 19, 2006

i think the heads are cause a bottle neck in the air flow.

autolite 25's gapped at .054 might help.

i would also go to a dyno and find out the a:f ratio

Pokageek · Mar 19, 2006

Man, with all those mods if it were me, I would just take it to a reputable spped shop and have it looked at. I had problems because I made so many changes at once that it was anybody's guess what was wrong.

If I had to guess I might suggest putting the stock maf back on and see how it runs for kicks. This was the source of all my problems. Good luck man.

tx2000gt · Mar 19, 2006

Maybe running lean?

bsedwebt70-5.0 · Mar 19, 2006

There are 2 miles on the rebuild - if that! Just put it in today - Car sounds awesome at idle with a little lope with 800rpm fairly steady idle - pat the gas it sounds great - smooth, no noises, 1.7 roller rockers make a little noise but I hear that is normal. Fuel pressure is good at idle and when you pat the gas it seems to respond by going up a bit. I am thinking I need to change the fuel filter and check the fuel pressure under load at this point. The car is a REAL DOG - hit the gas and it has 4 cylinder-like power under load - hit it wide open in 1st gear and it will get to about 15 miles an hour and fall on its face and not want to rev past 3500rpm - stays flat just about there - hit second and it does the same - hit third and it does the same.... Clutch is also new - Centerforce Dual Stage with new T/O bearing, Fork, properly adjusted cable, clean flywheel, new pilot bearing and all - I know it is not in the transmission - It feels almost like a rev limiter kicking in. I will get the NEW Autolite 25's in tommorrow w/ new wires, put some BG 44K cleaner in the gas and see how it does - If that does not work I will put the stock MAF back on (thanks for the idea) -- What about a chip? Have I gone beyond the abilities of the A9P computer - The check engine light has not come on yet and it has made it up to temperature so I would think it has not over extended the stock computer settings yet -- any other suggestions? Lots of dollars spent and no smiles yet....

bryce93lx · Mar 19, 2006

it's the 1.7's lots and lots of guys have gone way beyond what you have done and kept the stock computer, and if your maf sensor is calibrated to your injector it will be fine, i would call a motor builder, or a speed shop, you should easily have 280 horse and it should rip, gl

Pokageek · Mar 19, 2006

"The car is a REAL DOG - hit the gas and it has 4 cylinder-like power under load - hit it wide open in 1st gear and it will get to about 15 miles an hour and fall on its face and not want to rev past 3500rpm - stays flat just about there - hit second and it does the same - hit third and it does the same...."

Dam! That sounds EXACTLY like what my car did with changing the MAF. 1st gear, it sounded and felt like it was going to go ..then ..BAM weak power and sputtering too.

I had also changed from 19lbs to 24# which made my diagnosis harder. They had to program my stock MAF b/c of the 24#'s BUT they said if I had put back the stock MAF, I would have figured it out on my own b/c it would have run lots better.

shttygtstang · Mar 19, 2006

bsedwebt70-5.0 said:
Just installed the rebuilt 5.0 FI in my 1993 GT - now it is slower - feels like 100 hp vs 250hp - all this is new - Cold air intake, 76mm C&L MAF w/ 19lb calibrated tube - stock 19lb injectors, MAC 70mm T/body & EGR spacer with water lines hooked up, Edelebrock Performer 5.0 upper/lower intake, E303 cam, Crane performance roller lifters, Crane high performance springs 110 seat pressure w/ apx. 350lbs open (recommended by Summit for this combo), Motorsport 1.7 roller rockers, MAC equal length shorties, flowmaster dual exhaust - cat back, MAC underdrives, 200amp 3g alternator,new starter, new water pump, all new hoses, new belt, 3.8 Taurus electric fan, 192* thermostat (factory type), stock oil pump, stock pistons and rods, stock bore with new rings - just honed out, New stock crank, mild porting done to exhaust side of E7 factory heads, timing 14* w/ spout out and plugged back in after setting it, Adjustable fuel pressure regulator set to 34lbs with vacuum on and 42lbs with it off, all vacuum pipes/fittings accounted for and hooked up properly - no vacuum leaks found, 3.27 gear (soon to be 3.73) ... I thought I did everything right - replace everything while in there and do it once. Checked orange O2 sensor ground wire, Engine ground wire, electrical connectors.... The gas is 87 octane purchased on 2/01/06 when the car was taken off the road for this rebuild, the plugs are autolite 1's (looked good so re-used) wires are 8mm gray high temp silicone style (looked good so re-used) cap and rotor looked good so I re-used.... Have I exceeded the capacity of the stock A9P computer? Do I need to burn a chip? Could plugs be causing this? The next things I am going to do are plugs (autolite 25's) fuel injector cleaner (BG 44k) since the injectors are stock with new o rings and plastic tips from Federated Auto Parts (they did not look dirty but who knows) -- any other ideas..... HELP PLEASE -

Sounds like a timming thing to me did you let your liffters bleed down while reinstalling them, Did ya use a cam card on that cam . Also are those rocker arms solid or rollers if rollers did you install them right there not the same as the stockers, if there solids some may need shims. When you were timing it did you pull that gray thing out i belie its called a pip?

bsedwebt70-5.0 · Mar 20, 2006

timing 14* pip out & then re-installed after it was set. Roller Crane hydraulic performance lifters. Roller Motorsport (Crane) 1.7 rockers, Crane performance valve springs 110lbs seat 350lbs open (appx). Rockers installed while intake off - looking at lifter when it just started to plunge down backed off and then started counting on the rocker arm tightening sequence - it took 3/4 turn on each one with no shims needed to properly preload. Cam was installed straight up as suggested by my engine builder (he did the work and I watched a bit) -- all of these items were supposed to work together and went in and fit perfectly with the exception I had to take out the oil filler baffle and make a thin sheet metal piece to replace it with for rocker clearance on stock valve cover. I do have another mustang with another 76mm C&L MAF for 19lb injectors that I can switch to see if it changes anything - good idea and I also have the stock one I can try as well to see what happens. Good to hear I have not over extended my computer -BUT- would a chip from Jegs help? I fear I may have a fuel delivery problem and pulling the tank is not a fun job - stock pump does sound loud - comes on when key is turned for a few seconds and goes off as normal but is a bit loud - pressure goes up instantly but seems to waiver just a bit when at idle on my schrader valve guage - I am thinking fuel filter outside the tank 1st after I try the plugs, wires, MAF, BG 44K, etc.... Thanks guys - Keep those ideas coming..... lots o' buckage spent with no truckage =(

jrichker · Mar 20, 2006

The only chip that will do anything for your combo is a custom burned chip using data from several dyno runs. Anything else is a waste of time & money.

Pokageek · Mar 20, 2006

jrichker said:
The only chip that will do anything for your combo is a custom burned chip using data from several dyno runs. Anything else is a waste of time & money.

:Word:

Jozey · Mar 20, 2006

bsedwebt70-5.0 said:
There are 2 miles on the rebuild - if that! Just put it in today - Car sounds awesome at idle with a little lope with 800rpm fairly steady idle - pat the gas it sounds great - smooth, no noises, 1.7 roller rockers make a little noise but I hear that is normal. Fuel pressure is good at idle and when you pat the gas it seems to respond by going up a bit. I am thinking I need to change the fuel filter and check the fuel pressure under load at this point. The car is a REAL DOG - hit the gas and it has 4 cylinder-like power under load - hit it wide open in 1st gear and it will get to about 15 miles an hour and fall on its face and not want to rev past 3500rpm - stays flat just about there - hit second and it does the same - hit third and it does the same.... Clutch is also new - Centerforce Dual Stage with new T/O bearing, Fork, properly adjusted cable, clean flywheel, new pilot bearing and all - I know it is not in the transmission - It feels almost like a rev limiter kicking in. I will get the NEW Autolite 25's in tommorrow w/ new wires, put some BG 44K cleaner in the gas and see how it does - If that does not work I will put the stock MAF back on (thanks for the idea) -- What about a chip? Have I gone beyond the abilities of the A9P computer - The check engine light has not come on yet and it has made it up to temperature so I would think it has not over extended the stock computer settings yet -- any other suggestions? Lots of dollars spent and no smiles yet....

dude the motor is not even broken in yet.you have to give it time for the rings to seat.wait till about 300 miles then start getting on it more.nothing over 4000 till then.the more you drive it the more you will feel it getting better.just give it time my son

bsedwebt70-5.0 · Mar 20, 2006

Thanks guys - worked on it a little today - put BG 44k in the tank - full can to 1/4 tank of gas to get max effect and drove it about 10 miles. Replaced the fuel filter, put in Autolite 25's, replaced wires and re-set timing to 14.5* with the spout out and put it back it - idle is even better than before - sounds really mean - just perfect!!! but still quite smooth feeling just the way I want it - gotta love FlowMasters! Car feels lots better now but still not as fast as my basically stock other 1993 GT engine in my 1970 Mustang. I am going to let the BG 44K work its magic for a few days and drive it a little - 300 miles like you said and see what happens then. I can still swap out MAF's if needed and check some other things but at least now I can see some light at the end of the dollar tunnel. Thanks for the word on the chip - Anybody know of a place in central VA (charlottesville area) that can dyno-tune and burn chips?

Synned · Mar 20, 2006

Just try the MAF ... no harm done if it doesnt work 5 minute check.

2_fast_4_ya · Mar 20, 2006

im running the same combo basically with out the intake. i had a similar problem and mine was the injectors. i put 24 lb'rs in it and it runs awesome.

2_fast_4_ya · Mar 20, 2006

i have basically the same combo minus the intake. i had a similar problem and i pulled my hair out but i put some #24 injectors in it and it runs awesome. you may be running out of fuel

Jozey · Mar 20, 2006

bsedwebt70-5.0 said:
Thanks guys - worked on it a little today - put BG 44k in the tank - full can to 1/4 tank of gas to get max effect and drove it about 10 miles. Replaced the fuel filter, put in Autolite 25's, replaced wires and re-set timing to 14.5* with the spout out and put it back it - idle is even better than before - sounds really mean - just perfect!!! but still quite smooth feeling just the way I want it - gotta love FlowMasters! Car feels lots better now but still not as fast as my basically stock other 1993 GT engine in my 1970 Mustang. I am going to let the BG 44K work its magic for a few days and drive it a little - 300 miles like you said and see what happens then. I can still swap out MAF's if needed and check some other things but at least now I can see some light at the end of the dollar tunnel. Thanks for the word on the chip - Anybody know of a place in central VA (charlottesville area) that can dyno-tune and burn chips?

i hope you dont think that 300miles and you can beat the ***** out of it.just drive alittle harder then at 500 miles check everything.readjust your valves,check oil and stuff like that.if it all looks good then let her rip and see what it does.if your rings are tightly gaped then it might take just alittle more mileage for them to break in.my rings are not tight but not loose and my motor has about 250-300 miles on them and im raping pretty good right now.it just takes time.if by 1000 miles it still dont feel right then you can get a dyno tune and chip if it needs it(the chip).you can always use a dyno tune.good luck bro

bsedwebt70-5.0 · Mar 22, 2006

Worked on it some more - Cleaned the MAF heated wire coils with electric parts cleaner - gained 100hp - now it still is a bit slow feels like 200 rwhp - I feel with this combo I should have about 250 rwhp - but nowhere near as embarrassing. Next I will adjust the TPS, switch in my hotter coil from the other mustang, play with the timing again, put in fresh gas and more BG 44K cleaner once it runs some more. Thanks for the input guys - still letting it break in before I really wail on it.

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