5.0 questions

Speedy

Speedy

Club Member
5.0 tuning questions

Ok I'm new to 5.0 stuff and have some questions on the new project. It runs like junk. It's a stock 92 5.0 with a trickflow intake and Pro M maf and injectors. Not sure if it's the Maf or injectors causing the problem. It a a 76mm maf which says it's calibrated for 30# and 30# injectors. Is this way to much to even run on a stock motor? Car has no power. Haven't checked timing yet. Is the timing controled by the computer at all?

TIA
Mike
 
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30lb'ers is way overkill for the stock engine, but if tuned can be ok. But still overkill. Timing advance is controlled by the computer I believe, but when setting the timing you need to pull the spout connector which locks the timing while adjusting it (hangs off the harness going to the TFI module) They usually run best at 12-14 degrees
 
Ok maybe I worded it wrong but I know 30s are overkill for a stock motor. I wanted to know if it cause it to run bad and have no power. My GN is back to stock with 50s and it idles and drive without issues. Superstang answered my question though. Thanks Superstang. I'll start by checking the timing and go from there
 
I had 36s in mine..the car ran a little poor and ran 12.9X and changed ONLY the maf and 24s it went 12.1X. I thought I hit the lotto!!!
 
OK I pulled the valve cover to line up the dist. better and make sure no wires were crossed. I don't have a timing light right now so I'm just getting it close. Runs better under accel. but still idles all over the place. It goes from 1k to 3k whenever it wants. Found the EGR wasn't plugged in. Still no vacuum line going to it though. It's getting better but still need to check some of the other sensors. Like to get a adj. fuel pressure regulator and a fuel pressure gauge to see where its at.
 
egr partially stuck open? we only plugged the egr position sensor in. no vacuum to the valve at all. no tab/tad solenoids either. if the maf isn't cal'd to the injectors, it'll run poorly. i may have some stock stuff still around if you want to start with a fresh baseline. careful though. you may fall in love with the windsors and want a 9.5 deck for your car......:lmao:

lemme know if you need anything.......:handshake:
 
I have an adjustable fuel pressure reg and a gauge that will attach to the stock fuel line. I'm not to far from you. i'd let them go pretty cheap. Have to double check the pressure regulator but i'm pretty sure its adjustable.
 
To be honest I'm surprised with 30# injectors on that setup that it even idles fine enough to drive normally. That's way overkill.

19#s worked decent for me to poke around years ago when I had intake/70mm TB/70mm MAF/and a 10# blower setup. When I finally swapped to 30#s I had to hobble the car to the shop for a tune since I wanted to go with a full tune and use no FMU. It ran OK but under 2200RPM or so it choked like hell. The blower was centrifugal so really the extra air didn't kick in until around that RPM range; had it been a roots blower or similar then it probably would've run much better in that respect...

Anyway after you get your timing figured out I'd suspect you still might want to drop injector size. An adjustable FPR can only help so much in this case.
 
Speedy said:
OK I pulled the valve cover to line up the dist. better and make sure no wires were crossed. I don't have a timing light right now so I'm just getting it close. Runs better under accel. but still idles all over the place. It goes from 1k to 3k whenever it wants. Found the EGR wasn't plugged in. Still no vacuum line going to it though. It's getting better but still need to check some of the other sensors. Like to get a adj. fuel pressure regulator and a fuel pressure gauge to see where its at.
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Pull the IAC and clean it will brake cleaner or buy a new one for $25 that will help with the idle.

If the car is running stock fuel pump there is no need for a Adj. FPR

I have a few sets of 24# injectors, I would trade for you 30's? I don't need the 30's but it's always nice to have a set
 
Not sure if its a stock fuel pump or not. My thought with the adjustable is to turn down the pressure to reduce the amount of fuel delivered. I know the injector won't have as good of a pattern at a lower psi though. I'll clean the IAC today and get a light to set the timing. So keep the EGR wire plugged in but don't run a vacuum line? Any good site that give you performance tuning ideas for the 5.0? Thanks everyone for the help so far! +1's will go out when I get home. to hard to do them on my phone. Probably be calling Jim and Jason too lol
 
OK did some more playing around. Put on a gauge and adj. regulater. Fuel pressure line off is 26 psi line on and 35 line off. Pulled and cleaned egr to make sure it wasn't leaking. Pulled and cleaned IAC. With the IAC wire plugged in it idles at 2800 with it unhooked it idles at 1500 to 1800. Is the IAC bad? Can't set the TPS because I don't have a volt meter. So close but still far off. The idle isn't bouning/spiking anymore but is just high. Any thoughts? Thanks for taking time to talk today Jim!
 
Fuel pressure seems really low to me. Doubt that it will cause the idling issue but probably runs shitty.

I would check the tps and so the re learn.
 
Pwraddr said:
Fuel pressure seems really low to me. Doubt that it will cause the idling issue but probably runs shitty.

I would check the tps and so the re learn.
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Yeah I turned the fuel pressure down because of the 30# injectors. I need to set the tps but like stated I don't have a voltmeter. The IAC had this spacer on it. So what all controls the idle?
 

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Speedy said:
Yeah I turned the fuel pressure down because of the 30# injectors. I need to set the tps but like stated I don't have a voltmeter. The IAC had this spacer on it. So what all controls the idle?
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The IAC and the Idle screw control the idle. should be a little allen screw on the backside of the throttle body. Good rule of thumb when adjusting idle is to unplug the IAC and adjust idle to about 650 then plug the IAC back in, Idle should then be about 900-950. If your cant get it to idle down that far when setting it then you IAC is probably jacked up or dirty, but im assuming you've cleaned it. As far as that little spacer plate, Ive never really seen that before on the handful of fox bodies I've messed with. The TPS may affect idle a bit, but check that with a voltmeter (green wire) and make sure its around .98-.99V KOEO, throttle closed. If its a stock TB you'll probably need to egg out the mounting holes on the TPS to get any adjustablity out of it.

Oh and fuel pressure should be set @ 37-39psi with the vacuum hose disconnected from the regulator
 
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superstang9085 said:
The IAC and the Idle screw control the idle. should be a little allen screw on the backside of the throttle body. Good rule of thumb when adjusting idle is to unplug the IAC and adjust idle to about 650 then plug the IAC back in, Idle should then be about 900-950. If your cant get it to idle down that far when setting it then you IAC is probably jacked up or dirty, but im assuming you've cleaned it. As far as that little spacer plate, Ive never really seen that before on the handful of fox bodies I've messed with. The TPS may affect idle a bit, but check that with a voltmeter (green wire) and make sure its around .98-.99V KOEO, throttle closed. If its a stock TB you'll probably need to egg out the mounting holes on the TPS to get any adjustablity out of it.

Oh and fuel pressure should be set @ 37-39psi with the vacuum hose disconnected from the regulator
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Good information! Thanks! TB is aftermarket. I pulled and cleaned the IAC and the port but it didn't change anything. I know the TPS needs to be adjusted for sure. I turned down the fuel pressure to try and cheat the amount of fuel add. Once I get everything set I can inch it back up. Do you know of any good site that give tips on adjusting sensors and performance tuning?
 
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Speedy said:
Yeah I turned the fuel pressure down because of the 30# injectors. I need to set the tps but like stated I don't have a voltmeter. The IAC had this spacer on it. So what all controls the idle?
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That spacer is an old IAC adjuster that Ford Racing used to sell, it's a O.E piece off of a 460.. Leave it off they really didn't work
 
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Speedy said:
Yeah I turned the fuel pressure down because of the 30# injectors. I need to set the tps but like stated I don't have a voltmeter. The IAC had this spacer on it. So what all controls the idle?
Click to expand...

Yeah that's an IAC adjuster plate. Whomever had this car before you had idle issues and probably gave up and resorted to this plate that really does not do shit. Just for reference I have a stroked 325 and use 24lb injectors. If I were you I would stop dicking around and put 19s back on and a calibrated meter.
 
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