Refresh rebuild has me stumped

ahduckit · Aug 28, 2013

Well a somewhat fresh rebuild anyway. Rebuilt motor was swapped from an 87 mustang in a 95 mustang gt. Full rebuild with 87 5.0 block, edlebrock heads, 35-351-8 cam, .200 domed pistons from keith black, eagle h-beam rods, factory intake, throttle body, and crank. My problem is that I cant keep the it from running lean. The headers and temp gauge heat up after about 5 mins. of running. Wideband shows my ratios being between 14.3 and 15.5. Brand new Spark plug so im sure its getting good spark. Fuel pressure is at 36 or 37 psi with it plugged in and 40 unplugged. Any ideas? Im at a lose :dontknow: :BangHead:

If you feel that I left out any details, or need details just ask.

CC'S95GT · Aug 28, 2013

what injectors are you running

RichV · Aug 28, 2013

You may just be making too much power for the injectors.

What CR are you making with the dome pistons?

Is it tuned? Or just stock electronics?

ahduckit · Aug 28, 2013

Stock injectors and electronics. No tune. Unsure of the compression ratio, keith blacks website says 10.6:1 with .30 over. My motor is stock bore and stroke.

RichV · Aug 28, 2013

So you're running a 10.6 CR, big heads, big cam, assuming big intake and exhaust, and stock injectors??

The stock 19# are only good for about 260-280rwhp, and that's at a higher than ideal duty cycle. I'm thinking your pump and injectors are not cutting it. You can adjust the static fuel pressure to 44ish, that will give you a little more fuel until you upgrade/tune it. Put it on a dyno, I'd be curious of where you're at on power.

ahduckit · Aug 28, 2013

Yes, I know I should have bigger injectors but I was just trying to get it to idle right. Factory upper and lower manifolds and bbk equal length headers with a cat less xpipe. I did do a full smog delete. I did put in a new wahlboro 255 fuel pump. Could I be maxing out the 19lbs injectors at idle?

ahduckit · Aug 28, 2013

I'm curious at what the dyno would say as well. Hoping for at least 300 at the wheels

toyman · Aug 28, 2013

ahduckit said:
Could I be maxing out the 19lbs injectors at idle?

No. When I was using my stock headers they would glow at idle with a good AFR readings. I think many would be surprised if the checked their headers in the dark. My engine rebuilder believes it's a common occurrence as well.

ahduckit · Aug 28, 2013

The headers glowing red worried me but why would my motor temp skyrocket as well? That's what leads me to it running lean

RichV · Aug 29, 2013

So these AFR readings are at idle? :tard:

The ONLY time my headers were ever glowing red is when my timing was set to 0* instead of 10* btdc.

ahduckit · Aug 29, 2013

Yes afrs are only at idle. Timing has been double checked. Even with another balancer to make sure it didn't slip. I'm sure it's something simple that I'm over looking but I'm going crazy trying to figure it out

ProKiller · Aug 29, 2013

i think it's your timing. i had a similar problem when i put my 331 in. couldn't get this thing to run/idle right. down on power but just made a lot of noise. headers would be glowing. ended up switching out the distributor and it fixed the problem right away. not saying your ditzy is bad, but it definitely sounds timing related to me.

also, there is no way you'll get 300hp with the current setup. that stock intake is a huge bottle neck on that car right now. get rid of that and get 24# inj and you'll be sitting pretty.

ahduckit · Aug 29, 2013

I'll check timing again today and burp the coolant again. Just to eliminate it from the equation. I'll report back with my findings

Addermk2 · Aug 29, 2013

Posted in your thread on Corral. Cam timing or ignition timing.

Period.

ahduckit · Aug 29, 2013

Thanks. Ill check them today, or at least try to. Thanks guys for the help!

RichV · Aug 29, 2013

Wait ... idle is running closed loop. Of course it may look lean, it's looking for 14.7.

I still think you're maxing out the injectors. Specially at your altitude.

toyman · Aug 29, 2013

Maxing out the injectors at idle? WB readings of 14.3 - 15.5 in closed loop doesn't seem lean to me. My 42's at idle are running 1%-1.5% duty cycle with a steady 14.7 AFR.

hottwheels04 · Aug 29, 2013

ProKiller said:
i think it's your timing. i had a similar problem when i put my 331 in. couldn't get this thing to run/idle right. down on power but just made a lot of noise. headers would be glowing. ended up switching out the distributor and it fixed the problem right away. not saying your ditzy is bad, but it definitely sounds timing related to me.

also, there is no way you'll get 300hp with the current setup. that stock intake is a huge bottle neck on that car right now. get rid of that and get 24# inj and you'll be sitting pretty.

umm yeah why would u run bigger heads and cam and pistons etc etc, but wrong stock 19lb injectors and the stock shity intake manifold lol thats why it runs like shit that and needs a real tune lol ur not getting enough fuel and air lol