Issue.. Big issue...#8 on a good supercharged tune

[Dave5.0]

Having some real issues now.

Car has 14,000 miles on it. NEVER driven very hard at all.

Bought the car last April. Put an intake, exhaust, and tune on from Bama. Never drove the car hard.

A few months later I splurge for a FRPP Supercharger (624 kit), and use the Ford Racing tune for a little bit. I then switch over to Paul at GetTorq for a real tune. It made good power at a safe AFR. Once again the car wasn't driven hard and rarely every taken above 100.

I then get dyno tuned from Adam at Revolution Automotive, who is a genius. He made 621 and the tune was very conservative and not lean at all and he did not run that much timing.

Flash forward to Ford Nationals. Car is acting fine on the way down. 30 miles down the highway, it stalls out. Slowly loses power and then stalls out completely.

Had it towed back home. Turned out a wire that went from the fuel pump to the injectors got shorted and burnt on the exhaust and that was fixed. Up and running again!

Drove the car away from the shop and I feel like the car sounds like it's misfiring. I put my foot down to see and at 5K RPMS it just shudders miserably and didn't want to go any more. I bring it back to them.

They drove it today to figure out diagnostics and low and behold it's #8 misfiring. From what I've learned about #8 from AED, Shawn says it's because after a certain amount of time at full throttle (10 seconds+ or something) the car reverts back to Stoich, causing it to lean out and #8 is the first to go.

I've never held WOT for that long at once.

Going to the shop to see the compression test for confirmation. Any ideas/recommendations etc?

 

[mebcop]

"after a certain amount of time at full throttle (10 seconds+ or something) the car reverts back to Stoich, causing it to lean out"....

Really???

 

[alcarames]

624 hp to the wheels is right at the threshold of what the stock motor can handle. Regardless of how well tuned it is. Your pretty much at the limits with the fine tuning and then all you need is a bad tank of gas and no with no buffer zone.

 

[Dave5.0]

When my tuner tuned the car he said the motor would be trouble free for a long time. It's strange because the car never showed any indication of having trouble.

 

[jymboslice]

Pull the #8 spark plug and see if there is any oil or whatever on it. If it's not normal, then chances are you blew the #8 piston.

 

[Dave5.0]

Pull the #8 spark plug and see if there is any oil or whatever on it. If it's not normal, then chances are you blew the #8 piston.

That's what's happening at about 130 today. If so, MMR shortblock time!

 

[djniknala]

When my tuner tuned the car he said the motor would be trouble free for a long time. It's strange because the car never showed any indication of having trouble.

You had a fuel problem caused by a shorted wire. Later you thought it was misfiring so you put your foot down through the fatest part of the torque curve. You don't think you had any troubles with the car? I would say that you in fact did have some troubles. Best of luck.

 

[Dave5.0]

You had a fuel problem caused by a shorted wire. Later you thought it was misfiring so you put your foot down through the fatest part of the torque curve. You don't think you had any troubles with the car? I would say that you in fact did have some troubles. Best of luck.

Well at first I thought I was imagining things that's why. I didn't even go WOT, maybe half throttle and it happened.

 

[mebcop]

The way you claim to drive it... why did you modify the car at all?

 

[Vic2186]

sorry to hear waiting on details

 

[Dave5.0]

I like having the power for a short burst and not going crazy. I like doing runs from 30-100 and having the instant power of a blower on tap.

 

[Dave5.0]

So who is good at offering built 5.0 short blocks aside from MMR (keeping them in mind) around that wont charge through the butt lol?

 

[boduke0220]

Check out shrader performance in NC. very honest guy and does great solid work. also own the car "brightmare"one of the fastest 2vs in the country

 

[blackbeast12]

Got $15k here's a good choice:

COYOTE Stroker Short block 351CI - Justin's Performance Center

 

[apex32]

http://www.svtperformance.com/forum...hp-capable-boss-headed-longblocks-8499-a.html

 

[Chuck@Evolution]

621 rwhp is a bit high for a stock motor to handle. How much boost were you making?

A #8 failure on a supercharged application is very uncommon unless there was an issue developing before the supercharger was installed. On a boosted application where the motor fails it is usually 5,6 or 7 that goes or a combination of the 3.

Wire from the fuel pump to the injector? Are you sure you werent told a line of bs there? There is no wire that connects directly from the pump to the engine.

 

[Need4Speed03]

Yeah in for details...wheres a fuel pump wire that runs close to the exhaust?

 

[me32]

You could have damage the motor from the bad wire. Also you have had 3 tunes so who knows what could of happened.

 

[WHITEMACH]

Did ford install the kit? if so let them look at it, if its a bad wire they fix it,,if its a bad tune You fix it

 

[Dave5.0]

Okay got to the bottom of it. It was the violet wire from the engine harness to the injectors that was melted on the header. Cylinders 5,7, and 8 are the ones that are toast. All the others are fine. Weird however, that all the cylinders on the driver side have oil all over and the other side has nothing at all. Cylinder 6 tested 145PSI in leakdown, 5 was 80, 7 was 30, and 80 was 25.

And Chuck, I was making between 9.5 and 10.5 pounds of boost on a 3.25'' pulley.


Next step:

Tow down to Adam for built shortblock from Livernois.