need help, car falls on it's face at higher RPMs

[Herknav]

I've been reading through different threads and I havn't quite found anyone with this exact problem.

After the car warms up (15-20 minutes), it falls on it's face when I gas it hard, or moderately gassed but after it gets to ~3000 rpm. It's like it is just suddenly at idle or something. It doesn't throw any codes. The fuel pressure is also all over the place. After it warms up, it cycles between 18 and 40 back and forth, and every third or so cycle, it hits 60.

I've replaced the fuel filter and fuel pump, (kinda hoping the easy fix would do it). My next move is to inspect and maybe clean the MAF sensor and have a look at the TB... if I can even find either of them, (I have the supershaker setup now). Anyone have have any other suggestions? Could it be the BAP?

 

[1lowtoy]

You need to do some datalogging to see what is going on here. First you need to see if the throttlebody is closing when it falls over. If you need anyhelpmwith this just let me know.

 

[Herknav]

I assume I can datalog with my SCT; I've never done it before.

 

[06silverbullet]

I assume I can datalog with my SCT; I've never done it before.

yeah just download the sct software from their site and install it, hook it up to your car and laptop a the same time and do some pulls very easy to do.

 

[Herknav]

yeah just download the sct software from their site and install it, hook it up to your car and laptop a the same time and do some pulls very easy to do.

Thanks. I'll look into that tonight when I get home from work. Its a damned shame, the weather is fantastic right now.

 

[1lowtoy]

If you need any help finding the right things to look for just send me a PM with your strategy and your email address and I'll send you a file to use with LiveLink.

 

[Herknav]

If you need any help finding the right things to look for just send me a PM with your strategy and your email address and I'll send you a file to use with LiveLink.

Thanks! I looked at the websight last night and couldn't figure out what I needed to do. Granted, I didn't give it a ton of time, (busy night). I'll look again tonight after work.

 

[ski]

The fuel rail sensor that monitors fuel pressure/temperature and manifold vacuum can also be the cause, as indicated by an unusually high fuel pressure fluctuation(18-60).
It may either be bad, has a loose/broken/grounded electrical wire, a loose/corroded electrical connector, or a loose/kinked/broken vacuum line.
However, each of these occurrences normally triggers a code.

 

[TexasKyle]

I had the exact same thing happen to my Saleen S/C 07. It ended up being a bad plug for the TB. It was cracked (if I remember correctly) I would not have thought it could have been that, but it was. Check the connections at the TB would be my first advice.

 

[Herknav]

The hits just keep coming... now the car won't even start. It cranks and seems to have good volts, but it just won't turn over.

 

[TexasKyle]

Did you ever get this sorted out Brandon?

 

[Herknav]

Nope. When it started not starting, I quickly ran out of skills/ability. Had it flat-bedded to...the dealership yesterday. I feel like a failure.

 

[TexasKyle]

Not the Stealership! Man, keep us posted.

 

[Herknav]

Will do. I expect to hear from them on Monday.

 

[Steedman07]

bad alternator? Maybe the alt was failing and causing your original issue..Just guessing though..

 

[kevinatfms]

did you replace just the pump motor or the entire sending unit assembly? if just the pump motor i would bet the sending unit had high resistance in it.

 

[Herknav]

did you replace just the pump motor or the entire sending unit assembly? if just the pump motor i would bet the sending unit had high resistance in it.

You might be right as I only replaced the pump.

 

[cdynaco]

Nope. When it started not starting, I quickly ran out of skills/ability. Had it flat-bedded to...the dealership yesterday. I feel like a failure.

Probably wise. Failing fuel pressure would cause lean condition right? Better to flat bed than eat pistons.

 

[94tbird]

could be fouled spark plugs. you should/ or next time, can try startign the car with the gas pedal at WOT. It will stop the injectors from firing and the car might start.

after that id look at the Fuel Rail Pressor Sensor. mine ruptured for no reason one day. car drove fien all day, parked it, next day no start.

 

[kevinatfms]

it sounds like the computer is pulling timing and trying to add fuel which is why it would fall on its face. im betting the sending unit is toast. any word yet from the dealer?