Loss of power in the upper RPM's(Update!!!)

[91taurisho]

I did a search and found nothing relevant...

My problem is when I floor it it runs fine and has a smooth power curve throughoout until it hits around 6400 RPM's. At 6400 it seems to just stop(accelerating) then jumps forward as if nothing happened and then does it all over again... All this happens from around 6400 to 7000 RPM's It's never done this before today. It happens really fast. When I filled up my tank last, I had ran out of gas and had to go to 7-11(I normally go to Shell). I filled the tank and poured in some STP fuel system cleaner. Do you think the cleaner or 7-11's gas is bad, or my fuel pump. I replaced my fuel pump around 8,000 miles ago with one from checkers. I know, I know, bad choice. Has any one else had this problem before or have an idea on what it could be? I'm stumped.

Thanks in advance!

<small>[ December 16, 2003, 07:43 PM: Message edited by: 91taurisho ]</small>

 

[BeatDaSHO]

Running the tank to the bottom can cause any debris to get sucked up from the bottom of the tank. Perhaps your fuel filter is now dirty. Check it out.

Greg

 

[sdpatt]

BeatDaSHO:
Running the tank to the bottom can cause any debris to get sucked up from the bottom of the tank. Perhaps your fuel filter is now dirty. Check it out.

Greg

This is an old wives tale. The pump always draws from the bottom of the tank and the debris is always down there. Floating debris can't get inside the baffle that surrounds the pump if teh level is low, but it can when the level is high. There is a polymer "sock" around the pump suction that filters out any debris larger than a grain of sand and the fuel filter traps the remainder.

The power problem could be a bad tank of gas. One of the most important ways to keep the unwanted debris out of your gas tank is to NEVER fill up at a station where the tanker truck is filling, or has recently refilled the underground tanks. That stirs up a large quantity of silt and debris that can get pumped into you car's tank.

Did the CHECK ENGINE light illuminate at any time during these power losses? If the problem occurs at the same rpm or condition each time, it could be ignition system or fuel system related (read: plugs or wires or fuel pump). How old are the plugs and wires and what brand/model is installed?

If the problem occurs every time to exceed 6,400 rpm at full throttle, the problem is likely a low pressure/flow output from the fuel pump. When you got the pump from Checker, was the pump for the SHO or the standard Taurus. The SHO engine needs more than the 60 something liters per hour that the standard Taurus' pump can produce. A 155 or 190 lph pump can feed the SHO engine with reserve capacity for a much longer span of miles.

 

[91taurisho]

The check engine light never came on during the power losses. Plugs and wires are around 500 miles old(Autolight plugs and A/C delco wires) The fuel pump I got was the one listed for the SHO but I heard others saying that the checkers pump was rated lower than the stock unit. shrug
I'm going on a trip this thursday and I would like to figure out the problem before hand. Thanks again!!

 

[sdpatt]

Those Autolite plugs need to be checked. You should only use the Motorcraft AGSP32PP with the SHO engine as they are the only plug specifically designed for the SHO: correct double platinum tips, heat range, thread length and height. I reserve comment on the AC Delco wires out of lack of information.

 

[yamahaSHO]

Are you still running your LPM programmed for the 80mm with a stock MAF??

 

[91taurisho]

yamahaSHO:
Are you still running your LPM programmed for the 80mm with a stock MAF??

No I have a 73mm and the 80mm is in the mail... But I've been running that for a while now. I don't think that could be the culprit. shrug

 

[91taurisho]

sdpatt:
Those Autolite plugs need to be checked. You should only use the Motorcraft AGSP32PP with the SHO engine as they are the only plug specifically designed for the SHO: correct double platinum tips, heat range, thread length and height. I reserve comment on the AC Delco wires out of lack of information.

The A/C delco wires look to be the same size as stock, they fit fine too. I plan on changing the plugs to the motorcraft ones I just didn't have the money at the time, nor do I now because of the holidays. I also don't think the plugs would have gone bad in ~500 miles... If they did would they cause the loss only in the upper RPM range.

<small>[ December 16, 2003, 03:30 PM: Message edited by: 91taurisho ]</small>

 

[yamahaSHO]

91taurisho:

yamahaSHO:
Are you still running your LPM programmed for the 80mm with a stock MAF??

No I have a 73mm and the 80mm is in the mail... But I've been running that for a while now. I don't think that could be the culprit. shrug

Maybe not immediately.. its the long term affects you have to worry about.

 

[91taurisho]

Jason, do you think that that would cause my problem only in the upper RPM's?

 

[yamahaSHO]

Not sure, just bringing out the facts to better diagnose your problem.

Personally, I would take out the LPM and put the stock MAF back in. That *may* be your problem, but it is just safer that way. At least, until you get your 80mm... Even with the 80mm you might have problems it it is not dynot tuned. Tunning by mail is very cumbersome.

Good Luck!

 

[91taurisho]

Thanks Jason!!!

 

[91taurisho]

When I drove it today I couldn't reproduce the problem... shrug It feels like it always has. It was 15 degrees or so last night. I have done the TB coolant bypass. Do any of you think that was the problem???

 

[oh_SHO]

Before I you go changing a bunch of stuff I would run that tank of gas out and go with what you normally run. Just my .02.

 

[91taurisho]

oh_SHO:
Before I you go changing a bunch of stuff I would run that tank of gas out and go with what you normally run. Just my .02.

That's exactly what I was thinking. thumb Thanks for all of your answers!!!