very wierd problem

87foxstang · Jul 13, 2007

The mods done to my car are in my sig....but the car is running rich

The plugs are fouled, the gas is diluting the oil in the oil pan...I put the cobra intake on and i did it right, checked for vaccum leaks and there are no signs of any. BUt heres the thing, its running rich yet my fuel pressure guage on the schrader valve says 36psi, which is lower than what it should be, should be 39 if i remember right.

Well i put the BBK adjustable fuel pressure regulator on because the stock one was shot, and when i adjust it leaner or richer it doesnt change on the gauge

I am at a serious loss, can anyone please help me out here.....thanks in advance

izzleon · Jul 13, 2007

gauge

try a different gauge oh and make shure ur checking the psi with the engine on

vristang · Jul 13, 2007

What gauge????
Wideband O2 sensor or the stock O2 sensor???

Are you checking fuel pressure with the vac line disconnected from the regulator????

jason

87foxstang · Jul 13, 2007

yes the engine is on, in not that bad hahaha.

The O2 sensors are bosch, and yes the vaccum line is dissconnected

the gauge is from NAPA

bill302 · Jul 13, 2007

i dont know much about speed density but if you are sure you have no vacuum leaks do you have the bap sensor hooked up properly with the vacuum hose and where are you pulling the vacuum from...intake right. also you might want to check the line for leaks to ensure its not stopped up.

87foxstang · Jul 13, 2007

What is the BAP sensor?
And yes the vaccum is being taken from the intake, and the hoses are all new and i checked for leaks, so thats ruled out

Hizzle · Jul 13, 2007

One thing I have found from experience and talking to others is the BBK regulators are junk. Also, I had a ton of problems with speed density with just a couple of mods and then I did the MAf conversion and all was well

bill302 · Jul 13, 2007

i may have made a mistake bp sensor...i know enough about speed density to get me in trouble...lol

Here is a quote from the Ford Fuel Injection page.
"The Barometric Pressure (BP) sensor operates as a piezoelectric (pressure-sensing) disc. However, rather than generating a voltage, its output is a frequency change. The sensor changes frequency relative to intake manifold vacuum. The sensor frequency increases as vacuum increases. The BP sensor is used to sense the changes in barometric pressure, allowing the PCM to sense the altitude at which the vehicle is operating. Its signal affects air/fuel ratio, spark and EGR for altitude compensation."

bill302 · Jul 14, 2007

http://kemparts.com/TechTalk/tt11.asp

HISSIN50 · Jul 14, 2007

Any codes?

Bill was leaning towards what I was pondering - the MAP and BAP are the same, but the function of a MAP is about 100 times more important than a BAP. Ensure the MAP is receiving a true vac signal.

FWIW, at idle you should see near 20" of vac.

Good luck.

jrichker · Jul 14, 2007

Dump the codes and see what the computer says is wrong…Codes may be present in the computer even if the Check Engine light isn’t on.

Here's the link to dump the computer codes with only a jumper wire or paper clip and the check engine light, or test light or voltmeter. I’ve used it for years, and it works great. You watch the flashing test lamp or Check Engine Light and count the flashes.

See http://www.troublecodes.net/Ford/

IF your car is an 86-88 stang, you'll have to use the test lamp or voltmeter method. There is no functional check engine light on the 86-88's except possibly the Cali Mass Air cars.

89 through 95 cars have a working Check Engine light. Watch it instead of a test lamp.

Codes have different answers if the engine is running from the answers that it has when the engine isn't running. It helps a lot to know if you had the engine running when you ran the test.

Trouble codes are either 2 digit or 3 digit, there are no cars that use both 2 digit codes and 3 digit codes.

For those who are intimidated by all the wires & connections, see http://www.actron.com/product_detail.php?pid=16153 for what a typical hand scanner looks like. Normal retail price is about $30 or so at AutoZone or Wal-Mart.

Or for a nicer scanner see http://www.midwayautosupply.com/pc-7208-90-equus-digital-ford-code-reader-3145.aspx – It has a 3 digit LCD display so that you don’t have to count flashes or beeps.. Cost is $30.

v8only · Jul 14, 2007

the single most important thing to keep a speed density system in check is a good vacuum signal to that map.

btw, I'm guessing the cam you're running is speed density compliant?? If not, there is your problem first.

before checking anything, even codes, you need to start off checking your vacuum signal. 17-20 pounds is fine, don't accept less. I had a vacuum problem to my map, and it didn't pull a single code.

after checking vacuum pressure, then pull off the vacuum line from the map with the car off, and suck on it, if the line is free and clear, you should be able to suck air through it no problem. If you're blocked up, then clear it out.

87foxstang · Jul 14, 2007

thanks for the resoponces guys...i do have vacumm, about 17"...i guess ill have to try to pull some codes

very wierd problem

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