View Full Version : fuel pressure troubles

08-09-2006, 10:02 PM
i took the advice from the experts and put a hot wire kit in my car...i was adjusting the fuel pressure to help reduce the knock that didnt end up working...my fuel pressure will not stay up and sometime bleed down and not go up when i get on the boost i know this is very bad but i need to know ware to go from here...I have an adjustable fuel regulator hot wire kit and an upgraded in tank fuel pump which is maybe 6 months old... when the fuel pressure bleeds down the pump sounds like it is in over dirve making a higher pitched noise then it normally dose i think it is bad....should i try the regulator or is this the pump

08-09-2006, 11:30 PM
When the pump goes to a higher pitch, that usually means it is sucking air. Which is bad. You need to determine if that is the case.

First, what pressure levels are we speaking about? Give us a picture of the situation here.

Second, how full is your tank? You should never run hard with under 5 gallons in the tank.

A better picture of your combo would help, too.

08-10-2006, 07:37 PM
well the other night the pressure droped to the worst ive seen it all the way down to around 20 psi and when it dose this that i have noticed its with about a quarter of a tank...but it has never done it until now could my sending unit be screwing up it is really rusty and im thinking its not getting a great ground...this is really annoying and im trying to learn more but its tough...im going to fill the tank and see if it helps at all...im also having dificulties with the knock according to my fuel pressure i need to have it set real real real high to stop the knock around 55 to 60 psi vacum on to reduce it am i doing something wrong?

08-10-2006, 08:44 PM
You may have an internal leak.

What is your combo? (i.e. injectors, turbo, chip, etc.)

08-10-2006, 09:50 PM
that is awfully high. do you know if your chip is burned for your injectors?

08-10-2006, 11:37 PM
i think i have the blue chip injectors or something like that they are the just above stock ones and my chip is a pitbull this is getting more involved then i thought

08-11-2006, 07:51 AM
Don't worry you will be fine.
How old is your adjust. FP reg?
I think the pitbulls are alittle outdated, if not mistaken, and run alot of timing, that could be half your problem with the knock issue. Do you know if it is a street or strip?
A newer chip is pretty reasonable if that is your problem at all.

First, the Bosch blue tops should have a blue ring in the center of the injector, do they?

Second, if you take your ps kick panel down and remove your chip, disconnect the orange ECM pwr feed coming from your battery, it should be indentifiable or we can help you with that.

08-11-2006, 06:35 PM
i think the regulator is 6 or 7 years old or so i have a new one...yes those are the injectors with the blue ring... wat if i try putting the stock chip in will that help? and explain more on the kick panel removal and wire thingy

08-11-2006, 07:26 PM
a weak, leaking diaphram in your reg. could cause you trouble.
Try changing it out with the new one if you on the way/have it already.
Do not put your stock chip in.
There is an orange lead coming off of your pos. batt. cable coming from the terminal, this goes into a small black circular plastic connector, this is the fuse. This powers your ECM directly off the batt. Simply pull the clip up and disconnect, now you have no pwr to the ECM.
Inside the car, remove the small screw on the bottom, maybe one on top as well. Slide ECM towards rear, pulling down the wire assemble with it. If u look at the backside you will see a metal plate on the bottom, this is where your chip is located. Remove one screw and flip plate up, take your chip out and see what it says. Buy and updated chip if it shows it does not match your Blue Tops.

08-12-2006, 12:30 AM
how do i know wat chip to use i had a pitbull chip in it and i would like to know the price of an upadated chip...do you think the regulator would stop the 18degrees of knock i get along with a better chip

08-12-2006, 09:31 AM
Check it out to try to find the true status of your fuel system. Upgraded chips run anywhere from 75-100.
yes, an outdated, malfunctioning, misburned chip could cause that.
there are also many other, mechanical reasons for knock.
what are the O2 counts when your are getting all this knock, do you know if it is a rich or lean knock?

08-12-2006, 12:46 PM
well i just replaced the fuel pressure regulatior and that brought my knock down to only 8 degrees at wot...before i replaced the regulator it was lean knock i brought the fuel perssure way up and go it to reduce the knock.. but with the regulator i have it set at 45psi vacum off at idel and now im only getting 8 degrees of knock do you think uping the pressure a bit will bring it down some more

08-12-2006, 01:54 PM
what is your boost at WOT?
race gas or pump gas?
what is your MAF readings at WOT?
any BLMs at WOT?
what are the 02 volts, how lean is lean?
what is the status of your O2 sensor?
can you confirm your FP is going up with boost, ie 45 static + 15 boost FP is at 60.
45 does seem to be alittle on the high side, need to have the WOT O2#s

08-12-2006, 01:56 PM
yes those are the injectors with the blue ring
Any numbers on the top of these? These are NOT the Bosch 'blue top' injectors. Sounds more like a Lucas part.

I very much agree that you need some O2 data to make the call here. A FP of 45 is not all that high, but you should not need to go higher.

08-12-2006, 05:36 PM
i will go someware tonight and race her and get some readings back to you but its already alot better