Will 28psi fuel pressure cause this....

[cecil bass]

I found out my fuel pressure is at 28psi with engine in park... The car starts very good with no help from the gas pedal even thou its below 10 degrees outside, but the problem is that once its started the car idles up and down till its warmed what can cause that? Is it because my fuel pressure is low? I just orders a scan master so I should have more insight what's going on

 

[Hotrodbuick]

If the car idles up an down then there is a vacuum leak some place. Start checking all of your vacuum lines for cracks or to be unplugged. And I believe fuel pressure is supposed to be 43 lbs with line off then put line back on an should drop to 35 lbs or so (have to go back an check but I believe that is right)

 

[forcefed3.8's]

Low fuel pressure will be lean, the same as a vacuum leak, so yes, you need to fix the fuel pressure issue.

 

[TexasT]

Fuel injected car shouldn't need the pedal depressed to start like a carb car. No matter what the weather.

Get your pressure where it needs to be before you hurt the engine. Also could be a vacuum leak as mentioned above. Also might need to clean the iac valve and passages. A new fuel filter probably wouldn't hurt either. Has the car had a "spring cleaning" lately?

 

[fastblackracing]

Stock fuel pressure should be 36-37 pounds at idle with vacuum line OFF the regulator. And 28 -30 pounds with vacuum line ON the regulator at idle. This is assuming he has a 233 stock bosch regulator which was 2.5 bar. He says all stock in his sig.

 

[GNONYX]

First thing, you claimed your sig is an 87 all stock un-molested motor, which means you still have an un-adjustable fuel pressure regulator. What is the mileage on the motor, and also do find if any vacuum leaks.
If you want to upgrade the fuel system then check out both of these on board vender's of their web site on fuel system
http://www.fullthrottlespeed.com/items.asp+Cc+BUFUEL
http://www.turbotweakstore.com/SearchResults.asp?Cat=7

 

[cecil bass]

Just ordered a new Walbro gas pump and fuel filter with a scan master from g body hope this fixes my problem!!!

 

[Hotrodbuick]

If you ordered that stuff then you should get an adjustable fuel pressure regulator also if you don't have one already.

 

[ttaowner]

what about a hotwire kit too???????????????

 

[GNONYX]

I know you already got the fuel pump from Gbody, you will need the fpr and the hot-wire kit for Racetronix http://www.racetronix.biz/itemdesc.asp?ic=FPWH-006&eq=&Tp=

 

[cecil bass]

It was already hotwired ..... What's the other kit you mentioned.....?

 

[salvageV6]

The stock chip wasn't the best for winter driveability either, you need to check the IACV counts with the scanmaster.

Then again the Kenne Bell chip I put in for performance years ago sucked worse in the winter than the stock chip.

Check the air filter setup as well.

What is the range of rpm, and amount of time, of the idle "hunting" while warming up?

If it's only a few hundred rpm and goes up and down a only few times it's probably okay.

Cleaning the IACV may help, but I'd check the counts with the scanmaster before I pulled it out and did that.

 

[GNONYX]

It was already hotwired ..... What's the other kit you mentioned.....?

I don't understand that you are claiming you have an un-molested motor, but now it has a hot wire kit installed?
How long and what type of hot wire system is in this un-molested motor?

 

[cecil bass]

Isn't the IACV under the up pipe on front of intake?

 

[cecil bass]

I guess you would call it a Hotwire kit the other last owner of this car installed a new relay under the hood and ran a wire to the trunk where the fuel pump wiring is that's the only thing that was done to the car other than pm stuff..... Everything else is all stock

 

[GNONYX]

The problem here is you don't know what the last owner installed as a hot wire system. If you checked the #10 thread and read the Racetronix hot wire kit system you will see a 40amp relay which is mounted in the underneath the rear by the fuel tank, and the wire size is a #10awg.
you still didn't mention the mileage on the car, as there might be other things you may need to know of a stock engine.
Majority of the board members are well educated with these cars and have different avenues of troubleshooting according to what your problem is, even if you don't know them yet.

 

[cecil bass]

The car has 122,000 miles on it.... So you guys think I should get another Hotwire kit and replace the stuff the last owner did

 

[GNONYX]

For the cost of $47.50 I would replace it with a complete hot wire kit from Racetronix, at least you know what's in your car.
It seems for a stock car you might need to a spring cleaning (http://www.gnttype.org/maint/basics.html) as one member has suggested.
I too have a stock engine and if you read my sig of having a ScanMaster, Racetronix hot-wire kit with fuel pump, Full Throttle Commander chips w/ matching 60# injectors, adj. fuel pump, and triple pod gauges w/ Auto Meter A/F gauge, oil pressure gauge, vac/boost gauge, and a Kenne Belle rear seat brace.
Your original fuel injectors definitely needs to be professional clean, or just replace them. I asked some members who claimed to go with the 60# injectors as this will cover any or many upgrade mod on your engine. Personally, I might want to change my injectors from 60# to 36# or 42#.
One major change you will need to do is the nylon cam gear sprocket, and with that many mileage you are taking a chance of having pieces of nylon teeth flowing around your oil pan, and blocking your oil pump pickup.
A minimum of having the following: oil pressure gauge, vac/boost gauge, air/fuel gauge, and a fuel pressure gauge to set the adjustable fuel pressure regulator as these will help you in tuning the engine without going to a lean condition.

 

[salvageV6]

I wouldn't worry so much about the hot wire kit, but you can double check the voltage at the back of the car, preferably with it running.

I'd double check what you are using for a fuel pressure gauge first some are not that accurate, especially if there's one of those little ones permanently on the fuel rail.....

A hunting idle is usually chip related or to a lesser degree air related (IACV), especially if it goes away once the car is warmed up.

Yes the IACV is under the up-pipe into the throttle body.

It has a gasket that's often missing or destroyed and you can break the white metal housing by overtightening it putting it back on so be careful with it.

I'd clean that first and make sure the pintle is okay where it contacts the inner part of the housing which should also be cleaned.

What chip is in the car? You sure it's the stock one?

 

[cecil bass]

Here is the relay he put in. The orange wire runs all the way to the trunk