Horrible gas mileage

[BIGJOE]

ive been bothering me, ive been getting horrible gas mileage lately i havent changed anything to the car, im getting about 18-22 miles per 2-3 gallons of gas shes running fast and strong but when you shut it off you can smell it been burning rich, any ideas and if so how would i go about doing them. thanks guys

 

[williamsGN]

Chip ? Leaking injectors ? What is your fuel pressure ?

 

[BIGJOE]

fuel injectors are 42.5 guage is reading 42.5 on rev how do i go about checking for leaking injectors

 

[williamsGN]

Turn the ignition to run after shutting down and watch to see if the fuel pressure drops if electric, or just watch gauge if its on the fuel rail. Gauge should read about 38 with vacuum line on the regulator, approx. 42 with the line off, car running. Is your chip burned to match your combo ?

 

[BIGJOE]

hoenstly i have no idea what chip its running, i purchased this car about 2 months ago and have just been restoring it. so im currently leaning more and more everyday but i shall check what you said. i dont have scamaster or anything but do have a gauge on my fuel rail so i shall check that. tonight and tell you what it reads. how can i check the chip>?

 

[williamsGN]

Its in the ECM which is behind the plastic panel on the passenger side - kickpanel. You slide it out and it takes, I believe a 7mm wrench to remove the two bolts on the front. Carefully pull the chip out and look on the bottom, like your avatar. Obviously car should be off and touch the car body first to sort of 'ground yourself out' .. ECMs don't like static electricity.

http://www.gnttype.org/techarea/ecmsensors/ecmpage.html

 

[BIGJOE]

k boss checked the guage on the fuel rail when its idling its at like 38-39 rev it hits 42.5 shut off with the key on the run position its at 20 i did not have time to pull the chip out its night time out to dark. will do tommorow and update

 

[williamsGN]

I would guess an injectors leaking, mine stays at 38 after I turn it off. No idea how to figure which one short of pulling and having them tested/cleaned. One or more plugs may look like they've been running rich.

 

[Chuck Leeper]

" i dont have scamaster or anything..]

FIRST THINGS FIRST!!
Get the proper tune/diagnostic tools, before you end up doing an engine rebuild....

 

[bison]

Too put it simply when you get a scan tool and everything is up to temp and the o2 sensor is fresh and there are no ambient air leaks in your exhaust prior to the sensor and the block learn is at 128 cruising the ECM thinks it's at 14.7:1. If the block learn is higher it's trying to add fuel if lower than 128 it's trying to pull fuel.

 

[BIGJOE]

ah i see, problem is i currently dont have the funds to buy a scanmaster, and im overseas so there not readily availble for the buick, lol so i guess ill just have to keep driving it until i can afford the scanmaster if theres no other way

 

[williamsGN]

Just check for fouled plugs

 

[BIGJOE]

Ill give them a check tonight see if there is any

 

[Chuck Leeper]

Ya, that'll cure the problem.....

 

[fitz3820]

BigJoe - I would turn the boost down, or disconnect the wastegate until you get a scanmaster - if you don't have the $ for a scanmaster, you will need to save for headgaskets or a full engine rebuild. You are flying blind without any feedback, especially knock.

 

[williamsGN]

Ya, that'll cure the problem.....

Chuck, it'll show if one is running rich, if you don't have anything to add to the thread why not be quiet... I know your post count is important to you.