90 Lumina 3.1 Starts/ruff idle/stalls

[ibbobud]

Hello,

I just aquired this 90 lumina from my aunt. The car will start when its cold and idles but you can hear a slight miss. then as it starts to warm up and the idle speed comes down it starts to miss worse and worse, finally stalling like its flooding out. If you try and start it just cranks, if you feather the gas it will try and start but acts like its flooded. If you let it set for a bit it will start again but starts the cycle over again... if you get it started it will run as long as you constatly feathering the throttle and reving it like crazy. It does not set off a engine light. I also hooked up a timing light to the front 3 sparkplug wires and they are geting spark while its missing, i havent done the rear yet, but i dont have a reason to think they are not geting spark.

Things that have allready been replaced by prev. mechanic:

Fuel Pump/filter/strainer
Fuel rail
(1) fuel injector
Spark plugs/wires
upper and lower intake gaskets
coil packs

Please advice on what the next steps to diagnosing this issues.

Thanks!

[maxwedge]

Start by checking fuel pressure when this occurs, look for 37 psi at the rail.

[ibbobud]

Here is a list of things i believe i need to start testing. If anyone thinks ive missed anything let me know. I will start testing these throughout the week:

ECM Codes
Fuel Pressure / Fuel Pressure Regulator
Fuel Injectors (depending on fuel/spark tests)
Ignition Spark while in non-starting condition
ICM / Coil Packs (depending on spark test)
Crank Sensor (unlikely - depending on spark test)

If anyone has any information on the test procedures for the above components any advice would be appreciated.

I will post results of these test as they are made along with notes on how i preformed the tests.

[ibbobud]

**** UPDATE ****

It seems that there is air in my fuel lines!

I have not aquired a fuel pressure tester at the moment but after power cycling the ignition switch to rais the fuel pressure i pressed in the shreader valve on the fuel rail and all i got was a small spurt of gas and a bunch of air. I removed the fuel pump relay and used a jumper wire to turn on the pump and same results. I held open the shrader valve and all i got was spurts of gas and air. I added a extra gallon of gas incase it was out of gas and the fuel guage wasnt accurate and still the same results. The gas guage currently reads 1/4 of a tank. There is not any gas leaks that i can find and with the pump on to does seem to pump air into the system so i have to assume that the fuel strainer on the pump is either not properly installed or not fully submerged in fuel allowing the fuel pump to draw air.

The prevoious owners mechanic had replaced the fuel pump strainer and fuel filter and im assuming that it was a botched job. So anyone have any tips for removing the fuel tank and diagnosing the air in the lines issue?

[maxwedge]

Disconnect the line at the tank a get some low pressure air into and see if you can pinpoint any leaks, but if air getting into the lines then fuel should be leaking also.

[oldntired]

I have same trouble
car starts right up
runs a little rough
put in gear/auto trans
hesitates,stumbles as you acelerate
after 10-20 mins driving/running,it dies
sometimes it starts right up
sometimes takes 10-20 mins cool down?
seems to run better if cooler out
fuel filter clean/clear
while fuel filter was out,
checked fuel line
turned ignition to on position,
could hear pump whine few seconds and a slight trickle of fuel came out line from tank
cranked eng. fuel came out of line from eng.
how much presure/amount of fuel should come out of line from tank with key in on pos, ?

[oldntired]

also,there are no leaks in fuel line,or under hood

[ibbobud]

im geting mostly air and a little gas.

Ive checked the gas lines from the motor all way back to the fuel filter and no signs of leaks.

The problem has to be in the gas tank, either the fuel pump strainer/sock is not submerged in fuel or has came off or i have a defective/leaking fuel pump pulsator.

anyone here had issues with fuel pump pulsators?

[ibbobud]

oldntired, which line are you talking about? the one coming from the fuel pump to the engine before it screws into the fuel rail? or the shrader valve where you check fuel pressure? either way it should be close to 40psi.

Have you tested the fuel pressure yet?

[oldntired]

I was only under car by fuel filter lines
I never checked presure,I do not have a gauge

[bsr2002]

Go out and get a gauge! They are cheap!

http://www.amazon.com/gp/product/B00...D96SS4K7KZFWEM

Check Autozone or O'Reillys!

[ibbobud]

maby i am taking the wrong aproach but i know the newer lumina models have a access panel in the trunk to get to the fuel pump. i attempted to drop the gas tank this weekend but due to injurues from my past and lack of help i aborted the mission. my idea is to go to a junk yard and find a newer lumina with the access panel and take it off, using it as a teplate to cut a access panel and as the new cover for the opening in my 90 lumina. i know it sounds like the hard way and im wondering if anyone else has done this and has any tips.

[maxwedge]

Wow, are you off track here, the Lumina never had an access panel the tank must come out, and again, have you checked the fuel pressure.!?

[ibbobud]

I dont have to because the pump is just bearly pumping any gas, mostly air... alot of air like its out of gas. i put 2 extra gallons of gas in the tank just to make sure. Im assuming if its pumping alot of air out of them shrader valve that im not going to get much fuel pressure. I know this car does not have a access panel for the pump. I was going to make one for easier access in the future. Im not physically able to get that gas tank out of the car alone, im on my own on this project and low on money so i cant afford the tow bill plus repair cost at a garage. My aunts new husband borrowed my fuel pressure tester and im having a hard time geting it back from him.

Im assuming if i press that shrader valve in while the fuel pump is running (bypassed fuel pump relay) that it should be a steady stream of gas not spurts of gas then air then gas?

Im going to take some extra steps and test the fuel pressure and regulator anyways, if i can get some money, harbor freight has a cheap fuel pressure tester for $15.99.

http://www.harborfreight.com/fuel-in...ter-92699.html

[ibbobud]

### update ###

I tested the fuel pressure finally after geting a new guage....

0 psi

I am having it towed to a mechanic near where i work next week to drop the fuel tank and investigate where its sucking air from.

I will let you know what we find.