coughing and snorting

BenDiesel

NAXJA Forum User

Location

lynnwood washington

• Jun 24, 2010

• #1

so my jeep starts and idles fine. it accelerates fine to. but when trying to cruse at a light thorttle/ light load it acts like its out of fuel and backfires. i been running it with no o2 sensor and put one in this last weekend helped a little but still doing it
any ideas?

 

BenDiesel

NAXJA Forum User

Location

lynnwood washington

• Jun 24, 2010

• #2

oh its a 89 4.0

 

C

cruiser54

NAXJA Forum User

Location

Prescott, Az

• Jun 24, 2010

• #3

BenDiesel said:

oh its a 89 4.0

Click to expand...

I noticed that. ^^^^^^^ Did you put a new O2 sensor in?

 

K

kcjeep6

NAXJA Member

NAXJA Member

Location

Castro Valley,CA

• Jun 24, 2010

• #4

Check your distributor for endplay, remove the cap, grab the rotor and try to turn it. If it rotates and the shaft moves up or down the thrust washers are gone.
This is a easy check before you start replacing stuff.

 

BenDiesel

NAXJA Forum User

Location

lynnwood washington

• Jun 24, 2010

• #5

i put a junk yard sensor in. the way things are set up with my ho header and 99+ intake i had to use a ho s-pipe which put the o2 next to the pumpkin on the axle. so any time i hit a bump hard enough its gona make contact. broke it clean off last time i went wheeling. so its a junk yard sensor, till i get the lift on

thanks kcjeep6 ill give that a look this weekend

 

B

birchlakeXJ

NAXJA Forum User

Location

Melrose, MN

• Jun 25, 2010

• #6

Verifying proper fuel pressure is something that should be done early in the game.

Get a fuel pressure gauge and hook it up to the schrader valve on the fuel rail. You should have approximately 31 psi at idle and you should have approx. 39 psi when you disconnect the line leading into the fuel pressure regulator.

 

BenDiesel

NAXJA Forum User

Location

lynnwood washington

• Jun 26, 2010

• #7

i have noticed it only dose it when im crusing at or more the 2k rpm. when im doin the low rpm stuff round town it dont do it.

 

B

birchlakeXJ

NAXJA Forum User

Location

Melrose, MN

• Jun 27, 2010

• #8

Could be a marginal fuel delivery problem (pump/regulator/filter)

Checked fuel pressure as I mentioned yet? Must be ruled out before moving onto more complex possibilities. Easy to do.

Also; when was the last time the filter was changed? Easy to do on an 89 and only a few bucks.

 

kastein

NAXJA Member

NAXJA Member

Location

Rainy side of Washington

• Jun 27, 2010

• #9

I'd cough and snort too if someone ran over my face

(seriously though, check your fuel pressure then check your sensor readings... hope you have a voltmeter on hand!)

Did you use the right year O2 sensor?

 

BenDiesel

NAXJA Forum User

Location

lynnwood washington

• Jul 13, 2010

• #10

well i did check the fuel pressure its fine. it will do wide open throttle just fine. and the fuel filter was replaced a few months ago. it seems to only do it at or above 2000 rpm. dosent feel like its worst at 55mph it still does it when i put it in 3rd gear and cruse but not as bad