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Xj backfiring???

K

Ken

Registered User
Location
Salt Lake
Hey everyone I just had an issue with my cherokee. It's a 90 straight six and the exhaust manifold was leaking and cracked. After welding it up really good and putting the jeep back together I started it up and it's now backfiring. I did my best to check for leaks and couldn't spot any. It's backfiring out of the throttle body and now idles kinda rough. I thought I may have put it back together wrong so I broke it down again and everything checked out but when I put it back together I still have have this backfiring problem. Any suggestions????:confused:
 
Brett

Brett

Meat-Hippy
Location
Salt Lake City Utah
I've had that happen on mine occasionally (89 4.0.) I changed out my TPS recently and haven't had any problems since, but I dunno if that was the actual cause. Might check it out though.
 
K

Ken

Registered User
Location
Salt Lake
No I took off the exhaust, sandblasted and welded it. I guess I could be running too lean now cause my fuel pressure seems low but why didn't it do the backfiring before? I'll need to get a tester for the fuel and see where I end up.
 
DaveB

DaveB

Long Jeep Fan
Location
Holladay, Utah
Ken said:
No I took off the exhaust, sandblasted and welded it. I guess I could be running too lean now cause my fuel pressure seems low but why didn't it do the backfiring before? I'll need to get a tester for the fuel and see where I end up.
Click to expand...

I have a fuel rail pressure gauge if you wanted to stop by and measure it. You can also test the timing with my timing light. Did you put in a new gasket on the manifold when you did your swap ? it may have a vacuum leak.
 
K

Ken

Registered User
Location
Salt Lake
Hey thanks dave but I've been away from the computer for a bit. I actually went out and bought a guage and the pressure tested out at 22psi and when I took off the vac line it stayed at 22. I did a leak down test and as soon as I shut of the engine all the pressure goes down even with the fuel return line pinched or open? Could be running too lean so the next step is that fuel pump then maybe the regulator!!!!!:ugh:I did get all new gaskets and it doesn't appear to be leaking.
 
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