Hello
I just finished up rebuilding a 1993 XJ Sport, 4.0L. The issue I'm observing is randomly it will have a hard start - seems to not want to crank, really stumbles, engine sounds like it's eating itself but then fires and idles fine (no rough idle, steady RPM at idle, sounds fine, no valve train noise or anything). When it starts like this, it also has reduced engine power through all gears until you shut it off and get a 'normal' restart. Other times it fires up, and engine power is as expected.
Below is a list of things I did to this rig while rebuilding (that would be associated with the this starting/loss of power issue)
-New fuel tank, pump, filter and lines. Fuel pressure seems normal (40-50 psi if I recall last I checked)
-New 4-hole injectors from K-Suspension
-New starter
-Battery seems good, only a couple years old, and it does this odd starting thing even when fully charged (I left the battery on the boiler for a few hours to make sure it was fully charged and it still did it). Also terminals are clean and tight.
-New distributor and coil, new plugs.
-Replaced the MAP sensor, and cleaned the throttle body and IAC while they were off the vehicle.
-No check engine light although it's ODB1 so not sure how much data it would provide anyway, I don't have a lot of ODB1 experience.
-Checked all vacuum lines (most I replaced) and electrical connections.
As far as rebuilding I did not tear the engine down. I removed the valve cover and oil pan for gasket replacement, as well as the intake for replacing the exhaust manifold. The valve train felt ok with the valve cover off, no loose rockers or obvious issues.
The only thing I can think of is the hood prop rod does not stay in the clip and I often find it really dang close to the negative terminal of the battery. I'm wondering if while starting it is contacting the terminal, but since the prop rod is just connected to the chassis and it would contacting the negative terminal I don't see how that could be causing any electrical issues.
Any ideas form the 4.0 experts out there would be appreciated because I'm stumped.
Thanks, Ryan
I just finished up rebuilding a 1993 XJ Sport, 4.0L. The issue I'm observing is randomly it will have a hard start - seems to not want to crank, really stumbles, engine sounds like it's eating itself but then fires and idles fine (no rough idle, steady RPM at idle, sounds fine, no valve train noise or anything). When it starts like this, it also has reduced engine power through all gears until you shut it off and get a 'normal' restart. Other times it fires up, and engine power is as expected.
Below is a list of things I did to this rig while rebuilding (that would be associated with the this starting/loss of power issue)
-New fuel tank, pump, filter and lines. Fuel pressure seems normal (40-50 psi if I recall last I checked)
-New 4-hole injectors from K-Suspension
-New starter
-Battery seems good, only a couple years old, and it does this odd starting thing even when fully charged (I left the battery on the boiler for a few hours to make sure it was fully charged and it still did it). Also terminals are clean and tight.
-New distributor and coil, new plugs.
-Replaced the MAP sensor, and cleaned the throttle body and IAC while they were off the vehicle.
-No check engine light although it's ODB1 so not sure how much data it would provide anyway, I don't have a lot of ODB1 experience.
-Checked all vacuum lines (most I replaced) and electrical connections.
As far as rebuilding I did not tear the engine down. I removed the valve cover and oil pan for gasket replacement, as well as the intake for replacing the exhaust manifold. The valve train felt ok with the valve cover off, no loose rockers or obvious issues.
The only thing I can think of is the hood prop rod does not stay in the clip and I often find it really dang close to the negative terminal of the battery. I'm wondering if while starting it is contacting the terminal, but since the prop rod is just connected to the chassis and it would contacting the negative terminal I don't see how that could be causing any electrical issues.
Any ideas form the 4.0 experts out there would be appreciated because I'm stumped.
Thanks, Ryan
