1995 jeep xj 4.0

Papa_Jon

Papa_Jon

non speller
Joined
Jul 27, 2007
Location
China Grove
Sold this Jeep thought it was running good
new owner having trouble since day 1
When its hot outside and Jeep gets up to normal temp 210
starts to buck and hesitate and back fires wont go above 2k rpm
if you let it sit for a few hours runs great until warms up again
if cooler out side like in mornings runs great
new parts
iac
tps
complete tune up ,plugs,wires,cap,button]
all fluids changed
new transmission shift sensors
 
Papa_Jon said:
what do you suggest I use ?
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First thing is to diagnose it. With it hot see if there is fuel in the rail. My bet is there is vapor. Safe way is with a gauge that has a vent tube. Easy way is with a screwdriver and push the Schrader valve in.

You can also open the hood and put ice on the rail and see if it fixes the issue.

Fixing is the issue. Some have had success with the kit you can buy.


Design Engineering 010378 Fuel Rail and Injector Cover Kit for Jeep
 
Low fuel pressure. It'll run with 20 psi, spec is 35-45. Pump getting hot and failing. Restarting bumps pressure back up. Check pressure under load (brake torque in bay after running it for thirty forty minutes or an hour) better yet, have him run it to where it messes up and you'll be able to check pressure with gauge if you can hook it up while it is still running like crap.

But it can't be fixed. You should pay me and I'll dispose of it for you.
 
Last edited:
95 hs a return line not likely vapor lock. I'd heck fuel pressure at rail and make sure the fuel pressure regulator on the rail is not faulty. The other thing is coil. Coil might have cracks on the base where they mount to the engine. It You can retrieve them with switching the ignition on and off 3 times.
 
You can also scan it with a good scanner and the ChryCo adapter. Way more info than cell method. Almost obd2 amount & live data, though limited by the lower sensor count. Nevertheless, indispensable. My money's on the pump. And the return systems will get hot enough to vaporize fuel if the check valve is bleeding in the pump.. (lowers fuel boiling point, same principal as pressurized cooling systems)
 
ghost said:
95 hs a return line not likely vapor lock. I'd heck fuel pressure at rail and make sure the fuel pressure regulator on the rail is not faulty. The other thing is coil. Coil might have cracks on the base where they mount to the engine. It You can retrieve them with switching the ignition on and off 3 times.
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received_2275993105846767.jpeg
found this other morning goes to fuel tank , where is other end go to ?
 
a_kelley said:
You can also scan it with a good scanner and the ChryCo adapter. Way more info than cell method. Almost obd2 amount & live data, though limited by the lower sensor count. Nevertheless, indispensable. My money's on the pump. And the return systems will get hot enough to vaporize fuel if the check valve is bleeding in the pump.. (lowers fuel boiling point, same principal as pressurized cooling systems)
Click to expand...
HUH?
 
a_kelley said:
You can also scan it with a good scanner and the ChryCo adapter. Way more info than using the engine light to read the codes. My money's on the fuel pump. Check fuel pressure hot and under load.

And the return systems will get hot enough to vaporize fuel if the check valve is bleeding in the pump.. (lower pressure lowers fuel boiling point - higher pressure raises the boiling point)
Click to expand...
@Papa_Jon that make more sense?
 
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