1991 z34 3.4 hard start/runs rough

[newtec04]

Help Please...I recently purchased a 1991 z34 the body is mint but the engine has issues. First off I changed the timing belt on the engine setting it to the factory marks on the cam gears then replaced wires and checked voltage and ohms on all sensors,everything was within spec,The vehicle will only start when I have a fuel pressure guage on the rail and have about 20 to 25 psi flowing thru it and the rest of the fuel is bleeding off into a gas can ,it runs ruff but it will only run this way. But when I close the guage to get the full 45 psi which is about factory spec the engine stalls. I sprayed starting fluid in the intake manifold an it sounds great. Has anyone experienced this problem before or does anyone have any suggestion......Thanks

[meuhus]

Originally Posted by newtec04

Help Please...I recently purchased a 1991 z34 the body is mint but the engine has issues. First off I changed the timing belt on the engine setting it to the factory marks on the cam gears then replaced wires and checked voltage and ohms on all sensors,everything was within spec,The vehicle will only start when I have a fuel pressure guage on the rail and have about 20 to 25 psi flowing thru it and the rest of the fuel is bleeding off into a gas can ,it runs ruff but it will only run this way. But when I close the guage to get the full 45 psi which is about factory spec the engine stalls. I sprayed starting fluid in the intake manifold an it sounds great. Has anyone experienced this problem before or does anyone have any suggestion......Thanks

i don't know about the pressure gauge thing but
i have a 91 w/3.1 had a injector go bad
the car would run very rough and i could only get up to about 10mph
i check the restance of the injectors found 5 were ok but one (#6)
was bad 2.2ohms
(11.8 ohms to 13.8 ohms i think is what they should be)
but i changed them all found them online for 17.00 each
it could be a bad injector
i pulled wires and plugs when it was running bad to figure out witch cylinder it was
#6 plug was dry 2 and 4 plugs seemed kind of fouled but not bad
could smell gas a little
i guess when the #6 injector failed it made the other injector pump more gas into the other cylinders

could also be a vacuum leak
try spaying carb cleaner around the manifold gaskets plemun gaskets
(if you have one)

[newtec04]

I checked the injector resistance and they were all within spec,I am coing to pin out all the sensors and check all pins at the ecm,thanks for your input.

Originally Posted by meuhus

i don't know about the pressure gauge thing but
i have a 91 w/3.1 had a injector go bad
the car would run very rough and i could only get up to about 10mph
i check the restance of the injectors found 5 were ok but one (#6)
was bad 2.2ohms
(11.8 ohms to 13.8 ohms i think is what they should be)
but i changed them all found them online for 17.00 each
it could be a bad injector
i pulled wires and plugs when it was running bad to figure out witch cylinder it was
#6 plug was dry 2 and 4 plugs seemed kind of fouled but not bad
could smell gas a little
i guess when the #6 injector failed it made the other injector pump more gas into the other cylinders

could also be a vacuum leak
try spaying carb cleaner around the manifold gaskets plemun gaskets
(if you have one)