another "wont start" thread

i'm working on my '90 xj 4.0. when i first got it, the car ran fine and strong, but had a tick. i diagnosed a bent rod and changed it out. at the same time i installed a head unit, painted it, and did minor cosmetic stuff to the body panels. everything now is back together, filled up with oil, and the thing wont start. im suspecting i messed something up in all my tinkering.

just out of curiosity, what would everybody else's thought processes be in trying to diagnose this new problem? any ideas as to what have gone wrong? something i'm doing wrong?

thanks guys, im just trying to get the war wagon back in service, appreciate the help

Gotta ask--cranks, no start OR won't crank? Auto or manual trans?

If it cranks: do you have spark, and is it good and strong, blue, or weak, yellow? If you have good spark, have you tried spraying ether into the intake?

sorry about the missing info.
automatic
and yes it cranks, turns over well, and stutters for a split second, but then nothing. i'll check the sparks now, get back to ya in a few.

anybody else?

bumping to the top^^^^

checked, have a good spark, and even replaced the battery last night as well.

HuntMarsh said:

bumping to the top^^^^

checked, have a good spark, and even replaced the battery last night as well.

Click to expand...

Did you try the ether in the intake to fire it off? I have had numerous times after working on an engine the damn things won't light off until I shot some ether in there, once fired everything ran fine.

That said, using the ether will determine if fuel is the problem--it fires with ether you just need to find the fuel system problem.

With the Renix initial power to the fuel pump is through the B Latch relay (later models ASD relay), bypassing the ballast resistor. This relay also provides power to the coil. The B Latch relay only provides power when the key is turned to the ON position, and only for about 3 seconds. When cranking, the fuel pump receives power from the starter relay, also bypassing the ballast resistor. When running normally, the fuel pump receives its power from the fuel pump relay and that goes through the ballast resistor. When at WOT the fuel pump gets its power from the oxygen heater relay again bypassing the ballast resistor.

Then there is the synch sensor in the distributor that provides information to the ECU, along with the crank sensor, so the ECU knows when to fire the injectors and spark. You should check the injectors for firing with a NOID light, test lights and multimeters usually won't read the signal.

Don't mean to lecture you. Good luck.

Try squirting some carb cleaner or starting fluid in the intake. Does it run for a few seconds longer? If so, the problem is fuel related. Look through the no start thread in the FAQ section.