Please help! I have a '92 RS w/305 TBI. It had started running really rough, when idling it range from 500-1400rpm and stalled a few times at long red lights (automatic trans). Then it finally quit running while driving. I've replaced the fuel pump, fuel filter, the 2 injectors w/new filters. Its still not running. Fuel gets to the throttle body but does not go through the injectors. I also replaced the fuel pressure regulator about 3 months ago. I'm confused!

 

How are you determining that the injectors are not firing? Visually or with a test tool of some kind?

Try these two tests. First turn off your air conditioner and the heating system blower motor so that you can hear the fuel pump during the tests.

1. Turn the key from OFF to RUN (do not try to start the car). Do you hear the fuel pump run for two seconds?

2. Turn the key from RUN to CRANK for just a second then let the key return to RUN. Did you hear the fuel pump run for another two seconds?

Do you feel comfortable taking voltage readings at the injector connectors?

Do you have a NOID light or another tool (like oscilloscope) that you can use to detect pulses at the injector connectors?

 

I had my wife try to start the car i watched the injectors not spray into the throttle body. When i turn the key on to get electrical power i hear the fuel pump prime 2 secs. I've taken a test light grounded it to the shock tower and checked each wire on the injectors while she was cranking the the engine saw the light was fluttering. Used a multi-meter got 11v at the injectors and 1.7ohms.I had replaced the old injectors cause i was getting a resistance of 14ohms, when my Haynes manual states that for the TBI it should only be 1.0-2.0ohms. The only thing i haven't listened for was the pump after they key when back to RUN.

 

OK. On my TBI injectors they measure about 1.5 ohms. Yes the results of the second test could be important if indeed it is a valid test that tells us that your ECM is seeing DRP (Distributor Reference Pulse). According to what I have read, if you do not hear the fuel pump run for two seconds at the end of the second test then that means your ECM will NOT fire the injectors because it does not SENSE that your distributor shaft 'sender' is spinning.

If the second test FAILS then:
Since that DRP signal comes THROUGH the 'ignition module' screwed in at the bottom of the distributor cap (inside), it might be very smart to replace that (it is relatively cheap) and see if it solves the problem. I believe the bolt heads for the distributor cap are 7/32'' so a small socket head and medium length extension will do the job nicely. Make sure all the spark plug cables are replaced in their proper order and on the proper connectors.

If your ECM is not seeing DRP and you replaced the ignition module it is POSSIBLE that the 'sender' on the distributor shaft is not functioning and will need attention. Also, not to overlook a simple thing, make sure the wires connected to the distributor via connectors have not been damaged thus preventing conduction.

I assume you DO have spark.

 

I just attempted the second test 3 times. I made sure the pump ran for 2 secs then turned the key from RUN to CRANK all 3 times pump did not run. I also pulled a spark plug wire off a spark plug and put a screwdriver in the end of the wire and held it 1/4in off the shock tower to see if it would arc when cranked it did not arc.

 

I would suggest you replace the ignition module as the next step. Then run test 2 again. Let us know what happens. If you hear the pump run at the end of test two with the new ignition module it is likely the engine will fire up. If not then the next issue might be the 'sender' that provides DRP through the ignition module to the ECM.

Spark would deal with the ignition coil, distributor cap and rotor, wires, etc. I would replace the ignition module first so you can then rule that out as a possible problem.

While you have the distributor cap off:
1. Look at the inside of the rotor cap for excessive contact pitting.
2. Look at the rotor for excessive wear.
3. Make sure the rotor is actually spinning while you crank.

 

Yesterday I finally had time to work on the car. I replaced the distributor and cap. Fuel is now getting into the throttle body. But I was not able to get it back exactly where it was. I believe the timing is off because when I attempt to start it, it makes this "loping" sound.