Ignition System: Cranking very well but won't start 75 1.8FI, Fixed: Major concern Ignitor and #3 fuel injector. :THANKS TIM! Options

[ndfrigi]

Need help diagnose from members!

Well, last saturday Feb. 13 I joined fellow members at the Aliso Viejo Cars and Coffee which is about 30 miles one way. After the event, drove home and for less than 2.5 miles away from home at a traffic light, my tachometer is bouncing between 2.5k to 3k rpm (sorry not 3.5k to 4k rpm on what I have said on the other thread). But the actual is pretty much on normal idle of less than 1k rpm. When about to go on green light, engine died. Tried to start the engine but it is just cranking (cranking very well), but the engine won't engage.

Some good members here already mentioned about ignition circuit. Well today, I was able to checked and opened the rotor cap, and I found out that I have/had Pertronix Electronic Ignitor which I already forgot since the last time I opened it last 2011 (Since the engine is running very well after I was able to make it run after fixing it from the time I bought. I haven't open it since then. I even bought lately a spare of contact points and condenser to replace it soon).

So a friend of mine was here this morning and asked him to start the engine and try touching at the base cover of my front mounted fuel pump and I don't feel any vibration. So we tried to unplug fuel hose from the SS engine tunnel lines which is a direct supply line from fuel pump to engine bay before the fuel injector line. We did crank the engine but no fuel is spitting out from the line.

So is it fuel pump issue I have?

In addition, a member also mentioned about the fuel pump relay from the relay board. But after opening my relay board cover. I noticed there is some wiring that was changed/modified. No round relay for the fuel pump terminal.





Thanks again for your help!

[timothy_nd28]

I don't think one needs to worry about a phantom resistance when the circuit is under load, but there is another way of testing this circuit for resistance while under load. Leave the 14 and 12 pin connector connected to the relay board. Slip off the back plastic clam shells of the 14 and 12 pin connector, exposing the wires. Set the multimeter to DC, put a meter lead on pin 1 of the 14 pin connector (should be a big yellow wire) and the other meter lead on pin 6 of the 12 pin connector (should be a smaller yellow wire). Have someone start the car as you are watching the multimeter, you should observe 0 volts, anything higher than 0.1 indicates you have resistance in the circuit.
The Ljet will have no fuses for the fuel pump. One of those many red wires at the positive battery post lead feeds directly to the dual relay which then feeds the fuel pump.
I'm somewhat confused with what is going on at the relay board. I don't think that the start circuit is what is being bypassed. The start circuit is a solid yellow wire that is on pin one of the 14 pin connector. The wire in the picture being spiced is a yellow/red wire. It might make more sense of what is going on if you peel back the electrical tape of the other end of the spice in the 12 pin harness to reveal the color.

Isolating the problem by applying power to the fuel pump is a great way of diagnosing your issue. If that does work, you may want to try leaving the ignition switch to "on" and deflecting the airflow meter flap inside the airflow meter. This should also turn on the fuel pump.

Since you will be doing troubleshooting with the key on, you may want to consider unplugging the red wire on the ignition coil that leads to your petronix module. These modules will smoke if you leave the ignition switch on with the engine not running.