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!

[Series9]

The wiring bypass on the relay board is for the starter. That suggests the relay board already has high-resistence issues (like many of them).


Unplug the fuel pump and put 12V on it manually. See if the car will start.

Report your findings.

[ndfrigi]

The wiring bypass on the relay board is for the starter. That suggests the relay board already has high-resistence issues (like many of them).


Unplug the fuel pump and put 12V on it manually. See if the car will start.

Report your findings.

Thanks Series9!

[timothy_nd28]

Start at the relay board, remove the 14 pin and 12 pin connectors. Next, use a multimeter that is set to read resistance and put one meter lead on pin one of the 14 pin connector. Put the second meter lead on pin 6 of the 12 pin connector. You should read 0 ohms.

[ndfrigi]

Start at the relay board, remove the 14 pin and 12 pin connectors. Next, use a multimeter that is set to read resistance and put one meter lead on pin one of the 14 pin connector. Put the second meter lead on pin 6 of the 12 pin connector. You should read 0 ohms.

thanks also Timothy! any picture of the board that indicates those pin numbers? but I try Series9 suggestion first since it is more easier for
me than with those pins on the board.

[ndfrigi]

Like what other member said from my initial thread responsed, they said my issue is ignition circuit (like contact point) and since i have pertronix ignitor, thus it mean not on the distributor area?

[Series9]

One of the problems with continuity readings is that they are performed by a meter putting milli-amps across the circuit.

The circuit can pass the "milli-amp test" but show high resistance under load.

I'm just saying, take a positive continuity test with a grain of salt.

[Series9]

And before you go too far:

Check your fuses. If they are okay, check for 12V on the positive side of the coil with the key in the "run" position.

[ndfrigi]

And before you go too far:

Check your fuses. If they are okay, check for 12V on the positive side of the coil with the key in the "run" position.

Thanks again Joe!

[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.

[ndfrigi]

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.

Wow a lot of information and i'm learning more! thanks again Timothy and Joe for your helped! I will try doing some of those suggestions tomorrow!

God bless!

[Geezer914]

Check the dual relay near the battery.

[ndfrigi]

Check the dual relay near the battery.

Since you and Timothy mentioned about the dual relay underneath the battery tray, is this trigger the fuel pump to engage? And yes my dual
relay in there is in bad shape but it was working well for the last 5 years unless it broke now! thank you too Geezer914!

[Dave_Darling]

The dual relay powers the FI, and powers the fuel pump.

Don't leave your key on without the engine running for too long, or you'll fry the Pertronix.

--DD

[ndfrigi]

The dual relay powers the FI, and powers the fuel pump.

Don't leave your key on without the engine running for too long, or you'll fry the Pertronix.

--DD

Thank you too Dave! You are 1 of those guys here that normally or always to support fellow members in sharing your expertised with this car.

Maybe that is one of those I will check tomorrow!

[ndfrigi]

Update:

Joe (Series9)

1. Unplug the fuel pump and put 12V on it manually. See if the car will start.

Report your findings.

My Reply: Instead of putting a 12v to the fuel pump, what I did is to turn the key to run position and immediately went to air intake sensor (with square plastic cover) and swing the arm and i feel the fuel is running along the fuel hoses. Meaning fuel pump is okay. Or should I still place a direct 12 volt to the fuel pump and try to start the engine again?

2. And before you go too far:

Check your fuses. If they are okay, check for 12V on the positive side of the coil with the key in the "run" position.

My Reply: All fuses under dash (only the fuse panel showing outside and didn't check anything at the rear of that fuse panel.) All fuses are okay and has resistance on both sides of the fuses.

Coil positive side has 12 volts power


Timothy_nd28

1. Start at the relay board, remove the 14 pin and 12 pin connectors. Next, use a multimeter that is set to read resistance and put one meter lead on pin one of the 14 pin connector. Put the second meter lead on pin 6 of the 12 pin connector. You should read 0 ohms.

My Reply: Unplugged the 14 pin and 12 pin connectors. #1 pin from 14 pin board with #6 pin from 12 pin board has a full resistance using multimeter. So meaning this is bad?



2. 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.

My Reply: Sorry was not able to do this since I don't have anyone can help me start the car.


Geezer914

1. Check the dual relay near the battery.

My Reply: I was able to replaced it with a used dual relay from my friends running 1.8 engine. Still engine didn't engage/run.


In addition: I also used another blue coil from the 71 car and still didn't help.
Any next step I should check?

Thank you again fellow teeners!

[timothy_nd28]

Full of resistance? What did the meter say exactly?

We need to rectify the issue with the relay board, but it can be done at a later time. The fact that the airflow meter does engage the fuel pump is a good sign. The next step is to see if the fuel delivery is the problem with the no start condition. Either jump the fuel pump with 12vdc or at the dual relay find pin 88d and jump that terminal to the positive battery post. The wire on pin 88d should be a big black wire with red stripe.

It doesn't matter which method you choose to turn on the fuel pump. Once the fuel pump is whirling away, go ahead and start the car. Report back with the results.

Remember to reattach the pertronix module when attempting to start the car if you happened to remove it earlier like I recommended.

[timothy_nd28]

Update:


My Reply: I was able to replaced it with a used dual relay from my friends running 1.8 engine. Still engine didn't engage/run.


In addition: I also used another blue coil from the 71 car and still didn't help.
Any next step I should check?

Don't be a part changer, it only adds extra variables. This is a pretty simple system to troubleshoot, it makes it much harder to diagnose if you randomly change parts.

[ndfrigi]

Update:


My Reply: I was able to replaced it with a used dual relay from my friends running 1.8 engine. Still engine didn't engage/run.


In addition: I also used another blue coil from the 71 car and still didn't help.
Any next step I should check?

Don't be a part changer, it only adds extra variables. This is a pretty simple system to troubleshoot, it makes it much harder to diagnose if you randomly change parts.

yes sir i'm like that! i will try a part one at a time and also return my original part if the replacement does not help. thanks!

[timothy_nd28]

It's a blind and expensive way to go about solving a problem.