Ok.. here's what happen.
I have a Clifford alarm installed last year on my Integra. There's a wire from the alarm that is tapped into the wire that connect to Cylinder #1 Fuel Injector to detect the RPM.
Last Friday, the Check engine light goes on, the report is that there's a Misfire on Cylinder #1.
This has happened to me in the past, but I thought that was caused by bad gas.. and it's been a while since this happened and usually it goes after a couple of minutes..
This time, it's been 3 days, so this morning I took it to the dealer but the dealer said that it might be because of the shorted wire and want me to take it to the place where I install the alarm. Dealer also said that Cylinder #1 basically is not running.(totally).
so I took the wire from the alarm out and check it whether that's the cause or not..
but it didn't change a thing..
here's my question:

1.Is it possible that the wire from alarm damaged my ECU?
2.Can a Melted electrical tape makes the open wire not conductive any longer?
3.is there a way to see if that connector to the 1st Cylinder is working or not?

any help or advice is welcomed since i am exhausted to try things..
(I replaced the gas from the tank, so bad gas is out of the question; I use different spark plug wires, swap the spark plugs, but still.. cylinder no:1 is dead.)

TIA

 

is there a Recall or TSB about
"ECM - MIL ON/Multiple Misfire DTC's Stored" for a 2000 Integra?

 

I believe it's more common to attach the alarm to a wire coming from the distributor. Tapping into a fuel injector wire obviously changes the circuit from how it was designed to be, so who knows everything that could go wrong...

I think it's possible that the injector or the ECU was damaged. The alarm's connection draws some current that was supposed to go to the injector, but the injector still tries to draw it's normal amount of current, so the result is the ECU has to supply more current to the #1 injector every time. Drawing too much current can easily melt wires and ruin components.

Usually, circuits have a fuse to prevent them from using too much current. The fuse is the weakest link in the circuit and will blow once the current draw exceeds it's rating. So, if the weakest component can only handle 6 amps, they will likely use a 5 amp fuse, and if the current draw exceeds 5 amps, the fuse will blow and the circuit will no longer have power. Fuses prevent damage to components, but I'm pretty sure that the individual injectors don't have fuses of any kind on them.

I doubt the alarm caused a huge extra current draw, but when it happens several thousand times a minute, it could gradually wear down the weakest link until it eventually breaks.

Well, that's my theory anyways... I'm sure there are plenty of other possibilities.

 

I agree with Wenston, but unfortunatly there are no individual fuses for the injectors.

I would prefer to check some electrical connections with a multimeter.

Disconnect the connector of the injector. Measure the resistance (ohm) between the brown cable of the injector connector to pin A4 (when it's a OBDII ECU) of the ECU (should also a brown wire). This should be a very low resitance (max 5ohm). If not the wire from the ECU to the injector is broken. Maybe on the point where your car alarm was tapped in.

If this is fine, measure the resistance from the brown wire to ground (chassis). The resistance should be very high. If the resistance is very low (just some ohms) then there is a short of the injector signal to ground. Find it and repair it.

Check the resistance between the tow contacts on the injector plug. It should be a high resistance. If the resistance is very low, there is a short between +12Ign (the yellow cable) and the injector signal (brown cable).

Check the resistance between the two terminals ON THE INJECTOR. This should be around 12 Ohms. If you see a very high or very low resitance, the injector may be blown. Exchange it.

Still nothing found, then switch your multimeter to VOLTS to measure voltage.
Switch on the ignition but don't start, measure the voltage between the yellow wire on the injector plug via ground (chassis). The result should be around 12-14Volts. (batterie voltage).

If anything above looks fine, then maybe your ECU is broken. the easiest way to check ist just to replace the ECU. Otherwhise i would prefer to check the signal on the brown wire when the engine is running. It should jump between a few volts to 12 volts. But the signal is so fast (just some miliseconds) you can't measure it with a multimeter. (it shows maybe some volts). {just a idea left: You could build a quick and dirty tester with a led and a resistor. The led should flicker very fast but noticable. (at a close look)}

If you're not expirienced with elcktro/electronics, maybe a friend could help you out. Maybe a nice mechanic at your honda dealer.

Hope this helps, and sorry about my bad english

Doc

 

You can hook up a "noid" light and see if it flashes or not.

 

Or you could improvise a stethescope type device and listen for the mechanical click of the injector. (garden hose, screwdriver, whatever)

 

Thanks all for the help..
it seemed that the Injector on CYL 1 is not working..
(I can't hear the ticking using a screwdriver)...
Then I put the connector from CYL 1 to Injector no 2 to see if the connector to CYL 1 is bad but it is working on the CYL 2..
then I put the connector from CYL 2 to CYL 1, still it is not working..

can I conclude that CYL 1 injector is faulty?