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No FuelInjector Electrical Pulse; Sometimes Dies, No Fuel Delivery, Usually Restarts After A Few Hours
Topic Started: May 26 2013, 01:06 PM (1,055 Views)
crankcase


Hi all,

Just got the stepdaughter a 2000 3cyl 5-speed Metro.
It has run pretty well, but has started having a problem with starting, and dieing while driving.
It has become worse in recent days.

I finally looked at it when it died and found no injector spray pattern.
It runs briefly with a shot of gas in the intake.
I verified fuel pump operation by checking that the return fuel line is passing gasoline.

There is constant 12 volts on the radiator side of the plug that goes to the injector (tested with plug removed from socket).
There is no pulse on the windshield side of the plug (again with plug removed from socket).
That is to say, no test light indication (ignition on, motor off) and also with motor cranking.

I used a cheap Harbor Freight test light with one end clamped to ground.
I assume a test light is fast enough to catch pulses.

There is no check engine light indicated.

I have been checking the archives, but thought I would also post to see if anyone had any quick ideas.

Thanks
Edited by crankcase, May 27 2013, 12:53 AM.
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crankcase


Looked at it again, looked at grounds behind throttle body = good.
Looked at resistance at injector = open circuit = bad.

I think when I was checking the pulsed line to the injector I was looking at a line which was remaining basically at solid ground, not one which was doing any pulsing between 12 volt and ground. That kind of makes sense if the computer was seeing an open circuit at the injector and was trying to make it turn on.

Now my problem is that every time I've tried removing an injector I snap the screws that hold the cover on. I'm in Central Texas, and the extra heat may be why this is so ???? Maybe the Locktite cures extra strong? I've got an impact screwdirver to use and will have to rig up my heat gun for side of the road operation and use both to try and stack the deck in my favor.
Edited by crankcase, May 28 2013, 11:03 PM.
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crankcase


I finally did a removal without breaking the screws:

1600 watt Harbor F. heat gun, nozzel about 2 inches away, back and forth between screws for about 1.5 minutes, spending about 20 seconds over each screw before moving back to the second screw.

Then Harbor F. impact screw driver for about another 1.5 minutes untill it cooled, then repeating heat/impact.
It helped to give the driver a little pre-twisting action before giving a good tap with the 2.5 lb hammer.
I could have hurt something, or cracked castings if hit too hard.

I tested the injector again after all the heating and impacts, and it improved to around 145 Ohms,
but still way too much according to good sources on the Forum.
It shoud be about 1 to 1.5 Ohms. Now to look for a replacement.
Edited by crankcase, May 28 2013, 11:06 PM.
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crankcase


I found an old throttle body with an intact injector having about the correct resistance.
It measured 2.5 ohms in the old TB and 1.5 Ohms when out.
On this one I only used the impact screw driver with no heat.
It worked on one screw, but on the other striped out the tip of the screw on the first blow.
Luckilly I was able to turn it out with some Ampro high leverage needlenose pliers.

I sprayed the injector down with carb cleaner,
fished out the little O ring for that goes at the tip of the injector,
put all back together, and it fired right up!

The O rings were a little stiff,
but I hope , and think, they will hold until a replacement comes from the mail order.
They are about $200 at all the locals and $30 by mail order. WTF?

Thanks to Doc/Blue/Big for posting the injector resistance check.
Edited by crankcase, May 28 2013, 11:07 PM.
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scubaman
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scubaman

:gp
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Woodie
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Nicely done.

Beware, MWebb is due any second telling you that measuring ohms will destroy your car and turn you sterile. Despite the fact that it led you directly to what your problem was.

When first testing voltage at the injector, it should have 12V on BOTH sides with key on engine off. Then, when cranking, one side should start pulsing.
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