Hello, I've been having cold starting problems with my Fj62 (3fe) for a while. I pulled the cold start injector the other day with the fuel line and plug still attached, and turned the key. Engine cranking but no fuel being sprayed. (Canadian winter with truck engine completely cold). So I tried following the test procedure in the fsm. I connected +B and FP on the test connector, and I connected the terminals on the actual injector to the battery (found ground terminal by doing continuity check to engine block on the wire side of connector, and assumed other was positive). Turned key to ON, heard a click when I'd touch the + battery terminal with my test lead, but no fuel. Does that definitely mean the injector has failed?
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There is a sensor on the thermostat housing that tells the cold start injector the car is cold and needs to fire. Connecting the +B and Fp bypasses the fuel relay but I would have to look at the FSM to see if it also bypasses the sensor on the t-stat housing. That may be the culprit rather than the injector itself.
Show us a picture of your driver's side engine bay.
Show us a picture of your driver's side engine bay.
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- #3
When I tested the injector (fsm instructions) the electrical connector was completely disconnected from it. It was powered directly from the battery. I thought that meant that I bypassed all other components and electrical except for the injector itself? I'm not 100% on it though. Electronics are not at all my specialty.
If you put voltage right to the injector and heard it click its probably good electrically. Don't hold power to it for more than a second or it will burn up especially with no fuel flowing thru to cool it.
So it's either plugged or there is no fuel pressure or flow to it. If you have fuel pressure to it maybe it can be cleaned by a shop that specializes in that.
So it's either plugged or there is no fuel pressure or flow to it. If you have fuel pressure to it maybe it can be cleaned by a shop that specializes in that.
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Thanks a lot. I'm gonna try to pick up another one today. I think it has pressure, but I'm not really sure how to check.
Which reminds me that this injector does not pulse like a conventional one. It sprays continuously as long as it's active. So continuous 12v to it shouldn't hurt it.
Finally had some time to go over the FSM schematics. So you connected the Fp and +B terminals. That connects your ignition power +B to the fuel pump Fp. Connecting those two terminals in your diagnostic port bypasses the EFI Main Relay and the Circuit Opening Relay. This allows fuel to flow. My guess is it allows fuel to flow to the injectors but not to the Cold Start Injector unless the cold start injector time switch tells it to. If the switch says yes, then the injector coil energizes. Theoretically you could apply 12V directly to the correct wire and bypass the switch.
I would do two things:
1. test your cold start injector time switch (it's located on your upper t-stat housing).
2. pop open the fuel rail banjo with the Fp and +B terminals connected. It should squirt fuel.
3. Re-evaluate and look deeper.
I would do two things:
1. test your cold start injector time switch (it's located on your upper t-stat housing).
2. pop open the fuel rail banjo with the Fp and +B terminals connected. It should squirt fuel.
3. Re-evaluate and look deeper.
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Testing the cold start injector time switch on the t-stat housing:
cold start injector resistance check:
If your truck is not in park the cold start injector won't fire. The Neutral Safety Switch protects that from happening. It's a long shot but make sure. If you can crank the starter then you are in park.
Glad I found this thread. I just ran through all these test procedures on my 3fe. At first, with test circuit in place and power supplied directly to the CSI and with ignition on, CSI would click, but no fuel. Tried again, and then strong spray....and continue spraying after I removed power to the CSI...nonstop spray. So now the truck runs super rich. I think this means the injector was sticky....stuck closed at first, and now stuck open.
Is it realistic that the CSI could now be stuck open? Randy88FJ62
Is it realistic that the CSI could now be stuck open? Randy88FJ62
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If the injector is stuck open, it should not be clicking when power is applied or removed, so that might tell you something.
