Need info about 1G part

[FWD98GST]

Hey guys, attached are pics of some sort of relay that makes clicking sound everytime the key is turned on the ingition and the car won't start. Can anybody identify what this part is? Definitely, the clicking sound can be felt from this part and could be hindering the car from starting and also when the car is started momentarily, the car will die also after a coulple of seconds...

The first pic shows where the part can be found which is closer to where the white zip-tie is at... Just to let you know where it is...

Thanks...

 

[GVR4592]

That's the MPI relay and if it were to fail it could cause the car to not start. I'll see if I can find the procedure for testing it.

Edit: I just thought of something else. The ecu is what sends the signal to the relay to turn the fuel pump on. It's possible the caps in the ecu have leaked and damaged some components.

 

[FWD98GST]

Yah thanks!! I've read about the caps on 1G's tend to leak.. Didn't get a chance to open it up, but that was the part that was clicking upon turning over the key... You could be right also about the fuel pump.. I wish there was a simple to diagnose and single out what is the problem...

 

[steve]

I would hope that relay clicks once when you turn the ignition on since it's how the MPI circuit powers up under ECU control. The CEL/MIL light should go on and after a few seconds turn off is the ECU is getting power from the relay and working. If the relay is chattering first check the battery voltage and make sure you have >12v.

Steve

 

[FWD98GST]

yah.. unfortunately, the car has been sitting outside for a while and jumped it and got it started and after about 5 minutes of idling, the car just died.. and won't start over again.. This symptoms of intermitent shutdowns while driving or idling has been with this car for over months and only now that we want to get this car running... It's really scary to drive this car, back then on the freeway, cause you never know when this car is going to die on you.

 

[steve]

I'll assume your asking about a 1G part installed in a 1G. If so you should have the ECU checked since the capacitors leaking is a universal problem and will cause this sort of symptoms.

Steve

 

[FWD98GST]

Steve,

The part that i'm showing you guys online is the original part... I'm assuming that you're thinking that we installed it? Not sure, but its an original part...

 

[steve]

What's not clear is, since you have a 2G in your profile, why you asking about a 1G MPI relay. So what I was trying to get at is that if your question is for a problem with a 1G car then I suggest you look at the ECU before spending too much time on the MPI relay itself. The relay is pretty simple and robust. Easy to test and most the the time the circuits that control it that are acting up.

Steve

 

[FWD98GST]

Steve,

It's my uncle's car.. I'm just trying to help him out..

 

[steve]

Not a problem, It just wasn't clear.

So when you get a chance watch what happens when you turn the ignition on for the CEL. The car isn't going to do much if the ECU isn't running.

You can download the 1G wiring diagrams off the Manual CD sample site to get an idea how things are hooked up. and start diagnosing the problem.

 

[91talontsiturbo]

also when the car is started momentarily, the car will die also after a coulple of seconds...

Sounds like the ecu is just sending the "fuel pump prime signal" to the relay, thats why it will only run for a few seconds.

And right when it dies it clicks agin dosnt it?! That would be the sound of the relay cutting the power to the pump.

I actualy took the relay apart one day and seen how it worked after the same problems were happing to my car as well. And seen that the ecu wasnt keeping the relay on after it primed it the first time before the car acctualy starts. So there was no power to the fuel pump right after the intial start up.

I would deffenitaly check the ECU first and swap it out with one that is known to work to see if it cures it.

 

[steve]

Sounds like the ecu is just sending the "fuel pump prime signal" to the relay, thats why it will only run for a few seconds.

And right when it dies it clicks agin dosnt it?! That would be the sound of the relay cutting the power to the pump.

I actualy took the relay apart one day and seen how it worked after the same problems were happing to my car as well. And seen that the ecu wasnt keeping the relay on after it primed it the first time before the car acctualy starts. So there was no power to the fuel pump right after the intial start up.

The ECU doesn't send the prime signal to the relay. That's hardwired into the starter circuit driving the second winding on the FP side of the MPI relay. The ECU is intended to drive the other winding once it see the CAS spinning without the starter signal. If the ECU can't activate it's winding because of leakage damage the car will runs for a few seconds and stalls.

You'll note that the FP side of the MPI relay clicks with the starter activation and the engine dies a few seconds after it clicks in this case.

Steve

 

[91talontsiturbo]

Man, I thought i had this

Steve, I have no doubt in my mind that you are right!

I thought the ecu sent the prime signal since it also controls the signal that keeps the pump on after starting.

So i guess what your saying makes since because if the acid from the caps ruined the fuel pump signal to the relay then it would have also ruined the prime signal aswell but since thats only controlled by the starter then you are right! I never thought about it like that but i did wonder how that was.

Sorry if i mislead anyone, and thank you Steve for correcting that for me.

 

[DSM007]

I had an ECU fry on me once,replaced the ecu and my relay was doing the same thing as yours......turn on the key,hear the relay click on,runs for a couple seconds,hear the relay click OFF,then the car would sputer and die.......I replaced the relay and the car ran fine.....somehow when the ECU caps went bad it took out the relay along with it..........so go pull a working relay out of a buddies car and give her a try there