MFI relay

2001 MITSUBISHI ECLIPSE
112,098 MILES • 2.4L • 4 CYL • 2WD • MANUAL
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REAPER1992
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I started my car let it sit there and run for about twenty minutes and then shut it off. the next day i went out to start it and it would not start. i am getting very little power to my MFI relay. thought it was the ground so cleaned all the grounds, but they were already pretty clean before cleaning them. so i am not sure what is going on. any ideas?
Apr 1, 2018 at 12:00 PM
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HARRY P
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If the service engine light is on, then I would say go ahead and get it scanned somehow or another. You can buy an OBD2 scanner on Amazon for like $20.00 and maybe cheaper on eBay. I would stay away from the really cheap Chinese Bluetooth ones though, as they only halfway work.

If the light is not on, then it is time to go with basic diagnostics. Here is a little guide that I have written:

Engines need several things in order to start. They need (1) fuel, (2) air, (3) compression, (4) sparks, and (5) 1-4 have to be on time, in the correct strength/amount. Unfortunately, when you get over 150,000 miles on any vehicle, any of those could be the problem. The most common causes are with (1) and (4).

I would start with simply listening for the sound of the fuel pump coming on. When you turn the key on, without turning the engine over, the pump should come on for two to three seconds. It makes a humming sound. If you can, get a helper to turn the key on while you listen for it. If you do not hear it come on, try tapping on the bottom of the tank with a hammer or other blunt object immediately after the helper turns the key on. If you then hear the pump come on, then you need a new fuel pump. Simple as that. You freed up the brushes in the electric motor inside the pump. This is a very temporary fix (might give you an hour or two of running time).

If you still do not hear the pump come on, then you need to check the fuses. There is a fuse box diagram attached below. The fuse box to look at is the one that's under the hood, along the left side. In particular, look at the fuses for "fuel pump", "ECM/TCM," "PWR Train," and "ENG Ign."

Just because the pump receives power and comes on, does not mean that it is pumping enough. We will circle back to checking the pressure output later on, if necessary.

If the pump is coming on, the next easy thing to check is for sparks. You can do this with a tester that is available at AutoZone or any other auto parts store. Here is a link for one on Amazon: https://www.amazon.com/Lisle-20610-Inline-Spark-Tester/dp/B0002STSC6/ref=sr_1_3?ie=UTF8&qid=1501325755&sr=8-3&keywords=spark+tester

Basically, you pull the plug wire off of the ignition coil (also pictured below) and plug in this tester between the coil and the plug wire. Then get someone to turn the key while you observe it. If it flashes, then you have spark. Check all of the cylinders.

Let us know and we will go from there. There are more advanced tests that you can do for free or very cheap. We will go through them if needed.

Apr 1, 2018 at 7:50 PM
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REAPER1992
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That is the thing I already did this and this is how I know I am not getting the proper voltage from the MFI relay. I did however go ahead and replace the fuel pump and the relays just because why not. I kept the old for spares and ran test on them they are good. my issue is that I am not getting the power to the MFI relay that is right there by the fuel pump. I thought it was ground issue, but I checked all the grounds. It will not throw a code at the moment and it will not start. It turns over but with out the MFI relay not getting power. I do not have power to the fuel pump there was suppose to be a 20amp fuse in line for the MFI relay and I cannot find one this really has me stumped and ready to light the car on fire but I have over $2,000.00 in the car. I know it is not the timing as well. I already checked crank position senor and I checked relays and fuses all good, all the ones I can find any way. I have already checked spark and air and all that stuff as well. I did have a low spark on one of them so I changed coil and fixed the low spark. I do not have power to the fuel pump and the only relay I am not getting good reading from is the MFI relay. I was told that the MFI can cause the fuel pump to not come on. So I am trying to fix that issue but I am unsure what to really do to fix the MFI relay power issue.
Apr 1, 2018 at 8:34 PM
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HARRY P
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Exactly what are you getting at the MFI relay? And have you inspected the wiring to the relay itself? It is possible that it is burnt or that there is a short somewhere along the way. I would check for continuity between the lead and the ground to check for that short. Any resistance less than infinity indicates a short in the wiring. I would also check for continuity between the terminals of the MFI relay itself. Again, resistance of less than infinity indicates a short.

Number 13 in the image below is what you want to check. I would go ahead and change it out, as sometimes (rarely but occasionally) a visual inspection looks good but the fuse is no good.
Apr 2, 2018 at 3:40 AM
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REAPER1992
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I am getting around four volts to it and the fuse number 13. I tested with a tester I will test the wire today and see.
Apr 2, 2018 at 5:29 AM
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HARRY P
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Okay, here is the information that we have on that MFI relay and testing. It does not say how much voltage should be getting there, just that it should be consistent. It also tells you how to test the relay.
Apr 2, 2018 at 6:55 PM
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REAPER1992
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Sorry I was not able to test the wires today due to the rain the last couple days. Hoping it will get better soon.
Apr 3, 2018 at 6:41 PM
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HARRY P
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No problem. I have got all the time in the world.
Apr 3, 2018 at 6:51 PM
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REAPER1992
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okay, thanks bud.
Apr 3, 2018 at 6:52 PM
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REAPER1992
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It does not look like I am getting a connection from the MFI to the pig tails to the ECU.
Apr 6, 2018 at 10:31 PM
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HARRY P
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You will have to inspect the wiring and the connectors for issues. I would bet on the connector to the MFI relay being bad.
Apr 7, 2018 at 3:35 AM
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REAPER1992
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Sorry I have not replied lately been busy.
Apr 14, 2018 at 11:48 AM
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REAPER1992
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I will try to test it out on my next day off. Is there a way I can get those parts for it that you know of? My store does not sell them. It does not sell much of anything for the Eclipses at all.
Apr 14, 2018 at 11:51 AM
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HARRY P
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The local parts shop should be able to order some things that they do not have in stock. Also, you can always go to the dealer, or the junkyard/pull-a-part for things. Personally, I love Amazon.com, rockauto.com, car-part.com, and the local junkyards.
Apr 14, 2018 at 6:56 PM
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REAPER1992
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Okay thanks bud. I appreciate all the help you been giving me over the weeks.
Apr 14, 2018 at 7:42 PM
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HARRY P
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That is what we are here for. Glad to help.
Apr 14, 2018 at 7:43 PM
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REAPER1992
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Well I hooked a OBD2 scanner up to my car today and the speedometer started going up in speed with the car off and the scanner was not reading anything as well.
Apr 17, 2018 at 1:09 PM
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REAPER1992
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If that is the ECU is there anything that would keep a new ECU from just plugging in and working like it is suppose to?
Apr 17, 2018 at 1:10 PM
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HARRY P
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I do not think it will require programming. Just make sure that you get one with the exact same numbers on it. I am attaching Prodemand's info on the PCM. Pin #38 is for the MFI relay ground. You could probe that to see if the PCM is at least attempting to ground the MFI relay. If not, then replace it. If so, then the PCM is not your problem. Note: I skipped the info for the automatic transmission.
Apr 17, 2018 at 7:20 PM
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REAPER1992
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Awesome, thanks.
Apr 17, 2018 at 8:07 PM
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REAPER1992
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Okay, so the other day before I went to work I started tracking the wires and making sure that it is not the wiring causing the issue. on three of the wires I am getting nothing. I am getting a connection from the ground but nothing from the other wires so I started trying to find where the short is or the wire. I do not see any burn areas but there is a spot where wires come threw the firewall and got a bundle of pig tales or something like that. I do not know if I am explaining that correctly but i hope you understand. I was wondering if that was factory or from the person I bought the car off of? also, I wanted to thank you again for helping me out so much. I know that understanding and getting a car running is not easy over the internet or phone and it is worse when you get someone like me who does not know much about electrical on cars and trying to fix a possible electrical issue. I would like to be able to have someone fix it but I cannot afford the money at the moment as my hours at work got cut. So thank you for taking your time and helping. I know how frustrating it can be.
Apr 22, 2018 at 6:32 PM
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STRAILER
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Use 2CarPros anytime, we are here to help. Please tell a friend.

Cheers, Ken
Apr 27, 2018 at 9:10 AM
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HARRY P
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Sorry, I meant to get back to you earlier. It is probably factory with those wires coming through like that, because only a manufacturer would do that, really.
Apr 27, 2018 at 6:55 PM
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REAPER1992
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Not sure what is going on with the car. I had the ECU tested and they said it was good. Then I checked the pig tails they are fine. I could not find a wire burnt in two or any other damage. Did find a fuse on one side did not make contact but on other side did and on top made ground.
May 21, 2018 at 6:49 PM
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STRAILER
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You will need to go over the wiring power ground and connection to make sure we do not have an open or shorted wire somewhere. Here is a guide to help you get the job done:

https://www.2carpros.com/articles/how-to-check-wiring

Check out the diagrams (below). Please let us know what you find.

Cheers, Ken
May 22, 2018 at 10:22 AM
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REAPER1992
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Thank you.
May 22, 2018 at 11:46 AM
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HARRY P
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Thanks for taking care of that Ken. I have been a bit tied up lately and have not been able to get on here much, so that really helps.
May 23, 2018 at 4:17 AM
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We are the team helping the world.
May 23, 2018 at 10:14 AM
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REAPER1992
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Hi guys, I know it has been awhile sorry about that. I wanted to give you an update on the car. I was able to get the fuel pump to kick on again, but the car still has not been started. Going to try to start it tomorrow after I fix issue with fuel pump assembly not all the wires on the fuel pump assembly was put back right my sisters husband had it apart testing the wires in the fuel pump assembly today and for got to plug them in correctly. So tomorrow I will be taking it apart to fix that and then I will try to start it now that everything seems to be working right again. After tomorrow I will have three days to work on it so that is a plus. It will be nice having some time to myself to get the car fixed. I am working on it and my 2001 Dodge at the same time, but my Dodge is almost fixed now, I just need a driver side fender and headlight assembly for it then it is done. I found some will cost about $200.00 for them. I forgot I need new back bumper to i been working on that and the Eclipse but trying not to over whelm myself with that Eclipse. It is hard for a big guy like me to work on something so small. I wanted to thank you guys again for being so nice and caring and all the help you have given. Thank you Ken and Heyman I appreciate all the help you two have been you have helped me a lot on this issue.
Jun 29, 2018 at 7:48 PM
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HARRY P
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No problem! It sounds like you have a real strong handle on it from here, but we will still be glad to help any time.
Jun 29, 2018 at 9:41 PM
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REAPER1992
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I hope I do this car has been a pain in my butt for awhile. The people I bought it from was treated it poorly and then when I got it I started fixing everything I found wrong with it and I think that is why it messed up. It did not know how to act being taken care of. All joking aside, I think what happened was the car has a after market hood with air vents that catch air and pull air into the engine bay helping it keep cool, but water every time it rains gets in there as well and gets into the fuses and relay plus the ground is in there as well both frame ground and the ground to the transmission was getting wet and causing them to corrode. I think that is where the problem started I will be fixing the hood to where water cannot get in it. In the future was thinking about making a home made fiber glass hood put the vents where I want them and how I want them if I decide I want to keep vents. I am not sure if I want the vents or not they seem like they can cause massive issues that is unwanted.
Jun 29, 2018 at 10:18 PM
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STRAILER
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Yes, water causes all kinds of issues whatever you can do to stop the leaks and seal things up would be beneficial. I do not like to see everything misused so I feel ya.

Cheers, Ken
Jun 30, 2018 at 11:43 AM
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REAPER1992
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I need help with this car once again. If you guys do not mind here is what happened: I had these last three days off work so I spent it working on the car and I got it to start up then it back fire and shut off. Now it will not start. I looked at all the sensors and throttle position all that all the sensors look fine. I made sure they was all fully plugged in but I am once again at a loss with this car. Is this still a electrical issue? I am not good with electrical on vehicles.
Jul 4, 2018 at 8:57 AM
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Please post your new question here, you must be logged in.

https://www.2carpros.com/questions/new

Cheers, Ken
Jul 4, 2018 at 3:28 PM