The Top DSM Community on the Web

For 1990-1999 Mitsubishi Eclipse, Eagle Talon, Plymouth Laser, and Galant VR-4 Owners. Log in to remove most ads.

Please Support Fuel Injector Clinic
Please Support STM Tuned

2G mpi relay

stheodore10

Proven Member
78
0
Apr 3, 2012
Hillsborough, New_Jersey
so ive searched and searched and searched and still have questions... the contacts in the mpi relay... are they both supposed to connect? only one of the coils is making connection on crank. also would that prevent the car from starting? thanks a lot
 

iugrad92turbo

Supporting Member
12,960
874
May 22, 2007
Kalamazoo, Michigan
You need spark for combustion, the contacts, do you have a working relay, any other starting issues, it could be more than that for a start. Spark, fuel, and compression. The realy should make contact with whatever its connected too, I guess im kinda confused as to what contacts your referring too?

http://www.dsmtuners.com/forums/articles-miscellaneous/217951-how-diagnose-no-start.html


http://www.dsmtuners.com/forums/newbie-forum/263224-mfi-mpi-relay.html


check out the above thread for more information on the wiring diagram for your 2g dsm.

95 MPI relay E8t08474, DSMpartsonline.com * Powered By MadDSM.com

How to Check MPI Relay (DIY DSMers)
 

steve

DSM Wiseman
14,878
1,724
Feb 3, 2002
Boulder, Colorado
so ive searched and searched and searched and still have questions... the contacts in the mpi relay... are they both supposed to connect? only one of the coils is making connection on crank. also would that prevent the car from starting? thanks a lot

By both contacts I assume you mean the two relays inside the box?
The MPI thread linked should make it clear, if not what don't you understand?
 

stheodore10

Proven Member
78
0
Apr 3, 2012
Hillsborough, New_Jersey
the how to check mpi relaylink is for 2g... and i opened the cover to see the contactors like so
You must be logged in to view this image or video.

and when cranking only the fuel pump coil makes contact tried looking at the no start guide which says
Fuel: If there is fuel to the rail then put the line back on (make sure the o-ring isn't cut) and tighten it up so it doesn't leak. Un-bolt the fuel rail from the head, leaving the injectors in the rail and plugged in, after you remove the rail. Set the injectors on the head, facing the front of the car, once again placing them toward a bucket so it can catch the fuel as it sprays out. Have someone crank the car and watch the injectors, ensure ALL of them have a nice spray pattern and pulse as the engines cranking. Wearing eye protection while doing this check isn't a bad idea either, there is a chance you get sprayed with fuel.
Some or NONE work: Don't give up yet, there are still a few things to test with a multimeter to make sure its working.
Test your injector resistor pack

Measure resistance across the injector terminal with the plug disconnected, it should be 2-3 ohms across it.
Test the MFI/fuel pump relay
You must be logged in to view this image or video.

ALL of the injectors work: Put everything back together, making sure none of the o-rings are torn, and go to the next step.

now what i dont understand is
#1 why the pic only shows a 4 pin connector and not the other five
#2 if i made the correct assumption and chose the side of the harness with the 4 pins, im not sure im doing this right cause i tested 2 different mpis and they were both bad, imsupposed to test for continuity on the side pins? if no continuity im screwed?
 

steve

DSM Wiseman
14,878
1,724
Feb 3, 2002
Boulder, Colorado
the how to check mpi relaylink is for 2g...
and when cranking only the fuel pump coil makes contact tried looking at the no start guide which says

now what i dont understand is
#1 why the pic only shows a 4 pin connector and not the other five
#2 if i made the correct assumption and chose the side of the harness with the 4 pins, im not sure im doing this right cause i tested 2 different mpis and they were both bad, imsupposed to test for continuity on the side pins? if no continuity im screwed?

The link isn't just 2G specific. I talk about how it works on a 1G and then we clarify the 2G details http://www.dsmtuners.com/forums/newbie-forum/263224-mfi-mpi-relay.html

#1 The information you quoted from the no start guide is for the 2G's that use two individual relays. The 1G's use the type of relay the picture showed.

Testing the MPI side:

Applying +12v to pin 10 and the ground (-battery) connection to pin 8 should make 12v show up at pins 4 and 5.

Testing the Fuel Pump side:

Same deal (applying 12v battery voltage across) for pin 3 and 7 causing 12v to show at pin 2. Applying 12v across pins 9 and 6 will cause continuity between pins 3 and 2. (on 1G relays. They have the second fuel pump input)


So if the MPI relay is good and the ECU works, when you turn on the ignition the MPI side of the relay should activate and stay on until about 5-10 seconds after you turn the ignition off. When you start cranking the starter the fuel pump side should activate and if the engine doesn't start turn off about 2 seconds after cranking stops. If the engine starts the fuel pump relay will stay activated until you shut off the engine or it stalls and again timeout about two seconds after the last CAS pulse.

2G's are slightly different in how they handle the fuel pump. Both cars have people reporting glitches (from the CAS) causing the fuel pump to trigger when the ignition is turn on.

Since you only see the fuel pump side activate it doesn't sound like the MPI side is working and your ECU wouldn't be turning on either. No ECU, no start.

I hope that you've heard people say check that the CEL turns on for 5 seconds when you first turn the ignition on.
 

stheodore10

Proven Member
78
0
Apr 3, 2012
Hillsborough, New_Jersey
So I got the car to start :hellyeah: swapped the ecu for all those wondering how i solved the problem, got tired of testing and went out on a limb and bought another for $120.

only problem now is that it'll start but it cranks to 3.5/4k after the slightest touch to the pedal then dies after a couple seconds, after it climbs to that number the gas doesn't seem to make a difference ... very confused
 
Support Vendors who Support the DSM Community
Boosted Fabrication ECM Tuning ExtremePSI Fuel Injector Clinic Jacks Transmissions JNZ Tuning Kiggly Racing Morrison Fabrications MyMitsubishiStore.com RixRacing RockAuto RTM Racing STM Tuned

Latest posts

Build Thread Updates

Vendor Updates

Latest Classifieds

Top