No Start, Need help from someone who know's our ECU's in & out. (Blown Drivers)

[ShadeTreeDSM]

On x-mas i wired up some speakers in my car & rewired my radio because the guy who did it before ghetto rigged the wiring harness. I have MSD DIS-2 and the thick red power wire was tapped into the radio harness. Its now at the battery. So after i was coming home one day from work my blows off a coolant line (due to not being tight enough) and i shut it off to fix it, i go to start it back up and it wont start, so i keep trying to start it and eventually it kills the battery. so i leave it at a friends house. and come back to get it later that night, still no start, i tow it home. I wake up the next day to start it and starts right up, so im like wtf ? I drive it up the road and come back and as soon as i pull in my driveway it stalls again and no starts AGAIN. so i decided to change the plugs & see if that helps, nope, i checked fuses, & checked for fuel & spark, its all working. So then i finally suspect the ECU might be the case, i pull it out & what do i see, silicon holding some of the chips on the board together & a blown ISC driver. THIS ISNT MY ECU BUT THIS IS WHAT WAS BLOWN.

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so i go to this place by my house, Auto Computer Exchange, i have them rebuild me a new EPROM ECU for my car, meanwhile i still have my old one in my car. I told them my situation and they told me my ISC driver was blown because of a BAD ISC , so they said disconnect it, so i did. So they give me a loaner ECU so i can get running, thinking it would fix my car, i go home & put it in and it fires right up, im heading out to dinner and im at a stop light and it turns green i stall by accident and it does it AGAIN no starting !!!! after like 10 minutes it start right back up.. I get it to run & take it back home & leave it there, try & start it the next morning & no start & once again killing my battery. I take the ECU out to take back to Auto Computer Exchange to get my EPROM ECU. I tell them my car is still stalling & no starting, they open up the loaner ECU & the ISC is good since i disconnected it but then they smell the board & say the Fuel Pump driver was burning. whyyyy ?

I told them i recently relocated my battery to the trunk and i only have the ground from the battery to frame & the starter grounded to frame. He said to check the MPI RELAY, if its going bad he said it could cause it to fry the fuel pump driver, also said to check every & all grounds, add some if i have to just to be safe. Having those 2 grounds i mentioned earlier, are they NOT ENOUGH GROUNDS? I relocated the battery to the trunk 2 months ago, i was running fine then.

Added slim fan about 4 months ago and i tapped it into the wiring harness for the A/C, so when i turn on the A/C my slim fan will turn on. I see that the IC109 Driver is for A/C & the fuel pump. I have a walbro 255lph HP pump. is that driver getting to much current ? should i wire the slim fan to a separate switch ?


I found this searching through this forum.

I fix a ton of ECUs, the 3 most common problems are the caps, the solenoid/actuator drivers, and the sensor ground trace on the back of the PCB(in that order).This apllies to NT ECUs as well.

There is plenty of info around the net on the caps, I've noticed there is a small surface mount decoupling cap(C14-removed and circled in the pic) that is usually bad as well, and most info doesn't say anything about this cap.I usually just replace it with a non-surface mount .1 ceramic cap closer the the connector(also circled in the pic)

The drivers fry due to excessive current, usually from wiring problems(shorts,etc) or faulty actuators/solenoids.Swapping ECUs in most cases will just damage the new ECU.If these are damaged inside your ECU, check the actuators/solenoids and their wiring BEFORE you swap ECUs.These are common in all 1g ECUs(T and NT), they can be replaced, without replacing the whole ECU.Note problems with the drivers usually lead to problems with the sensor ground trace(below).

These are M5269L low saturation output drivers labeled IC104-IC109:

IC104 is MAF active reset filter(turbo only)
IC105 is ISC coils B1 and B2
IC106 is Wastegate and Fuel pressure solenoids(turbo only)
IC107 is ISC coils A1 and A2
IC108 is Purge and EGR solenoids
IC109 is A/C and Fuel pump relays

Finally, the sensor ground trace.If you are getting a CEL, and the codes are sensor related but the sensors are OK, this is usually the problem.You can test this by checking for continuity between the main ground and sensor ground pins on the ECU.If there is no continuity, check the back of the ECUs PCB for a fried/broken trace.I don't have pics of this, but it should be fairly easy to spot.After checking for shorts to the sensor ground under the hood(and fixing above problems), you can just solder a jumper to restore the connection.

So what why is my car doing this all of the sudden ? ?

 

[NN4S]

Check the grounds for corrosion; there's a chance the rapid changes we've all been having with the weather could be affecting them. A clean, solid mechanical joint is necessary for reliable electrical behavior from your electronic components.

 

[ShadeTreeDSM]

Check the grounds for corrosion; there's a chance the rapid changes we've all been having with the weather could be affecting them. A clean, solid mechanical joint is necessary for reliable electrical behavior from your electronic components.

all grounds were good, i dont know what else it could be, i dont wanna put my new ECU only to fry it again

i still cant see what im missing ....

 

[steve]

You'll notice that there are 6 driver chips on a turbo ECU.
From your posting it seem like you not sure exactly which is blown. Please post a picture of your damaged ECU board.

The drivers burn up from being shorted or a lower than normal resistance to 12v. They are only rated to pass an amp or two for a couple of milliseconds. Any shorted solenoid, relay coil, or the ISC windings along with loose connectors in the engine bay that should be connected to one of the driver devices can cause the problem but we need to know exactly which of IC104 through IC109 burned up to tell you more.

People with 1Gs disconnect the BCS or FPS all the time and forget that there is a hot 12v wire sitting right next to the ECU wirre in the connector. Let that get wet and you can have burned ECU very quickly.

 

[ShadeTreeDSM]

You'll notice that there are 6 driver chips on a turbo ECU.
From your posting it seem like you not sure exactly which is blown. Please post a picture of your damaged ECU board.

The drivers burn up from being shorted or a lower than normal resistance to 12v. They are only rated to pass an amp or two for a couple of milliseconds. Any shorted solenoid, relay coil, or the ISC windings along with loose connectors in the engine bay that should be connected to one of the driver devices can cause the problem but we need to know exactly which of IC104 through IC109 burned up to tell you more.

People with 1Gs disconnect the BCS or FPS all the time and forget that there is a hot 12v wire sitting right next to the ECU wirre in the connector. Let that get wet and you can have burned ECU very quickly.

i know exactly what was blown, IC107 was blown. i had it checked at that computer shop.

I did get rid of the BCS & FPS, i didnt tape it off though, ill cut the connectors off and tape off the ends so it doesnt short out

and as of today i made 2 battery grounds, a ground from the ECU ground straight to the battery & a few more grounds from engine block to frame and im going to recheck all my grounds and see if there is good contact or not. Im getting a new ISC

also could a faulty MPI relay cause that burning up or messing up of IC109 A/C and Fuel pump relays?

 

[steve]

i know exactly what was blown, IC107 was blown. i had it checked at that computer shop.
also could a faulty MPI relay cause that burning up or messing up of IC109 A/C and Fuel pump relays?

IC107 as you know is one of two ISC drivers. (from the posting you quoted) You'll need that new ISC.

The MPI relay is actually two relays in one box. The MPI side doesn't connected to any of the drivers but the FP relay coil is connected to IC109 and if that winding shorts or somebody taps into the wrong wire it could blow IC109. Remember what I said about danging wires, people like to pull the AC and leave those wires flopping around too and that wouldn't be good for IC109 either.

But since you know that only IC107 is blown I assume the question is only educational.

 

[ShadeTreeDSM]

IC107 as you know is one of two ISC drivers. (from the posting you quoted) You'll need that new ISC.

The MPI relay is actually two relays in one box. The MPI side doesn't connected to any of the drivers but the FP relay coil is connected to IC109 and if that winding shorts or somebody taps into the wrong wire it could blow IC109. Remember what I said about danging wires, people like to pull the AC and leave those wires flopping around too and that wouldn't be good for IC109 either.

But since you know that only IC107 is blown I assume the question is only educational.

so the Fuel pump relay of the MPI unit could possibly have a shorted winding, hmmm how would i go about testing that with a multimeter, i would assume i would be testing for OHM's. id rather know if this is the problem than going out & buying an MPI unit, theyre pretty expensive. i also did get rid of my a/c and do have those connectors still on, ill have to cut the ends off and tape them off just to be safe.

also is there a way i could make an INLINE fuse for the fuel pump ? if so id be all about that, more protection for that ECU

 

[steve]

The fuel pump isn't directly connected to the ECU. The pump side of the MPI relay is. Measure the resistance of the coil of a good one and you can figure out the current draw to select a fuse by. You'll need a fast acting fuse and it's very possible it won't blow before the driver if there is a problem.

Since the MPI relay's coils going bad is a really low odds failure you have to weigh the value in fusing the control circuit. The drive circuit is fused by the ignition fuse but if you wind up doing the FP rewires it will get it's own fuse.

 

[ShadeTreeDSM]

The fuel pump isn't directly connected to the ECU. The pump side of the MPI relay is. Measure the resistance of the coil of a good one and you can figure out the current draw to select a fuse by. You'll need a fast acting fuse and it's very possible it won't blow before the driver if there is a problem.

Since the MPI relay's coils going bad is a really low odds failure you have to weigh the value in fusing the control circuit. The drive circuit is fused by the ignition fuse but if you wind up doing the FP rewires it will get it's own fuse.

as of right now im not blowing the igniton fuse, if i hook up the ECU & start the car up itll run fine. but like 20-30 mins later if i stall my car wont start for about 10-15 mins. and when thats happening my fuel pump still turns on, i can hear it.

so i wonder if my MPI unit is really the cause of all my problems.

my engine bay was painted before i bought the car, and i noticed all the grounds were not on a clean ground, they were just over the thick black paint. WTF

 

[ShadeTreeDSM]

so i rewired my cooling fans to there own relay & fused them both.

cleaned all ground connections, added some extra grounds.

I cut off the connector ends for the original cooling fans, and taped them off, one connector ends was pretty slimy & wet.


now im stuck with the MPI relay, was wondering though if the dohc non-turbo MPI was the same as the turbo ??

i wanna put the ecu in and attempt to start it but scared too, id hate to burn up that driver, but i dont want to buy another MPI relay if that isnt the problem, theyre pretty expensive & MITSUBISHI doesnt stock them

 

[architechnik]

I would highly recommend scuffing off the paint on all of those grounding points. If you do not want to remove all the paint, you could run a parallel ground wire that jumps from point to point along the body. Then, remove the paint at one point that the others are linked through.

For a clean look, you could pick up some bolt-on screw mounts for grounding points (for hardwiring ground wires in a house) at a local hardware store. These can be bolted onto the metal after removing the paint and then painted over again.

Make sure that the screws used are also free of dirt, grime, and paint, as much of the current actually travels through the screw.

Unfortunately there is no real test for any of this except for taking it out for a run. If you want to be certain of not having grounding problems, running a line from the battery to the engine bay really is your best bet and will keep the current traveling through your car away from your ecu.

 

[ShadeTreeDSM]

I would highly recommend scuffing off the paint on all of those grounding points. If you do not want to remove all the paint, you could run a parallel ground wire that jumps from point to point along the body. Then, remove the paint at one point that the others are linked through.

For a clean look, you could pick up some bolt-on screw mounts for grounding points (for hardwiring ground wires in a house) at a local hardware store. These can be bolted onto the metal after removing the paint and then painted over again.

Make sure that the screws used are also free of dirt, grime, and paint, as much of the current actually travels through the screw.

Unfortunately there is no real test for any of this except for taking it out for a run. If you want to be certain of not having grounding problems, running a line from the battery to the engine bay really is your best bet and will keep the current traveling through your car away from your ecu.

yea i cleaned all the grounds off the bolts/screws & the mounting points. As far a battery being grounded, i have an optima battery that is side & top post, so what i did was ground one of the posts to the rear frame and the other post was grounded to body. also ran a 14 gauge wire from the battery ground to the ECU ground. im about to go work on my car right now & finish adding two more 0 gauge cable grounds from motor to frame. also have no ground from the exhaust piping to the frame for my O2 sensor. never to many grounds !

 

[architechnik]

It sounds like you've got that angle fairly well covered! Now, how about the line going from the alternator to the battery?

You said you installed it about 2 months ago - I would guess that's just about the amount of time needed to have a point wear through the shielding on that cable if there was a sharp point. If the problems have been occurring when the vehicle stalls, it could actually be stalling from power loss through the frame back to the battery.

As for installing a ground directly to your ECU, I'm not so sure that it will provide a significant improvement unless you are running it directly into the ground points inside the ecu. There is still the significant reduction (bottleneck) that would occur inside.

 

[ShadeTreeDSM]

It sounds like you've got that angle fairly well covered! Now, how about the line going from the alternator to the battery?

You said you installed it about 2 months ago - I would guess that's just about the amount of time needed to have a point wear through the shielding on that cable if there was a sharp point. If the problems have been occurring when the vehicle stalls, it could actually be stalling from power loss through the frame back to the battery.

As for installing a ground directly to your ECU, I'm not so sure that it will provide a significant improvement unless you are running it directly into the ground points inside the ecu. There is still the significant reduction (bottleneck) that would occur inside.

as for the alternator i didnt do anything with the wiring, my car still puts out plenty of voltage, my turbo timer shows about 12.8 volts all the time. none of the wiring for the alternator is messed up, what my car does is just crank over until the battery is killed, its getting spark & i hear the fuel pump running, but dont know if those injectors are firing, so before i put that ECU back in im going to check the tension of the pins for the ECU harness and im going to get an MPI relay.

 

[ShadeTreeDSM]

as of now my car starts and runs fine. what i so far was.

i added multiple grounds
throughly cleaned existing grounds
put in a new MPI relay


hopefully its fixed, but i dont know if it is for sure, if i take it for a good drive hopefully it doesnt stall on me again and not start for sometime.

 

[architechnik]

I wish you the best of luck!

 

[ShadeTreeDSM]

i got it running, i drove it and it seems to run fine, but i duno if im going crazy or if im smelling electrical smells, but i duno