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2G Help Revive My Talon - Doctor, Doctor, Give Me the News

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shinzon

15+ Year Contributor
350
72
Sep 11, 2006
St. Petersburg, Florida
Some background: During the summer of 2015, after nearly a decade of daily driving, my '96 TSIAWD (stock with the exception of a 14b swap) developed a nasty exhaust leak so I parked it. It ran fine otherwise. Sometime in early 2016, I attempted to start the car, but realized the battery harness was severely corroded. After purchasing a new harness from Mitsu (one of the last in the country at the time), I took the car apart, life got in the way, and I never put it back together.

So about a month ago I started working on the car again. I drained the fuel, replaced the fuel filter and all other liquids and filters, new bpr6es plugs (.28) and NGK wires, finished the harness swap and she fired up.

Symptoms: The car now starts, idles, and moves under it's own power, but it gets real unhappy when you start trying to make boost: bucks, and it backfires when you lift. If you stay below 5psi or so, the car is drive-able, but I've noticed that as soon as the engine warms up, and the ECU enters closed loop, it starts to stutter, run/idle very rough, and struggle not to stall.

The car still has the exhaust leak that made me park it. Might be a bad turbo to manifold gasket, cracked turbine housing on the 14b, or cracked manifold, or bad manifold gasket. Seems to be coming from that area.

It's throwing CELs for Fuel Pressure Solenoid, Wastegate Solenoid, and Crank Position sensor

What I've checked: I suspected Coolant Temp Sensor so I hooked up EVOScan and logged it, but it seems to be reporting temperature correctly. MAF sensor, intake air temp sensor, and barometric sensor seem to be giving sane vales. CPS reads zero while the car is running (this is what it's supposed to do right?), but I see it change value when starting. I only have a many-year-old NGK narrowband O2 sensor, so I can't ascertain much about a/f. I did notice a couple counts of knock after crossing the boost threshold at half throttle.

I've also done a compression test. Warm with WOT, results were: 4)192, 3)195, 2)195, 1)192. All four cylinders were high (maybe carbon deposits in the cylinders of a factory built 150k mile engine?), but they were almost bang-on in relation to each other.

Where should I be focusing my attention?
 
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A Tale of Two ECUs is about to become a tale of three. It's nowhere near as bad as my original, but the capacitors on this ECU are bulging too:

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I think I may just contact ECMTuning and have them repair and socket this ECU instead of chasing down another.



Wasn't aware there were any important grounds down there. I'll check it out and clean them off.

:p

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But I’d send it off to ecmtuning and let them figure out the ecu problems. They might be able to give you a better idea of why it’s doing it. I know over never seen anyone go through ecu’s like this. Lol
Correct me if I'm wrong, but what generally kills capacitors is heat (which we have in abundance down here) and age, so I may just be unlucky with these last two and there's nothing wrong with the car. Still, I've cleaned all the grounds in the engine bay, and next I'm going to mess with the grounds in the cabin.

Sent the ECU off to ECMTuning today, so hopefully I'll know more soon.
:p

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OMG yeah I'd say that'd cause a problem haha

Hopefully mine aren't anywhere near that bad...
 
Mine is a Texas car. I assume the rust there is from the a.c. condenser seeping down

The ecu ground is in between the drivers and passengers side. You know the bolt hole that keeps the middle center console panel held to the center, that hole is the bar that runs drivers side to passengers side. The ground is nearly in the middle. It is easier to access from the passengers side

On 99+ cars the ecu ground cable was mounted on the ecu mounting bracket that has a galvanized finish on it to prevent this issue.

It should be noted that My black box ecu never failed. I believe mitsubishi found the steel case ecu's were prone to failure and changed the design of the ecu to be in a plastic case, and then followed up engineering the 99 to completely get rid of the problem moving the ground

Being extremely analytical about it, this problem probably came up alot more often in the Japanese market evos being near the ocean. By 99 dodge had abandoned the platform so it was most likely an engineering team implementing the ecu and wiring changes remotely to production models. (Based on the black box ecu mimicking the evo 8 ecu very closely) that and the fact by 99 dodge probably was overlooking production costs and looking at the next platform and mitsubishi probably had a little more pride about it
 
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Mine is a Texas car. I assume the rust there is from the a.c. condenser seeping down

The ecu ground is in between the drivers and passengers side. You know the bolt hole that keeps the middle center console panel held to the center, that hole is the bar that runs drivers side to passengers side. The ground is nearly in the middle. It is easier to access from the passengers side

On 99+ cars the ecu ground cable was mounted on the ecu mounting bracket that has a galvanized finish on it to prevent this issue.

It should be noted that My black box ecu never failed. I believe mitsubishi found the steel case ecu's were prone to failure and changed the design of the ecu to be in a plastic case, and then followed up engineering the 99 to completely get rid of the problem moving the ground

Being extremely analytical about it, this problem probably came up alot more often in the Japanese market evos being near the ocean. By 99 dodge had abandoned the platform so it was most likely an engineering team implementing the ecu and wiring changes remotely to production models. (Based on the black box ecu mimicking the evo 8 ecu very closely) that and the fact by 99 dodge probably was overlooking production costs and looking at the next platform and mitsubishi probably had a little more pride about it

Very interesting, thank you for the information. Makes me wonder if it'd be worth moving the ground and putting the ECU into a blackcase when I get it back. Not sure how the plastic cases are constructed, but I worry the ECU board grounds to the metal case through the screw holes, and if they tweaked that design in any way when they moved to plastic cases...
 
Had a chance to clean the ECU grounds under the dash. Holy hell was that a bi*** of a place to work. chrysler kid, you said you suspected your a/c was leaking down onto the ground. Fortunately or unfortunately, however one might see it, the A/C hasn't worked in this car for a decade, and the grounds themselves look to be in decent shape:
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but the "E" bolt and the bracket the grounds bolt to were pretty rusty. Cleaned it all up and it should be ready for when I get the ECU back.

Changing topics, one of the minor mysteries of this car for me was that the VIN/build date sticker on the door sill is missing:
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I was young and didn't notice before I bought it, and when I did was I worried someone had done a VIN swap on this car. Over the years of working on it, I've confirmed that every security sticker I've come across on the car including the hood, liftgate, fenders all match the VIN on the dash, so I stopped worrying about it. I did still wonder from time to time why someone would remove that sticker...

Well, today I found this sitting behind the ECU ground:
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I'm dumbfounded. How the hell did this get down there? I can think of two scenarios: it somehow made it to the floorboards and, given its proximity to the accelerator, someone kicked it up there with their shoe. Option 2: someone slipped it in between the gap in the console and the radio and it fell down to where it's been hiding for more than 11 years.

While I had it apart, I also removed my broken Pioneer DEH-9400MP I've had on the car since 2006, reinstalled my original MR225576 CD/Cassette back into the car, and to my surprise it still works!

ECU should be arriving at ECMTuning tomorrow so hopefully I'll have some idea what's wrong with the ECU soon.
 
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Got news back from ECMTuning and apparently, I must have misdiagnosed the computer. They said there was some slight leakage on the capacitors, but nothing to indicate a MAF circuit malfunction. They tested airflow, ITS, and BPS and they came back fine.

So back to the drawing board...

Since, after a week of commuting with the car, this EPROM ECU fixed all of the previous symptoms I had--the phantom p0335, the IAC problem, the problems with the fan, etc-- it's likely this new MAF problem unrelated to the previous problem.

Current symptoms are the engine stalls, backfires, runs rough/surges when at part throttle, and acts like hitting fuel cut when trying to cross the boost threshold. When experiencing these symptoms, the stock boost gauge on the dash is dead implying the ECU is not receiving airflow readings, or not outputting the estimation of those readings to the gauge (rest of the cluster functions correctly). Car runs fine when cold, but symptoms worsen the longer the engine runs. Computer reports P0100 Volume Airflow Circuit Malfunction.

So to recap, when I tested the MAF per the service manual, I had:
  • Battery voltage on pin 4 (red wire) of the MAF harness. Looking at the wiring diagram of the MFI system on page 8-102 of Vol. II, the MFI relay controls this circuit. This implies that the MFI relay, and the wiring between it and the MAF are okay.
  • I measured 4.97v on pin 3 of the MAF harness (blue with yellow). It would appear that pin 3 is the ECU's 5v reference circuit for the volume airflow meter. From this (and from the fact the car starts) we can infer that the ECU was putting out a good reference signal to the sensors and none of the sensors on the circuit are shorted to ground.
  • Had continuity and minimal voltage on pin 5 (black) and ground, so the MAF has a good ground.
  • Had good voltage drop on pin 3 with the engine idling. This implies that the MAF is varying the voltage waveform when it detects airflow.
  • Measured .96v with the engine idling at pin 7 (red with white), and 7.47 at 3500rpm. This wire is the MAF reset switch. From what I can gather, this functions similarly to a closed throttle position switch, and should read less than 1v when it detects the airflow of an idling engine with the throttle plate closed, and between 6-9v at 1/3 throttle.
  • Measured 7.47v with the key on at ECU connector B-53 pin 19 (red with white). This is the other side of pin 7, the MAF reset switch, on the MAF connector.
  • Installed known good MAF with no change on symptoms.

If the MAF is good, and the ECU is good, I'm left with a wiring problem. Maybe an intermittent connection problem and I happened to do my test during a period where it still making contact... The engine was running fine when I performed the test. When I get the ECU back I'm going to, if the problem is still present, perform this test again, and see if I made a mistake somewhere.

Any advice you guys could offer me would be appreciated.
 
I mean the battery harness isnt much, its just 3 wires, 2 from the alternator and 1 from the fuse box of I remember correctly

Did you perform a boost leak test, did you check and listen for vacuum leaks?

I did a boost leak test prior to the week I commuted with it, but I've made so many changes to the car since it last ran it wouldn't be a meaningful test without the ECU to confirm the fault is still present. I intend to do another boost leak test once the dealer gets a new IAC o-ring to me later this week.

While the car has been laid up waiting for the ECU to get back, I got a big shipment of parts in. Got my hands on the very last high pressure fuel hose (hose that runs from the filter to the rail) left in the country, the second to last 2g turbo overflow bottle, and an assortment of gaskets and hoses. I've been doing maintenance: replaced the lower injector seals, throttle body to manifold gasket, throttle body elbow gasket, FIAV gasket, and map sensor o-ring. Replaced all the vacuum hoses on the car, and all the coolant hoses with the exception of the radiator and heater hoses which were done in '15 and seem to be in good shape still. Got the rotors turned, replaced the front pads, and I intend to replace the fluid this week--might as well do the PS fluid as well. Changed out the oil cooler o-ring, and with that and the work I did while I had the timing cover off, I'm one oil leak at the turbo drain away from having this car not dripping oil on my driveway for the first time in my ownership. Got a new set of Federal 595EVOs I need to have mounted this week too.

Looking at the wiring diagrams, there can only be three causes for my P0100 problem: a fault with the MAF, a fault with the ECU, or a fault with the signal, 5v reference, or ground wire. In a worst case scenario, I'll run new wires down to the MAF plug and this'll be problem solved.

One simple thing I didn't test: I never reseated the connectors on the ECU. It could simply be that when I swapped the new ECU into the car, the MAF pin didn't make good contact for whatever reason.

I'll have the ECU back by the end of the week, so I should know more soon.
 
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Yeah but you mentioned an exhaust leak at, or around the turbo in your first post. Has that been adressed?

I was mistaken about the location of the exhaust leak. It sounded like it was coming from the manifold area, but after taking the heat shields off I can't find anything leaking there. I have, however, found a pretty sizeable break after the flex section about parallel with the firewall. I haven't fixed the exhaust leak yet, no, but with it so far back from the front o2, I doubt it would be affecting readings.
 
Is your throttle position sensor calibrated correctly? Can you view live data and see it go from zero to open?

Sounds like you might have a short or something. If you have the intercooler piping off inspect the wires and the wiring around the fuse box. Might have had a mouse or something nibble a wire that rubs itself loose over time. Also check connectivity on those maf wires. Seems like it could be related to the main power wire you replaced
 
Is your throttle position sensor calibrated correctly? Can you view live data and see it go from zero to open?
I calibrated it years ago, but I didn't confirm calibration after I revived the car. I just had the throttle body off the car, cleaned it, replaced the gaskets, the BISS screw, and the FIAV o-ring; while I did all that I re-calibrated the TPS on the bench. It had smooth operation all the way from throttle closed to WOT--no dead spots. When I get the ECU back (hopefully tomorrow) I'll check the live data.

Sounds like you might have a short or something. If you have the intercooler piping off inspect the wires and the wiring around the fuse box. Might have had a mouse or something nibble a wire that rubs itself loose over time. Also check connectivity on those maf wires. Seems like it could be related to the main power wire you replaced

Intermittent short or connection problem is what I'm thinking too. There was evidence of squirrels or mice in the engine bay as there where a few acorns on top of the spark plug cover. Fortunately I've seen zero evidence they used the car as anything more than a nut stash--no nests, and I haven't found any chewed wires yet, but you never know. I traced the MAF harness back from the connector to where it enters the main run and I didn't see any obvious problems. I need to pick up some longer leads (or some wire) and do continuity tests between the MAF and ECU connectors while shaking the harness.

I've been thinking about the battery harness too, but I can't figure out how it would be related. The harness just has the battery ground, positive, and the starter positive, and starter signal wire. I did notice I put the main ground on the wrong starter bolt. I put it on the lower bolt that's towards the firewall because that's how I had it on the '97, but I checked the service manual and it should be on the upper bolt near the head. I'm going to change that before I try to run the car again, but it shouldn't be the problem--I cleaned where I put the ground before I bolted it there too.

In other news, the dealer got me my IAC o-ring and I did another boost leak test on the car. I found a few minor leaks (slow seepage) and, despite a new gasket, I still have one moderate leak at the throttle body elbow. Might have over-torqued it at some point, but the flange seems a bit out of true. I'm going to take it to my buddy's machine shop and have him sort it out.

In any case, this setup isn't long for this world anyway. If I can ever get the damn thing running right, I've got an EVO3 intake manifold and an EVOIV throttle body waiting in the wings.

Thanks again for all your help through this, by the way.
 
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On a tb gasket I would just use copper gasket spray or rtv coating.

I rebuilt my tb last week with new seals, it was not as difficult as I imagined. The blade shaft seals really get worn out on the spring side of the tb shaft. They look like wheel bearing seals, metal outer ring with a rubber section inside.

My car had the ground on the wrong bolt on the transmission as well, I actually left it there and added the extra ground cable to the original spot. Ive also got another ground off of the power steering bracket on the front of the motor to the radiator support, and an extra ground from the cam sensor to the bracket on the cruise control. (You saw my ecu main engine ground LOL, it took a while to find my error)

There is 1 other ground in the engine bay, it is behind the passengers headlight, right next to the hole for the upper intercooler. From the engine bay you can only see the back side of the bolt, but that ground typically would just affect the headlights

My other suggestion if the car has the bucking problem is to disconnect the front oxygen sensor and see if that clears it up. But it's just a hunch
 
I did the shaft seals on mine about ten years ago and, shockingly, they still don't leak. Hardest part was getting the plate screws off because I didn't own impact driver back then. I was expecting it to be much more of a chore, especially considering how little experience I had working on cars back then.

Bucking problem hasn't returned, but I've only put about 15 miles worth of short trips on it since I got the ECU back. It's been getting absolutely atrocious gas mileage, so I suspect the car is running pig rich for one reason or another. I'm going to commute with it again this week to get a decent drive-cycle on the car and then I'll check out what the fuel trims are doing. I've got a check engine light. P0400 Exhaust Gas Re-circulation flow Malfunction. I was just back there replacing vacuum hoses, so maybe I put the hoses back wrong.

I also don't think my turbo is in the greatest shape. I got this 14b off a 1991 GST with god-knows how many miles on it, and I've put about 50k on it myself since I installed it. From what it sounds like, when I do a boost leak test on a cold engine from the turbo inlet I get a significant amount of pressure leaking passed the turbo seals and into the exhaust--like so much so that it's hard to build 15psi. When I do the test from the LICP, the system hold much more pressure (obviously I've checked the turbo outlet for leaks). It does better with the engine warm, doesn't seem to leak oil or coolant yet, and shaft play is minimal, but after nearly 3 decades of service I'm sure it needs a rebuild.

No big deal. I just need it to hold together a bit longer; project for the summer of '18 is to get a bigger turbo on this car.
 
My 14b does the same thing, I can hear the air bubbling into the oil feed line after I turn off the air pump. It wouldn't hold any pressure at all, but it doesn't smoke and isnt spraying oil. I had to bypass it to do my boost leak test, and then I couldn't get pressure to stay at the manifold either so I use a coke can cut out to block behind the tb to test the system. It was fine, and I verified the boost leak test is stupid and highly substantial to the air source power.

My bucking and power loss was from the fuel pump fitting into the assembly. On the fwd its an overly delicate balance of 2 o-rings and 2 plastic fittings. The pump would get hot and leak out tons of pressure. Fuel pressure gauge showed normal but the volume was not behind it causing fuel cut when hot. A factoy style pump from rock auto for $13 solved my problem
 
Might be a 14b thing then. I generally do boost leak tests from the LICP, but I had just spent time getting the turbo outlet to stop leaking and didn't want to break that seal again.

In other news, after about 80 miles, the car has had no further issues other than a couple of small fuel leaks I fixed, and the EGR code I haven't gotten around to investigating yet. I intended to do a voltage drop test on the IAC reference and signal wires, but without a problem to troubleshoot, I'm left with a couple of explanations: because of the leaking caps, the ECU was bad in such a way that it produced problems on the car, but wasn't detectable on the tests ECMTuning ran, or the issue was simply that it didn't make good connection on those pins when I swapped in the EPROM ecu originally. I guess it could still be an intermittent wiring problem, but I shook the hell out of the harness wherever I could and I can't get the problem to show itself again. Guess the DSM gods decided I've tithed enough, and bleed enough, and blessed me for my devotion.

Thanks again for your help. I'm going to call this car revived.

I've been stock piling parts--this summer is going to be a blast. :)
 
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