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1991 GVR4 Questions from a Newbie


Galant VR-4 org Post #: 1244161 posted 09/24/18 06:43 PM     Remind Me!  Send Private Message   Edit Post      

I am contemplating the purchase of a non-running or poorly running GVR4 from a friend of a friend. I will preface my questions with this: I have worked as a mechanic, welder and fabricator for twenty years. I am very familiar with how cars work, but I lack specifics on the bugs that arise in Mitsubishis, particularly the VR4.

The car is a 1991 GVR4. I have not yet seen it in person, but I want to learn about what to look for before I go to look.

The story behind its not running is this: the owner bought the car at auction and drove it home. A few days later, it would not start. He replaced the ECU, but it only ran poorly afterward. He believes that the ECU was for an automatic car.

From what I have seen, ECU failure is surprisingly common for these cars. Now the questions:

Is ECU failure a plausible explanation for the car not running?

Is an auto ECU a plausible explanation for the car running poorly?

Would an auto ECU do any harm to the harness if installed in a MT car?

Can I reasonably expect to find a still-good correct ECU?

Which other models have the correct ECU? FWD manual trans turbo cars?

What else should I watch out for? I assume that power steering lines for the rear steering are leaking, and I know they are irreplaceable.

What are the expensive fixes?

Iím about to go scouring these forums to learn more about the cars. Thanks in advance.

Posts: 1 | From: Columbus, Ohio | Member Since: 09/24/18 | IP: (2600:1700:d180:1) | Report this post to a Moderator

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Galant VR-4 org Post #: 1244162 posted 09/24/18 07:57 PM     Remind Me!  Send Private Message   Edit Post      
What's the situation on if/any rust on this car? I think that may be the biggest factor here. Too many variables to say what is exactly wrong with this thing. You would just need to start somewhere like if it's getting fuel, spark, ign etc.. also I would assume that you can idle ok with the auto trans ecu but prob not be able to drive on it (dont quote me on that). You can open the ecu and see what the condition is, if you think it has blown caps. The price will also need to be relevant with the condition of this car considering how many parts/labor it may need. With that said it's a unique car, extremely fun to drive, and somewhat rare. Post pics if you buy it.

91 GVR4 1450/2000 - 2.3 Stroker - HKS cams
FP3052 - Spal puller - EVO MAF 3"intake - EVO8 560 injectors - EVO8 ECU tephramod v7 - Walbro 255 - FRH intake mani - EVO3 exhaust mani - 44mm tial wg
EVO3 5spd

Edited by Eztoril (09/24/18 08:00 PM)

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FlyingEagle Galant VR4.org Moderator
Eager Beaver

Galant VR-4 org Post #: 1244165 posted 09/24/18 11:30 PM     Remind Me!  Send Private Message   Edit Post      
ECU's can be had all day long for $50-$200 USD.

Things all Mitsu's/GVR4's suffer from:

Thermostat wiring frayed and or broken causing the ECU to think it is -40C and will cause a brutal no start - this is on the top of the thermostat housing and nearly all harness's suffer from this if never having been repaired - first place to look
Timing belt age related issues - preventable loss
Rust in the sill behind the doglegs if left full of leaves/debris
Rust in the sub frame at the front or rear
Rear steering lines leaking if not deleted
Transfer case leaks - Mitsu recall, parts available from JNZ
Lobro joint wearing out over time causing misalignment of the driveshaft
Turbo manifold will crack in the collectors if old or not an updated part like the 2G or EVO3 part
Alignment has to be performed with the rear tie rods in a particular fashion, and then start the whole process or it will be off - assuming rear steering still intact/not deleted
ABS system issues - can be deleted, using DSM parts
ETACS system woes if people have gotten into the wiring or door locks start acting up/strangely - ETACS controls many things electrical in the car
Fuel tank line fittings and fuel pump sending units are not great to deal with when severely corroded or just have not been dealt with yet
Brake hoses will be rotten if original - determine if newer lines are installed by their built date code on the rubber line itself
Windshield trim seems to feel the need to fly off while driving down the road - clips get old with age
Sunroof issues if leaking seals are present, or the roof is equipped with a sunroof at all
Rear seat backs will split under constant sun and if the leather is all dried out
Rubber suspension mounts and transmission mounts and engine mounts need to be attended to when they start acting spongy/cracked
Leaks from the crank seal/timing side area if shoddy work performed
Question what timing belt tensioner is installed and only use OEM Mitsu in that spot
Oil pan leaks or turbo return line to the oil pan - accordion used on the turbo return line and threads in pan connection can be over tightened/cross threaded easily
Clutch master cylinder and slave leaks from age or a stiff clutch pressure plate
Shifter bushings completely deteriorated in the interior floor console portion, and continued into the engine bay on the top of the trans case
Powered seat belts that stop working because the module suffered the same capacitor failure (reversible if caught in time - cheap repair) as the engine ECU
Cracked engine block mounting points due to loose bolts or missing bolts mating the trans bell housing to the engine block - some successfully repaired/ other not
Syncros in the transaxle wearing out or not shifting properly due to improper fluid being used
Driveline noise from certain styles of clutch and flywheel being used - also the reason for so many trans input shaft splines being worn past use and causing clutch engagement/disengagement issue - or a complete lack of clutch control
TOB bearing noisey or not riding the sleeve properly because the riding area is ovaled
Rear calipers seizing from sitting and brake fluid with lots of moisture still in the system
Those are the biggest issues we see with some repetition, but the car you are looking at may or may not exihibit any of this.
The more it is passed around, the more the chances of shoddy work having been done, forgotten to be completed or incorrectly completed start to skyrocket ... we see it all too often.
Bring a friend who is GVR4 knowledgeable.

Also, the ECU usually dies from capacitor failure (they all will if they aren't repaired in time) and it will be very evident if you ask the owner to pull it out before you get there, contingent on you showing up at all in fact. If it smells like bad fish, and you can see the capacitors have leaked ... that is one direction which may be reversible, but it can suffer from the idle speed circuit having shorted coils in the ISC on the TB, so it can take out parts on the board as a result - sometimes also survivable, but again replacements are available.
I believe you can use DSM ECU's in this scenario also.

You could find a car with any or all of this at some stage of repair/disrepair, so go in with your eyes open and your wallet shut ... take your time to a decision.

Hope that helps and if you decide to join the club, let us know what you are dealing with.

C53A 1 of the ~1500

Edited by FlyingEagle (09/24/18 11:38 PM)

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FlyingEagle Galant VR4.org Moderator
Eager Beaver

Galant VR-4 org Post #: 1244166 posted 09/24/18 11:48 PM     Remind Me!  Send Private Message   Edit Post      
To answer our question about the ECU's:

Auto ECU's might be expecting to see the P or N indication to allow a start function.
Plugging in any Mitsu ECU that has the plugs from this era will be okay, even if plugging in a 1990 versus 1991-1994 where pins 6+14 are swapped - this also causes a no start. It will not likely have caused any harm to the harness or other connected electronics - but we would like to know the ECU numbers in play here - both ECU's being used.
ECU's that are compatible are the 1991-1992 GVR4 ECU and the DSM 1991-1994 (not sure if any function is left out using these but the motor will run regardless).
You can use a turbo ECU with Eprom or no Eprom - and if the board is Eprom and has no chip - stock Eprom chips can be made quite easily by a few members here.

If the ISC isn't tested for low resistance or shorts in the coils, then plugging in could cause damage to any ECU that is plugged in. Essentially drawing too much current through the board circuit, and the ISC will stay locked at whatever position it falls at - thus running poorly.

Also, the TB could have a poorly operating FIAV (Fast Idle Air Valve) that normally controls high idle when cold, as the gasket likes to leak and cause idle issues - mainly surging IIRC. Any leaks in the TB blade gaskets pre TB, can cause very wonky idle conditions as the ECU has a hard time compensating.
If the owner installed a BOV that vents to the atmosphere and is not recirculated, then that is a bleed of metered air - not good.

Check for leaks between the MAF and the TB, obvious stuff like a cracked snorkel tube unhooked vacuum lines, etc.

C53A 1 of the ~1500

Edited by FlyingEagle (09/24/18 11:54 PM)

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Forever Member

Galant VR-4 org Post #: 1244167 posted 09/25/18 09:28 AM     Remind Me!  Send Private Message   Edit Post      
Do you know what auto ECU? I believe the 1G TEL auto had 350cc injectors. Galant VR4 came with 450cc injectors.

I'd inspect to make sure the timing belt and timing marks are correct as well as the front balance shaft belt. I'd also do a compression test. If you can, do a boost leak test too.

I'd also avoid a rusty car too.

1992 Nile black w/sunroof
15xK miles. 2nd owner since 1998

Posts: 5945 | From: central Indiana | Member Since: 08/06/02 | IP: ( | Report this post to a Moderator

I ain't no puny human

Galant VR-4 org Post #: 1244169 posted 09/25/18 11:15 AM     Remind Me!  Send Private Message   Edit Post      
Auto Turbo 1g DSM's had 390 injectors at a higher fuel pressure, and a 13g turbo.

866/1000 (PTE 1200's, billet 20g+, DSMLink v3, eagle/ross, .020 over, 272's, GC/AGX Coilovers)

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mass moment of inertia

Galant VR-4 org Post #: 1244183 posted 09/26/18 12:08 PM     Remind Me!  Send Private Message   Edit Post      
Also, If the car is modified with a higher fuel delivery system and had a modified ECU, even plugging in the correct stock ECU could cause a poor running condition.

Posts: 893 | From: Fremont Ca | Member Since: 03/16/01 | IP: ( | Report this post to a Moderator

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Galant VR-4 org Post #: 1244184 posted 09/26/18 02:12 PM     Remind Me!  Send Private Message   Edit Post      
Quoting thomcasey:

Auto Turbo 1g DSM's had 390 injectors at a higher fuel pressure, and a 13g turbo.

That's right. I helped a friend do a turbo, injector, ECU upgrade maybe 18 years ago.

1992 Nile black w/sunroof
15xK miles. 2nd owner since 1998

Posts: 5945 | From: central Indiana | Member Since: 08/06/02 | IP: ( | Report this post to a Moderator

Junior Member

Galant VR-4 org Post #: 1246305 posted 06/08/19 08:53 AM     Remind Me!  Send Private Message   Edit Post   
This has been pretty helpful.

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