Cold start issue ect?

[einstein]

I have a galant vr4 1991 and its extremely cold here in utah, the issue i am having is if i dont let it warm up for 10-15 minutes it is pretty low on power, what would cause this the engine coolant temp sensor or what?


I try to let it warm up as much as i can but sometimes i get in a hurry.


Also the exhaust manifold has a small leak till it warms could this coorelate to the issue?


Thanks


Matt

 

[coolclean577]

577 is do the same thing in a way.

 

[Jesh]

A little bit of info about your car would help us figure out what the problem is. How many miles on the engine? Does it have forged internals? My first suggestion based on the limited information would be to do a compression test when the car is cold, And then add a small amount of motor oil to each cylinder and check your compression again. If the numbers change drastically you probably have bad rings. But on the other hand, it could be a different problem all together.

 

[Hondasi88]

My car had the same issue until I replaced the wires that plug into the thermostat sensor. Now, the car cracks on one turn and heats right up.

 

[einstein]

Motor has 182k miles on it and runs about a maximum of 8-10 lbs of boost on it. Its all stock and has never been modified with regular oil changes.


The car runs perfect when its completely warmed up just runs a little rough if i dont let it warm up in the morning. I would think it has something to do with the ect sensor but i may be wrong. When i say rough i mean its just kinda low on power until it warms up.


Matt

 

[einstein]

It also has md 165531 ecm in it which according to the tage is for a auto transmission with a manual trans would that be the main cause of the issue?


Where is a good place to get a manual ecm?\



Thanks


Matt

 

[CSMShaun]

Do you have a Check Engine Light?

 

[einstein]

No check engine light. I do have a small header exhaust leak till it warms up.


Matt

 

[toybreaker]

Quoting einstein:
It also has md 165531 ecm in it which according to the tage is for a auto transmission with a manual trans would that be the main cause of the issue?



Matt,

There's a few factors related to running a dsm automatic ecu in your vr4 that may make things a little funky untill things are warmed up and in closed loop.



The dsm automatic cars ran a smaller fuel injector (I *believe* they were 390's vs. the 450's in the manual trannydsm/vr-4's) and they ran them at a higher fuel pressure (I *believe* the auto's run 41-46 psi vs. the manual dsm/vr-4's at 36-38 psi, (vacuum hose disconnected))

The two factors almost cancel each other out, but the size/pressure difference will alter the amount of fuel the ecu "thinks" it is delivering versus what is actually being delivered to the engine, especially when you apply a varying load on a cold morning drive.



In addition, the vr-4's had the lower honeycomb in the airflow meter removed from the factory, and the dsm did not.

That probably skews the fuel trims a meaurable amount.



The two factors working together will definately affect the actual vs. targeted warm up mixes the ecu is shooting for and make for a wonky idle/funky driveability when cold.

It will especially affect the base idle because the ecu is targeting 800rpm on the vr-4, versus the 750rpm of a dsm)


Prior to the engine warming up and the ecu allowing closed loop fuel control, it's just using simple temp/rpm/load look up maps (with no feedback control,) and the occasional lean stumble/rich bog may result when it's recieving erroneous info on airflow from the maf, and shooting more/less fuel at the injectors.

It will be able to trim most of those problems out when the engine is warmed and the system is in closed loop.



Quote:

Where is a good place to get a manual ecm?



All may not be lost!

Is this an e-prom ecu?

If so, the old chip can be removed, the board can be socketed, and then a new chip can be made to bring things up to the vr-4 spec programing, (or you can even add/modify a few features for a better match with your set-up.)

A pic of the ecu board you're working with will tell many tales. /ubbthreads/images/graemlins/smile.gif

 

[toybreaker]

Quoting Hondasi88:
My car had the same issue until I replaced the wires that plug into the thermostat sensor. Now, the car cracks on one turn and heats right up.



^^^excellent post! /ubbthreads/images/graemlins/cool.gif

Logging the ecu data stream will tell many tales and shorten the troubleshooting process considerably.

 

[einstein]

So where could I get a socketed ecu at? Maybe I can just keep this one as a spare ecu. where are u guys getting your ecu at? Thanks for all ur help. Matt

 

[mitsuturbo]

Is your GVR4 an automatic? I think it says above you have auto ecu with man trans?

What does the "ect" in the topic mean? Typically it stands for Electronically Controlled Transmission.

If it's auto with ECT, it could be a built-in thing. Many transmissions have such things built into the system for cold weather operation. I don't think it was built directly into the ECU though. That would have been built into the TCU.

 

ECT is more commonly used to shorten Engine Coolant Temperature sensor. Based on the OP's comments, I believe that he is referring to this and not the transmission, which was stated to be a manual.

 

[einstein]

I am actually looking for a computer or ecu or ecm whatever you call the computer for a 91 vr4 with a manual transmission where is the best place to get one at? Also can I send in my current computer to get it configured for the vr4? Thankd matt

 

[mitsuturbo]

Gibson Engineering
Salt Lake City, Utah

That guy can help you fix your ECU if it's messed up. He does LOTS of ecu work for mitsu owners, or has in the past.
He charged me $65 to replace caps and socket my ecu that was non functional. He fixed up some traces too.
I hear he charges a bit more now. It's been YEARS since i saw the guy, but he was one hell of a cool dude.

You don't live far from him. At least if you don't have the right ECU for your car, you can get one and take it to him to have it refreshed for relatively cheap.

Gibson Engineering
3575 S West Temple # 6
Salt Lake City, UT 84115-4485
(801) 261-8181

Check Pick n Pull in SLC every thursday evening or friday (during the early part of the day) if you can. They put out new cars in the mitsu hyundai section on those days, generally. Or at least they did 4 years ago when i was there. I doubt it's changed, as it was like that for at least the 6 years i was there. Ask around there.. they'll tell you when new cars go out to sections, usually. I found many an ECU out there... for $35 a pop.