Starting Issues

[Paleface]

Its a 90 4g63t block and head. Im not running a turbo right now. I have a 1990 turbo harness I have N/A injectors, and a 4g63 N/A ECU "Known good".
This motor is in a 1990 Mitsubishi Mirage. I am a member and have posted this topic on 4g61t.org

Any help would be appreciate guys




Im having starting issues. Its turning over, I have fire, I know the ECU is good. Ive tried two good ECU'S, It is in Time. Double check it. Its got GREAT compression. Im getting fuel. A good friend came by to help and he double check everything and he knows its in time. He notice #1 and #2 spark plugs wasn't firing and strong as #3 and #4. Could it be a bad coil pack?


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[cliffkemp]

Gotta love electrical problems....Are you using a 90 turbo ECU? The 90 is different. Check your coolant temp sensor as well and the CAS. It could be a bad CAS or temp sensor.

Stock injectors means 450s right? If you run that engine, it will have virtually no topend at all with just 7.8 compression. You really need to hook up a turbo to it and run it as it is designed or just put an NA engine in it if you do not plan on running a turbo.

Maybe someone with more ecu experience can chime in but, running a "turbo" engine with an NA setup will not work as far as I know. What I am trying to say is that you have a turbo harnessed car using an NA computer....I do not think it will work that way. I do not think you can mix and match like that.

 

[Paleface]

Gotta love electrical problems....Are you using a 90 turbo ECU? The 90 is different. Check your coolant temp sensor as well and the CAS. It could be a bad CAS or temp sensor.

Stock injectors means 450s right? If you run that engine, it will have virtually no topend at all with just 7.8 compression. You really need to hook up a turbo to it and run it as it is designed or just put an NA engine in it if you do not plan on running a turbo.

Im running a 90 N/A ECU. I didnt have the coolant temp sensor hooked up last night, would that cause it not to start?

Yes, it has 450s in it. I plan on putting a turbo on it in July, seeing my funds are low right now.

Thanks for the quick response.

 

[TurboLaserRS]

I'm not an ECU expert by any means but let me try. You have compression, you have spark. Weaker spark on 2 cyl aside, when you pull your plugs are they wet with gas? You might want to make sure everything is plugged in, and also make sure your MAF/MAS isn't dead. Also check your CAS.
If you can and you have a shop manual, I would try testing the fuel pump to make sure it's kicking on when its supposed to.

 

[Paleface]

I'm not an ECU expert by any means but let me try. You have compression, you have spark. Weaker spark on 2 cyl aside, when you pull your plugs are they wet with gas?

Plug are new and look normal after trying to start it. To answer your question, no there not wet with gas. I have good compression all across also.

 

[GRAVEDIGGER]

Why don't you have the coolant temp sensor hooked up? You need to have it hooked up, so the ecu can tell how much fuel it needs to inject. I believe with it unhooked it will default to it's coldest reading which will inject way too much fuel.

 

[TurboLaserRS]

I have heard of cars not starting with the temp sensor being bad. You definitely need that plugged in. Do that before anything else and see what happens.

 

[cliffkemp]

Im running a 90 N/A ECU. I didnt have the coolant temp sensor hooked up last night, would that cause it not to start?

Yes, it has 450s in it. I plan on putting a turbo on it in July, seeing my funds are low right now.

Thanks for the quick response.

Yes the coolant temp sensor is a must. Again, I am not sure it will start since you are running a turbo harness and a stock NA ecu. There is a big difference in compression and therefore, a difference in how the engines run based off of fuel maps in the computer vs. what you are actually running. The CTS has to be working or will cause a no start. I believe you are going to have to find a turbo ecu....it will have to be a 90 but, you can use a 91-94 but, you will have to swap 2 pins, if I read about it correctly.

An NA engine has over a 9 compression vs. 7.8 on a stock 1g turbo motor. The fuel maps from an NA computer are going to be much different in both fuel and timing especially above 2k rpms. Even if you get it started, it is going to run horribly.

 

[Paleface]

Thanks for the quick responses. When i get out of school i will go over everything. Ill updated this later today. Once again, thanks for the tips guys.

I have heard of cars not starting with the temp sensor being bad. You definitely need that plugged in. Do that before anything else and see what happens.

It started!! But, there is still a problem. When i try to give it a little gas, it dies on me.

Any ideas for this problem?

Sorry for the newbie questions. I'm new to DSM's

 

[TurboLaserRS]

Grats! Its feels great when you finally get it running doesn't it? There is a lot of reasons it could be dying. Your first order of business should probably be going over ALL the clamps to make sure you don't have a massive vacuum leak. Another thing that comes to mind is that your CAS might be turned all the way down or even 180* out.
Get it running and pop the hood (if it will idle) then loosen the CAS up slightly. Try twisting it a bit and seeing which direction makes the car run smoother.
That's all I really know, I'm not sure if the turbo harness may be causing your issues.

 

[chadillac2820]

The n/a ecu will run different idc than a turbo ecu thinking it is running the na injectors. The stock turbo injectors may be too large for the na computer to compensate for the turbo not being there if that makes any sense. Basically it may be running rich.

 

[Paleface]

The n/a ecu will run different idc than a turbo ecu thinking it is running the na injectors. The stock turbo injectors may be too large for the na computer to compensate for the turbo not being there if that makes any sense. Basically it may be running rich.

I have N/A injectors in the car. Im going to try the CAS.

 

[Paleface]

I tried adjusting the CAS, still having the same problems. I check all vacuum lines, there all tight, or caped off. Im stuck.