420A High Idle, With almost no cool down

[L_23]

Hi, I have a 1996 Mitsubishi Eclipse RS with a turbo conversion, on a 420a motor.
I have the issue of little communication with the cluster. The RPM gauge will only start reading after starting to increase in RPMs but only go up to about ~500rpm then stop.

I also have no speed being displayed, that needle stays still through driving of the vehicle.

Another thing is that I have a very high idle it sounds, that also will not come down. it continues to stay high until putting into gear, then it acts normal, but when pushing clutch in it goes back up.

I can get pictures if needed for more help and videos

 

[waltah]

How did these problems begin? Did you purchase the car with them already there? Did they show up when you did the turbo conversion? Did the whole mess show up at once? Or ???

The instrument problems sound like a grounding problem.

The idle RPM problem may be separate or it may all be one problem. Certainly if the PCM doesn't know what RPM the engine is turning there are going to be issues.

 

[L_23]

Hi, so i bought the vehicle from a guy that was wanting to make it into a race car. But he had neglected it for about a year and i recently got it back up and running and it was a little rough in the beginning but it has calmed down a little. the rpm gauge has also started working again, but i do not believe it is a hundred percent accurate atm. But still no speed showing. So everything that is happening is new to me. The guy i bought it from said both gauges did work when he drove it before. Could it just be taking some time for the computer to relearn everything? and the speed will soon show?

 

[motomattx]

Hi, so i bought the vehicle from a guy that was wanting to make it into a race car. But he had neglected it for about a year and i recently got it back up and running and it was a little rough in the beginning but it has calmed down a little. the rpm gauge has also started working again, but i do not believe it is a hundred percent accurate atm. But still no speed showing. So everything that is happening is new to me. The guy i bought it from said both gauges did work when he drove it before. Could it just be taking some time for the computer to relearn everything? and the speed will soon show?

No its not going to relearn anything, that doesn't really happen in the automotive world, I am not sure where and when the "relearn" thing started to be an answer for problems that people cant fix but forget that term, the only thing that gets relearned is the idle speed, fuel trims and transmission shift points, even on newer cars, so what kind of ecu do you have? stock? Megasquirt? with the removal of the stock ecu you can loose the rpm and speed in the dash cluster unless you rework them, I recently turbo'd a 420a so I have dealt with these same issues, the car works fairly flawless now and pulls really well.

 

[L_23]

As of right now I am running stock ECU, with stock injectors. But upgraded coil pack and sparks. What is the pressure at which you maintain your fuel pressure regulator? I installed an aftermarket one but not sure on the correct psi atm.

 

[L_23]

As of right now I am running stock ECU, with stock injectors. But upgraded coil pack and sparks. What is the pressure at which you maintain your fuel pressure regulator? I installed an aftermarket one but not sure on the correct psi atm.

The guy i bought it from said it is at about 6lbs of boost rn but that is as high as it will go. I haven't tried to push it yet since it is only my second day of driving it

 

[motomattx]

As of right now I am running stock ECU, with stock injectors. But upgraded coil pack and sparks. What is the pressure at which you maintain your fuel pressure regulator? I installed an aftermarket one but not sure on the correct psi atm.

You need a rising rate 1:1 ratio fuel pressure regulator thats boost referenced, then set the base pressure with the vacuum line pulled off at 42psi.

 

[L_23]

ahhh i had the vacuum line on trying to set the pressure. So once I do that, how do i get it to run decently smooth with the new turbo on until i get my megasquirt and a tune. which I am going to get in the near future just not atm.

 

[L_23]

Also that GST build you have on your profile is sick!!

 

[motomattx]

Also that GST build you have on your profile is sick!!

Aww, thanks! honestly, without a way to tune the car for forced induction (turbo) I cant see how you could drive it like that and have it run decently, you would be better off bypassing the turbo for right now if you have to drive the car, a way to do that would be to keep the wastegate open the entire time you drive it so that it cant make boost.

 

[BLACK'98DSM]

Once you've checked all your grounds and wiring, check the speedometer gear in the top of the trans. You can remove it by only removing the intake pipe off the throttle body, one connecter and one 10mm bolt. The gear is plastic and I've seen them fall apart. If it still looks ok, shine a light in the hole in the trans and look at the gear on the diff. It's also plastic.

 

[L_23]

Aww, thanks! honestly, without a way to tune the car for forced induction (turbo) I cant see how you could drive it like that and have it run decently, you would be better off bypassing the turbo for right now if you have to drive the car, a way to do that would be to keep the wastegate open the entire time you drive it so that it cant make boost.

ahhh thats a good idea, this way it would be like a normal 420a motor with just like assisted or better breathing since the turbo will help get more air through the tubes.