Turboed but running lean...

[UCF201101]

I have a 1997 Mitsubishi eclipse rs (420a). I rebuilt the motor last year with no forged steel parts; however, I did have the block punched out. Anyways, I just put a turbocharger on my car. I have everything hooked up except the programmer. I purchased a fuel cut defender and hooked it up to my map sensor. I have a fuel pressure regulator ( set at 50psi) and also a 255 walbro fuel pump. However, this is isn’t in my gas tank yet. I plan on installing this tomorrow. My concern is tearing my car up. I have a wideband gauge and sensor. Every time the car idles it runs 17.2. When I accelerate, the car bogs down terribly. It also runs hot and it runs lean (17.2-18.0). Another thing, I have to much crank pressure. I did a compression check on the car and it reads 185, 185, and 190,185. I am lost on this issue and need help. One more piece of information. I hooked up my pcv hose to my oil catch can and from the oil catch can to the intake. The other side I had pitched off. I decided to t this into the hose but it caused my oil cap to whistle loud. I ended up disconnecting the line and placed a breather on the side closest to the battery. It seems to run worst with this method. I need help and I want to get the car fixed before I get it tuned. Thank you for your time and consideration.

Daniel

 

[1stgenracer1993]

it is going to run lean until it is tuned. thats just how it is.

 

[Slightlystoopod]

You'll need to tune the car for the excessive air flow produced by the turbo and add more fuel to compensate. You may need bigger injectors also if the stock ones don't put as much fuel as you need out. I'm not a mechanical genius but my friend went through this same process when he decided to turbo his Civic and we had to upgrade some things to compensate for the bigger air flow.

 

[BoostedPhoenix]

What regulator are you running ? You dont mention anything about any fuel control. If you are just using a 1:1 regulator this will not work on a stock ECU on stock injectors. You need a method of adding fuel in boost, on a Stock motor a FMU is a common route, or if you want to go wild you will need a stand alone ECU. If its running lean at idle and you are using stock injectors then you do not have your fuel system setup correctly.

 

[darrell rainey]

try the tuning...your car is running lean..make sure u have some nice size injectors for your setup..at least 550cc .

 

[UCF201101]

Thanks guys for your response. I use to have a fuel pressure regulator but I took that off because a local guy I was refered to said to remove it. Well, 1800 dollars later with a fully built engine, I decided that I want to see 13psi and no higher. I have those 750cc injectors but they seemed to big. So, my question is, what would I need to control my fuel? I have the greddy ultimate blue, bigger fuel pump and injectors. I seen that there was a fuel management unit that gives you different types of fuel to boost ratio. So Stock is 1:1. The website said I would need a 12:1 if I had stock injectors. The higher injectors the lower the ratio. IS this true? Sorry for so many questions. I like to have the right answer before I blow an engine. Thanks

 

[jason91dsm]

you are defanitly going to need to tune that car.

Running 750's with no fuel compensation is just dumping fuel into the engine. To the point it wont even burn, and is causing the wideband to peg lean from 0 combustion of oxygen. The sensor reads oxygen, not fuel, so blowing unburnt fuel out the exhaust shows as lean, just like wot misfires.

put some 550-650cc injectors on and turn the AFPR down to about 38-42 psi. when your turbo spools it will bring the pressure up so if your at 50 psi when you spool at 16 pounds your fuel will spike to 70 psi and that is way to much.

also with your 2g maf take out the side and bottom honeycombs and have the scre =w set flush with that being done you might be able to get away with the 750cc injectors but you will need to turn the fuel down to around 39psi.

 

[dino4g63]

If you are running lean it is not from fuel being dumped in the exhaust. The sensor reads percentage of oxygen content. If oxygen is displaced by excess fuel it would read rich. More fuel in the exhaust equals less oxygen. Less fuel in the exhaust equals more oxygen.

 

[UCF201101]

Thanks again everyone. I called a tunning shop and.they said for me.to put those 750cc injectors on the fuel cut defender and that they will be able to tune it. Im running a cheap greddy blue emange. I know they are difficult but i dont have that much money left. The tune.job is going to cost 695. Think its to much but they are suppose to be good. They are titian motorsports in orlando. What do you guys think? Btw i have a built 420a. So i dont have a maf. I have a map. Thanks everyone

 

[95talongirl]

No one stated this yet; but in concern about our crank pressure; that's normal for the 420A engine. So no worries there.

But yea, you'll need to get this car tuned. I'd recommend something like Megasquirt if you want to tinker with this yourself and will give you more precise control over a Speed Density setup. Honestly, I do not know much about tuning SD in a piggy-back kind of way.

 

[UCF201101]

I have been back and forth to what setup I wish to have. Like I said, I have a afpr, fuel pump, greddy emange and injectors. Will this work for 15psi? I do trust the shop but I don't want to dolly the car down t here and pay 200 bucks in advance for them to tell me I need this or that. I rebuilt the motor because a local guy tuned my car and busted all the piston ring lands. He blamed me for not putting an engine together properly. I have been told that if the ring lands are messed up, that is a poor tune job. In addition to this, it had a boost cut of 5psi . One quick question, on my fuel rail, I have no return line on it. Weird I know but I was wondering how do you actually hook up the fuel pressure regulator? I think the gas line has some return line that cuts into it towards the middle of the car.

 

[95talongirl]

I have been back and forth to what setup I wish to have. Like I said, I have a afpr, fuel pump, greddy emange and injectors. Will this work for 15psi? I do trust the shop but I don't want to dolly the car down t here and pay 200 bucks in advance for them to tell me I need this or that. I rebuilt the motor because a local guy tuned my car and busted all the piston ring lands. He blamed me for not putting an engine together properly. I have been told that if the ring lands are messed up, that is a poor tune job. In addition to this, it had a boost cut of 5psi . One quick question, on my fuel rail, I have no return line on it. Weird I know but I was wondering how do you actually hook up the fuel pressure regulator? I think the gas line has some return line that cuts into it towards the middle of the car.

Depends on what fuel pump and what injectors. You could probably get away with a 190, but if you want to run the 255, it won't hurt, since you'll have a fuel pressure regulator. Injectors: at least 550cc's.

You are running lean, so that could've been the cause to the damage prior. I could see the fuel cut at 5psi also because you are running so lean. It's only trying to protect itself.

As far as the fuel rail issue, that I'm not sure on. Would have to see it.

 

[UCF201101]

The car was running.12-13 when it was tuned. It blew up on 5 psi. It was purposely put.no more than.5 psi. Im going.to take a.picture and show you guys what it did to my pistons

 

[WES_393]

The car was running.12-13 when it was tuned. It blew up on 5 psi. It was purposely put.no more than.5 psi. Im going.to take a.picture and show you guys what it did to my pistons

The engine was probably damaged from running lean. Detonation is the #1 killer of engines when going from NA to Turbo. 17-18 AFR's is incredibly lean. Even 12-13 is a little on the lean side. Since fuel helps cool the cylinder through evaporation and heat absorbance, that could explain your engine running hot.

How much boost are you wanting to run? What size turbo do you have? If you want to run 5-10psi on something that flows around 400CFM (14b), there is no need for anything above stock turbo DSM 450cc injectors. Anything above that would just make it that much harder to tune IMO. You also need to have a larger fuel pump installed, your new injectors will be pointless without more fuel being delivered to them.

 

[95talongirl]

Agreed.. 12-13 is pretty lean under load. Yes, 12 is "in theory" the ideal A/F ratio for max power; but it leaves you almost no wiggle room if something goes awry. I usually shoot for 11:1; just to keep it "safe."

 

[BoostedPhoenix]

If you have a regulator setup properly you will have a modified return line, there is no set way of doing this properly its all depending on your hardware.

I do not know alot about the greddy systems, but its not a common route amongst the 420a turbo community. There is no simple way of tuning bigger injectors without a replacement computer that has its own map sensor, i do not know about the unit you are reffering to.

The OEM pressure regulator for your car is located on the fuel filter in front of the rear right wheel underneath the car, you will have to disable this one way or another and route your return line from the new regulator to the same location that the hose that comes out of the old one goes in the tank. If you use a 1:1 regulator then you will also need an ECM to control the injectors that has is own MAP sensor.

On a 420a without any control of the ignition your air/fuel ratio should be very rich to try to fight knock, 11:1 or lower depending how high the octane of your fuel.

I also forgot to mention that the stock regulator is not 1:1, stock is a static 50psi or about 3.5 bar regulator it does not increase pressure in reference to pressure or vacuum. Obviously this is less than ideal for a turbocharged car. You will need very large injectors with a standalone management if you wish to use the stock regulator, but there is no one in there right mind that would recommend keeping it with turbo use.