Fuel Pressure Sending Unit

[b11dragone]

Ok...I found out what is causing my car to get fuel cut under hard accleration. It is the piece that the fuel pump sits in, I think Its called the fuel pressure sending unit. So the O-ring that holds this piece in is cracked and I need a new one. I called Mitsubishi and they want $500 for the whole unit when all I need is the O-ring. Can anybody help me find just the O-ring or possibly the whole sending unit for cheaper. And can somebody give me the oem part number for this piece. Thanks alot.

 

[steve]

2G AWD's have a pump on one side and a sender on the other. The gasket for both sides are the same part # MR342213 about $12 list from the dealer.

How is that causing fuel cut?

Steve

 

[b11dragone]

I don't know. I asked for just the gasket and they said that I needed to buy the whole piece that goes into the gas tank, including the stock fuel pump. They said they couldn't sell me just the gasket.

I think its causing fuel cut because fuel is leaking out of the gasket. Or the gas tank is no longer pressurized because air is escaping.

 

[steve]

The gasket is listed as a seperate part. I looked it up in CAPS and then checked a couple of online mitsu parts dealers for the price. Try calling the dealer with that part number.

Steve

 

[4whlbst]

That shouldn't make the difference for your fuel cut problem.

I mean, it is good to fix a leak, but the tank has a pump in it. The pump sucks fuel in and pressurizes it from that point till the rail, not before the pump. The only pressure in the tank is for the emissions not performance. I think even if you fix this problem, you will still have the fuel cut.

This gasket was most likely damaged during installation of the Walbro pump.

The GSX differs from the GST in that the sending unit and pump are on the same side while on the GST the pump is seperate from the sending unit. I believe that the GSX uses a different type of gasket from the GST, it has an insulation ring instead.

You should try checking in a phone book for a shop that sells sheets of gasket, or try taking it somewhere where they could try and match it to anything else, like a parts wholesale distributor, you don't have to buy it from Mitsubishi. You could even try looking under gaskets in the yellow pages, you might find something.

 

[b11dragone]

no on the gsx the sending unit is on the other side i looked at it today
it looks almost like the fuel pump but is on the other side

 

[b11dragone]

I don't know why the guy at mitsu was being such a jackass. He was like well I can't help you. I asked him to look at it from my point of view. I was like it cant be worth more than $10 and you want to charge me $500. He was like I don't care thats how we do things here. Im about to flip.

 

[PaulPDX]

Tell him to stick the $500 up his A** because you're going elsewhere.

 

[4whlbst]

Do you have a 1g or 2g? Cause when I changed my fuel pump on my 2g the sending unit and float comes out with the pump as a whole assembly, there only seperate on the gst. Showed it in vfaq that way too. I'm not arguing with you about it, just curious why it would be different.
As far as the gasket, why don't you check out one of the online mitsubishi dealerships? There are a few that take internet orders for parts, I think there is one in the sponsors page on here. I think the dealership you are dealing with is just trying to screw you for a little extra money.

 

[PaulPDX]

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[Defiant]

Originally posted by b11dragone
Or the gas tank is no longer pressurized because air is escaping.

It..... what? What the hell is that?

"Should the ECU ever see an intake air mass greater than a certain preset level, it will stop fuel delivery and spark to the engine cylinders. This 'critical mass' depends on air volume, temperature and pressure, as measured by the MAS sensors. The act of the ECU cutting off fuel delivery to the engine is known as the infamous 'fuel cut'."

from

http://members.shaw.ca/costall/ECUprimer/ECU_ch7.html

A fuel pump O ring will have nothing to do with "fuel cut", which I rather doubt you're experiencing anyway.

 

[b11dragone]

I don't know if its fuel cut either. But the whole reason for me getting the new fuel pump was the under WOT my car would studder and backfire.

The only thing I am confused about is that everytime I take the fuel pump out and try to put it back in my car works fine for about 10 minutes then starts running like shit again? And yes your right, the GSX does have the fuel level sending unit attached but there is a sub-gauge level sending unit on the other side. I believe it just tells the gas gauge how much fuel is in the tank.

Believe me I don't know whats wrong with my car, If I did I wouldn't be asking you guys. I know you all know a lot more than me, and I just don't want to get jerked around by some bastard on the phone.

If its not fuel cut why would my car start acting this way after I put on the aftermarket parts listed in my profile? Before I installed these parts my car worked fine.

For some reason my car started to boost creep up to 20psi when I installed these parts. That's the other reason I felt it was fuel cut because the turbo was spinning to fast. Don't know what caused the increase in boost, but either way it caused this fuel problem as well.

That's the reason for the new fuel pump. I was just trying to find a solution to my problem, and when I listed my symptoms a lot of people said to upgrade my fuel pump.

 

[4whlbst]

That still sounds an awful lot like fuel cut to me. Now correct me if I am wrong but I beleive defiant was saying that the leaking gasket does not cause the problem your having, as I was also trying to say. It doesn't mean that you don't have fuel cut but the leaking gasket wouldn't be the culprit. I think you have two seperate problems. I still think you have fuel cut due to the fact that you say your boost creeping. That can cause you to hit your fuel cut. Do you only get the stuttering when you creep up too high at wot? I would still look into the fpr for the pump, because it is too big for your stock reg. and if you haven't already done it, port the o2 housing and the exhaust side of the turbo to cure the boost creep. I think that might solve the problem.

 

[b11dragone]

Ya...I am going to have to try alot to solve this problem. Thanks for everything guys you have been very helpfull. I will try to fix my boost creep by doing what you said hopefully it will work. Thanks