Different Fuel pump?

[slvrbllt]

My friend and I were talking about fuel pumps on dsms so we decided to place a bet and get answers from people on this website. I say that fuel pumps are the same on 1g regardless of turbo or not. He says they have to be different due to the turbo. I searched this site and vfaq but I see the only difference is internal vs external.

 

[Dsmkauai]

Well they used different size injectors between turbo and n/a even auto and Manual. So I'd imagine the pumps on a n/a would flow less then a turbo one therefore being different. If you look up on Rockauto it shows the same pump part numbers between both. But if you search on Mitsuparts they seem to be different. Not sure if any of that helped . I would have to say on 1g pumps where the same between n/a-4g63 and turbo-4g63t. But for 2g rs/gs-420a have one pump and gst/gsx-4g63t have another

 

[bryanwheat]

2.0 and 2.0 turbo both call for the same pump with like 8 different brands.

 

[thomcasey]

Incorrect. The non turbo has a lower-flow fuel pump than the turbo model does. Though you can use a turbo fuel pump on a N/T, you cannot use the n/t on a turbo. It will not flow enough.

 

[bryanwheat]

Incorrect. The non turbo has a lower-flow fuel pump than the turbo model does. Though you can use a turbo fuel pump on a N/T, you cannot use the n/t on a turbo. It will not flow enough.

Well 8 different companies sell the same pump for the 2 cars.

 

[swiftdeathtsi1]

Well 8 different companies sell the same pump for the 2 cars.

He is right. Every where i have looked they sell the same pump for both cars.

 

[slvrbllt]

i guess the answer is not as easy as i thought

 

[BogusSVO]

For my .02... I would believe they would use the same pump for both turbo and the non turbo.

Since both the Turbo and non turbo cars are a return fuel systems, the injectors will pull what they need, and the rest is sent back to the tank.

The FPR and injector size is what will seperate the turbo from non turbo parts.

The car maker wants as many parts to cross over as possiable, to keep production cost down.

The true way to get a proper awnser for your question is to pull the pump from a turbo and non turbo car and check the factory part number on each.

 

[swiftdeathtsi1]

the difference between non turbo and turbo fuel system is smaller high impedance injectors with higher fuel pressure vs larger low impedance injectors with lower fuel pressure.

 

[9!'clipseDOHC]

I have always heard that they were different but I don't have access to CAPS to confirm it though.

 

[thomcasey]

I checked with the normal parts stores (O'Reilly's, Napa, AZ), they all showed a different pump for the Turbo and Non-Turbo.

 

[swiftdeathtsi1]

2nd gens are different. they have different motors. 420a vs 4g63. 1st gen turbo and non turbo pumps are the same.

 

[slvrbllt]

For my .02... I would believe they would use the same pump for both turbo and the non turbo.

Since both the Turbo and non turbo cars are a return fuel systems, the injectors will pull what they need, and the rest is sent back to the tank.

The FPR and injector size is what will seperate the turbo from non turbo parts.

The car maker wants as many parts to cross over as possiable, to keep production cost down.

The true way to get a proper awnser for your question is to pull the pump from a turbo and non turbo car and check the factory part number on each.

yeah i agree both pumps are going to have to be pulled....

 

[19Eclipse90]

All part numbers are assemblies, not the pump itself; as far as I can tell, the pump alone is not available through Mitsubishi.

FWD
All 2.0L 1990-1991: MB400420
All 1.8L 1990-1991 except late model 1991: MB400420
Late model 1.8L 1991: MB658436

1992
2.0L 1992 w/o turbo: MB400420
2.0L 1992 w/ turbo: MB845502
1.8L: MB923663

1993
1.8L; 2.0L w/o turbo and manual transmission: MB923663
2.0L w/o turbo and auto transmission; 2.0L w/ turbo and manual transmission: MB400420
2.0L w/ turbo and auto transmission: MB845502

1994
w/o turbo: MB923663
w/ turbo and manual transmission: MB845502
w/ turbo and auto transmission: MB400420

AWD
1990-1991: MB597728
1992-1994 w/ manual transmission: MB597728
1992-1994 w/ auto transmission: MB831742

Parts store replacement pumps seem to range anywhere from 45-60 gallons per hour in flow. Take it for what it's worth.

 

[91Bomb]

So from reading this thread we still don't know whether turbo + N/T 1g pumps are the same or different, right? We do know assemblies are different but not if the actual pump is. Because I have a 2.0 N/T parts car and getting ready to pull the pump out and would be great to know if I should save it as a spare for my turbo m/t

 

[AWD_FIEND]

This thread is on the older side, but since my search for the same answer came up short I have decided to comment on what my personal findings were for this topic. Is the N/T fuel pump the same as the Turbo fuel pump with respect to its dynamic flow characteristics? While this seems like a simple question to answer, there’s nothing in the FSM or other qualified DSM technical media that suggests there is a difference in how much fuel they can deliver. While it’s all too common for non-performance related cousins of factory performance cars to feature parts that aren’t up to par for higher power models, that’s no guarantee the N/T fuel pump is theoretically different from the Turbo pump. So I decided to test this theory on a personal vehicle that would offer the perfect “scientific model” to determine once and for all if the 1G pumps in question are compatible.

The test vehicle is a basic farm field rescue 1992 Talon TSi FWD. The goal of the car was to build a 99% stock grocery getter that is ready for Saturday track duty when the interest arises. The car is bone stock except for a few choice mods: 3” Turbo back exhaust with O2 Eliminator, a Hallman Pro Boost Controller set to 18 psi, and DSMlink V2. The car also has a Zeitronix ZT3/ZR3 gauge combo for measuring accurate A/F Ratios. After rescuing it from the crusher, during my initial attempts to get the car running I discovered the fuel tank and pump were one gigantic bucket of rotted rusty metal. Being on a very tight budget, and an even tighter time crunch (race season was starting) I procured and installed a replacement tank and pump from a 1993 N/T Eclipse GS 2.0L.

After installing the tank assembly and a brand new stock fuel filter the car fired up and purred like an uncorked 4G63 should. But during the tuning process a significant issue emerged. No matter how much fuel I added in ‘link the car would go deathly lean on the top end, in the range of 13.5-15.0 AFRs. Initially I suspected at 18 psi the system was simply out-flowing the 1G MAF, so I hacked it and threw it back in. While I logged more reasonable MAF Raw figures of around 1600hz the car was still dangerously lean from about 3000 RPMs-7000 RPMs. Next I dropped the boost to 12psi, and the car finally hit 12.5 AFRs until about 4000 RPMS at which point it was back to 15s. All of this tuning was done with a full tank of gas BTW.

With the duty cycle on the stock injectors showing 85% calculated I decided to upgrade them in case they had become the flow restriction. In went a set of PTE 1000cc injectors, and while the DCs were a much friendlier 60% the car was still lean. I decided to test voltage at the pump and it read a solid 12.9 volts which rules out the wiring, although the car could benefit from a rewire kit. At this point with all the common culprits known to impede fuel flow addressed, I have concluded that in fact the N/T pump does flow significantly less fuel than the Turbo pump.

Yes, there are a couple other possible issues that can explain my WOT lean condition such as sock filter contamination, a collapsed secondary filter element, fuel sloshing/starvation. Personally I don’t believe those variables would explain my issue without providing their set of diagnosable symptoms. If I had a Fuel Pressure gauge I could show scientific measurements to definitively prove my theory, but frankly I don’t have that much interest in convincing the community of my opinion. I simply want to offer my experiences as an opportunity to possibly lay this question to rest. My conclusion is for those out there hoping to run a N/T fuel pump in a turbo/performance setting I would advise you make arrangements to use a better pump.