Update: Fuel pump rewire / install?

[brandon]

Hey guys,

Only plan on running 7-8 lbs of boost max, using 450cc injectors and an AFC...

Will the fuel pump rewire be sufficient or should I opt for the Walbro 190?

Just waiting for my gaskets to come in and I'll be ready to start. Mounted my AFC Tuesday and will be wiring it this weekend hopefully.

Anyhow, thanks for any input.

[sethmo]

Id go with a 190. It will leave some room for upgrades and you wont have to worry about anything...

[sabzi5858]

i'd go with the supra TT fuel pump (actually i did) it's supposed to be more reliable, and quieter than the walbros. (i have no experience with the walbro so i can't speak personally, but i went on a search for fuel pumps when i needed one and i came to the conclusion of the supra fuel pump b.c of those things as well as flowing more than the 255) note: you will need an adjustable fpr with the supra pump.

[JiP]

I got a 190 its not loud to me, I dont hear it over the engine so once the car is running I just hear engine noise. You should do the rewire, and then install the 190 it will be a much happier pump =D

[brandon]

But initially will I be okay? I've read some posts here and there on forums saying that the rewire is ok, but for any added boost it would obviously be wise to go bigger.

I hate to cut corners but I funds are low and I'm hoping to get everything done before temps get steadily into the 90s.

[brandon]

FYI, I've decided to go w/the Walbro.

I've come this far and another couple weeks obviously isn't a big deal. Thanks for the input.

[ken inn]

a stock gsx fuel pump, rewired, is good for about 15 lbs boost. since you are only going half that, and using 450's, a 190 is overkill. and you will definetly need an adjustable fpr. dont get one that only adjust upwards, like the b&m. get one that can go up AND down. get your fuel pressure in line, then you can use it to fine tune the car. the stock gsx fuel pumps are probably a dime a dozen because there have been so many upgraded cars.

[brandon]

<div class='quotetop'>QUOTE(ken inn)</div><div class='quotemain'>a stock gsx fuel pump, rewired, is good for about 15 lbs boost. Â*since you are only going half that, and using 450's, a 190 is overkill. Â*and you will definetly need an adjustable fpr. Â*dont get one that only adjust upwards, like the b&m. Â*get one that can go up AND down. Â*get your fuel pressure in line, then you can use it to fine tune the car. Â*the stock gsx fuel pumps are probably a dime a dozen because there have been so many upgraded cars.</div>

Even better... thanks. I'll take a peep on ebay and then see how mitsubishigraveyard.com wants for one.

Would I still need the FPR with the GSX pump?

[ken inn]

depends. what is the stock fp of your car? 90-94 t/e/l/g is 36-37 static, 95- is 43. if your injectors are early, you should try to run the pressure for that injector. when i installed the 3kgtvr4 pump on my car, with no other mods, the egt's went to .99. they were at around .89, which means the car immediatly went rich. even after ecu adaptation, egt's only came down to around .96, still rich. i then got an adjustable fpr, and brought pressure back to stock, and egt's came back down. much later, i rewired the pump. by then, i also had a datalogger. pressure increased a tad, i had to adjust fuel on the afc about another -2 on the low side. an adjustable fuel pressure regulator is a very handy tuning tool. since you are modding the car quite a bit, i would recommend it. on my car, a simple b&m gauge that sits on top of the filter is all you need. a better one would be one that is inside the car, so you can see flow at all rpms, but they are pricey.

[brandon]

So I rewired my fuel pump a couple days ago, and was going to install the fuel pump (2G) I won on ebay.

The issue, however, was I couldn't get the feed line bolts to budge, and ended up twisting the line a bit (shitty).

I was looking at the 2G Denso/Walbro installs on VFAQ and they say to get at the line from under the car... is this what all of you who've changed pumps have done? Or is there a trick to it?

[sabzi5858]

i used a pair of flare wrenches from under the car, i set them so that i could stick a bar in between them and pry them apart, worked great

[JiP]

I am not gonna be able to explain it, but you gotta use 3 crecent wrenches all together, one that has a closed 16point end. Two of them youll put one on each of the 2 fittings the third you interlock over one of 2 other guys in a way that it will act as if its 1 long handled wrench giving you all the leverage you will need to break the bolt loose. This works for any bolts where you have the room to interlock the wrenches, defintly a great trick to know for timing belt jobs.

I will try to post a picture so the explanation makes more sense. But that will break the top loose, you will still have to undo the bottom fitting most likely in order to get the hose off the top, I had to atleast. The bottom comes off very easy.

[JiP]

BTW I run a 190 with both the 270cc when I was still sohc and then the 450cc after the swap and the stock FPR work fine I have always had a FP guage installed, the pump never raised the pressure so no need to get an adjustable fpr unless you want just another gadget to tune or confuse things =D

[sethmo]

Thats how I did mine. I ended up using a pair of vice grips for the longer bolt and a flare wrench for the smaller. I kind stripped the smaller bolt a bit but I got it off

[ken inn]

<div class='quotetop'>QUOTE(JiP)</div><div class='quotemain'>BTW I run a 190 with both the 270cc when I was still sohc and then the 450cc after the swap and the stock FPR work fine I have always had a FP guage installed, the pump never raised the pressure so no need to get an adjustable fpr unless you want just another gadget to tune or confuse things =D</div>

lots of cars with heavy mods DONT use an adjustable fpr. but, they dont care that the car is overpowering the fpr, and running rich as hell at idle and part throttle. all they want is wot flow. if you log your o2 sensor, you will see if the pump is overpowering the regulator, the o2 goes open loop, and the car defaults back to preset fuel/timing maps, which is rich. anytime the car is in open loop, you are not getting the best performance/economy. by using airflow control(like afc) and adjustable fuel pressure, you can increase injector output by merely raising base fuel pressure, and you can use the afc to adjust idle and part throttle, staying withing the parameters of closed loop operation.

[JiP]

Actualy if you want to see my logs my idle is way too lean. My 1k setting on the afc is +25 in the low otherwise my fuel trims shoot through the roof. I have a fuel guage pressure guage installed I can see the pressure isnt going out of spec.

Actualy was talking to this kid the other day who doesnt use the vacuum line which defaults pressure to like 40-46psi for 1g/2g turbos, and 47-50psi for 4g64. Then just uses the AFC to tune. His reasoning was its just one less thing to worry about having to tweak. Prety much the same reason I junked my ISC.

I never said adjustables arent needed in some applications...but it depends what you are trying to accomplish, and how you want to tune.

Also keep in mind there are 2 different kinds of Walbro 190s a low pressure and a high pressure one. I got the lph, but I dont think the outputs are massivly different, just something to consider.

[ken inn]

Actualy was talking to this kid the other day who doesnt use the vacuum line which defaults pressure to like 40-46psi for 1g/2g turbos, and 47-50psi for 4g64. Then just uses the AFC to tune. His reasoning was its just one less thing to worry about having to tweak. Prety much the same reason I junked my ISC.
<div class='quotetop'>QUOTE</div><div class='quotemain'>

everyone has their own tuning methods. Â*personally, i would NEVER disconnect the vacuum/boost line. Â*my low boost setting is 18 lbs, hi boost is 23. Â*losing 18 psi of fuel pressure at wot is not my idea of good tuning. Â*losing 23 psi would be asking for trouble. Â*if he is using afc, then he is still depending on the ecu to tune. Â*at max boost, if it is 2g, everything ok, he is getting about 15 lbs of boost. Â*the ecu is thinking he is getting about 58 psi fuel pressure, when he may actually only be getting 43. Â*there is no way his hi throttle can be linear, and i would bet he is running out of injector. Â*if boost spikes to 20, even worse. Â*
Â* Â* when i installed the hks cams, i also tried it with the isc disconnected. Â*it worked well, i was able to increase the base idle so it was smooth, but when the a/c kicked on, it would die. Â*after the install of the fidanza, it would be all over the place. Â*reconnecting the isc was way better. Â*different strokes.</div>

[JiP]

I havnt had an ISC hooked up for long time, never had a problem so far. I idle at a solid 850 rpm, and when I kick the A/C on it drops to ~800 and still runs smooth. Just incase I ever have a problem since I dont have any emissions junk on the car, I took the old EVAP Purge solenoid and wired it up to a switch with a line runing from the breather niple on the intake to the old evap nipple on the manifold, I could raise the idle ~250 rpm from inside the car with a flick of the switch.

As for FPR he's stock spyder engine only running like 10psi ( IIRC), FP just sits at like ~50 psi I duno what his afc settings are, or what injectors he is using. You know how it goes, you ask 10 people how do you tune? and you get 10 different answeres, what works for some doesnt seem to work for others...

BTW Ken, are the stock turbo model fpr's rising rate?

[ken inn]

BTW Ken, are the stock turbo model fpr's rising rate?<div class='quotetop'>QUOTE</div><div class='quotemain'>

yes, 1 psi/1 lb boost. Â*the stock fuel system on the 1g cars can handle 15 lbs boost. Â*i would rewire the fuel pump to be sure, but one of the first mods i did was up the boost(with an mbc AND a real boost gauge) to 15 lbs. Â*50 hp for about 75 bucks investment. Â*what a deal!</div>