HELP! Fuel Pump Install gone wrong

[SquattingDog]

Hey guys,

Recently installed a new SARD FPR into my RVR. Everything went smoothly, was able to adjust pressure no problem. At 1.2bar was beginning to lean out a little, so I thought it was about time I dropped in my Walbro GSS 342 255lph fuel pump to sort things out so I could seriously start tuning.

First things first:

I didn't quite fit in the fuel pump holder, especially not with the rubber isolator on the bottom of it. So I ditched the isolator, and clipped the platic bracket onto the fuel pump holder, which held the fuel filter in place, then proceeded to put it in the tank.

Tested it without hooking up the hoses, fuel gushing out from the pump side, which is correct. Hooked everything up, cranked her over (this is the only way my car primes). Car spluttered, started, then died. This happened numerous times, and I got my flatmate and missus to have a look at the gauge on the FPR. It reads less than 15psi of fuel pressure - usually around 10psi at all times.

I can get the car to barely run - and it runs very rough, but fuel presssure is still low. I have tried changing back to the stock reg with no improvement (no idea what fuel pressure is with stock reg, but it acts exactly the same.

I am using the fuel filter which came with the walbro, although it doesn't really fit in my tank with that - was previously using the stock fuel filter off the old pump, as it fit perfectly with that.

What am I missing?

I have tested priming the car using a 12V battery hooked straight up to the fuel pump, and fuel sprays out of the fuel rail return, so fuel's getting up there, just not enough.

I have already upgraded the wiring using a 4-pole relay to give it a +12V (+~14V when car is running) using 8 AWG wiring direct from the battery, so that the punp comes on when its meant to. Previously wiring was burning under the hood, as it was trying to draw too much amperage on start up, and only getting 6.3 - 6.8V at the pump. This issue has been resolved with the 8 AWG wiring.

I've read about there being different pumps for different vehicles - perhaps I have the wrong Walbro? It's a genuine EVO kit from Paul @ NZPerformance.co.nz.

My factory pump is a Denso 195130-4472. Other numbers on it in white wiriting (above the 4472) are 22 and 12S.

Please help me, I need my car back on the road, and the stock fuel pump is on it's way out.

One more thing to note - I had the same issue when I swapped the stock fuel pump back in...Is there a non-return valve of some description I should be looking for to check if it's clogged?

I have just over 1/4 tank of gas left now, had over 1/2 when I started this installation. Pump is submerged around the pickup and return lines.

[Turbo_Steve]

Are you sure your FPR is operating normally?

[Ryan]

I believe that the Walbro GSS 342 is the correct one to use too.

[Turbo_Steve]

For a VR4, maybe...not so sure on the RVR, Ryan.


First thing I would suggest is to try "priming" the fuel rail. So don't crank the car, but disconnect the return, and then just switch the ignition to "on" so the dash lights come one. The fuel pump should run for maybe 2 seconds. You should get a brief squirt of fuel from the return pipe. If you don't, your fuel lines were too empty (drainback valve is stuck open) or pump is not lifting fuel properly.

Block the return pipe (hose clamp) and try cycling the pump. You should see good fuel pressure on your gauge whilst the pump is running.


Other stuff to check:
Not sure if the RVR does the bizzare "low voltage" mode that the VR4 does for the fuel pump. You may want to wire your own feed to the pump, and have it activated by the ECU feed.

The early Evos have a bizzare system of richening up the fuel at startup: they simply bleed the vacuum from the FPR with a Tee'd in solenoid. Try taking the Vaccum line off your FPR: see if it makes any difference.

[elnevio]

The early Evos have a bizzare system of richening up the fuel at startup: they simply bleed the vacuum from the FPR with a Tee'd in solenoid. Try taking the Vaccum line off your FPR: see if it makes any difference.
It might well still apply, but the RVR X3 is more related to the Evo IV/V/VI than I/II/III.

[Nick Mann]

The Evo and 8g VR4 use slightly different pumps from what I understand. The 342 is the pump for the VR4, again from what I understand, but the Evo uses a different one. I'm not sure what the difference is, or what problems it would cause if your RVR needs the Evo design and not the VR4 design.

[TAR]

The Evo pump will fit the VR4 and is a GS342 (also listed sometimes as an ITP237)

The Walbro is a little bit longer than the stock VR4 pump.

On a VR4 you need to adapt the fitting to ensure a good seal between the pump and the holder so that fuel cannot circulate directly back into the tank. It may be that you have missed a sealing ring or spacer somewhere.

I did this very thing and had very little pressure as it was not being forced into the fuel line properly.

:happy:

[SquattingDog]

For a VR4, maybe...not so sure on the RVR, Ryan.


First thing I would suggest is to try "priming" the fuel rail. So don't crank the car, but disconnect the return, and then just switch the ignition to "on" so the dash lights come one. The fuel pump should run for maybe 2 seconds. You should get a brief squirt of fuel from the return pipe. If you don't, your fuel lines were too empty (drainback valve is stuck open) or pump is not lifting fuel properly.

Block the return pipe (hose clamp) and try cycling the pump. You should see good fuel pressure on your gauge whilst the pump is running.


Other stuff to check:
Not sure if the RVR does the bizzare "low voltage" mode that the VR4 does for the fuel pump. You may want to wire your own feed to the pump, and have it activated by the ECU feed.

The early Evos have a bizzare system of richening up the fuel at startup: they simply bleed the vacuum from the FPR with a Tee'd in solenoid. Try taking the Vaccum line off your FPR: see if it makes any difference.

Ok, thanks for your replies guys. Drainback valve stuck open could be the culprit - I have no idea where this valve is, but I'll give it a shot. The RVR does not prime until it turns over, and when the engine turns off it primes for 2 seconds...its whack, but has always done that.

The Sard FPR requires the vacuum hose to be disconnected for you to accurately set the fuel pressure, as the fuel pressure to the injectors drops or raises based on the vacuum line (run by a solenoid of sorts). Have tried it with and without vacuum hose - with seems to work better to keep the car going despite the low fuel pressure, just very rough and very lean - think 19 - 20:1 AFR....

I have rewired the fuel pump with 8AWG using the factory (ECU) line as the "signal" to swich the 30A relay on.

It definitely seems to me that a non-return valve of sorts is open, causing pressure not to be built up.

I'll track down a hose clamp and work from there.

[SquattingDog]

The Evo pump will fit the VR4 and is a GS342 (also listed sometimes as an ITP237)

The Walbro is a little bit longer than the stock VR4 pump.

On a VR4 you need to adapt the fitting to ensure a good seal between the pump and the holder so that fuel cannot circulate directly back into the tank. It may be that you have missed a sealing ring or spacer somewhere.

I did this very thing and had very little pressure as it was not being forced into the fuel line properly.

:happy:

Oh really?

I believe it has a good seal where the top of the pump goes into the fitting now, however the at the filter end this may not be the case - but shouldn't be a problem, right?

My flatmate decided to help me and was a bit rip, **** and bust with the install, so it's possible he missed some parts (pissed me off tbh).

[Wodjno]

The Evo pump won't fit a VR4, the fuel pickpup is on the wrongside. The Walbro pump for an Evo is a GSS341(342 for VR4) The walbro pump is shorter than the stock pumps. I'm not sure what the pump housing on ur RVR looks like, so can't comment on it's fitment.
But with the Vr4, the mounting bracket bolt hole needs elongating to allow it to slide down a few mill and clamp the pump down firmly.
As also stated if the 'O' ring is not snug then u will get drainback
I fitted a thin rubber sheath to the end that fits the 'O' ring to make it a snug, tight fit and no drainback.

[Turbo_Steve]

TBH the rubber ring sounds like a very likely culprit, rather than the in-pump valve on a brand new pump.

[TAR]

[quote=WODJNO]The Evo pump won't fit a VR4, the fuel pickpup is on the wrongside. The Walbro pump for an Evo is a GSS341(342 for VR4)

Sorry Wodj but you are wrong.

The GSS342 is the recommended pump for the Evo 6-9 and is also the correct pump for the VR4.

An internet search for Walbro Evo fuel pump will bring up lots of results which confirm this.

:happy:

[Wodjno]

[quote=WODJNO]The Evo pump won't fit a VR4, the fuel pickpup is on the wrongside. The Walbro pump for an Evo is a GSS341(342 for VR4)

Sorry Wodj but you are wrong.

The GSS342 is the recommended pump for the Evo 6-9 and is also the correct pump for the VR4.

An internet search for Walbro Evo fuel pump will bring up lots of results which confirm this.

:happy:
So the Evo 1-5's must take the Walbro GSS341 pump!
So the the Evo pump is the wrong 1 for the VR4 :p
(depending on which model Evo your specifying)
I purchased 50 341's and sold them to Evo owners. I never specified them as Evo 1-5 pumps! So i must have just got lucky that the purchasers were Evo 1-5 owners :D

[SquattingDog]

TBH the rubber ring sounds like a very likely culprit, rather than the in-pump valve on a brand new pump.

Which rubber o ring are we talking about here guys? One that sits on the top of the pump and holds it in the housing? I'll pull it out and show you guys what it looks like (although this may destroy the housing, as it's getting damaged from me pulling it out and putting it back in all the time.)

I'm not currently at my place, but will be heading back there today to give a few more things a try.

[EDIT] Just found this write-up
http://www.evomoto.com/tech_info.php?tPath=13&tech_id=9&osCsid=a1add00b52731f1aeacf59d810ea88c2
which is identical to the RVR's set up. I have even followed all of the steps in it bar the following:

1. I did not lube the grommit with oil before reassembling
2. I am not using the "rubber isolator" on the bottom, as it does not fit in the assembly if I do.

Thouguhts or suggestions?

[TAR]

Pictures of the old and new pumps would be really helpful in identifying the various parts.

:happy:

[Turbo_Steve]

Agreed: pics please.

FWIW I reckon Wodj is bang on the money: your problem sounds VERY similar to his, and there are definitely fitment issues between models.

[SquattingDog]

Problem solved, it was a rubber o ring in housing of the pump. It was on what must have been the drainback feed - it was stuck further in than it should have been and consequently was not sealing correctly. Just pulled it out, lubed it with oil and put it back on where it was meant to be.

Changed fuel filter back to original one as the Walbro one was about 5mm too long for my fuel tank. Runs fine again now.

Thank you guys for your suggestions and help - I was really stumped until I read your replies :)

[TAR]

Excellent news, glad we were of some help.

:happy: