Walbro 255 Pump w/ DSM Link but no AFPR?

[Spoolin96DSM]

Ok I have read almost every thread about the Walbro 190 and 255 Fuel pumps. Now I was wondering if you have a Walbro 255 pump and DSM Link, but no AFPR if that's ok or do you still need one. I will be putting in a Big 16G with 550 injectors. Now I've seen some people run it with the Walbro 190 Fuel Pump. However, eventually I will be upgrading my Big 16G to an FP Green most likely. So I was planning on just getting a Walbro 255 pump and my friend said I would just be running rich until I got DSM Link. So do I need an AFPR with a Walbro 255 Fuel Pump and DSM Link or is the stock one fine?

 

[Locke]

You can't tune out overrun. To avoid overrun on the 255, invest in an AFPR.

 

[Boostdclips99]

Any sort of upgrade in fuel system needs to be done thoroughly. I ran without an upgraded FPR and really didn't notice a big change in base idle or anything after buying my Aeromotive. It's just the thought that I don't have to worry about the stock fpr crapping out on me. Eventually it will happen since you will be over running it with the walbro and 550s, has nothing to do with the tune. Invest now

 

[bmoha2]

the 255 will definitively over run the stock fpr

 

[MidShipCivic]

As the others said, I have to add :

I have this same exact setup and it killed the FPR, car never ran right the day I put it on.

I'm waiting on my Aeromotive to correct this.

 

[CanadianTSi]

I'll just add my .02 cents. Been running a 255 on the stock FPR for 4 years now. All fuel trims are within 3%

 

[jtmcinder]

It would be a pain, but you can use DSMLink to deal with over-run. You keep pulling air at 50Hz (and maybe 100Hz, as well) to compensate. The best way to do this is by having a wideband, but I've come close enough without one.

- Jtoby

 

[turbotalon1g]

It has been done, not upgrading the AFPR when upgrading to a larger pump, but i figured why take the risk for an extra $100.
Plus you will probably do it in a while anyway.

 

[MidShipCivic]

2g and 1g FPR's must be different because mines is totally done the 255 damaged it.

 

[mini zilo]

I just listened to what AMS told me... You don't need an AFPR with a 255 unless you are running over 500 hp. Disagree with me all you want, but I am damn sure that you did not build the worlds quickest and fastest evo 8. ( I think they know what they are talking about)

 

[Locke]

Some of the worlds fastest and quickest turbo Dodges' are just hacked together with extra injectors fired by a constant signal from a pressure switch. Thats high tech fuel control right there. You can be fast and unproper at the same time.

 

[fwdeclipse]

Just my experience I changed my 190 for a 255hp and without the afpr the car idles like trash. When I put the afpr on the car everything is golden now.

 

[jtmcinder]

I'm not sure if everyone is aware of the main problem when you put a high-flowing pump on a 2G. The problem is that the OE FPR and return line can't get rid of enough fuel to get the pressure back down where it needs to be at idle. You can tune around this by reducing the amount of air that the ECU "sees" at idle (using the 50Hz slider), but that's a bit of a pain you'll probably never get the LTFT-lo correct.

Again, HP is irrelevant to the problem. The issues are at idle.

(edit: my daughter walked in wanting to play a game while I was writing ... the above post probably covered it)

- Jtoby

 

[No_Skillz]

I'm not sure if everyone is aware of the main problem when you put a high-flowing pump on a 2G. The problem is that the OE FPR and return line can't get rid of enough fuel to get the pressure back down where it needs to be at idle. You can tune around this by reducing the amount of air that the ECU "sees" at idle (using the 50Hz slider), but that's a bit of a pain you'll probably never get the LTFT-lo correct.

Again, HP is irrelevant to the problem. The issues are at idle.

(edit: my daughter walked in wanting to play a game while I was writing ... the above post probably covered it)

- Jtoby

Peope come back and read this. Alot of people have it backwards. The stock FPR is not being overrun. It is holding the pressure to high since it was designed for a weaker pump. The injectors are being over run.

 

[jtmcinder]

Um, in the DSM world, when the FPR (and/or the return hose) is not able to dump enough fuel, causing the pressure in the fuel rail to be too high, causing the injectors to inject more fuel than the ECU "planned," the problem is usually referred to as "FPR overrun." This happens at low RPMs (such as idle), because as soon as you start using fuel, you don't need to dump as much. That's why the "fix" using DSMLink is to pull air using the 50Hz slider.

Example: http://www.diamondstarmotorsport.com/fuelparts.shtml

In other places, the term "overrun" might be applied to other parts of the system (or even other systems, such as when you "overrun" the air-metering ability of your MAS), but I think my post including the details, as well as the name, would be a fine thing for someone to find when searching.

Cheers

- Jtoby

 

[badgti]

oh well, i'm using a 255 too and i have since went through 2 FPR's, both of them couldn't take the preassure and instead of it getting the preassure to rise during high revs, it drops instead.

 

[thekellbeast]

That doesn't mean that the FPR can't take the pressure. It means that the pump can't flow enough. If you're losing fuel pressure as the rpms go up (and boost), it's because your fuel pump can't flow enough fuel to keep up with the raising intake pressure. Either run a dual pump setup or upgrade to a full on external.

 

[jtmcinder]

Was it rewired?

- Jtoby

 

[badgti]

nop, it was wired in to the stock fuel pumps power supply .

 

[jtmcinder]

Well, then that's likely to be the problem. The voltage at the pump on the stock wires can drop quite low. The new problem is going to be overrun (as I use the word) at idle after you rewire it. You will need a good FPR and return line or you can "tune around it" using DSMLink.

- Jtoby

 

[No_Skillz]

But even with "tuning around it" with DSMLink, wouldn't it still be off since the overrun changes depending on how much load is on the motor, rpms, throttle position, and probably some other factors I haven't thought of?

 

[jtmcinder]

Yep. The "tuning around it" approach is to allow the pressure to be higher than desired at idle. The higher pressure causes the injectors to inject more fuel than "intended," so you want the injectors to be open for shorter periods of time. You achieve this by "pulling air" at idle, using the 50Hz slider (in DSMLink). This gives the ECU a false (low) measure of air-flow, so the ECU opens the injectors for shorter periods.

As soon as you are using significant amount of fuel and/or aren't at 18" vac, the FPR ceases to be "overrun" and all is well. It's really just an idle issue. But if you're anal about getting the LTFTs near zero, you have to deal with the overrun first or you'll drive yourself crazy. (Ask me how I know.)

- Jtoby

 

[badgti]

so the best is to wire it directly to the main power supply, ok, i'll try this then.Initially he FPR was ok once i installed it but once i increased the preassure, the car started to puke, as if it had no fuel coming to the injectors, weird but i'll try to rewire it today.

 

[bird man]

255 walbro, FIC 750's, and dsmlink here for twp years now with stock FPR, no problems at all

 

[Burnett03]

With a walbro 255pump, dsmlink and 680CC injectors, on a stock FPR i was at 58psi base pressure.. Supposed to be 43PSI. This is way to much. Please explain to me how pulling air at the 50 and 100HZ sliders is going to solve this problem of to much base pressure? At 20psi of boost i was flowing 78psi of fuel pressure! Adjusting airflow sliders is not going to fix this. I was getting 200miles to a tank. Added an aeromotive regulator and got the base pressure to 43psi. At 20psi boost im at 63psi fuel pressure, and am now getting almost 200miles to a tank. DSMLINk will not solve high fuel pressure, only the regulator can. I know you can use the sliders to get the car to idle correctly and get the fuel trims within spec, but you WILL not lower fuel pressure with them.