install injects/fpr before pump

[eoseitz]

I was wondering if its safe to go ahead and install my fuel rail, fpr, and 650 injectors before I install the walbro 255. The bolts are all rusted and I'm actually going to go ahead and pay someone with a lift to change the pump for $100. It's worth skipping the hassle to me.

If I keep the boost down and set the fpr to stock pressure will it be ok to drive the car until I get the new pump in? I also have a programmer so I can set the ecu to see it as 650 injectors. Thanks for your help.

 

[matthewdesigns]

Yes.

 

[20gbeast]

be careful, if youre pump is old and weak it might burn out with the extra load that youre new injectors will require.

 

[steve]

As long as your not asking the engine to make any more horsepower the fuel requirements shouldn't be any different with the 650's. Once the ECU is reprogrammed you should be safe as long as you keep the boost at stock levels.

The only way the new injectors would create more "load" on the fuel pump is if you try to turn the boost up so that more fuel is needed.

 

[Littlebeeper]

what he said ^^^ by the way, the pump is replaced from the trunk area. using a lift would require the tank to be removed which is not needed. it would make it easier to get to the lines but it seems like a lot of extra time and money spent for a simple pump. then again, my lines were not rusted and PB Blaster helps get them all off right quick and in a hurry

 

[eoseitz]

On pretty sure on the 1990 the pump was located under the car. Then they realized how dumb the design was and moved it into the hatch area under the carpet. I checked the back and there isn't any. My shop manual tells me its under the car and I'm pretty sure I saw it when I attempted to crawl under the car.

PS.

The injectors, rail, and fpr are in. Doesn't seem to be leaking. However, I need to adjust the boost. If I go over 5 psi I get real bad knock. Anywhere from 3-14. I really need to change out the pump soon. I'm guessing there isn't enough fuel going to the injectors though my wideband never shows the car running lean now.

 

[matthewdesigns]

Is your fuel pressure set correctly? You need to be at 37psi with the vac line off and plugged.

Did you compensate for your injectors correctly?

Is your wbo2 really old? If so, it may be reading incorrectly. If not, trust it that you are not lean knocking and start digging around for other issues.

There's not really much of a way for you to be lean knocking at only 5psi. You need to look into other causes, like rich knock, a faulty knock sensor, phantom knock, etc.

 

[eoseitz]

Well I really started looking at the datalogger today and I noticed when it knocks the o2 sensor is reading .94 Also the wideband is showing me as running around 12 afr when just normal driving. I'd guess I'm getting rich knock. I also realized in all the excitement of getting everything back together I forgot to change the deadtime. I only changed injector size. . Hopefully once I correct the deadtime that will fix it. Pulling the ecu every time I need to change something is getting old. I think its time to quit pinching pennies and buy dsmlink. Anyone want to sell there dsmlink? . I can't afford a new one right now.

 

[matthewdesigns]

Hopefully the deadtime change will fix you up. Do a boost leak test while you are in there for good measure, as any larger leaks could be contributing to your rich condition.

As for pulling the ECU every time, you can get an extension for the socket, on a ribbon cable, and mount it somewhere that's easier to access.

 

[steve]

Pulling the ecu every time I need to change something is getting old.

That's one reason people buy an Ostrich.

 

[eoseitz]

I thought about buying ostrich but I don't have a laptop any more. Where exactly would I find the ribbon extension. I'm assuming its similar to an ide cable?

 

[JStoops]

On pretty sure on the 1990 the pump was located under the car. Then they realized how dumb the design was and moved it into the hatch area under the carpet. I checked the back and there isn't any. My shop manual tells me its under the car and I'm pretty sure I saw it when I attempted to crawl under the car.

Strange, my 1990's pump was accessed through the interior of the car. Mines a TSi is yours AWD as well? It's all the way at the back of the hatch in the rear drivers side corner. Mine was easy to find cause I tore out my interior . And don't be afraid of replacing the pump, it's really not bad at all. Just use patience and don't break any hard lines

 

[EVO]

1990 Pump access is inside the car! No different. I just sold a 1990GSX and I have worked on Dozens of them. You will have no problem with adding a larger rail and Injectors, The FPR may give the OL' pump a fit but other than that you should be ok. Keep in mind, if your OL' Pump dies, shoe leather express Bro!

 

[EVO]

PS.

The injectors, rail, and fpr are in. Doesn't seem to be leaking. However, I need to adjust the boost. If I go over 5 psi I get real bad knock. Anywhere from 3-14. I really need to change out the pump soon. I'm guessing there isn't enough fuel going to the injectors though my wideband never shows the car running lean now.

Not sure what size turbo your running, but your knock is obviously from over fuelling, be careful you dont wash the rings out. Even with a stock pump, that FPR and Big injectors will overfuel the car at idle and low boost loads with low duty cycles compared to the 450's at stock base fuel pressure.
Good Luck - BTW Read your plugs, they tell the TRUTH!!