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· Registered
1998 2.5 RS
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2,032 Posts
Discussion Starter · #1 ·
Would it work/be worth it to put a battery in the car and test the electrical stuff while I'm waiting on my engine? I just want to try to get as many bugs worked out as I can before the engine gets here.
 

· Mobile Diagnosis Guy
97 Impreza L
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5,319 Posts
yup. things to check:

1. lights
2.cluster
-check for check engine light, should come on with the key on. If it doesn't...something isnt right
3. ebrake light

etc etc. just make sure you be VERY careful when you connect the battery. Touch the terminal and watch everything for smoke or a burning smell. Dont want to connect it then realize something is shorted and melt your entire harness.
 

· Registered
98 RS Now with more interior!
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11,329 Posts
What swap? Probably not because if you don't have a motor you don't have engine grounds. No engine grounds, nothing is going to work right.
 

· Mobile Diagnosis Guy
97 Impreza L
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5,319 Posts
psh, i dont have a motor....just grounded all of hte wires to the chassis...no biggy.

Yes, you cant test much, but you can test that there aren't any major problems like shorts. My car is wired (by me) (awaiting my built engine) and i put the battery in and tested the ECU, fuel pump, lights etc.
 

· Registered
98 RS Now with more interior!
Joined
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11,329 Posts
psh, i dont have a motor....just grounded all of hte wires to the chassis...no biggy.

Yes, you cant test much, but you can test that there aren't any major problems like shorts. My car is wired (by me) (awaiting my built engine) and i put the battery in and tested the ECU, fuel pump, lights etc.
Did you wire a WRX ECU?
 

· Mobile Diagnosis Guy
97 Impreza L
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5,319 Posts
I don't.

Well if you ever do an STi and don't have the engine in it does some really wacky stuff.

STi stuff is weird, i did an 07 STi swap into a 02 WRX wagon....we didn't know that we needed to "calibrate" the pedal (throttle by wire)...imagine our suprise when we took it out for a test drive and after going close to WOT, the car idles at 2000rpm no matter where the throttle is at. Lesson learned.

how wacky came it get without an engine in the car? lights flashing or something?
 

· Registered
1998 2.5 RS
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2,032 Posts
Discussion Starter · #12 ·
Ok so I got it all back in and threw a battery in there. I get most of the stuff functioning as normal. There are a few things that I have noticed that are odd.

First, the fuel pump doesn't prime. I get 11.5V at the FPC and 10.4V coming from the FPC. I also get 10.4V at the fuel pump plug, so I'm guessing that the "brand new" pump that came with my swap is not any good. Is there really a difference between the 98 RS pump and the 07 WRX pump?

Also the blower works only on high speed. I know this is usually a symptom of a bad blower motor resistor, but it worked fine when I started things. Could banging it around while taking out the blower box have messed it up? What are the normal readings for resistance?

Also is there any way to check if the immobilizer is functioning properly? There is signal sent to the fuel pump, but is that proff the immobilizer is working?

Any help would be appreciated guys, thanks.
 

· Registered
98 RS Now with more interior!
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11,329 Posts
It's easy to check. Pull the resistor out and see if there is a piece of metal making noise. Kind of like a dead light blub. You can actually fix it. If you cut it open you can solder the part that came off back on. You are getting different voltage at the FPC because it's doing it's job. It's modulating the ground so that your fuel pump does less work at idle and when you hit the gas it will dump more fuel.

As far as the immoblilizer you could hook up an LED to the security light wire from it. But it will turn on the fuel pump when you put the key on, however the pump will stop a few seconds later.
 

· Registered
1998 2.5 RS
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2,032 Posts
Discussion Starter · #15 ·
Ok pulled fuel pump back out and connected directly to a battery, it runs. Put it back in the assembly and did some more testing, still doesn't work. Rechecked all the connections they are all fine. When I bypass the FPC it runs. I notice that when the FPC is connected it gets a voltage, but no amps. I'm hoping this is one of those strange things you talked about Keener.

Oh and the resistor was bad. A little ball of solder had fallen off. Resolder it, and its good as new. Thanks a lot!!
 
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