P1105 is Fuel pressure solenoid malfunction (turbo) in my manual.

Look at your fuel rail. Then trace it to the end of it (driver's side). There should be a small BOV looking thing bolted to the end of your fuel rail. With this, a vacuum line should extend up to a black plastic looking piece alongside your firewall. That is your fuel pressure solenoid. Try cleaning out the connection with some electric cleaner first and then reset your ECU. If not, your FPS will need to be replaced.

Hi!

I had the same problem with my 98 GSX M/T last year. I replaced the fuel pressure regulator, but the CEL was still there. On a hunch, I started running "good" gas from Shell (Shell V-Power) and after two tankfuls, the light went off. I was running cheap premium crap because gas prices had gone up so much, but I won't any more. I also think I have a vacuum/boost leak, which I haven't diagnosed yet, but give the gas thing a try.

Good luck!

I got the same code:1105 after pumping 91 chevron.......evrything is completely stock on my 97 gst. is it really jus my fuel pressure solenoid failing? is that all i need to replace??

97gst_707 said:

I got the same code:1105 after pumping 91 chevron.......evrything is completely stock on my 97 gst. is it really jus my fuel pressure solenoid failing? is that all i need to replace??

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Well, I don't drive my GSX much anymore, but two years later, I still have the P1105 code and the CEL. As I said before, it began coming on when I used cheap gas, but now it's on all the time. I've tried replacing the fuel control solenoid, checked for leaks, replaced the manifold O2 sensor and still no luck. I might try the downstream o2 sensor next, or finally break down and take it to the dealer.

Thanx man, well i jus reset my CEL and drove it yesterday and it hasn't come back on yet....hopefully it stays off.

As Tom said, clean the connections and check the vacuum lines. Otherwise the sensor needs replaced. Just running better gas won't help.

95blackGsTurbo said:

As Tom said, clean the connections and check the vacuum lines. Otherwise the sensor needs replaced. Just running better gas won't help.

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What sensor are you talking about? I've checked all the vacuum lines under the hood, checked connections on the Fuel Pressure Solenoid (FPS), replaced the FPS. I even monitored the FPS control voltage...0 volts on start-up, then 13.5 volts after several seconds, which is what it's supposed to do. I reset the CEL and it still popped back on after the car warmed up, so it's not that. Any other ideas?

95blackGsTurbo said:

As Tom said, clean the connections and check the vacuum lines. Otherwise the sensor needs replaced. Just running better gas won't help.

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its been a few days and it hasnt come back on.....but if it does i will definitely clean my hose and connections.

blcknspo0ln said:

Look at your fuel rail. Then trace it to the end of it (driver's side). There should be a small BOV looking thing bolted to the end of your fuel rail. With this, a vacuum line should extend up to a black plastic looking piece alongside your firewall. That is your fuel pressure solenoid. Try cleaning out the connection with some electric cleaner first and then reset your ECU. If not, your FPS will need to be replaced.

Click to expand...

does this have anything to do with the front O2???

this shouldn't have anything to do with your o2, if your o2 was bad, you would be getting different check engine codes.

I'm having the same problem with my gsx, I already replace my FPS with another used one, my next step is to replace all the vacuum lines and add small hose clamps/zip ties to the lines coming from the Mani... if that doesn't do anything I'm going to check the wiring

I clearly over tightened the bolts at some point I'm sure, duh at least now I know the specs and stuff and I really appreciate the help guys. I guess I could give it a shot and try to clean it up and paint it before ordering a fancy new powder coated one. Should I just use High temp spray paint is there a certain temp I should shoot for?

I will say this I am minus a heat shield and its hotter than balls under there because of it, I really need to take care of that somehow just cant seem to find anywhere to get one since I changed the O2 housing to 3 inch and somewhere along the line my original one got lost so cant mod that one. I did see a guy on this site that looks like he makes a nice one.

I read that thread you linked to about the FPS and regulator I'm going to clean that stuff right away and focus my attention on the fuel problem as soon as I get this valve cover sorted out.

Thanks again guys.

Just wanted to throw in the fact I replaced the 02 sensor when I did my plugs and stuff so it is like brand new.