nezlyfe

Hello all, car was fine and went on vacation for a week and now car isn't working. here's the run down of what i've done to help narrow things down. i'm thinking the fuel ecu but not sure how to test that one other than just bypassing it. I can get the car to run if i power the fuel pump manually or if i prime the system like 5 times but then dies once the fuel rail is drained/low pressure i guess. I can hear the fuel pump running with the car on so it is powered but maybe not enough? the car is not responsive to any throttle and "pops" almost like not more air is going in but not enough fuel.

-battery checked, disconnected and reconnected, even charged it again
-fuel pump/filter checked (replaced both since i had new and been meaning to do it)
-fuel reg on fuel rail does move up/down while cranking
-not immobilizer, no flashing security light, tried 2 different keys
-spark plugs/coils good
-no codes

when i prime the system as mentioned above and not give any throttle it runs fine, idles i mean, for 15-20 seconds, give or take, so i don't think timing is an issue either. Its a 2003 GS300 with 206k, thanks.

Mr Jokster

iTrader: (8)

Can you explain what that ^^ means

Is it possible you have no gas in you tank?

nezlyfe

I mean I turn the key on/off 5 times so it engages the fuel relay which should cycle the fuel pump a little. and yes there's a little over a quarter in the tank (visually seen with fuel pump removed) which wouldn't explain the issues out of no where

Mr Jokster

iTrader: (8)

Ok, just read it agian. This part helps a little.

Try this. Unplug your TPS sensor, get the car to start, then hold your throttle to the floor. Yes to the floor. Not sure if you know, but that last inch of throttle (at the floor) opens the throttle body mechanically at about 10%, rather than electronically. If by flooring it DOES give you some throttle response, they it may be a sensor issue. Either a MAF, TPS or APPS.

This is just a start. Those sensors will give your issues of 'not enough air' or 'not enough fuel'.

nezlyfe

to the floor it'll hold at about 1600rpm...it didn't die right away this time or maybe i didn't run it long enough to die. ran rough but it ran, so what does that mean the tps sensor?

Mr Jokster

iTrader: (8)

I'd start with the cheaper "fix", the MAF sensor. Clean it out and see what happens. Know anyone near by with a GS to swap the MAF just in case?

If it were the TPS or APPS, I believe the car would stay on when you unplugged the TPS, but I could be wrong. I'm leading more towards the MAF. No, I'm not an expert, but its just my educated guess by my experience and studies. It too could be an o2 sensor, but not too certain that would shut it off so soon.

nezlyfe

Went to the local yard and picked up a throttle body with all the sensors. Got rained out so cleaned it and the MAF. Installed and slight hesitation and delayed response. Disconnected MAF and good response. Reconnected and now everything was fine. Put 1500 miles and no issues starting or anything.

burteboy

I understand you said there is fuel but adding a couple of gallons would not be costly. If that dont help check you efi relay or the fuel pump controller.

silverbul

Cleaning the throttle should be a regular routine maintenance thing. My car use to cut off whenever I took my foot off the accelerator coming to a stop. I had to put the car in neutral while in motion & use my left foot for braking & keep my right foot on the accelerator to keep the car idle. Once I cleaned the throttle with carb spray & brush & got all that carbon buildup off, I have "0" issues. But I do clean twice a year. I use the spray gun cleaner kit brushes from harbor freight. Gets right up in there and cleans.