Fuel Filter or Fuel Pump Filter Replace??

[Rod K]

I have a '91 DX 5 speed wagon 4AFE FI, I replaced the gas after it sat for 5 years, (full tank of gas) I previously started the car it ran fine, now it can't idle for more than a minute without stalling. I waited several days before I started the car in case I disloged any junk at the bottom of the tank, Thats when my problems began, so should I replace just the fuel filter as its probably dirty, but should I drop the tank and replace the fuel strainer as well? AND is there anyway of checking to see if any of the crap got past the fuel filter and into the injectors without pulling any of them to test? OK what is the best start on my quest anyone???

[86camota]

I would just drop the tank and start from there. Just change the strainer and the filter. Play it safe. Then go from there. But thats me

[ERROLAE92]

building on the subject ... will recommend how to change the original fuel pump and put a jet of 3s ... and step change injectors upstream by 3s .. this for a 4AG

[cEtnA]

im honestly having a hard time understanding ERR

[cEtnA]

its not needed to change the fuel pump for a 4age unless your planning a big build

[ERROLAE92]

Originally Posted by cEtnA

its not needed to change the fuel pump for a 4age unless your planning a big build

I have plans to supercharge .... in this case if it would be necessary to inject more gasoline. this is where my question arises from the change of pump and injectors

[Rod K]

I have been told ther are 2 Toyota fuel pumps an Asin or a Denso. I am told you can use ONLY 1 type if the original is Asin then it is to be replaced with the same or Denso for Denso, but never mix 1 for the other. Is this true? What fuel pumps have any other Corolla owners used? I have changed the fuel filter, the car still runs poorly so it is off with the tank then.

I have no idea what "step change" is!?

[ERROLAE92]

spark plug wires and spark plugs? changed?
if you changed the fuel pump could be the problem of ignition and no injection ...

[Rod K]

I have not changed the fuel pump yet, I’m trying to find out which one I need, as I have been told if it is an Asin I must replace it with such and if it is a Denso it must be a Denso type. Only way I know for sure is pulling the tank down. DAMN! I’ve replaced the fuel filter only so far, the old one had large bits of crud in it so I am presuming when I siphoned the old gas out and poured the new gas in I may have swirled up the 19 years of crud on the tank's bottom and it has settled the fuel tank strainer. So I will be have a weekend on my back lying there and thinking of England… I guess that is a joke Americans won’t understand-sorry! Toyota Canada wants big bucks for either unit $400 and $500 for a pump. It is cheap in the states by more than half, even after duty. I’ll keep you informed.

[retiredat44]

why do you have to pull the fuel tank? in the corolla I have you pull a plate off the tank under the rear seat, and pull the fuel sending unit.. then there is a paper filts by the engine ont he firewall..

In fact since mine has a carb, and hence a fuel pump on the engine.. the fuel sending unit (in the fuel tank) is flaky, making the gas gauge send flaky fuel level readings... the fuel sending unit really should be replaced, but it is at least $50.00 the last time I did a search...

so we just fill it up with the 13.5 gallons whenever a week goes by..

[Rod K]

I tried that route by checking out the same year car at the wrecker, the only hole accesable from the floor the the fuel level guage, the fuel pump is at the very back at the rear of the tank. Thought my fuel level is fine, full is full, I'm just using less gas now-before all this with the synthetic fluids, the K&N and watching my speed.

[Rod K]

Since last here I have changed the fuel pump, cleaned the out gas tank AND installed a new fuel filter and the car still idles rough when cold start running @ 1500 RPM+ - then when warmed it will drop to 1,000 + -RPM and then suddenly surge back OR stall out completely.

So now everything is been renewed and replaced from the Fuel tank to Gas Filter. My next question onwards and upwards? Fuel Pressure Regulator dity Fuel injectors? or what else? Ignition - distributor cap and rotor are clean fresh and new. I am stuck. I also discovered my strutts needed replacing as well as the muffler so that took lots of extra time, mostly becasue I have so little time to begin with. Where do I go from here or what can I test? Fuel injectors clogged?? Fuel pressure regulator gone bad? HELP! PLEASE. I need my wagon back!


PS I even drove it around the 2 x's around the block, rather fast -well 25PMH it was after the fast idle kicked off, the car stalls even when driving it. SIGH!

[90 GP]

Try cleaning the IAC valve. It elevates the idle when cold. That may be causing your fluctuation in idle speed.

"If you want to clean the IAC then take off the intake tube and spray some intake cleaner into the hole on the bottom of the throttle body just in front of the throttle plate. This will clean all the crud off the passage and spindle of the IAC. Fill the passage with cleaner and let it sit for a couple of minutes. Clean the throttle body and throttle plate while you wait. Then put it all back together and start the truck. It WILL be hard to start; but don't worry about it. You're just letting all the cleaner get sucked in the intake."

[Rod K]

Thank you, I tired that PLUS I did the Seafoam thing and guess what? No Change! Dies on drop from fast idle to regular RPMs, I drive it it does at stops, taking my foot off the gas, down shifting and slowing and simply stopping. Yes it starts right up again and again. Oh I also filled up my gas tank $$$ OWCH! not like that made a difference except my wallet.

What to try next? Before I give up and pay somebody.

[90 GP]

Try checking to see if any trouble codes are stored . Check out the link on how to do it. Check all the vac lines in particular the one that runs from MAP sensor (on firewall ) to intake. Check the rubber seals where the fuel injectors mount in intake manifold for leaks too. Have you ever run a compression test on it see if you have a weak cylinder? Have seen some other posters that had slight head gasket leakage and coolant leakage into cylinder roughened the idle up. The compression test would rule it out. Is your temp gauge run midway when engine is warmed up? If not try replacing thermostat. The computer may be keeping engine in the cold mode

http://www.troublecodes.net/Toyota/