HELP! 4AGZE Engine Bogging - Toyota Nation Forum : Toyota Car and Truck Forums

ericlee303 · 04-07-2002, 05:35 PM

Something strange has happened to my car, and I think I know what it is. After a spirited day at the drags (more about that later!) I was driving home and everything seemed fine.

Later on that night, I noticed that the motor was bogging when given throttle/boost. I think I'm losing fuel pressure somewhere, likely in the old fuel lines that are rusty. (scheduled to be replaced because of this). But I am not seeing any fuel on the floor when I'm parked. I checked the Supra fuel pump that we installed a year back. That appeared to be in tact and working properly. Does this sound like a fuel pressure problem, or could the problem be in the injectors? The fuel map and other settings also appear to be okay as well.

Help! Any suggestions?

Eric Lee 303

bondobondo · 04-07-2002, 08:10 PM

air or spark

check both.

ericlee303 · 04-08-2002, 12:59 PM

Andrew you are right again (I think). This is wierd. The oil cap can't hold the pressure so it leaks. Where does the oil go? Pools up by the spark plugs, of course! Looked in the vicinity of the spark plugs and there is a pool of oil in there. I'm probably losing spark through the oil. At least the oil will eat away at some of the grime in there! I'll try it out and see what happens! Thanks man.

goodcookiedrift · 04-08-2002, 01:16 PM

you sure its the cap and not seals? the same thing happened on one of my earlier 86's...still yet to accurately pinpoint the problem.

ericlee303 · 04-08-2002, 02:17 PM

yeah, I can see the stream.

ericlee303 · 04-08-2002, 10:55 PM

SIET !!

That's not it..I cleaned all of the oil up and it still does it. WTF could be wrong? I'll try replacing the plugs or something, and on Thursday I'll replace the fuel lines.

goodcookiedrift · 04-08-2002, 11:31 PM

o2 sensor maybe? afm? vacum leak?

ericlee303 · 04-09-2002, 01:04 AM

Can't be O2 because I don't have one (and still passed emissions, hehe!) I'll check other sensors if plugs aren't the problem. Someone from the toyota mods list suggested that hard runs at the track damaged a plug or wire...

bondobondo · 04-09-2002, 01:06 AM

i think plug or wire

take off all the leads and put them on again

you check all the plugs too? try replacing with an older set and see what happens.

check for vacuume leaks too.

ericlee303 · 04-09-2002, 11:30 PM

Nope. Replaced the plugs and still no go. I'm not so certain it's the wires either. I called SDS and they suggested replacing the Throttle Position Sensor - he said that they tend to go bad fast on 4AG motors. Has anyone heard such a thing??