95 Lexus Es300 Wont Run After 2 Min

[carsan]

Hello i have a es300 with a build date of 9/95 it does have an OBDII port so i believe its actually an 96 model year.

it was runninig great then all of a sudden lost all power, it will idle but if you give it gas it revs up a little and spudders and dies, it never really revs up completely. when you first start it it runs great for about half a block.

when i check the codes at first start up when its running good theres no codes, after i let it runn for a minute or two and it starts running bad the check engine light comes on but when i go to check the codes it says no communication, check cables and recheck after doing it a couple times just to make sure it wasn't me or the scanner, got the same results.

it has 200,000

new timming belt from dealer at 106,000

plugs, wires, air , and fuel all good

PLEASE ANY HELP WOULD BE GREAT

[George_Jetson]

Check voltages at several spots, such as battery, alternator output, and some of the main fuses in the power distribution box. Check both DC voltage, and AC voltage. It sounds like a ECM problem, but you need to eliminate other possibilities before replacing the ECM. If there is any damage to the batter terminals, or any other odd things going on, Such as intermittent Tachometer, odd things with fans, or lights, make note of them. These might indicate the next possibility of what you should look at.

[carsan]

When i said it lost all power i should have said the engine lost power, i checked voltage at several points, runninig and not, and it seems to all be good, always above 12v and over 13v when running at the battery.

[George_Jetson]

I would suggest checking the 12 volts at the ecm connector next. There are to 12 volt inputs, one is constant, and the other is present only when the ignition is on. I would monitor both, wait until the engine starts acting up. Also check the grds to the ecm (making sure to monitor it while it is acting up). I would also do the same at the OBDII connector (not that I think that is the problem, but I think that it may possibly reveal a symptom). If all that looks good, shut the engine off, remove the battery grd terminal, and then remove the ecm. Open it up and give a good visual inspection for corrosion, or signs of heat damage.

[Funkdoobiest]

I would also check your intake hose to see if it's split open, they all go bad. This caused the same symptoms on my 94 and my buddy's Avalon(same engine and intake hose).

[carsan]

I would also check your intake hose to see if it's split open, they all go bad. This caused the same symptoms on my 94 and my buddy's Avalon(same engine and intake hose).

Hose has already been replaced, but yes it is the same type of problem just alot worse.

thanks

[George_Jetson]

It doesn't sound like a hose issue in this case. The fact that you lose communication with the ECM when the engine starts to run poorly, points more to a electical problem. Once you have eliminated the 12 supply and grds, you should inspect the ECM. The fact that once it cools off, communication is re-established, and the engine runs well tends to confirm this. But before suggesting that you replace it, you need to confirm that the power is good. Make sure to measure the AC voltage because problems with the full wave bridge rectifier inside the alternator can really freak out a computer. Unless you place your meter onto the AC scale, you will not see some of these symptoms.

[carsan]

It doesn't sound like a hose issue in this case. The fact that you lose communication with the ECM when the engine starts to run poorly, points more to a electical problem. Once you have eliminated the 12 supply and grds, you should inspect the ECM. The fact that once it cools off, communication is re-established, and the engine runs well tends to confirm this. But before suggesting that you replace it, you need to confirm that the power is good. Make sure to measure the AC voltage because problems with the full wave bridge rectifier inside the alternator can really freak out a computer. Unless you place your meter onto the AC scale, you will not see some of these symptoms.

as long as im checking it right it is NOT losing power, could it have to do with going into closed loop? and can you keep from going into closed loop.

[George_Jetson]

I would think the fact that you are loosing comunication with the ECM, while the engine is acting up is the most significant clue. You should be able to comunicate with the ECM whenever the ignition key is on, (engine running or not, hot or cold). This is why I believe that you should look very closely at a electrical problem. Checking both the supplies, and grds, because the next logical step would be to open the ECM and inspect for any signs of dammage, and then replace. But this is of course expensive, so that is why I am stressing that both the supply and grds be checked closely.