johngeiser

So I have a 1990 LS400 with 68k original miles. Runs amazing, besides the low pitch whine/hum, but its been like that for 2k miles and hasn't bothered me yet! (I'm pretty sure its the tensioner, new one is on its way)e r

But I ALWAYS fill it with 93 octane. ALWAYS.Well, I let my brother drive it. He ran it so low on gas I doubted its ability to get to the gas station. And it's the only one for several miles. I pull in...they're out of premium. And mid. I was livid. So I reluctantly put $10 worth of regular in my tank, full of shame. Then i drive home and to work. On my way home my check engine light comes on. Did the whole OBD1 wire jumping thing. Codes 25 and 26. Could this be the garbage fuel I put in. It runs totally fine. But would fuel cause that?

cgawelko

code 25 and 26 would be????

But also think about this part. 68k original miles means that puppy sat a bit. You run it down to the bottom of the tank, god knows what is lurking down there that you sucked up.

johngeiser

Code 25 and 26 are Air/Fuel mixture too lean and too rich. I'm assuming its the fuel, however it could be another issue, like o2 sensors or MAF or something of hat nature.

timmy0tool

iTrader: (7)

first i would put premium gas in there as soon as possible, clear the codes and see if they return. it is possible gas could be bad, i mean never have i run in to gas stations where not one but TWO types of octane are tapped out! i would question the gas station.

python

iTrader: (4)

..coincidence maybe, but those codes are 02 related

Yamae

Those totally different two conditions too lean and too rich are often caused by the unballanced or worn out injectors. Sometimes a partially clogged and another badly clogged injector show the problem too. The ECU tries to compensate the gas and fuel ratio but unbalanced injectors can't be controlled well enough. As a result there happens the condition too lean and too rich.

python

iTrader: (4)

I had both of those codes..i replaced my 02 sensors..fixed the issue. have a shop check to see if they are switching properly

johngeiser

Well, I have a 4 hour trip coming up tomorrow. So I filler her up with premium, cleared the codes, and it hasnt come back in the 30 miles I've driven. If they come back I'm going to replace the o2 sensors. So we shall see. I will report back with my findings.

python

iTrader: (4)

good luck..hope the codes don't come back...weird if they don't tho

Yamae

I don't think your problem codes 25 and 26 is caused by the regular gas. What I worry about is that the fuel pump had to pump out the remaining gas and others. As you wrote, the fuel tank was almost empty and the pump was pumping out not only the gas but also some objects like dusts and small particles accumulated in the tank for the past 24 years.

I have seen workers were collecting gas from fuel tanks at a junk yard. I could see small foreign objects a lot at bottom of the collecting tank.

This is just my guess but your fuel filter must have stopped most of those foreign objects but very small pieces which passed through were sent to injectors. Since those were very small and those didn't fully block the passage but temporarily disturbed the gas to be injected required amont. Then those passed through the gate of injectors and the injection was recovered. At the transient of the cycle, there happened the problem too lean and too rich.

I just asked this to a shop owner who often calls me for a help about the ECU and related affairs. He said, “There come drivers like you mention time to time. Don't drive an old car when the tank is almost empty. It causes fuel line problem quickly”.

I hope your fuel filter is not clogged too much.

Kingsoup

I'm with the other guys, its probably just a coincidence. I've run my car on 87 for longer trips and its totally fine, it just pulls a bit of timing to compensate.