JCC615

Help please! I bought a 2000 es300 with 163,000 miles. CEL came on and had p0325 and p1351. I looked up all the DIY stuff I could find and got busy on the p0325, knock sensor. Four hour job and I replaced both while I was in there along with a new wiring harness and the Rad bypass hose. For the p1351 I went ahead and replaced both OCV's, bank 1 & 2. Previous owner had done them before and broke the connectors, evidenced by zip ties. Anyway, hooked battery back up and she fired right up. Test drive only got me 3 miles before CEL came back on for p1351. Went back in and pulled the filters for both banks, and both were nasty. Reset everything, made it about 3 miles again before CEL for p1351. Decided to change the connectors. Lexus wanted $60. I went to the salvage yard and cut a couple from an Avalon, $2. Replaced connectors, tested with multimeter, all good. NOT! 3 miles to another p1351 CEL. Drained oil. Fairly dirty but no sludge or particles in it. Changed filter and filled her back up with new oil. 3 miles to p1351 again. Took front valve cover off, a little bit of sludge in the cracks and crevices, but not nearly as bad as some of the sludge pictures I've seen on here. Cleaned everything in that one best I could, holding a shop vac to everything I sprayed and brushed so none would be lift in there. Put everything back together, drove 3 miles and got the $#@! P1351 again.
Read that maybe I got a bad OCV. Took it back out and put 12 volts to it and it functioned. Put it back in and put 12 volts to it and the engine almost stalled, good test. Had also noticed all this time a little bit of a shake at idle and lights kind of flickering. Tested battery, low. Replaced old battery, same issues. Alt tested bad. Replaced. Issues remained. After research, swapped that alt for a 100AMP, power issues resolved but still get p1351 with very sluggish performance. ( My Hope was that somehow the power issues were causing issues with the OCV. Obviously not.) I'm at the end of my rope. ANY suggestions?

AmanES300

Check the OCV filters again. If they're clean, I'd take a look at the ECU and make sure it's OCV output is functioning properly. Check for corrosion on all the connectors too. Id also recommend hooking up an oscilloscope and check the signal the OCV is receiving.

JCC615

Thanks for the reply. I have taken the filters out every day this week (I can do it blindfolded now) and they have been spotless. The OCV I bought was a Dorman, so after MORE research I decided to try a genuine Toyota OCV. CEL after about 3 miles again! I don't have access to an oscilloscope, so I guess I better start searching the area for someone that won't charge me an arm and a leg to hook up.

JCC615

Also, is it possible it could be an ECU issue if there are no other codes or issues at all? If the ECU was bad, wouldn't there be other issues?

AmanES300

I'm not entirely sure about that, but its best to at least eliminate the possibility of it being the ecu by just checking it. That at least helps know what it can't be. Also, im sure you've probably seen this already but I found something: https://www.justanswer.com/lexus/9ws...gine-runs.html

JCC615

Read that one several times. I pulled the ECU and sprayed electric cleaner on all the ports and connectors. As far as timing goes, why would it run and drive fine for the first couple of miles? If it was timing, wouldn't it be crap from the start?

AmanES300

This is what that guy said: "The belt issue can happen virtually between starts. The 'slack' in the belt appears when the engine is running, if the belt is stretched."

How consistently does the code pop up? If it does it literally every 2/3 miles, then I suppose it could be a belt issue, stretching after the first couple of miles due to heat. but honestly I don't know much more.

I'd 100% try and get an oscilloscope on that OCV and make sure the signal it's getting is good. If you can't get that, I'd double check the continuity on the OCV connector, also checking to see if the metal tabs on the connector are properly straight, are angled the same way, and make a good connection to the OCV. Maybe the previous owner damaged those as well.

forgot to mention: check the sensor if possible. If OCV or it's connection were an issue, I'd expect a P1354 not a P1351.

JCC615

Thanks. I'll start looking for a reasonable shop with a scope. Also, Supposedly the timing belt was changed at 95,000, but it could have been a crappy belt I guess.

AmanES300

Check the timing

JCC615

Guess I'll get in there for another 4 to 6 hours to tackle the timing belt next.

AmanES300

Yeah I'm going to need to do mine as well soon. Don't know if/when it was done on mine so I have to assume it wasn't done. Pls update with how it goes. Would love to see it fixed after all your trouble.

JCC615

Absolutely. I'll let you know whether I figured it out, or it ended up in the bottom of the river. Lol. Thanks for your help.

JCC615

So, I've got it all apart and none of the marks on the cams or crank are lined up with the belt, so it appears my timing belt has slipped. I turned the crankshaft and aligned the marks on it with the timing mark on the oil pump, but when I do that the camshaft marks do not align with their timing marks. If I turn the crankshaft until the camshaft marks are aligned, then the crankshaft is not aligned. I've never done this before and all of the information I've been able to find just says to make sure all the marks are in alignment before installing the new belt. My question is, how do you get them all in alignment? I know the belt has marks on it showing where it should align with the cams and the crankshaft, but I first need to get the cams and crankshaft all aligned with their respective timing marks, correct?

LeX2K

You're over thinking things, line up the belt marks to the crank and cam gears and you're done. Make sure the direction arrows on the belt are pointing the way of engine rotation.

JCC615

So all that matters is that the belt marks are lined up with the cam and crank marks, no matter their position?