Restoring My '91 Es 250

[tmaki]

I've finally got the resources together to do a restoration. I bought my 250 10 years ago and have put 120,000 miles on it since then (ready to roll over 170,000). I can't bring myself to part with it, so I've purchased two more - one with overheated/shot engine, but decent interior and body parts, and another with excellent interior and mostly excellent body parts and 79,000-mile engine. This latest one was garaged-kept and properly serviced, but was struck by a truck on the right side, crushing both doors and pillar. The car is otherwise great, drives like a new one, etc. I've got about $1600 invested in both donor cars, so that's not too bad.

My original 250 overheated (split top radiator tank) in the mountains a couple of years ago, and I had a shop put in a Camry 2VZ-FE engine. It seemed to be the right thing to do at the time, but they didn't do some of the things they promised, and now I've got a miss, two codes (25 & 26) and a constant CEL. Another shop said the miss is from a "dead cylinder" (on the back side of course). I have my doubts - you can't check the compression without taking off the air intake, and nothing under the hood looks like it was touched. $210 for parking it on their asphalt overnight.

Anyways, I've made the decision to go ahead and do this restoration. My wife thinks I'm nuts, but there's no other car I'd rather have (except maybe a PT Cruiser). Maybe I can get a few more great driving years out of this one.

Thanks for this forum. It's good to know a "support group" is out there. I may ask questions or vent a little as I go through this. At least I'm not in a hurry. Any comment or advice is welcome. Pointers or "gotchas" from the experts also welcome. I have the factory service manual, and the tools and skills.

Didn't mean to go on so long, but wish me luck. It's an adventure!

TM

[Toysrme]

Welcome!

Code 25

Air/Fuel Ratio Lean Malfunction

The Air/Fuel ratio feedback correction value or adaptive control value continues at the upper (lean), or lower (Rich) limit for a certain period of time

Code 26

Air/Fuel Ratio Rich Malfunction

The Air/Fuel ratio is overly rich Open or short circuit in the oxygen sensor

If you think it's missing a cylinder, just pull the rear bank spark plug wires one at a time. If it runs the same when you pull a certain wire - that cyl is having problems.

Otherwise, I would replace the o2 sensor with the cheapest Bosch splice in unit you can find.

The 2vz-fe seires II used for 90-91 has an o2 sensor. 87-89 Seires I had no o2 sensor

If they put an 87-89 made 2vz-fe in your car; not having any form of o2 feedback, obviously, you will throw codes 25 & 26. I think they put the earlier engine in your car (or you've got like a broken o2 connector). It's very, very, very, very unheard of for the old OBD-I ECU's to complain about the A/F ratio no matter how far of it is. The only time they even store codes for it is when you put them in Diagnostic mode.

If you have the wrong engine, after you burn their shop down, either get the pipe where the o2 sensor goes off another engine, or drill holes in your pipe to weld a bung on.

[tmaki]

[quote=Toysrme,Oct 13 2005, 06:51 A

<good info snipped>

Thanks for the info and tips. As to the year of the replacement engine, I don't know. Is there coding in the engine number that will give a clue? (Sorry to appear ignorant, but my background and history is with Detroit iron that I grew up with in the 50s and 60s. I'm a little behind the curve since the late 70s. Too busy running a business, etc. to keep up with the automotive minutiae).

I've been thinking that the miss problem is an oxygen sensor or something similar. The diagnostic tree in the manual lists so many things that it is nearly overwhelming just to go through the list.

What's been strange is that the engine ran very well for several months, and then the CEL lit up. Admittedly, I'd been using regular gas (although always Chevron or Shell) for a while when the light came on, and a little miss started. I changed back to premium and after about two tanks (a couple of trips into L.A. and back) the light went off and the missing stopped. Hooray! It ran well for the next while, and the next day after buying a tank of gas in new place, the light came back and the missing started again, and hasn't changed since. I figure the new gas was purely coincidental. But the last shop I took it too that said the "cylinder is dead" seemed unable to explain how the car "healed" itself the time before. It's my experience that if a cylinder has lost compression (the reason they gave) they don't get better.

I don't know. But I'll do the checks you mention just to see. My ultimate goal is to change out this engine for the "new" one I just got, and put the Camry engine/trans up for sale. I ought to be able to get a few bucks for it.

As to the O2 sensor(s) - this is a California car, so there is another one near the CC - I guess I have to pull off the air intake to get to it? I can't even see it from the top.

Thanks again. My confidence level is increasing.

TM

[ArmyofOne]

Glad to see someone keeping a good 250 on the road. these cars were fairly rare. I am the resident expert here, along with JP Importz, ont he ES250. I have the toyota Service Manual. I completely Restored one myself. they are fun and fairly easy project cars.

any questions, feel free to PM.

[Toysrme]

The engine will run the lowest octane you dare buy just fine. Tho everything runs like &#33;Removed&#33; on E-85. Don't use that crap!

The older VZ blocks have more in common with old iron than you think. Don't let basic EFI scare you!

All I could tell you is find, or ask someone about the location of the o2 sensor on a 2vz, then check yours.