First post new member. Reciently bought a 94 sc300 produced 8/93 131K. Was diagnosed by previous owners NEIGHORHOOD machanic not Lexus as #6 ignition wire SHORT but plug OK? Dont know if they pulled the plug to test I assume NOT with coolant/oil in well (hope not) but they diagnosed as thowing (5) trouble codes only one given on service sheet was p0306 which should be an OBD2 code? How they assertained that I dont know? Shop also said oil and coolant in spark plug wells but no repairs performed by shop or previous owner. I drove the car home (a short distance) with check engine light and off track lights on. Car has been driven less than 100 miles sice last diagnosis. Seemed to be running on 5 cylinders? Disconnected battery ( neg terminal heavy oxodation 1 wire short at headlight repaired and broken antenna removed) to let her sleep and reconnected for small drive (running better no offtrack) and then engine light re-appeared. Did the paper clip OBD1 test and got code 25 running lean. Decided to remove TB including Y to replace wires, plugs, and valve cover gaskets, coolant hoses etc. The TB was heavily gummed up needs lots of CRC! I removed the neg terminal then the TB that EGR's a PITA, cleaned out the spark plug wells and pulled the plugs pk20r11 most all looked pritty good (all dry) but #6 looked possibly corroded AHHHH. Before reassembly feel it prudant to do a compression test possibly bleed down to check overall condition of head. The service history says head gasket replaced at 99K due to overheating problem. Apparently #6 had an emerging leak cought early?. The head was plained and head gasket, radiator, thermostat, replaced by reputable Lexus machanic problem of overheating solved. Now the questions!
1. Is it safe to battery crank the engine with TB off or do I need to hand crank compression test?
2. Whats an acceptable drop from high to low compression between cylinders?
3. Any easy way to clean valve, injector deposits w/o removing head?
4. Motor was noisy at shut down possible water pump but pump was inspected found good when overheating problem was resolved at 99K. Timing belt replaced at 89K. Figure I'll get it running on 6 (hopefully) before I can determine water pump failure or some other cause for noise. Any other possible cause of noise (pullys )other than water pump?
5. Anyone know of parts store that rents compression tester? Thanks for any reply.

 

New member second post: Hello everyone some are reading my first post but no help, feel free to help me out. Got ahold of a compression tester and performed the test this morning. My readings front to back are 198, 200,212,210,218,200. With the acceptable range of 156-185PSI I'm high! Looks like HEAVY CARBON DEPOSITS with the carbon I encountered in the TB and EGR thats not surprising. What do you think could it be anything else? Any easy fix w/o removing the head? I understand the previously owner burned regular gas! What gas conditioner should I use Seafoam? I'm a little concerned about reading #5 cylinder #6 by firing order 1-5-3-2-6-4. By the way should have mentioned in first post both oil and coolant looked O K. allthough I haven't flushed either yet though. I planned on installing new Denso PK20R11 with Denso wires but with so much carbon should I consider a hotter plug.
I'm having a problem locating a heater hose, its the one at the back of the engine top behind #6 plug and behind and between the valve covers. Both Dayco and Gates have incomplete discriptions and the local part stores are somewhat mystified that the 3 bypass heater hoses in stock for the car are not the one I brought them. Lexus and Toyoya can't definatively give me a part # since the engine diagrams are vague so I can't order the hose with any degree of certainty. It's a molded hose and I'd perfer an OEM replacement . Anyone got a part # for this heater hose from Gates, Dayco Toyota or Lexus? Anyway got to get it backtogether soon as its getting cold in Massachusetts please respond NOW if you can help. Thanks Peter

 

Got the hose Gates 19125 and ordered Denso distributer and rotor I'm surpried she ran at all, rotor had less than a 1/4 inch on the bar.

 

Next in line should get it done then see if she runs right.

 

Your numbers were cold, so the 15 psi difference between cylinders is negligible.

Usually the service limit is 15 psi between cylinders warm, but it's a JZ engine. They are tough.

Also, for the love of god please split your paragraphs. They are incredibly hard to read.

Good luck.

 

Compression tests should be done when the engine is warm. Also, see if you can get your hands on a mechanics stethoscope and listen to your injectors when the engine is running, you should be able to hear them opening and closing. They will produce a "tick-tick-tick-tick" sound. As for that heather hose problem, stop talking to whoever you're talking to at the dealership and find someone who knows how to work the Toyota and Lexus parts database. There are diagrams for EVERYTHING, they should have had NO issue finding that hose considering that you could be in a coma and that hose would slap you in the face when you open the hood.

Another solution to your deposits would be seafoaming the engine. There is a MASSIVE thread on this. read up!

-Cam

 

Thanks Spool and Cam both for responding,

The hose was more trouble than it should have been it was out of stock in five local parts stores no in hand and 3 days wait, whats up? My local Toyota dealer coulden't find it on a Supra since apparently its a different setup with the heater valve. I had two ES's and accessing parts through Toyota is easier than on the SC.

I don't see how you could get a warm compression test even while only splitting the TB. I'm not that quick.

Anyway it's REALLY good to read that 15 lbs between cylinders is an acceptable reading on a cold engine,

I'll readup on Seafoam as I plan to change out the Fuel pump flush some old gas and get a fresh mix of high test + going.

What's my best option for door window gasket seal, the bottom strip where window drops, any help is appreciated got a leak and its raining.



Thanks Pete

 

For the compression test, Take two three inch 5/8" pieces of rubber hose. Plug one end of each hose with something and then secure it with a small hose clamp. Remove the coolant lines that are running through the throttle body and use the two make shift plugs where the lines hook up to the engine block. Make sure you use clamps to secure them. Go for a drive and warm the car up to operating temp. Pull back in the garage and get moving on the TB separation. No hot coolant or tricky lines to worry about. Should shave 30 min off the TB part.

 

I've always loved the styling and engineering of the sc300. The Es300 is nice but its no SC so I finally got the car, a Jade 131K 1994 sunroof auto (yes auto) no spoiler that is/was a project car and priced right. I'm a happy camper!!!

Negatives were/are leaking bypass heater hose (Gates 19125), broken door handle passanger (clip) ebay, drivers door leaking window felt seal (serious rattle) and misplaced broken part left in door well (what were you thinking leaving a broken part in the door fella), broken antenna (motor good though) Radera ebay, smashed bumper cover replaced w/Jade OEM (almost perfect) off a 1992sc (Two Chiefs Carolina), broken head light (parts yard), dented left front fender (pulled), poor running engine (ongoing).

Positives sc300, excellant interior VERY CLEAN, no rust (little crud over windshield 6" though (eventual crop out w/new channel) before repaint, solid body, new timing belt @89K, new (used) transmission from "97" w/60K on it @110K, new radiator, head gasket, thermostat, cam-crank-waterpump seals coolant flush @99K, new starter @ 122K, new tires @111K, like new exhaust. Past owner put a LOT of money into this car in parts and repairs and probibly had CHECK BOOK FATIGUE hence parts car price and its yours take it away!!! My friends said the engine was shot no way its OK for the price. HAHA

My greatest fear after initial drive was the head repair was insufficient and returned then I was back to a rebuild. Anything short of that including water pump and timing belt and I'm happy. So far so good.

I thinks the plugs ,distributor/rotor, wires, fuel filter were all original. Replacing all with OEM Denso except Bosch fuel filter 1/3 the price of Denso. The TD was DEEP/DEEP in carbon and the EGR seriously clogged, the ROTOR I can't believe it was still running GO DENSO, holding on by a thread (literally) about 1/8 of an inch on the bar. Really 1/8" and still running YES the 2JZGE IS REALLY TOUGH.

As long as I can get ALL the vacuums line back in place I may be surprised and my time will be well rewarded. New high test and SEAFOAM. In any regard this car deserved a better fate than as a parts car. Only needed love and a 90K tune. YEHA lets get going. Times a waiting.

Thanks to all who have added to the library of threads that have helped me so far, its so much easier with access to Club Lexus to get the nuances of this car down so as to get the job done RIGHT!!!

Thanks Pete

 

OK put it all back yesterday and I was plesantly surprised it started right up. Running rough at first but then after warming up and reving the engine a few times it's running smooth again. No black smoke and no hichups VROOM VROOM. I guess I got all the vacuum lines on right (pritty easy with hose memory) took a test run and no engine lights and temp is normal. Looks like its running clean and on six again. Move to the next issue!!!

Now the front end engine noise? At 89K timing belt was done I assume the water pump was replaced but I'll need to check with the garage. At 11/01/06 @ 98K an over heating problem was dectected. New thermostat, radiator, camshaft seal, crankshaft seal, waterpump gasket (water pump inspecked OK). Finally head gasket replaced and problem solved. My point is after water pump inspection and belt replacment so receint (miles wise) abiet in 11/01/06 only 33k miles but 5 years. Could the engine noise be something else or am I trying to look past the obvious.

Other possible causes fan assembley pully bearing, worn serpintine, timing belt tensioner. Any other possible causes? Those other solutions addressed then its time for WP and Belt. What's the best way to diagnose the root cause while excluding the good parts and not throwing money at the problem and replacing everything. HELP

Is there any way to know without physical inspection weather I've got a 10 or 11 nut water pump on a 2JZGE produed in 8/93? Also I know Aisin WP is OEM how about timing belt and tensioner what are quality and priced well?

Thanks Pete