GhostEcho

Greetings Everyone,

I recently bought a 1993 LS400. I've had many problems with it and I'm hoping that experienced owners could help me figure things out.

Service History
The car had been sitting for about 2.5 years when I purchased it from a friend in May. It wasn't running properly. Since then I have done the following work to it...
*Fuel tank flushed and cleaned
*Fuel filter replaced
*Oil changed and oil filter replaced
*Battery replaced
*Alternator replaced
*Two tail lights replaced
*Throttle body cleaned
*MAF replaced with a junkyard one (this was due to shifty mechanics I originally dealt with)
*Replaced ECU with a refurbished one (this fixed the lack of acceleration I had and other issues)
*Replaced coolant temperature sensor

Inspection Issues
I first got it inspected after I replaced the ECU. Here is the pertinent information from the first Vehicle Inspection Report (New Jersey) in early June.
*Everything passed except Mode: Idle FAIL (HC ppm 241 - Standard 220)

I figured it was dirty from sitting so I ran a tank of premium with Valvoline Fuel System Cleaner through it, and then another full tank of premium through it. It has been running rich from the start so I replaced the coolant temperature sensor as suggested in a thread on here. Here is today's report. It got even worse over the last month.
*Mode: Idle FAIL (HC ppm 335 - standard 220 and CO% 2.30 standard 1.20)
*Mode High Idle FAIL (CO% 2.08 - standard 1.20)

I am truly at a loss. I am on a very limited (almost non-existent) budget and I need the car so I can get a reliable job. Does anyone have any idea what is causing the emissions? I will provide other information about the history of the car or recent events if I am able to.

Thank you very much,
Gavin

Justin2JZ

I suggest you clean the MAF with some cleaner. Welcome to the club and Im sorry about all the **** youre dealing with with the car. Check out the o2 sensors as well.

RA40

iTrader: (6)

Welcome to Club Lexus.

That's EGR related. Good thing is you already replaced the coolant temp sensor. Check the vacuum to the EGR valve, for proper operation. Fix as necessary, EGR valve and or any vacuum hoses. (By now, many of those will be hard brittle and possibly split resulting in a loss of vacuum.) Clean-replace the EGR tube which in high probability is plugged up.

Read any codes which I would suspect would show as O2 sensors in one or both banks being bad. Replace those and your inspection/smog test results should result in a pass. Also change the gas cap.

Caniac14

You have to pass emissions with a 1993 model? Here in NC anything 1995 and before is emissions exempt. Even the CEL can be on. Not to mention I thought Jersey only had safety inspection?

GhostEcho

Thanks for the welcome and advice everyone.

I am trying to perform these bits of maintenance.

http://www.lexls.com/tutorials/emission/egrfilter.html
http://www.lexls.com/tutorials/emission/pcv_valve.html (waiting on parts for that)

I can't find the Vacuum Modulator Filter. The tutorial engine in that link looks different than mine. I'll try taking off some of the plastic covers and seeing if it's underneath.

I have heard EGR and O2 sensor repairs are very expensive. I hope I can get this done without selling a kidney.

RugbyDad

It used to be something like that but it changed in 2010 I think. Safety and Emissions inspections for ALL. Except a wide range of vehicles, mostly diesel, electric, and commercial vehicles. There is 1 aside. Apply to register your car as a collector vehicle. I mean you can't drive more than 3000 miles a year (no idea how the DMV would monitor such a thing) but you don't have to pass an emissions test.

Caniac14

That's pretty weird and lame.

As for the DMV monitoring miles, assuming you have to get an inspection yearly before plate renewal like here, they would just record the cars mileage during the inspection, and if it's over 3000, they fine you.

I did a special registration that only allowed a certain amount and I went over by 2k. So I had to pay a $200 something dollar fine. 10 cent per mile over.

Doc Yota

My cousin had a similar issue with a 93 GS300. There is an additive called RXP that is kept behind the counter at most auto parts stores. You have to ask for it, its in a small orange bottle and it cleared his emission issues. Not saying it will solve your problems but its about 6 bucks and may be worth a shot.

GhostEcho

Thanks for the advice. I picked up a bottle and put it in the tank. After driving around this weekend I'm going to take it back to inspection and see what happens.

peterls

HC stands for "hydro carbons", in translation - fuel.
There is too much fuel in your exhaust, meaning your mpg suffers, and you fail the test.
It would be even better if you gave us all values, not just that one.

But for starters, your car is obviously running too rich at idle for whatever reason.

GhostEcho

Update on my car.

I want to thank everyone who took the time to reply and offer advice. I put a bottle of RxP into the gas tank, replaced the PCV valve and grommet, and disconnected and reconnected the battery. The 3rd time must be a charm, because today it passed NJ inspection.

Ironically, less than a mile after I drove off the check engine light and TRAC OFF light came on again. So it looks like there's more to do, but at least it's street legal. I guess I'll find an OBD1 sensor and try to get the codes and start doing more research. Thanks again!

Doc Yota

Glad you got past inspection. RXP is pretty powerful. If nothing else I'm sure it gave your fuel system a much needed cleaning but don't use it like you would your average fuel system cleaner. If your inspection print out says you still have junk in your system I would try another half bottle but wouldn't go much further than that.

RugbyDad

Have you ever used this RXP stuff? I been reading up on it and they just kinda market it as a more potent/less diluted run of the mill fuel system cleaner.

Doc Yota

Yeah a couple times. I had a CEL on my 02 LS430, and my 99 LS400 (at different times) and remembered my cousin used it with success and it worked for me both times. My neighbor works for O'Reillys and mentioned that its a great product but if you use it to often or incorrectly it may burn your injectors. When I used it on my Honda Del Sol it turned it to a rocket. Still trying to figure why... and a year later...its still running like a rocket.

Gene01

An OBD1 "sensor" is called a paper clip. If you have a pre '95 LS400, that's all you need.