aomdedude1

Hey, I want to try and figure out what going on with Lexy.. Brought her to Pep-Boys for an inspection because my stickers just recently expired.

My car is a 1994 ls400.

P.S. : (Please don't ride me too hard for that, I know my FIRST mistake was most likely bringing it to "pep-boys", but I figured if it is just for a state inspection than I could save a few bucks that way... )


Well I brought her there and I went and bought a snack slice of pizza across the street and mingled around at the best buy checking out some tv's and laptops only to return to my car that FAILED emissions!!! The "master mechanic" (ha) said that my hydro carbons were at 157ppm. He said if it was at 150 he might consider letting me slide. He also said that because my check engine light was on I automaticaly fail anyway (which I firmly believe is bull ****** because my car is pre-OBD 2. I thought that any pre-OBD 2 car could have the CEL on all day and still pass inspection ) I was pretty bummed out because the CEL was OFF the entire ride down there (about 12miles). When I got in my car to drive home the CEL was on but turned off as soon as I got to the edge of the p-boys parking lot. I was like WThecK!!

Anyway, here are the symptoms I have been encountering for the past few weeks of driving the car:

1.) CEL turns on with code 25 (lean).

This mostly occurs when it is cold out

2.) Experiencing electrical issues: dash does not light up when it is cold out and the steering wheel no longer comes out automatically when I start the car. (used to work when I first bought the car back in June)

3.) VERY sluggish low end. Almost NO torque and can not get the wheels to spin. (odd for a V8?)

4.) Transmission acts up on occasion and goes into neutral while I am in drive and on the brakes. If I go from drive to reverse the trans changes gears VERY rough and slams into reverse, In reverse the trans will suddenly leave reverse, go into neutral and then go back to reverse.



I have two thoughts as to the issue:

1.) My capacitors are failing in the ECU and screwing up how the car runs.

2.) The O2 sensors went bad, failed, and are telling the ECU the car is running lean so the ECU is throwing in more gas to compensate for the lean condition that actually does not exist and that made me fail inspection.

The car really does not smell like gas at all and there is no smoke when I drive the car. Only smokes when it get very cold out and really its not smoke just condensation/steam and usually goes away when I rev up the engine or give it some throttle. (note: it is getting cold around here in PA. ) No rotten egg smell and not other signs of running rich. Last time i pulled the plugs they looked pretty clean!

Does anyone have any ideas as to what I can do?
I have 30 days to go back to ***boys and re do emissions for free.
I went online to Digi-Key and Mouser to purchase the capacitors for the ECU and instrument panel. I ordered ONLY the CAP's recommended by LScowboy that had the proper capacitance, ripple current (low ESR), high temp, and voltage ratings. Got all United Chem Com caps. I am very familiar with soldering and have build my own Arduino micro controller boards, and a few of my own home made PCB's (with a laser printer transfer method) so I am very confident in my soldering abilities. I will take some pics and do the capacitor replacement as soon as the shipment gets here from Digi-Key and Mouser. Do you agree that it is probably my capacitors or could it be something else??

(Also just as a fun note.. they tried to get more money out of me by charging me for BOTH the emissions and safety inspection and I had to tell the guy at the check out that they never even did safety for my car since it failed emissions.... at which point he asked the mech and then believed me and only charged me for emissions (42$) ... phht)

PureDrifter

iTrader: (10)

yay arduino!

find a better shop than crap boys

standard tune up, run some seafoam through the gas, and give it a shot.

LScowboyLS

sounds like you are doing a great job of diagnosing this!

I agree with your logic so far on the ECU caps and pre-cat O2 sensors

here are the service manual pages for code 25

we will just get out of your way so you can work! - lol

aomdedude1

haha...

Yeah, I used the Arduino for an LED cube PLC (built the entire PCB from scratch) and then in my sophomore engineering class to read data from a 3-axis accelerometer sensor which I used as a controller for a game I made! (that time it was the retail pre assembled version)


Well your thought about the gas is a very legitimate point. Now that I am back in classes I barely ever drive the car and I only filled the tank half way on the DAY OF the inspection. Before I filled it up it had gas back from when I bought it (as in June or possibly before that depending on when the last guy that owned it decided to park it)

So there might be a little tiny bit of full on summer blend gasoline in the tank. After the failed inspection I took it for a 60 mile round trip from Doylestown to center city Philadelphia to drop off my sister and back so I used up most of the new (and old) gas. I will for sure try and use up as much of the gas as I can and put in a full fresh tank before the next inspection.

I guess a can of sea-foam might not hurt either. (but probably wont help a whole lot either since I hand cleaned all the backs of the valves when I did the timing belt and WP job with a scrub brush and a few cans of Berryman B-12 Chemtool. I spent hours on them and got them squeaky clean. I also cleaned out the TB and intake... but I'll still give it a shot!

I need to try and actually PASS the inception this time!

lol

aomdedude1

lol.... thank you LS!

I try...


Thank you for the Service sheet!!

LScowboyLS

here is the best smokin deal I know of on your factory Nippon Denso O2 sensors

that is some bad **** stuff, I bet it is banned in half of the states!

works good itself as a gas treatment

dc893

^^^ Rockauto has the denso ones for $45.79 downstream and $49.79 upstream.

aomdedude1

Tell me about it... I did all the work in our garage that is attached to the house but the whole house ended up smelling like this stuff for at least a day! (you can imagine how well that went over ...)


Rock auto 49$ price is not bad at all!

Lets see what the capacitors do first though.

LScowboyLS

I like Rock Auto but their shipping can run the price up on stuff when your are used to free.

aomdedude1

Okay, so this has been waaayyy over due, but I am a broke college student so for the past 6 months I have not had a job which = no money. Well I finally came across some cash and went to get my 1st gen ls400 inspected again.

IT PASSED!!

Solution:

It was one of two things. Either:

A.) The Engine Coolant temp sensor

or

B.) The Lambda/ O2 sensors.


I replaced both of these items. I use OEM O2 sensors and unfortunately cheapened out on the coolant temp sensor. (that is the ONLY non-OEM Lexus part I've ever put on the ls400)

Here are my new PASSING emissions results:

Co: 0.00 (1.10 limit)
HC: 36 ppm (275 limit)
NO: 940 ppm (3600 limit)

Here was my previous FAILING results:

Co: 8.56 (1.10 limit)
HC: 628 ppm (275 limit)
NO: 88 ppm (3600 limit)

aomdedude1

I would for sure recommend anyone experiencing similar issues to look at these two things. Put them at the top of your list!

Now despite this great victory my car is still giving me problems. The next problem on the list is that it is still sluggish. I have not timed it yet, but from my estimates it takes around 12-14 seconds to get from0 - 60mph.

Something is not right here. I know the car is heavy but it cant possibly be this slow. Its like ALL my low end torque is completely gone. The gas millage is still sucking although it is SIGNIFICANTLY better. I am going to unplug my MAF tomorrow to see if this has any effect.

I may also start a new thread tomorrow.

Please give your advice!

Remember all the work I recently did before parking the car for the last 6moths and not driving it one inch with all OEM parts:

- Timing Belt & pullies
- Water Pump
- Drive belts
- Plugs and wires
-Distributor caps and rotors
- Professional bench fuel injector cleaning and flow test by VAC motorsports
- Upper and lower intake removed and replaced with all new gaskets (to get to and repair the rear leaking water by pass joint)
- Air Filter
- Oil and OEM filter
- cooling sys. flush and OEM red coolant fill
- Power steering bypass valve replacement and PS sys. flush
- Front O2 Sensors
- Rear EGR bypass pipe replacement
- Coolant temp sensors
- ECU capacitor replacement (done by me as per LSCowboys guidelines.)
- Fuel Filter
...


The list goes on ...

Also I parked it with a nearly empty tank because I knew I would want to fill it with fresh gas prior to inspetion.

I have a fresh full tank of shell PREMIUM v-power 90somthing octane in there now so its not bad gas.
(Funny side note... I brought the car back to the same Pep-boys that failed it 6 months ago and had the same mech. do the work. He remembered me as I had argue with him about it being the O2 sensors. He's a nice guy though and complimented the car along with the checkout guy. This car gets a lot of compliments for being so old!)

aomdedude1

... Also here are a few problems I've noticed after driving it legally for the past two days:

The car is having some type of a transmission issue. If reverse out of my drive way, the car likes to "float" out of gear. It will never "float" out of gear while actually driving forward in D unless I come to a complete stop at a red light. Also The car stalled today at a red light. I almost didn't even notice because the car is so quiet in the first place. So far it has only stalled one time.Also, when the engine is cold it seems to have more power. The low end power goes down as the car comes to normal operating temps. The low power is not effeted by being in "power" or "Normal" modes. ]

Trans fluid was a little dark and smelled "stale" ihs when I check it this morning. I did NOT do a proper warm up and trans fluid level check. Just a quick fluid condition check

LScowboyLS

make sure after the fluid drain and fill that you have the fluid to the tip top of the hot area with transmission hot, running in Park, on very level ground.

aomdedude1

So in other words I should drain the old fluid (probably clean/replace the filter) and refill to ?cold? level...... Drive to warm the trans, then refill to HOT?

I'll obviously check the service manual first for procedure, but just checking the easy/lazy way with you first.

LScowboyLS

yes, except that filter replacement is a little more involved, you have to drop the pan, and not many people have a torque wrench cable of of rendering 65 inch pounds - so they often warp the pan by getting the bolts too tight, then it leaks