Hi folks,
Just joined, I'm hoping someone can give me some advice on an issue I'm having with my 2000 TL. A few times a week it will loose power not accelerate (I'm thinking this is limp mode) but there is no CEL. I've tried putting the trans into neutral when it happens, and there is no change, rpms still remain the same. Then the car will come out of it and drive normally. I've replaced upstream O2, plugs, and checked coil packs (all functioning). Oil is fresh, ATF (DW-1) is fresh. Anyone have any thoughts? Any helpful advice would be greatly appreciated. The only thing that i have spotted that is out of the ordinary is a random wire running to one of the coil packs on the front of the engine. (pictures below) I know the coil pack is working but this wire looks like something added from a previous owner (maybe) I have no idea if this could be contributing to the issue, but I have no idea why this wire would be running from a coil and into the firewall (remote start?)

I've been searching the forums like mad, but only find postings about limp mode WITH a CEL and thus checking codes.

Anyways sorry for the novel. Any guidance or advice would be awesome.

Thanks.

 

added wire at coil pack





wire at firewall

 

Next items on the list are, buying the gasket set for the intake manifold (SET!? fml) and giving the intake a good cleaning. And also a new radiator (old one developed a crack). Doubtful that either of these will help the problem but here's to hoping.

 

you installed the correct 8$ each NGK plugs?

LIMP mode limits the rpm to 3000 and is set when the ecu thinks something really bad has occurred but isn't sure what
Can happen if timing belt jumped a tooth, or it thinks an over-rev situation happened- which is supposedly impossible due to ecu limits the rpm!

No CEL light on dash? Have you gone to a parts store for a free code read-
no light doesn't mean no codes!
what exactly is it doing= what rpm? is it sticking at an rpm? or feel like its not holding in gear?
does it rev and not accelerate like it should in 2-3rd gears? like a bad clutch feel?

intake manifold gaskets- no set required- top gasket only
others are metal and reused

DO buy gaskets for TB to intake and the IACV cover gasket so you can clean that part too
We have a few diy on the intake job

a clogged egr passage and port system will cause all kinds of weird problems
Definitely do that soon, need 3 or 4 cans carb cleaner- non chlorine type, and a wire coat hanger- no kidding- that's the tool for the job!

 

have you been resetting the ecu after each major repair? after O2 sensor for sure
after new coil install etc

easy method: on passenger side end of dash or on the kick panel is a fusebox- remove cover and find the CLOCK fuse, clearly marked
remove for 1 minute and reinsert- ecu has now been cleared of all stored codes and reset- ready to self test and relearn your habits (clock fuse is the secret backup power to ecu)

 

did you install a DENSO brand o2 sensor- that's the factory supplier and plugs right in, no hassles with operation
note: bosch will give you trouble!

 

Ok that added wire to the coil is for an aftermarket device, I believe remote starter.
Looks like you have a factory rebuilt trans so this is less likely to be a trans fault.
Verify that the throttle plate is actually moving in the throttle body.

Does your check engine light go on for 3 seconds when the key is put on position II ?
Try and scan it with a code reader, sometimes theres codes without the light being on.

 

reminder: Codes are CLUES = not a diagnosis in themselves

report codes back here, we use those along with your actual symptoms and our combined experience to figure out the real problem

 

A plugged catalytic converter could also cause symptoms like yours without setting a code. Don't just replace it, have a shop check it out. Any decent independent garage or exhaust shop should be able to check it out.

 

Thank you for the feedback guys!!! really glad to hear i don't need to get the entire gasket set for cleaning egr ports! I did get the correct NGK plugs and Denso 02 sensor. I did NOT reset the ecu, so i will definitely do that. Thank you for the tip on the clock fuse! I'm planning to check for codes tonight (CEL is still not on, but I'll check anyways).

The most recent occurrence went like this... Started car (was still warm), drove about 150 ft. light acceleration (30 mph), then the engine looses power, RPMs go down to 2000, car will not accelerate, while pushing the gas I shift into neutral, no reaction from engine. Then about 3 seconds later, engine reacts and RPMs jump back up. I stop, shift into drive and continue on home (15 min. drive) with no other issues. And still no CEL the whole time.

 

part of that description feels like cat problem as primary concern

Did you install the other new parts- and reset the ecu to try drive again?

have you removed top engine plastic cover and watched movement of throttle cables?
remove throttle body to air filter box snout tube
observe TB air plate inside- clean both sides and edges (open throttle to gain access)
with carb cleaner or deep creep- wipe excess runoff up
Ck motion of air plate matches inside throttle application

 

I haven't checked the movement of the cables yet, I'll do that tonight. Parts store got the upper gasket in, so I'm going to remove and dismantle the intake manifold and go to town on it with some non chlorinated cleaner tonight. I'll remove, inspect, and clean the throttle body as well. I checked for codes last night and came up empty. Checked the O2 sensor readings as well and they seem fine.

Any hints for checking the functionality of the cat?

 

infra-red heat gauge, or bang with rubber mallet or hand
listen for loose material or dull thud
exhaust shop can test flow rate if still doubt

IACV- inside bottom of throttle body- get the gasket for its cover, just in case- its very small and fragile
Same with TB to manifold gasket(s) better new than take apart to again to fix vac leak

reminder you are wanting to clean the LENGTH of manifold- egr passage goes from under its valve to the opposite end, plus the ports at cylinders
That's why a wire coat hanger, unbend it and use as long poker

Torque Wrench to set manifold mounting bolts at 16 pounds when done

 

Well I took the throttle body and intake off last night and gave everything a good cleaning. It needed it! The egr passages were extremely dirty. And after I removed the throttle body and air box, I found a ground wire that was completely broken in half! It was only resting on the connector that it was once attached to. I got that crimped back together and reassembled the cleaned parts and so far so good! I haven't been able to drive it much yet, but haven't had the power loss happen again yet. So I'm hoping that the issue MAY be resolved.




Dirty EGR passages





Broken ground wire barely making contact

 

you did the actual egr passage inside the manifold too - correct?

meaning: remove egr valve to see the 2 passage/port holes under it- go from opposite end of manifold to those holes with the wire coat hanger and carb cleaner

retorque the manifold bolts to 14-16 foot pounds after 200 to 500 miles
A few will be 1/4 turn loose- not cool for being correct torque
Heat cycles thru different metals cause the problem, once redone it will be fine

 

nice find on the broken ground- something we mention often is to ck ALL the grounds including the small braided ones from frame to engine.

I totally spaced on the big one you found~
Is that located just above the ATF/ transmission oil filter?

reset the ECU for fun- in case bad ground was giving bad info to the computer- the garbage in garbage out scenario
Simply remove the CLOCK fuse on passenger end of dash or kick panel
its marked, and is the secret backup power to the ECU,
insert fuse after 1 minute and replace cover

 

tip for all doing the egr cleaning: make sure the upper gasket stays in the same position of UP or TOP, it will fit `flipped over` but block a crucial passage and cause the engine to rev and drop, rev and drop- making you take it all apart again to fix!
Match the gasket holes to the cover- not the manifold- to ensure correct positioning

this cleaning is needed every 75kmiles to keep the TL happy

 

Indeed. I cleaned the passage in the manifold, it was also extremely gunked up. I just didn't snap a photo of it. And I did the clock fuse reset after I put everything back together.

But now the bad news... My girlfriend was driving it the other day, and it had another stutter/power loss episode (this TL is her car). So it may not be fixed. So I'm going to check the cat, and see if there are any loose chunks that might be blocking flow. And I may change the down stream O2 sensor as well. AND finally put a new radiator in.

If it isn't the cat that is causing this, I'm not sure what to do.

 

what's this about the radiator? are you losing coolant? you know for sure from where = not getting into cylinder...

cats tend to either break into chunks, or the honeycomb design becomes clogged in the pores/openings
Muffler shops generally ck them for you free-maybe a small charge
they are in the business of replacing said part~

No vac leak?? from gasket issues during re-install= TB to manifold gasket?
there is a vac and coolant line at TB that can be confused

Does it stutter different now?
read the notes in above post about top cover gasket and the Up side issue?

This is a 2000, have we addressed the possibility of a carry-over from 99 ignition switch failure?
The electrical part- the back part not the key, had a recall for 99s and those failed again a few times. Aftermarket seems to be a better choice for replacement
See our DIY
Does wiggling the key ring do anything, does cornering effect it?
When it goes bad it burns inside! can cause shut off of ignition then comes back on without warning

 

The radiator has a small crack in the top and I can see that a small amount of coolant has seeped out. So its an unrelated (i think?) issue. The stutter was the same, but it only happened once since the cleaning/reset, and hasn't done it again. So I'm not sure what to think. It has never corresponded to any cornering, what would wiggling the key ring do? I suppose I'll just wait to see if it does the stutter again and then take it to a muffler shop to have the cat checked.

 

if the ignition back- electrical part is worn- wiggling the key will cause loss of contact = kills ignition!
this happens with g-forces on corners with lots of keys on the key ring

99s had a recall on the switch,,00 still has the same part for a while
even the recall installed ones wore out fast

If it really is a cat issue- don't wait- go get it ck'd by a professional NOW
The last thing you want is the material fully clogging the honeycomb or outlet- even enough to raise back-pressure can destroy the engine
Seen it happen with muffler coming apart internally on a race car, very exciting loss of power when crud pieces blocked the outlet!

 

after egr poking and cleaning, its not unusual for extra crud to hit the O2 sensor and give it a scare
sidenote:
Seafoam vac port method often causes a CEL that clears itself, as O2 sensor gets a dose of strange info, then resumes normal input signals

keep on the 91 octane

 

well it had been running great for a couple of days, no stutter at all. Then this afternoon, it didn't want to start at all! Starter would crank and engine seemed like it would fire up at any moment but nothing. Then after about 20 min and a few more tries, it started! I'm going to dive in tonight and see if I can find anything that looks amiss, but I'm about ready to trade this sucker in. Seems like its been one thing after another with this car for the last 6 months.

 

how many months did it go before it got any real service and preventative maintenance?
call it maintenance averaging, total divided over last 2-3 years si how much a month 50- 100? that's not so bad compared to other makes

refresh us: ckd for codes again? since the sputter? O2 sensors, NGK spark plugs and egr cleanout all done. NO vac leaks from egr job? verifies with carb cleaner shot at every opening? gasket etc?

non start: most often FPR Fuel Pump Relay has a bad solder connection underneath its mounting board- remove board and resolder--its in a recent thread on `no hot start` with pic of repair. Look under hood
Its often the simple prob that drives us nuts, don't let someone else profit off your TL yet!

(thinking) Unless it needs a valve adjust--wait a sec- how many miles,,over 150kmiles? valve adjust would be the logical thing keeping it from purring
Used the mechanics stethoscope on valve covers?

 

OR that ignition switch really is the problem and needs replacement!!
It will cause so many different symptoms related to `no spark`,,,,
seems easy to inspect the ignition and the FPR

what do I win if I guessed right?

 

Well It has been behaving for awhile now but yesterday it lost power starting from a stoplight, did not want to accelerate. after a few seconds of this, the check engine light actually turned on. I pulled the code, its shown below along with the O2 sensor test. I replaced this O2 sensor about 2 months ago.

I'm hoping to find out if something else is wrong that is causing the power loss and affecting the O2 sensor, OR if it is in fact the O2 sensor that is the problem.

Any ideas?

 

O2 test

 

there have been some odd things happening with bad ground wires- worn out on the inside from corrosion or not clean and tight connection
One ziner found the main battery ground cable was loose in its connector to frame!!
the cable not secure in its clamped fitting!!

ck every ground -braided wire or cable, remove clean tighten, replace as needed
Ck resistance on battery cables too, may look fine and be eaten away internally

Signal from sensors makes the car run, garbage in = garbage out

did you install a Denso O2?

 

I'll go through the wiring and see what i can find. Also, I found my old receipt from the O2 sensor and it was in fact a Bosch. Does the difference between Bosch and Denso, affect the car that dramatically?

 

YES!! of course there is a difference, any time we are hyper about a specific part-
a seriously good reason exist
Denso is the oe supplier, and the wire is plug and play

Did you have to modify- ie: cut and splice the wires to the Bosch?
If so I would start with that giving bad signal

NOTE!! Spark Plugs- do NOT use Bosch there!! problems problems problems

 

No the Bosch was a plug and play as well. I didn't have to cut/modify wires.

Since the Bosch O2 was plug and play, could there still be a problem? I found the Denso O2 sensor for $47 bucks so I'd have no issue switching it out.

I recently replaced the plugs w/ NGK iridium about 2 months back.

 

Some people have had trouble with bosch o2 sensors causing a cel, even the direct fit ones. You should be able to return yours under warranty, and exchange it for a denso or ntk brand.

 

Would having a bosch O2 instead of denso cause the stuttering, and power loss? Or do they just cause a cel from time to time?

 

I don't know the exact failure/poor running issues of the bosch, just read reports on here of probs with it

Did you ever fix the coolant leak? that could be a reason it acts up too

when you did the spark plugs - it started having this problem? or 2 months after plug install?

Its very possible to damage a coil during that work- frequent cause of coil death a few months later
Are you getting multi cyl misfire codes?

 

I replaced the radiator a couple weeks back, so no more coolant leak issue. It was having issues before I did the plugs. When I put the new plugs in, I also tested each coil pack. They all seem to be working fine, no misfire codes. I'm hoping to have some time to look over wiring later this week.

 

put in the correct part supplier O2 sensor for this car,, and I bet it runs way better

 

Got it on order, and fingers crossed! And just wanted to say, thanks again for your help on this stuff. I really do appreciate it!