sw20 check engine light

FXGTV · Post by **FXGTV** » Thu Feb 07, 2008 12:13 pm

After driving the sw20 for about an hour home from work the check engine light came on, and stayed on. Usually this indicates overboost, and turning the car off and then on again fixes it. But after yesterday the first time the boost kicks in the check light comes on - turning it off and on again does nothing.
The boost is definately spiking noticably so im guessing something has gone wrong somewhere along the line. What are the simple things I should check to figure out the issue?

Thanks in advance.

fivebob · Post by **fivebob** » Thu Feb 07, 2008 12:30 pm

The wonderful thing about a Check engine light is that if you follow the testing procedure and check the codes it will tell you what is wrong without having to consult the dubious opinions on a forum

in other words Check the Codes then post the results, that saves random guesses from wasting your time

My guess is a broken knock sensor (code 52) :twisted:

FXGTV · Post by **FXGTV** » Thu Feb 07, 2008 12:56 pm

Haha, yeah fivebob, i was out doing the tests while you were replying

Its come up with two difinitive fault codes, a 34 and a 52.
According to an mr2 FAQ site code 34 is is fuel cut off ue to excess turbo pressure.
And the 52 code you already know is an issue with the knock sensor.
So now what? :twisted:

FXGTV · Post by **FXGTV** » Thu Feb 07, 2008 1:02 pm

Upon further research (i googled

) i've read that that the fault code 34 can be caused by driving too hard on poor fuel. I was stuck in an area with no 98, so i was forced to get 95...i guess ill have to use up this fuel and wait to get some 98. Hopefully that fixes that code, and then its just a matter of fixing the knock sensor one

Learning is fun :lol:

fivebob · Post by **fivebob** » Thu Feb 07, 2008 1:21 pm

FXGTV wrote:Haha, yeah fivebob, i was out doing the tests while you were replying Its come up with two difinitive fault codes, a 34 and a 52.
According to an mr2 FAQ site code 34 is is fuel cut off ue to excess turbo pressure.
And the 52 code you already know is an issue with the knock sensor.
So now what?

Good guess huh

Replace the knock sensor. Fix the overboost or it will blow another sensor. Do a compression test to see if you've damaged any ring lands.

FXGTV · Post by **FXGTV** » Thu Feb 07, 2008 1:35 pm

I dont suppose you could give me a quick run down on how to replace a knock sensor could you?

Post by **Mr Revhead** » Thu Feb 07, 2008 1:40 pm

1: get under car
2: unplug sensor
3: using the right size spanner (26mm?) unscrew sensor
4: install new sensor in the reverse manner

fivebob · Post by **fivebob** » Thu Feb 07, 2008 2:26 pm

Mr Revhead wrote:3: using the right size spanner (26mm?) unscrew sensor

IIRC it's 30mm, a deep socket is a better alternative to a spanner.

Also be careful re-installing it, they're esay to break if you knock it on tighten it up too much.

Post by **Mr Revhead** » Thu Feb 07, 2008 2:34 pm

yeah 30mm that rings a bell

iv always used the ring end of the spanner.
mainly coz i dont have sockets that big!

FXGTV · Post by **FXGTV** » Thu Feb 07, 2008 2:45 pm

I saw a good thread on the nz mr2 site - all up it cost the guy $90 for a new sensor and to re-wire it so it would work. Its no biggie to not use genuine parts then. Ok, so whos got a sensor i can buy?

FXGTV · Post by **FXGTV** » Thu Feb 07, 2008 7:49 pm

How bad is it for the engine if i drive it around till I fix it?

flygt4 · Post by **flygt4** » Thu Feb 07, 2008 7:50 pm

pretty sure mr2SIK tried that and it didnt turn out well.

FXGTV · Post by **FXGTV** » Thu Feb 07, 2008 8:12 pm

Hmmm - well i better get on to finding a knock sensor, and fast!

MR2SIK · Post by **MR2SIK** » Thu Feb 07, 2008 9:15 pm

flygt4 wrote:pretty sure mr2SIK tried that and it didnt turn out well.

my engine lasted a good 6 or so months after blowing the knock sensor before it decided to lunch the big ends and blow the head gasket :lol:

but yea, not advisable, runs like a sack of unwanted xmas kittens, and cant be too healthy for it either

FXGTV · Post by **FXGTV** » Fri Feb 08, 2008 9:40 am

Its just really laggy when it coms to boosting. But when the boost kicks in the spike tends to shove your head back into the seat :twisted:

fivebob · Post by **fivebob** » Fri Feb 08, 2008 1:05 pm

FXGTV wrote:Its just really laggy when it coms to boosting.

Actually I think you will find that the boost builds quicker because there is more energy in the exhaust gas, but there is a lot less power due to the severe ignition retard.

But when the boost kicks in the spike tends to shove your head back into the seat

That will be becuase you're making too much boost, fix the overboosting problem before you join the "Dead 3S Society"

FXGTV · Post by **FXGTV** » Fri Feb 08, 2008 1:13 pm

I've tracked down a knock sensor from an st183 - will this fit?

fivebob · Post by **fivebob** » Fri Feb 08, 2008 1:56 pm

FXGTV wrote:I've tracked down a knock sensor from an st183 - will this fit?

Maybe if it's production date is after 91/08

Here's a list of the cars that use the same sensor

Code: Select all

HILUX SURF                       95/11-00/08  RZN18# 
HILUX                            99/08-       REN169,174 
REGIUS/TOURING HIACE             97/04-99/07  RCH41,47 
GRAEVIA/GRAND HIACE              95/08-98/04  RCH11 
DYNA/TOYOACE                     00/05-       RZU300,340. .EFI 
CRUISER PRADO                    97/04-       RZJ9# 
MR2                              91/08-93/11  SW20 
MARK 2                           96/09-97/08  JZX101 
CHASER                           96/09-97/08  JZX101 
CRESTA                           96/09-97/08  JZX1O1 
SOARER                           91/05-94/01  UZZ3# 
SOARER                           94/01-96/08  UZZ3# 
SOARER                           96/08-97/09  UZZ31 
CROWN/CROWN MAJESTA              95/08-97/07  JZS155,UZS15# 
ARISTO                           92/10-97/08  UZS143 
CELSIOR                          94/10-97/07  UCF2# 
HILUX                            91/08-95/11  VZN130 
DYNA 200/TOYOACE G25             95/05-00/05  RZU100,140. .EFI 
CARINA ED                        91/08-93/09  ST182,183. .GLIM 
CELICA                           91/08-91/09  ST18#. .GTR,GT4,GT4RC 
CELICA                           91/09-93/09  ST18#. .CV,GTR,GT4,GT4RC 
CORONA EXIV                      91/08-93/09  ST182,183. .TRG 
CORONA                           91/08-92/02  ST171. .GTR,GT 
CAMRY/VISTA                      91/08-92/06  SV32,33. .GT 
CROWN                            90/05-91/10  UZS131 
CROWN                            90/09-91/10  UZS131 
CROWN/CROWN MAJESTA              91/10-95/08  UZS14# 
CELSIOR                          90/05-94/10  UCF1#

Post by **Mr Revhead** » Fri Feb 08, 2008 1:57 pm

now theres a handy list.....

think ill FAQ this....

FXGTV · Post by **FXGTV** » Fri Feb 08, 2008 1:59 pm

If anyone has a photo of exactly where the sensor is it would be appreciated. I'm having trouble finding it as i dont have access to any ramps or proper jacks at the moment. Its hard to look around when your 1cm away from burning your nose off on the exhaust