silvertop diagnostic codes

[Boost_4_Life]

managed to get the diagnostics working properly on my starlet finally.

two codes coming up, 21 and 52. from what ive found these are No 1 knock sensor and oxy sensor correct me if im wrong? no oxy sensor connected on the car so thats fine. knock sensor code, does that mean im getting some knocking action goin on, or a problem with the sensor/wiring itself?

[Rick]

#21 is Oxygen sensor

#52 From What I can find is Knock Sensor signal, open/short signal in knock sensor signal.

[Boost_4_Life]

it would make sense. how does this compromise the ecu performance. will we be running rich etc but not in a limp mode obviously? the thing hasnt seemed to be pulling quite right for a wee while, this is most probably why. no oxy sensor wont help but until i wire a link or something tunable in it can stay like it.

[sergei]

it would make sense. how does this compromise the ecu performance. will we be running rich etc but not in a limp mode obviously? the thing hasnt seemed to be pulling quite right for a wee while, this is most probably why. no oxy sensor wont help but until i wire a link or something tunable in it can stay like it.

The knock sensor will certainly put it in Limp mode, also if there is code for Ox. then that will also put it in limp mode.
What will happen it will fail back to fail safe ignition and fuel maps, not turn on VVT and lower rev limiter. Mean while it will have performance of a lada.

[1hypo3]

it would make sense. how does this compromise the ecu performance. will we be running rich etc but not in a limp mode obviously? the thing hasnt seemed to be pulling quite right for a wee while, this is most probably why. no oxy sensor wont help but until i wire a link or something tunable in it can stay like it.

The knock sensor will certainly put it in Limp mode, also if there is code for Ox. then that will also put it in limp mode.
What will happen it will fail back to fail safe ignition and fuel maps, not turn on VVT and lower rev limiter. Mean while it will have performance of a lada.

The oxy sensor code will not nessacerly put in limp home mode but knock sensor definetly

[Boost_4_Life]

how will the thing run in limp mode? it still seems to pull and rev out to the limit... just not as crisp as it should be. I thought limp mode would limit it to certain revs etc, or is this not so?

[sergei]

how will the thing run in limp mode? it still seems to pull and rev out to the limit... just not as crisp as it should be. I thought limp mode would limit it to certain revs etc, or is this not so?

It will lower rev limiter, about 500-700rpm less.
It will retard the ignition, it will run extra rich.
Oxygen sensor will put it into limp mode if it is disconnected.

[Boost_4_Life]

ok ta, sounds right then. ill check out the knock sensor tonight. as for the oxy sensor, what voltage do these put out? Is it too dangerous to do something dodgy and wire something in to give a fake signal? ive heard of people doing this on honduhs, or is it completely insane? Its a lot easier than hooking up an oxy sensor on the harlet believe me...

[sergei]

ok ta, sounds right then. ill check out the knock sensor tonight. as for the oxy sensor, what voltage do these put out? Is it too dangerous to do something dodgy and wire something in to give a fake signal? ive heard of people doing this on honduhs, or is it completely insane? Its a lot easier than hooking up an oxy sensor on the harlet believe me...

Will not work, they put out 0 to 1V, depending on mixture.

[Boost_4_Life]

i could easily hook up like a permanent 0.5V signal, but i guess its best to do it properly. where is the oxy sensor located on a standard silvertop. before or after cat converter? Im obviously not running a cat

[RS13]

Oxygen sensor will put it into limp mode if it is disconnected.

Nope, oxy sensor won't, mine has been disconnected for months now, still runs normal. The ECU throws the code for it too, but no limp mode.

[sergei]

i could easily hook up like a permanent 0.5V signal, but i guess its best to do it properly. where is the oxy sensor located on a standard silvertop. before or after cat converter? Im obviously not running a cat

right below firewall, just before cat. and after flexy. It will have a 4 wire plug, and two nuts holding it in place.
Check if it is actually working, it should out put fluctuating voltage between Ox. and E1 on diagnostics tab, voltage should fluctuate between 0V and 1V about 8 times every 10 seconds (so period is slightly longer than a second, if it is doing faster that is fine). Voltage itself is not important, but it should be well above 0.45V on highs.
if it is stuck at 1V, most likely because ECU is ignoring it, in this case you will need to fix knock sensor first, then diagnose the Ox. sensor output.

So priority of fix should be on knock sensor, as it will certainly put the ECU in limp mode and screwing with what Ox. sensor out puts.

Have you tried to reset the codes? Perhaps some one was unplugging random stuff while the engine running/ignition on?

[sergei]

Oxygen sensor will put it into limp mode if it is disconnected.

Nope, oxy sensor won't, mine has been disconnected for months now, still runs normal. The ECU throws the code for it too, but no limp mode.

Most likely it will have a negative effect. You loose all advantage of fuel trims (it will run richer than it should), and ignition will default to static fail safe map (although I haven't confirm that in practice). These ECUs rely heavily on Oxygen sensor.

[Boost_4_Life]

yep codes have been reset. this thing was wired into the starlet by someone else, and ive suspected for a while it wasnt running quite right. It took a bit to sort the wiring to get the codes up as no engine check light was wired in. also the 12V batt feed to the ecu was wired from the ignition instead so no codes were remembered anyway after turning the thing off. Ive have fixed the above so i can at least tell what the hell is going on now.
There is more than likely a dodgy connection on the knock sensor, plug looks a bit suss. and there is no oxy sensor present at all in the exhaust.

what is the rev limit supposed to be for a silvertop? ive only owned a blacktop before and i would have assumed the same limit? this thing seems to cut at around 7800, which would make sense seeing as it obviously in limp mode..

[Dell'Orto]

7800 is about right I think.

[Boost_4_Life]

ah, chur. gonna pull this focker apart tonight anyway and see whats up with the knocker detector. stand by chaps.

[Loudtoy]

what is the rev limit supposed to be for a silvertop? ive only owned a blacktop before and i would have assumed the same limit? this thing seems to cut at around 7800, which would make sense seeing as it obviously in limp mode..

7800 standard 8300 if youve got standard box like me and don't want to unsettle the car in the high 2nd-lower 3rd gear corners that seem to be everywhere around here. Let it go a little more rather than hook another then drop it straight back, means i can keep using both feet for going faster and slower rather than the left one for clutch. Higher limit good for about 4 seconds at the last sprint

[RS13]

Oxygen sensor will put it into limp mode if it is disconnected.

Nope, oxy sensor won't, mine has been disconnected for months now, still runs normal. The ECU throws the code for it too, but no limp mode.

Most likely it will have a negative effect. You loose all advantage of fuel trims (it will run richer than it should), and ignition will default to static fail safe map (although I haven't confirm that in practice). These ECUs rely heavily on Oxygen sensor.

I'm pretty sure it actually uses less fuel than it did before, and it certainly hasn't slowed down at all, pulls well all the way to redline, so if anything I would say that its' leaning out.

[Boost_4_Life]

the wiring diagrams etc ive got from somewhere on the net seem to suggest it will run without the oxy sensor. ok it may not run perfect, but it doesnt seem to say it will go into limp mode...?

my knock sensor wiring tests ok, but the plug on the sensor itself is munted so probably a bad connection there. awaiting new sensor.

[Boost_4_Life]

ok knock sensor fixed, no code for that now. Now i just have 21 ( oxygen sensor ) and 42 up. 42 looks like its no speed signal, which is correct seeing as there is no speed signal wired up Will no speed signal affect performance? The thing pulls ok now, all the way to redline. Its tricky to judge in the starlet cos all ya can hear is the gearbox screaming its nuts off (straight cut box). Its bloody deafening without helmet on!