Rally.Ray

Did a few searches but haven't been able to solve my issue yet.

Vehicle: 1989 Toyota Pickup 4x4, 5speed, 250K mileage
Trouble Code: 51 (Switch conditional signal) and 52 (Knock Sensor)

Background: Truck was running solid. During my last oil change, I snagged the knock sensor wire. The wire going to the knock sensor connector then separated. I soldered the remaining end of the connector to another wire and then connected the other end to the wiring harness. I'm not sure why but I keep on getting the 51 and 52 trouble codes. Any suggestions? I'm thinking i'm getting the issue as a result of 2 possible scenarios; 1. The wire is not shielded causing the knock sensor to pick up noise 2. The connection of the knock sensor is insufficient. Either of these situations will require picking up a used connector and wiring it into the wiring harness. Does anyone think the shielding is that sensitive?

bbrideau

The wire to the knock sensor isn't just a regular wire. its shielded to prevent any other form of electricity or static charge to mix the signal up. the Knock sensor shakes and generates a voltage and tells the ECU that everything is okay or not okay so it can advance or retard timing. You can replace the wire on SOME 22re wiring harness not all. mine can not be replaced without running a whole new wire to the ecu. Essentially the wire from the ecu to the Knock sensor is the smaller version of a cable TV cord. So if you used just any wire laying around chances are your getting interference from something thats why you get the code 52. Or you may have snapped the housing on the knock sensor itself and damaged somethign inside it. Either way its a pain in the ass. If you have to replace the wire talk to toyota. If you have to replace the Knock Sensor better hope there is a autowrecker by you new one is about 250-350 bucks.

Your other fix is to say ˟˟˟˟ the knock sensor but without it it retards timing to 5 degrees i believe makes it run like crap and run really rich. In the long run its cheaper to replace the wire or the sensor.


Edit: Since you snagged the wire. You could have pulled it against something further back on the wire causing the shield to fail.

Rally.Ray

Problem resolved. Went to the auto wrecker and found a 88 truck with the 22re EFI motor. I just snipped the connector and wire off. Stripped off the shielding by about an inch off both the harness and the connector. I soldered the comnections together and wrapped it with electrical tape. Check engine light went off and the truck runs great now. Thanks for the info. I'm sure my old connector and regular wire were not sufficient to fix the issue. The wire I used first was less than an inch in length.

speedemon

i just changed my vavle cover gaskets and one of the fuel injecter wires came off so it was missing put it back and now the truck wont idle and miises and just runs like crap but i also get a code 51 but on the 89 4x4 3.0 it says 51 is a ecu or idle sensor i dont know what to do here any help would be helpful

Joesmo

I bought the truck about a year and a half ago
When I reset the codes by pulling the efi 15 amp fuse for at least 20 minutes I keep getting code 51 and 52
I've checked all the vacuum lines there hooked up correctly
it has new plugs wires plugs cap and button
I pulled and cleaned the egr valve , and throttle body and knock sensor replacing with new gaskets I also replaced the tps sensor
I recently put on new exhaust , 02 sensor
ive checked all the plugs
theres no exhaust leaks and or vacuum leaks

When I take off in 1st threw 3rd there's no power at all until 4-5000 Rpms
when in 4th gear going up a 60 degree hill going 60 mph when drops from 60-40 mph struggling to pull its self up with no load only its own weight
i don't have a voltage meter or a timing light

when I got the truck it had no exhaust , 02 sensor , egr valve gasket , throttle body gasket , no vacuum lines hooked up , clogged egr valve ,
rotted manifold gasket its running way better now but I'm still only getting 5-6 mph in town ! I'm using a quarter tank driving 10 miles

Co_94_PU

iTrader: (-1)

unless you are driving around with the test jumper installed you have serious issues.. (ECU or wiring) do you have a jumper in the diagnostic port between te1 and ground? Is the TPS idle signal set correctly?

Did you maybe plug that knock sensor into the oil pressure wire? If not you might need to replace the signal wire.

flg8r22

iTrader: (1)

A 60° hill!? Good god. I think a new diesel motor would have troubles with that

Joesmo

the manifold was glowing blood red it was over heating with a couch in the back
I need info on how to fix my issues not a diesel would have issues
madly unhelpful

Joesmo

i have no ideal anymore I've put a lot into it before everything was rigged and bypassed
at a full run down a hill running 70 and before I hit 1/5 of the way uphill I've had to down shift to 2 nd and 1st gear at 20 mph to the floor and then have to pull off due to overheating when I go to check the fluids the exhaust manifold is glowing blood red and I've having to drive with the heat on full blast but the thermostat is good just replaced it
as I said I've cleaned the throttle body put on a new gasket , cleaned the egr valve and replaced the gasket , full tune up the tps sensor is good
but it's still reading engine error code 51 -52
can anyone help he please

Joesmo

It seams to be getting worst but when I'm driving in town taking it ease it rides fine doesn't over heat and that's without having to use the heater and unless I push it hard it doesn't over heat real bad

Joesmo

in town it stil struggles going uphill

Co_94_PU

iTrader: (-1)

Verify the ignition timing, good battery voltage and grounds at the ECU also.

Disconnect your battery. Locate the test pin (Te1, I believe for a 90 model) in the ECU plug and unpin it from the plug(collapse the retainer and push it out) this will eliminate wiring issues. If you still get code 51 with this modification you have internal problems with the computer.

No knock signal detected, code 52, will force the ECU to retard the ignition. In extreme cases this means combustion in the exhaust pipes.. This leans towards an ECU failure also, if your knock sensor is functional and has a clean new wire with no breaks and good grounded shielding..

Co_94_PU

iTrader: (-1)

Just what exactly have you "rigged" and or "by-passed" and how?

Joesmo

it was rigged when purchased
i have since then fixed those issues


so so do you want me to unplug the ecu inside the cab