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Just bought my first 4runner, first Toyota as well, and I thought Id share my headaches and achievements as I experience them!
Details about the vehicle:
94 4 Runner SR5 5spd 4WD w/ 3VZE
277k on the clock
Looks like it has a slight lift with aftermarket suspension bits (more on this when later)
everything else looks stock
When I first picked up the vehicle, it had a CEL and the previous owner described an issue where it would lose all power once it reached operating temp. I flashed the CEL and it came back with a code 52 which turns out to be an open loop in the knock sensor, causing the ecu to protect the engine by killing power and adjusting the timing. Got it home, and started going to town in the engine bay. The fun thing about purchasing and working on old vehicles is finding all the weird stuff the previous owners / mechanics have done or messed up. After pulling the intake manifold, I found 2 out of 3 engine to harness/body grounds disconnected. Took me a few to figure out how to get the timing belt cover and coolant bypass off. Then proceeded to remove the hand tight plenum bolts! I found that the previous person to get this deep in the engine replaced the knock sensor, but kept the frayed pigtail hooked up, replaced that and cleaned the intake plenum real well and reinstalled it. After getting the bypass reinstalled, I began to check the timing by turning the engine manually. At this point I found the timing belt to be damaged so now I must wait for more parts. Gonna do the water pump, thermostat, and a new water bypass while I am at it.
It is always interesting to see what others have done before. Yours sounds pretty interesting. I hope it all works out in the end. It looks like a good truck otherwise.
It is always an adventure to see what the previous owners have done to a truck instead of fixing it correctly. Usually the cost to do it right is not much more then screwing it up. The second gen runners paint and interior seem to hold up well for their age. Looks like a nice truck. Welcome to Yotatech.
So in the past week or two, I replaced a long list of parts: 1/7/2017
Rebuilt Fuel Injectors, replaced 2
Water Pump
Tensioner pulley
Tensioner
Timing belt
Thermostat
Water Bypass
Spark plugs
Valve cover gaskets
Intake plenum gaskets
Knock sensor
Knock sensor pigtail
Power steering pump
Intake manifold gasket
After all of this, I am still stuck with the CEL 52 code Open Knock Sensor Circuit. My next step in the troubleshooting process will be electrical. I picked up some wiring and connectors to make new 10 gauge block to chassis grounds. I will also replace the wires going from the connector to the ecu and the closest grounding point. I also am having an over heating issue where the truck over heats when cruising or standing, under acceleration the truck stays cool. When I went to pull the old thermostat I found that it had been gutted leaving only the restriction plate. I removed the manual clutch fan and installed an electric puller fan and this did not solve my issue. I am going to see about putting the restrictor plate back in without a tstat and see if that solves the overheating issue.
Update! After sitting for a few months and once it cooled down a little I got back to figuring out my check engine 51 code. I found the wire running from the ECU to the sensor had good continuity through a body ground. However it was intermittent due to a frayed wire. I repaired that and rewired the electric fan switch to a more convenient location. I also repaired the thermostat housing and fixed the over heating problems. Currently it is up for sale.
Last edited by waldo170; 08-29-2017 at 02:36 PM.
Reason: None
12-31-2016, 03:13 PM
replaced that and cleaned the intake plenum real well and reinstalled it. After getting the bypass reinstalled, I began to check the timing by turning the engine manually. At this point I found the timing belt to be damaged so now I must wait for more parts. Gonna do the water pump, thermostat, and a new water bypass while I am at it.
