I purchase a 1995 4-Runner with 224 000 KM back in January and with it came two problems,first: difficult to start when engine is cold (also worse when outside temperature is cold like winters) and second: bucking/missing underload specially in cold weather on highways and more notice when engine warming up.
Not knowing history of vehicle maintenance and last owner using aftermarket tune up parts I decided to replace the following:
-Spark plugs=3Dold ones were Champion and tips were melted (wrong temp rating),new ones OEM Denso
-Spark plug wires=3Dold Bosch,new ones OEM Yazaki (same as Denso)
-Rotor=3Dold Standard,new OEM Denso
-Cap=3Dold Standard,new OEM Denso
-Air filter=3Dold made in Israel was dirty,new OEM Denso
-Fuel filter=3Dold made in China,new OEM Denso
-Oxygen sensor=3Dold Bosch was lazy,new OEM Denso
I also ran "Sea Foam engine treatment" in fuel tank,intake and engine oil, I pulled the ECU (EFI computer codes) and nothing came up, I also measured the voltages and resistance at each ECU wire and compared with FSM (factory service manual) still nothing.
I measured the resistance on the cold start injector, cold start injector time switch, intake air temp sensor, water temp sensor for ECU, AFM and TPS. I measured the wire harness for each of the above parts and nothing. I also did a spark test and unbolted the cold start injector and moved it back about 1" and had a friend crank cold engine and fuel spray came out and was uniform. I also removed cold start injector from vehicle and dipped in in Sea Foam for 10 minutes even though nozzle tip and it's fuel line entrance was clean.
When I say it's difficult to start with cold engine I mean the engine turns over but doesn't start until about 3 seconds (more in colder weather) and once engine is warm (after driving) she will start sooner but not instantly like Toyotas are known for. I found that when engine is REALLY COLD (in cold winters) I crank it for 2 seconds then stop then crank then she will start if I attempt another technique she will start then shut off right away.
I couldn't get the old Denso PCV valve off to inspect because it's grommet is not flexible anymore, I am afraid to break the grommet and have the small broken bits fall into engine.
I don't have a timing light to inspect for engine bast timing to make sure it's at 5 degrees BTDC with terminals T-E1 shorted together in Diagnosis box and 8 degrees BTDC without. The engine does have a somewhat small rattle at start up (the noise is less noticeable since I switched to OEM Denso oil filter with AWESOME anti-drain back valve) and more notice when engine is cold. The timing chain it's components were never changed and owner always used a Chrysler Mopar white colored oil filter.
The vehicle does have excellent fuel economy of about 500 KM with 65 liter gas tank.I usually re-fuel at 450 KM so there are about 10 liters of fuel left. I use Octane Rating 91 as she runs alot better than regular Octane 87 or 89. Although she doesn't seem to have any power like my old 1985 4-Runner with 22R-E even though this 1995 weighs 1400 Kg and my old 1985 weighed 1600 Kg.
Sorry for the long post but I cannot seem to diagnose the 3 problems which may all be one or three different problems:
1)Hard starting with cold engine 2)Missing or bucking underload more noticeable at higher speeds (highway) and more noticeable when climbing a hill and with colder engine 3)Lack of power (quick acceleration) like my old 4-RunnerCould all 3 problems be lack of proper timing because of timing chain stretch and tensioner wear? is so would re-adjusting engine base timing correct problem until I replace timing chain components? or ECU (EFI computer) automatically re-adjust timing?.
I didn't check fuel pressure regulator and on the second generation 4- Runners (1990-95) you cannot access the re-usable platic washable fuel pump screen/filter from the back passenger seat. Instead the whole gas tank must be dropped.
Here is where I download my free factory service manual:
Free 1995 Toyota 4-Runner Factory Service Manual:
Sidney=AE =99 Repairs TV's,VCR's,home/car audio out of my apartment E-mail:sidneybek(at)yahoo.com Dartmouth,Nova Scotia Canada
1995 Toyota 4-Runner,22R-E,G52 with 227 000 KM