SidneyCanada

I purchased a 1995 4-Runner with 224 000 KM back in January 2008 and with it came 3 problems which I didn’t know about:

1)Difficult to start when engine is cold (also worse when outside temperature is cold like winters), cranks fine
2)Bucking/missing under load specially in cold weather on highways and more noticeable when engine warming up but still present with warm engine
3)Idles fine at 750 rpm but once warmed up if you shut engine off and re-start idles low (not O2 sensor because I changed it), also idles low if coming from highway speeds and rpms are kept low while slowing down and not using brakes as fast and hard, meaning gradually coming to a stop. If using brakes quickly and hard usually she idles fine at 750 rpm

I replaced the following parts (90% OEM Toyota) because most needed replacing and hoping that it would solve my above 3 problems as well but they didn’t:

Complete tune up parts (spark plugs, wires, rotor, dist cap, PCV valve & grommet, air filter, fuel filter, O2 sensor, cleaned AFM housing and throttle body) & ran Sea Foam several times in the fuel, oil and vacuum system. The plastic washable/re-usable fuel pump filter (inside the gas tank) is in excellent condition.

Main fuel line, fuel pump bracket, fuel filler pipe (my mechanic replaced these parts)

Complete exhaust system, front to back, again all OEM except for stainless Magnaflow cat

Head gasket (head was corroded from prior head gasket failure where prior owner’s mechanic didn’t have head examined), head was welded and shaved, timing chain kit was replaced (an engine rebuilder shop replaced these parts)

I found 2 ground corroded/rusted wires, one connected on firewall and engine hoist hook (4th spark plug wire) and the other was broken because the battery was loose so the wire broke between the negative battery terminal and passenger fender wall. I replaced both wires.

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 also did a spark test and compression test. I used a timing light to check for engine base timing and it’s at 5 degrees BTDC with T-E1 shorted in diagnosis box. My mechanic took these fuel pressure readings after replacing main fuel line but before the fuel pump bracket and am not sure where he placed his fuel pressure tester:

Dead head=55 PSI (the factory service manual=38-44 PSI)
Idle=36 PSI ( the factory service manual=38-44 PSI)
Idle without vacuum=40 PSI (the factory service manual=33 PSI avg or 23-37 PSI)

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 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 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 know for an engine to run you need the 3 basics: fuel, spark and air. When I jumper Fp (fuel pump) terminal and B+ (battery) terminals in the diagnosis box thereby bypassing the AFM power switch and circuit opening relay (fuel pump relay) found behind the glove compartment, the engine starts faster almost instantly. The AFM and circuit opening relay are fine as I measured their resistance and voltages and compared the readings with the service manual as I stated earlier.

I was told it may be a vacuum leak or EGR valve but I don’t have an unlit propane torch to use and visually inspecting the vacuum lines I didn’t see any obvious cracks. I do have the factory service manual but am at a lost hence why my post, if it may be an air problem how do I find it?

Can anyone help me?, I have tons of very resourceful info dedicated to Toyota 4-Runners/pickups like free: service manual downloads, EPC catalog downloads, discussion sites, cross referencing parts, places to buy OEM parts for very low price, etc.

Sidney® ™
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 235 000 KM

Brian R.

Check the fuel pressure regulator and fuel pump by seeing how fast the fuel pressure rises at the injector rail during cold starting. Maybe one or the other is slow to build up pressure. Check fuel volume at that time and during idling. Maybe slow in building up sufficient volume when cold also.

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OzzyO

Hi Sydney, I live not to far from You, I'm in Cape Breton, and I have a 1994
4Runner 3.0 Liter Automatic, I went through what your going through now, I did get it fixed but the mechanic who fixed it wouldn't tell me exactly what he had done. But I know a few things he did and I'll pass them on to you.
Are you running a 4 cylinder or v6, mine is a v6, and the head gasket was leaking on me so I had it fixed BUT when it was fixed a Sensor at the back of the v6 engine by the Firewall was damaged and it took about another 3 years before it started completly breaking down. So that was Replaced, also on the passenger side of your engine you'll see a set of wires, small wires & there are 2 wires, and they go into a Chrome fitting, those wires were damaged and Not making a Good Connection. BUT The Main Culprit was that Sensor at the very back of the engine Close to The Firewall that seemed to be The main Factor for my problems. When I say Problems, my 4Runner was terrible, at times I couldn't even make it up a slow grade hill, it would stall on me. When I would restart it would miss fire badly it also would be making the vechile surge back & forth and you could hear a sound like the engine was sucking to get air, it would cough and spit and finally stall out and I would have to restart it. I got so good at it I could have it stall out on the highway and I would slip in neutral and restart it without stopping. Now I Know Your NOT Supposed To Do That BUT I was so fed up by then I didn't care if the
4Runner died on the spot, and if it did I would of put a few rounds of ammo to help kill it Completly, I was so Pi***d off lol.
But I went through that acting up for almost a year, I had it to every mechanic I knew and even the dealer and it came down to this Older mechanic that checked everything in that v6 engine until he was able to know for sure that it was that sensor that was the Main Cause of all of my Problems. I don't Know the name of the Sensor or it's exact location but thats as much as I know about it and since he fixed it I haven't had a Problem. That sensor cost around $200.00 CD so that may help You also.
Good Luck Sydney, I Know Exactly How Frustrating You Feel because I went through it also, but I Hope this Information Helps You in Some Way so You Can get Your 4Runner Fixed.
Take care And Good Luck, Fr: Cape Breton To The Mainland.

OzzyO and Yes I'm Still

SidneyCanada

I have a 22R-E engine, 4 cylinder engine (2366cc) and in your case the knock sensor's wire harness was rusted/corroded where it meets the passenger side on the bottom of the firewall leading into the ECU (EFI computer). Had any mechanic pulled the ECU codes (you could of done it yourself) they would of seen a trouble code for knock sensor and it's related circuitry, your problem could have isolated in under 1 hour as well those knock sensors seldom fail.

This problem is VERY COMMON on the 1988-95 4-Runners/pickup equipped with the 3VZE engine as well as headgaskets (which there was a recall and repairs done for free). On the other hand the 22R-E engine didn't have this problem.

Sidney
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 235 000 KM

SidneyCanada

Where can I check fuel volume at if I borrow that tool?, thanks Brian.

Sidney
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 235 000 KM

Brian R.

Check the procedure and specifications in the Toyota FSM.

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"What we've got here is a failure to communicate"