Stalling V6 4runner

I thought I would try this group in hope of more responses.
I have recently been having random stalling with my 1990 4runner 3.0 V6
5 speed. It seems to run fine. I will be driving along and it just dies
like it was turned off. It doesnt start right back up right away ...but
after a minute or so it starts back up and runs fine once again. Somedays it never stalls and today it stalled like 5 times on my way home from work Grrrrrrr. Hotrter than usual out today if that helps. Guages seem normal and there is no check engine light on.
So hmmm after reading a few posts in this group it could be a few things. Quite a few posts say it could be my EGR valve. Others guess at
coolant temp sensor, ignition coil, primary secondary ignition systems??? or fuel filter.
What I am wondering is there some way to test the EGR valve. Can I bypass or remove vacumm temporarily? Any other tests I can perform? How
about a cure for when I am stranded on the side of the road. Hopefully not...doh !
I was hoping to try and repair it myself before heading out to the garage.
Cheers Jason
Well I disconnected the vaccum line to the EGR valve to see if this would cure my random stalling. And of course on the way into work it stalled 3 times....:-( . I guess thats not it. But strange enough I thought my problem was getting worse but on my way home this evening it
didnt stall once !!! Yesterday it was really hot outside and stalled like 5 times. And this evening it was much cooler and raining and didnt
stall once. I dunno coincendince ? I havent noticed anything out of the
ordinary with the temp guage.
Someone had mentioned a temperature sensor failing in one post I read. Could this be the culprit? Where is this sensor and can I bypass it temporarily to see if this is the problem? But then again I am not getting a check engine light?
Hmmm
Cheers Jason
I am still reading as many post as I can about stalling 4runners and I found another post that seems similar to my problem. Except it was a 4 cylinder.
Where a wire wire to the ECU was shorting out intermittently. They insulated it, and the problem *finally* seems to be cured. The explanation written on the invoice says "Stalls due to loss of TGF signal to ECM. Shorted due to wire being worn through on fuel rail." The service manager told me that this was causing the ignition computer to shut off the fuel injectors.
and...
"This is actually called Igf, or ignition fired, this is a confirmation
that you have after Igt or ignition trigger , no igf, youll loose spark. there is a spot near the center of the fuel rail that rubs through the wire harness (fixed mine before it became trouble) but its usually blows the 15amp EFI fuse (power one side of injectors), they where probably being straight up with you.
Rick, Toyota Master/ASE Master/L-1 "
Where is this wire harness located...like what and where is the fuel rail ?
I would like to check this out. I suppose you think it would blow the fuse but anyway.
What do you think?
Cheers Jason
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Forget the coolant temperature sensor. Good or bad, it will not cause stalling.
I would check the wire harness near the fuel rail. The fuel rails are a metal tubes that feed fuel to the fuel injectors. The injectors look almost like spark plugs, there is one per cylinder but instead of thick black ignition wires, they have a couple of thinner wires.
A problem with the EGR valve and fuel filter will cause drivability problems before it causes stalling so I would not spend too much time chasing them. A bad fuel pressure regulator can cause hard starting but rarely does it cause stalling. A problem with the fuel pump does not usually allow the engine to be re-started.
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Ray O
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Thanks for the response Ray O !!
It was another miserable drive home today with constant stalling. I feel it has something to do with warmer temperature ? If this makes any sense. Cause it is usually fine when its cold but when its hot it just stalls stalls stalls. But starts up again like 30 secs later. It seems the hotter the temp outside the more problems I have? I had a guy with a 4runner like mine stop by the roadside to help me out. He said he was having the same problem and just to remove the vaccum line from the EGR and the return line to the regulator. But I had already tried this with no success.
I am going to check out the wire harness and see what I can find.
I will post my results.
Cheers Jason

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You're welcome. By the way, does the stalling only occur at idle? If so, check the idle air control valve and check for cracks in the plastic intake tube between the air filter and the throttle body.
Good luck!
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Well I took a quick peek at the wiring near the fuel rails..well only on the drivers side. I guess I hoping to find a wear spot in one of the wires. I am not sure where others were finding this problem. There is somewhat of a plastic box around the group of wires parallel to the fuel rail on the drivers side. I suppose I would have to unplug the harness and untape some wires to really see if there is a problem there. I sorta feel like I am looking for a needle in a haystack. Now if I wanted to check the harness on the passanger side...I guess the intake would have to be removed to get at those. I dont think I am prepared to do that.
Truck was not just stalling at idle..I could be driving along at 90km/hr in 5th gear and it would just die. I could push in the clutch count to 20 and it would start up again. Why one day it would not stall at all..and the next day I could hardly make it home is really baffling me. Something has got to be failing. I sorta told myself I would drive it until it died so that me or another mechanic could find the issue without guessing or changing parts.
Can any one pin point a known area on the v6 where this wearing was being located? Center of the fuel rail..hmmm but which side?
I have a rusting issue on the bottom corner of my passenger side windshield...where when it rains water comes inside the vehicle near the passenger side kick panel..oh ya right where the engine computer control is. Doh. Over the years it has caused quite a bit of rusting on the floor there and in that general area. The connectors to the computer look clean with no corrosion...but I almost wonder if this could possibly causing some isssues. I really wish that the check engine light would come on so I could get some codes to help.
After driving 11 years with my 90 4runner it is just getting old..with 315000 km. The Canadian winters have taken a toll on the body. The ..."what I think" is a leaky front seal is causing a big mess in my garage with the oil leak.
I am thinking of just retiring this truck and buying a newer one. But last year I put in a new clutch and had ball joints changed..and I will never get back what i put into it last year.
I shouldnt complain this truck has Never let me down and I could probably drive it for another few years easily. Just frustrated....:-)
Cheers Jason
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I have found some more post on the internet about stalling 4runners. I was thinking maybe the ignitor is failing when it gets hot? I was going to swap in a used ignitor if I can find one to see if that helps. Another person suggested the EFI relay? It was suggested to swap another similar relay to see if that helps. I dont see another similar relay to swap in..any suggestions on this thought?
Cheers Jason
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When an igniter fails, it tends to fail for good and doesn't come back.
The intermittent nature of the stalling makes me believe that the problem is electrical. The re-start after 20 seconds seems to rule out a fuel delivery problem.
qslm, a regular member of this group, can probably offer better advice that I can.
Good luck!
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Ray O
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Well was looking around at the 4runner again. I pulled the ECU (computer) out to take a look to see if it had taken any water damage. Internals looked clean and dry with no evidence of any corrosion.
I noticed a wire bolted to the positive battery terminal was loose...and well that wire goes to the EFI relay in the fuse box in th engine compartmant. I was sorta happy to find this. I tightened it up and went to go for a test spin. Just to see if I was that lucky.
NO luck....:-( .
I really had a lot of trouble my last drive home. It seems the problem has worsened. It only ran for 5 minutes and stalled. It took quite a bit longer to get it going. after it is warmed up it starts a runs fine and stalls like a minute later and again difficult to get going again.
So whatever component is failing is on its way out.
So could it be as simple as that EFI relay or could it be the Ignitor?
I guess I will have to swap in a couple of used parts to see.
Cheers Jason
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Take a look at the condition of the wire or contacts on the wire that you tightened by the battery terminal to make sure it is tight, not frayed, or corroded.
It is possible that the EFI relay is bad, to check, you can apply 12 volts to the control side and see if the power side has continuity.
Igniters usually do not come back when they fail. In other words, when an igniter fails, it fails for good and does not come back.
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Ray O
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Thanks Again Ray O for all your input. I found a guy on ebay who was parting out a 4runner. He is going to send me an Ignitor/Coil and an EFI relay for $30 shipped. I am hoping for the best. I can also get a distributor for about $25 shipped. I may go for that as well. It has to be one of these parts. I hope I get lucky.
Cheers Jason
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You're welcome, and good luck with the repair. Let us know how it works out.
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Ok ..had a chance to do some more testing with the 4runner. It does not run at all now. Well it started up but stalled like 20 sec later, and then would not start again. I think I got it running for a few more seconds after that..but now will not start at all. So whatever was failing is dead. So kind of helpful for finding out what is wrong with it. So I "do" have spark so now I guess it is a fuel issue or fuel control issue?. I pulled a plug and it looked dry and a nice tan color. I loosened the cold start injector and well I figured fuel should piss out when cranking...but nope. I crawled underneath to have a peak and all fuel lines look ok with no evidence of leaking. I folded up the back seat to get to the access cover to the fuel tank area...to measure some voltages at the connector to fuel pump. I was getting only 2.5volts? I dunno. At the time I was measuring the voltages..I had reconnected it and started up..I again disconnected the plug while running and it stalled so I am guessing this was indeed for the fuel pump and not the guage. So I guess the pump is working or at least sometimes. Where exactly is the fuel pump on this truck? The EFI relay seems to be clicking when the keys is turned on.
I am not really sure where to go from here?
Any thoughts?
Cheers Jason
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So after an hour later I went out to try and start the 4runner again. It started right up. But again stalled 10 sec's later.
Hmmmm
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The next step is to borrow or rent a fuel pressure gauge with banjo fittings from your local auto parts store. Possible causes of problems are the fuel pump, fuel pressure regulator, and fuel filter. I'm not sure where the fuel pump is located, but if you do not see it between the tank and the engine, then it is in the fuel tank. The fuel pump should be getting 12 volts, but the fuel gauge sender will be a lower voltage.
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Well took the 90 4runner to the garage. They tell me its the fuel pump. So Fuel Pump + Filter+ some lines + (excluding sending unit) + labour close to C $900 . $350 for the fuel pump.
Hmmmmm.... ???
I think I am going to go pick it up and change the pump myself. I think I can pick up a pump cheaper than that.
Cheers J
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Ok..I am going to bring the truck back home and try to get it going myself ..cause it is not really worthy of any more $1000 repairs. I ordered a used fuel pump for $50 and I have had the gas tank off before and I believe the sending unit has been changed before. As for the fuel filter....any suggestions? Should I just try and replace the pump without trying to do something with the fuel filter? Aftermarket stuff?
The mechanic I spoke with didnt seem to interested in fixing it cause of all the rust. And apperently it ran with a purge.
Any thoughts?
Cheers Jason
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I believe that the fuel filter is supposed to last the life of the vehicle so I wouldn't bother with it unless it is clogged.
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I went out and bought myself a Haynes repair manual...cause i needed to know where to look....
So turns out there is another relay " Circuit Opening Relay" located above the ECU computer on the passengers side kick panel area..I had to
take the glove box and speaker off to get at it. Well It definetly had a case of the "Green Monsters" (corrosion)
This truck has a bit of a water leak when it rains on the lower passengers side windshield...rust rust rust...Canadain winters...The ecu was the first thing I inspected because of this water leak. The ecu
seemed to be free of corrosion..but I didnt know there was a Main relay
right above it that absorbed some of this water over the years.
I did a simple continuity test on the relay and it seemed fine with some scratching on the terminals. I could hear it click....so I scratched it up a bit more and put it back in.
So I put my meter back on the fuel pump connector and cranked it over...Well Well Well...I now am reading well 11volts while cranking....closer to what it should be to run the fuel pump.
I will have to get the fuel tank back on and see if this sucker will run for me again.
Good news here !!!
I put the fuel tank back on.... and it started right up!!
I hope I have this problem beat !
I will have to clean up that relay a little better...or price a new one?
Then I will have to figure out a way to divert the water leak...
Yes I know I should fix the leak...easier said than done...:-(
Yeah !! Cheers Jason
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