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'86 4runner engine surges @ 2000RPM


calikowboy21's Avatar
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09-04-04, 06:27 PM   #1  
calikowboy21
'86 4runner engine surges @ 2000RPM

Hey Guys,
I need help with my 1986 toyota 4runner. I blew up the engine drivin from SC to NY (had 225K on it already), dropped a new engine in it, a DOA racing engine (i've heard the horror stories about DOA) it was my first engine swap, so naturally i fudged it pretty good. Anyway, everything has been fixed besides the fact that the engine surges when you pick it up to 2000RPM. IF you press harder on the accelerator it just increases the pace of the surging. As the engine warms up, it surges at an idle. Can't find any vacuum leaks (carb cleaner test), it's sittin at the dealer, and they wanna buy new ECU and air flow module for it, so please HELP QUICK!

 
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09-05-04, 05:41 AM   #2  
I doubt you need an ECU and an Air flow meter,

Most likely has someting to do with the engine replacement. Sounds like it is fuel cut. It sees TPS at idle and RPM is above around 1500. Surge is from injectors shutting off.

Air pocket in cold idle speed control valve, Big idle screw out to far.

Make sure all your basics are covered like timing set correctly.

 
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09-05-04, 09:48 AM   #3  
calikowboy21
how do i fix the air pocket in the valve? where is the big idle screw? i need to talk to these guys tomorrow about a yay or nay on the AFM.They told me, TPS is good, and timing is right. What can i tell them to try? Thanks for helpin me out.

 
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09-05-04, 10:26 AM   #4  
The air pocket is bleed out of the cooling system. Run it and vary engine rpm with rad cap off while topping up coolant.

It's not your place to tell the dealer what to try, they should be able to diagnose the problem. AFM is not going to cause your problem.....sounds like they are "throwing darts" at it. Weren't they the ones who told you it was an AFM and ECU?

The idle speed screw is on top of the throttle body next to where the cable hooks up.

If they are so sure of the AFM have them replace it under the conditions if it dosen't solve the problem they remove it at no cost.

 
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09-06-04, 12:40 PM   #5  
calikowboy21
That's just the thing though, they said it might be the AFM or the ECU. They don't know what's wrong with it for sure. They want me to tell them that I will pay for them to start throwing parts at it. I just wanna get the thing fixed.

 
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09-06-04, 04:19 PM   #6  
You brought it to them to diagnose the problem and not to throw parts at it.....you could of done that yourself.

Get the truck out of there, they don't have a clue. I wouldn't pay them a diagnositic fee either. Unless they can show you the crystal ball the used.


Look at the items I talked about, that will be your best chance

 
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