Omfg!!! Help!

mechagouki

New member
I've had a hard time with my first 4Runner, I paid too much for it and the guy who sold it to me turned out to be a lying SOS, I've had to have suspension work done, replace the tailgate, the battery and the horn. i had to change my insurance company because my old insurer won't touch vehicles over 20 years of age and jump through all kinds of hoops just to get registered and plated.

Finally on Tuesday this week I get to drive it legally for the first time - I take it out of the city on a little 180km round trip to a job site, it's nosiy as all hell, vibrates like a bas**** and the Firestone 32s don't work great in the snow, but at least it runs okay and the heat works! I do the same trip the next day after fitting some smaller winter tires and it's a little quieter (and faster), use my iPod to block out the exhaust noise (K7N filter/straight pipe) and actually start to enjoy driving it, there's a funny vibration from under the left side of the hood just in front of the windshield over 40kph, but I just crank the Metallica and ignore it.

Today I drove it across downtown Toronto and back, no problems, other drivers are a little scared, but the usual Toronto maniacs don't seem to **** with me as badly as usual so that's all good.

Tonight my wife asks me to take her to work, truck starts fine but then the battery and brake lights stay on - I know the battery is fine, it's less than a week old. After 10 minutes the engine starts to surge between it's normal idle 800 and about 1200, after a couple of minutes I notice it's only doing this when I have my foot on the brake?!? When I take my foot off the brake it surges up to around 1800 all by itself and stays there. I limp home and when I turn off the engine I can hear a gurging noise from under the hood - I open it up and nothings leaking (that I can see), but I can't locate the exact source of the noise either.

I really need the truck for work, it's already into me for over $2500 and I can't afford to spend another dime, can anyone please, please give me an idea what might be going on?
 
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A shot in the dark - may be a vacuum line / vacuum / brake booster issue. Old truck - lotsa miles could be most anything.
 
I just read a thread over on YotaTech where they talked about idle speed/automatic fuel cut issues - could this happen spontaneously?
 
Tonight my wife asks me to take her to work, truck starts fine but then the battery and brake lights stay on - I know the battery is fine, it's less than a week old.

When both lights come on it indicates an alternator problem, ususally the brushes.

After 10 minutes the engine starts to surge between it's normal idle 800 and about 1200, after a couple of minutes I notice it's only doing this when I have my foot on the brake?!?

When I take my foot off the brake it surges up to around 1800 all by itself and stays there. I limp home and when I turn off the engine I can hear a gurging noise from under the hood - I open it up and nothings leaking (that I can see), but I can't locate the exact source of the noise either.

There are a couple of possible causes for the surging idle.

One is that the idle speed is higher than spec. When you hit the brake the fuel cut circuit kicks in momentarily, then off, then on, ...

Another is low coolant level.
And your gurgling sound probably means there is an air bubble in the cooling system, which could mean the ECM coolant temp sensor is sending bad info to the ECM, causing the idle speed to surge.

Start by checking the coolant level and burping the cooling system.
 
When both lights come on it indicates an alternator problem, ususally the brushes.



There are a couple of possible causes for the surging idle.

One is that the idle speed is higher than spec. When you hit the brake the fuel cut circuit kicks in momentarily, then off, then on, ...

Another is low coolant level.
And your gurgling sound probably means there is an air bubble in the cooling system, which could mean the ECM coolant temp sensor is sending bad info to the ECM, causing the idle speed to surge.

Start by checking the coolant level and burping the cooling system.

:iagree: Expert above. Good luck!
 
I agree with too high of idle, thats what caused my surge while hitting the brake. However it going out over night would be strange, I noticed when my brake booster went out last week my idle increased due to the massive vacuum leak, maybe check that out
 
Thanks guys, I'll check the idle screw and the coolant level this morning, hopefully that will let me drive the truck at least. The brake booster is a possibility, the brakes will stop the truck pretty quick, but only if you press hard on the pedal.

Can someone give me ballparks for a new alternator (fitted) and a brake booster (also fitted).

Thanks so much for your help.
 
Alternator's about $50 from the parts store, and easy to replace. Not sure on the booster, but those are not hard to replace either.

If you're not sure about the booster, you can disconnect the vacuum lines to see if it solves the problem, just make sure you plug them.
 
So i just went out (in the rain) to try and figure this out and whilst fiddling with the idle adjust (I figured I'd start with the easiest option) I noticed that the belt that runs to the alternator is hanging loose! I'm guessing (based on zero actual 4runner knowledge) that this also drives the water pump and thus would be the cause of brake/charge light being on and the gurgling noise under the hood? Could this also cause the idle surging?

So - is there an easy way to reseat this belt, cuase just from a brief attempt I can tell it's not going to just easily pop back on - it's a newish looking Goodyear belt so I'm guessing it came off because the tension was wrong?

EDIT: Ignore what I just said about the belt - I checked the length of it and it has a section where it's almost broken through - going out to get one now - can someone point me to idiot proof installation instructions?
 
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There are two bolts on the alternator, loosen them both, and the alternator will pivot on the bottom bolt to allow you to slip the new belt on.

Use a pry bar to put tension on the alternator and tighten the bolts. Check the belt tension in a few days, as you'll probably have to re-tighten it to compensate for stretching.

It's a very easy installation.
 
So I'm guessing I have to take the fan-belt off also? I've heard I should change both belts when one breaks anyway. Are they standard sizes or should I take the old belts to the parts store?

Thanks again for all your help.
 
I believe that you need to remove the fan belt to get at the alternator belt, but I may be wrong.

Best bet is to bring both belts in. They should be able to look them up, but it's better to be safe.
 
i have this same problem!!!! i have done my pcv valve and check all sensors but nothing helped, now im thinking about changing my catalitic converter but idk what else to do...cause all my vacuum lines are fine. Do you think the injectors could be bad?
 
I chickened out of doing the belts myself - It got dark and I have nowhere sheltered or heated (it's -14 here today) to work. So I drove it very slowly with the engine over-revving like crazy to the drive in service centre at a local Canadian Tire. One hour and $135 later (taxes in) and the truck is running perfectly with both belts replaced - idles smoothly at a steady 800rpm, everything seems to work better, esp. steering and brakes - guess those belts were really worn out!

Thanks again for all the good advice and suggestions, I'm so happy I can drive my Runner to work tomorrow!
 
that is good to hear. Its always nice to get things running properly and for relatively cheap (i had my alt belt replaced for $30 not including the belt)... but for a chain that seems like a decent price, I bet you were stoked that the truck was running properly and better than before. I like that feeling
 
I chickened out of doing the belts myself - It got dark and I have nowhere sheltered or heated (it's -14 here today) to work. So I drove it very slowly with the engine over-revving like crazy to the drive in service centre at a local Canadian Tire. One hour and $135 later (taxes in) and the truck is running perfectly with both belts replaced - idles smoothly at a steady 800rpm, everything seems to work better, esp. steering and brakes - guess those belts were really worn out!

Thanks again for all the good advice and suggestions, I'm so happy I can drive my Runner to work tomorrow!

Okay so your telling me that replacing your belts fixed this problem? Maybe ill have to go buy me some belts and try it. If thats really the solution ill be irate that i spent like 4hrs changing the pcv valve for nothing
 
stupid pos 4 runner! this damn thing is a sack...it wont run!!! whys the belt layen in the skid plate!? o sht... lol. my 85 ran like crap when i pulled it outa the brush after sitting for 9 years. i replaced the belts and it purred like a kitten.
 
stupid pos 4 runner! this damn thing is a sack...it wont run!!! whys the belt layen in the skid plate!? o sht... lol. my 85 ran like crap when i pulled it outa the brush after sitting for 9 years. i replaced the belts and it purred like a kitten.

Yeah, I felt pretty stupid when I saw the belt, it's run fine the last couple of days - done about 4 hours driving - then when I was leaving work today notice it was leaking gas onto the customers nice new block-paved driveway - guess a new fuel line is the next fix - easy or not? anyone done this on a 1990?
 

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