AxleIke

This is on my brother's 95 4Runner.

It blew a head gasket, and was not covered under the recall. I replaced both.

I also replaced the timing belt, water pump, thermostat, and knock sensor wire.

I had the injectors cleaned, re-o-ringed, and flow balanced by witchhunter.

When it was all back together, it surges at idle. I set the timing (sorta, because of the rough idle, it was hard, but its close).

I then suspected a vacuum leak, but upon hooking up my vacuum gauge to numerous ports, I get 15 inHg on each port, though it surges with idle (expected).

Reading further online, I found that the TPS is a chronic issue, so I tested mine, and it was not acting properly. I replaced it, and set it using an Ohm meter and feeler gauges to the specified settings in the FSM.

More reading suggested a bad VSV on the EGR. I bypassed that, and the problem didn't change, at cold idle or at warm idle.

Its possible that there is air in the coolant lines still, but I'm fairly sure the symptoms wouldn't be this strong, as when I replaced my heater core on my 87, I had air in the lines for a while, but the stumble was very intermittent, and it went away after driving a bit.

The truck drives fine at higher RPM's. Just below 2500, it begins to surge, and it won't idle.

Any other ideas? I know a lot of folks have had this issue, hopefully someone has a trick that I haven't read about yet?

vasinvictor

iTrader: (3)

How many miles on the rig? Mine never would idle correctly but ran good over 2,500 rpm. Turned out to be valves were not fully seating b/c it was bad out of adjustment after 200k and no adjustment- ever.

AxleIke

Hmmm...That could be. I did not remove and grind the valves, just got the heads cleaned and machined. 206k on the rig.

However, according to what I've read, a bad or sticking valve will usually produce very sharp pulses in vacuum, and low vacuum overall. I think 15 inHg is decent? Maybe?

I forgot to add, that I also checked for vacuum leaks with a spray bottle of water, and squirted around all the vacuum connections I could get to, per instructions on another forum from BigMike from Marlin.

AxleIke

Finally got a CEL. Code 52, knock sensor. I'm not sure if that is helpful or not, as, on my 22re, every time I put on a new exhaust, the knock sensor CEL goes off until the computer adjusts to the new back pressure.

vasinvictor

iTrader: (3)

Your knock sensor would not cause your idle issues. I would look elsewhere for your idle issue. However, you code 52 REALLY needs to be addressed. My bet is still on a vacuum leak, and probably around the rubber intake elbow near the throttle body, or other cracked vacuum lines that really need to be taken off and inspected. I've NEVER had good luck with MAP torch, carb cleaner, starting fluid, water, or anything else.

HupDogDaddy

I have been fighting the same issues on my 95 3.0
I was getting CEL code 71--(EGR) I found several issues on mine -- 3 vacuum leaks.
But after fixing I still had bad idle. Find the Vacuum modulator for the EGR. Its the round thing on front right (engine side) I think the three ports are marked R-S-Q --
Anyhow I found My modulator was bad -- according to FSM And I also found that both vacuum lines that run from R-S on Modulator to the throttle body were clogged.
If the EGR is stuck open it will not idle either-- Make sure all Vac line in the proper places! Only one in the wrong spot will cause issues. Get a Mitivac also, Great diagnostic tool -- just got mine and I wish I had bought one sooner

AxleIke

Good to know. The vac lines are all in good condition, I replaced the cracked and bad ones. However, I'd thought the water trick would do it. Guess I'll double check.

Excellent. I will look into the EGR. I've done some preliminary tests, because I thought it might have been an issue, but haven't looked at the modulator.

I have a vacuum tool. I'll look at this Mitivac stuff.

HupDogDaddy

I will tell you how I checked my EGR
With engine off connect your vac tool directly to the EGR valve port on top. Pull a slight Vacuum. Let it sit for a minute and see if Vacuum bleeds off. if your pump is good it should not. If you look closely you should see the stem move as you apply vacuum.
with engine still off reconnect the EGR line and take the one off the modulator marked "Q" connect this line that runs under the intake to your vac tool and try to pull a vacuum. you should not be able to. The VSV should be vented --
Now leave the vac tool where it is and start the truck and bring it up to operating temp.
again try to pull a vacuum on the "Q" line. If the VSV is good it should now connect to the same port you had the vac tool on earlier and the EGR should open,
when you do this the correct response from the engine should be to sputter. If it does not then the EGR VSV is bad or the EGR itself is bad or you have a vacuum leak or vac lines crossed up.
Hope that helps.
If you have the FSR look for the page in the EGR section marked EG2-142. that is the plumbing diagram I used to diagnose mine. that section is pretty useful if you use your noodle

AxleIke

Thanks!

HupDogDaddy

Did you ever get it figured out?

AxleIke

Somewhat.

The idle is fixed, which turned out to be a timing problem. The engine was running so rough, that I tried to time it, but it was still way off. So, I thought I had installed the distributer wrong. I took it out, and moved it one tooth. I was also seeing two different "timing marks" with the light, which was because the pulley was rusty. After I realized that I could see two "marks" I shut down, and colored in the actual notch with black marker. Once starting again, it was plain as day that I was looking at the wrong thing.

I took out the bolt on the distributer, and advanced the timing enough that the engine ran smooth. Then, I could see the mark perfectly, and adjusted to 10degbtdc, with the short, and it moved to 8 when the short was pulled.

I then shut down, pulled the distributer, and put it back in where it was before. Re timed, and it idled great.

Unfortunately, I still have a knock sensor code, and there is a loud ticking noise, which is possibly from knocking, though I don't know. It sounds like loud valves, but I didn't change anything with the valves. It didn't make that noise before the head gaskets blew. Also, my brother says the truck feels more "gutless" than it did before. (I know, the 3.slow is always a dog, but it seems worse than usual for him.)

Anyway, I was hunting, so I haven't looked at it for a while. I'll get back to it after the holiday.

Mad Hauser

Which way did you move the tooth? I'm having similar problems with the timing mark and a rough idle.

AxleIke

I'm not sure what you mean? What tooth are you referring to?

Mad Hauser

You said you took out the distributor and moved it one tooth. And that fixed the two timing mark problem.

banoobee17

i have a rough idle issue to like when i am in neutral and i press on the gas it sounds like fuel shortage and its has bout 15,000 miles on it and i just changes spark plugs and fuel filter same rough idle and i dont know wut else to check my egr seems fine could it be as reed valve

teeps

did you check spark? i had problems with my injector getting power but not spraying. but other than that check the timing belt, and also check if the cat is pluged.

AxleIke

One tooth on the distributer.

Check the timing.