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Old 12-02-2006, 09:02 AM   #16
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Re: yet another surging idle problem!!!

had car tested for emissions, failed hc test by .04 gpm. pulled some codes off I had a 15 which i'm assumeing was the temp sensor that I unplugged and a 44 which came on on my way to the test station. I'm going to pick up a can of carb cleaner and try for a leak today. TKS!
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Old 12-02-2006, 02:30 PM   #17
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Re: yet another surging idle problem!!!

The 15 was the temp.
The 44 is lean exhaust
Make sure the temp. sensor is plugged in when hunting for a vacuum leak.
Also disconnect hose to vacuum booster and put a bolt in it.
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Old 12-02-2006, 11:28 PM   #18
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Re: yet another surging idle problem!!!

O.K. I just saw your post on the booster hose, i will try that tomorrow if I get a chance to mess with it. But, tonight I put new plug wires on it and it had a steady idle but seemed to take long to warm up, so there was a difference at start-up. It still fell on its face when I drove it. It did run alittle better when the car got warmer. I disconnected the temp sensor, and it stayed running, so I drove it and it was much much better. Does that mean the sensor is bad??? and How can you tell if the thermostat is bad?
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Old 12-03-2006, 05:45 AM   #19
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Re: yet another surging idle problem!!!

With the temp. sensor disconnected it should be running very rich not lean.
The only way to check the temp. sensor is to ohm it or check voltage when running. With the sensor disconnected you probably will get 5mpg.The readings vary by the temp. If you ohm it tell me what you get and and the outside temp. Or pull it out and take it to a parts store and compare readings.
If the thermostat is opening fell the top hose when fully hot. Then feel a top hose on another car that is fully warmed up. You can feel the difference.
I really think you have a vacuum leak fix that then worry about other problems.
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Old 12-03-2006, 07:38 PM   #20
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Re: yet another surging idle problem!!!

I tested the temp sensor, it was at 4 almost 5 ohms cold. I put the voltage meter on it. Cold it was just under 4 volts, and dropped gradually to between 1.9 and 1.12 volts. the outside temp was around 28 degrees. I tried checking for a leak, I pulled the vac. First I pinched the hose for the booster and right away it seemed to smooth out, but i think that was coinsidence(not sure). I did end up plugging the booster vac. and spraying the carb cleaner along the manifold but it didn't seem to change anything. I probably didn't do it right. I'm supposed to spray along the manifold and valve cover right? while givinig it throttle. The car runs like crap. It idles smooth when the surging goes away but when I drive it it stumbles. It is weird.
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Old 12-03-2006, 08:59 PM   #21
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Re: yet another surging idle problem!!!

Spray along the sides of the intake manifold where it bolts on and around the base of the throttle body. Spray around any vacuum lines to the throttle body. Does it run better with the bolt in the vacuum line to the brake booster. A leaking break booster will definately cause problems. Also spray around this hose. If you can't find a vacuum leak pull the throttle body and clean out any openings. If you find a leak try to tighten the bolts to the intake or throttle body and recheck. I will check in the morning the ohms but I think they are close. They way you are operating is equalivent to running with the choke stuck closed. So you are getting air somewhere.
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Old 12-03-2006, 09:15 PM   #22
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Re: yet another surging idle problem!!!

I scanned through your posts, so if I missed ae earlier reference to it, pardon me, but you may want to take a look at the EGR system. As rhand is alluding, TBI systems (speed/density) are very sensitive to manifold pressure (vacuum). The power brake booster, EGR, and PCV systems are suspect.

A leaking EGR vacuum solenoid valve or carboned EGR valve pintle can cause your symptoms. Check for this:



Don't forget to pull the brake booster vacuum line and cap it, and check teh PCV valve, vacuum hose, and make sure the PCV valve is the correct one for your engine - They all flow at different rates.
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Old 12-03-2006, 09:16 PM   #23
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Re: yet another surging idle problem!!!

BTW - The CTS/IAT sensor is not right. The resistance should be closer to this:

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Old 12-03-2006, 09:38 PM   #24
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Re: yet another surging idle problem!!!

tks for the table bb. it does seem that the resistance is a bit low. I'm sure it was close to 4ohms. I'll check it again. How can I clean the EGR valve. I took it off and look inside it, but did not scrape i to see how much carbon was built up inside. Tks!!!

P.S. I'm not sure if I mentioned this in the original post, but the tbi gasket was replaced also in trying to resolve this issue.
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Old 12-04-2006, 07:01 AM   #25
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Re: yet another surging idle problem!!!

His picture is of a newer egr valve. Push up on the vacuum port and clean around the valve with carb cleaner. Take a piece of heater hose and try to blow through the valve. If it leaks get a new one. The throttle body is in two pieces I'm almost sure. Tighten the upper part against the gasket. See if the vacuum diaphram part of the egr valve is leaking if so replace. If its your original pcv clean it out with carb cleaner or replace. Check pcv hose to be sure it isn't plugged.
If your brake booster is leaking get a rebuilt or good used one. Lay a ruler flat over the hole and measure the length. They can be adjusted so write the length down before turning in yours for a core.
What is your mileage on this engine? Do you know how to check timing? If you do can the computer advance the timing?
If over 100,000 and the timing chain hasn't been replaced turn the engine over by hand about 60 degrees past top dead center clockwise. Then turn back counterclock wise to zero degrees. Pull the distributor cap and use white out mark the dist. where the rotor tip is. Have somebody watch as you turn the crank by hand. Stop as soon as the rotor starts to move. Anything over 15 to 20 degrees the timing chain needs replaced.
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Old 12-04-2006, 12:02 PM   #26
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Re: yet another surging idle problem!!!

I took the EGR valve off, and tried cleaning it. didn't have much on it. but I pushed the diaphram till it stopped and plug the vacuum port and the diaphram slowly open. is this normal or is it leaking.
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Old 12-04-2006, 12:45 PM   #27
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Re: yet another surging idle problem!!!

I never checked one this way so I'm not certain. I usually put a vacuum valve on the solenoid valve gun the engine and if I get vacuum, I connect the egr valve gun the engine and if it opens its ok. I also have used a vacuum pump.
What did you decide about the vacuum booster does your engine run better or not.
Does it ever idle good with the temp sensor connected or not? Sometimes a bad knock sensor will retard timing when trying to gun the engine. At this time
exactly what is happening. What is the mileage? Any backfire or does it act like a dead cylinder I've had a worn valve guide that the rocker arm would turn and the engine would miss move back into place and run perfect. I found this with the valve cover removed and I could move the valve spring. I found the correct cylinder by doing a compression test. I've also had a cracked plug.
Does this happen all the time or is it hit and miss?
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Old 12-04-2006, 09:21 PM   #28
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Re: yet another surging idle problem!!!

Just for s@#ts and giggles, the ohms on the cts were 9600@25f

Well about the EGR, I did try to move the diaphram while the car was running, and when I did it sounded like it was going to stall. So may be it is o.k.

Does it ever idle good with the temp sensor connected or not? The idle seems fine at first until it starts to warm up then it starts to sruge up and down between 500 and 1000rpm. It seems when the car is at normal temp it smooths out for a few mins then surges a little bit, then smooths out and so on. The car when it idles normal it is really smooth. The odometer does not track properly, so the car may have close to 200,000 on it i'm not sure. I'm going by the service records that came with the car. Although when I drive the car it is the same thing everytime. it stumbles from a dead stop if I give it close to ful throttle. If I give it 1/4 to 1/2 throttle it seems better but not fuul power. Sometimes when I hit the throttle at around 25mph it hesitates for a second or 2 and then takes off but jerks until it shifts, sometimes it is smooth, but does not feel like ful power.


I have not tried the booster again. I need to put the EGR valve back on and stuff. I will try it again after that. It does seem like the brake pedal is a bit stiff when I brake. I will pay more attention to that if I drive it again.
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Old 12-05-2006, 07:24 AM   #29
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Re: yet another surging idle problem!!!

Before you install the egr look at the bottom I had a truck I worked on with a new egr but they didn't put the spacer washer in it. Aftermarket egr's have a washer with the proper calibration so it will fit many vehicles. So when this valve opened it pulled to much flow and the engine shook. This is one thing I would check before I put it on.
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Old 12-06-2006, 07:56 AM   #30
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Re: yet another surging idle problem!!!

there was no spacer on the EGR valve. I will try to post a pic of the EGR valve.
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