Idle Surge Problem

[iguanahotsauce]

So for anyone who didn't see my post a while back I received a 1992 eagle talon tsi for free about two months ago. It had been sitting for about five or six years so it needed quite a few repairs. So far I have replaced the fuel pump, fuel filter, Idle Control Motor, Oil, Drained the gas tank, Accessory belts, spark plugs, brakes, and one of the wheel bearings. The last things I have left to do are change the transmission fluid and the tires. I also installed an aftermarket boost gauge . Recently I have started having an idle surge problem. I took it to my mechanic and he said the Idle Control Motor was bad so I replaced it. Now it's not idle surging as bad and it won't start to do it unless you step on the gas while it is in park. It will also do it when you finish driving and put it into park. But when you are driving it doesn't seem to have any problem. I have been reading up on how to fix the problem and I plan on going through all the steps to try and fix it. What I am wondering is will it be harmful to the car if I drive it while it has this idle surge problem?

 

[razrman8]

I would not say that it is harmful for the car, just gets annoying and embarrasing. Have you looked at this? It only doe it at idle because there is a constant flow of air at idle to regulate the rpm/idle with the throttle body plate closed. When you are driving, constantly accelerating and decelereating, you are changing how much air the throttle body is allowing to pass through.

Terry's Talon Troubleshooting Tips #3 - Fast Idle (aka. Idle Surge)

 

[iguanahotsauce]

Yeah I checked that out. His problem was the ISC which I just replaced. I can hear the ISC working now which I could not before but it is still having the surge problem

 

[razrman8]

Is your biss screw leaking? Are you sure that you don't have a throttle body boost leak?

 

[misterjose]

check around your TB if you replaced the isc then thats good. check the gaskets between the intake and tb and the gasket between the tb and the tb elbow. when you get a chance replace the gasket and apply rtv

 

[iguanahotsauce]

razrman8 - I'm not sure and I don't know what a biss screw is. I am still very new to working on cars. The only experience I have ever had working on cars before I started working on my talon was changing the oil. But so far I have replaced everything myself. What was weird was when I got the car and started repairing things it didn't have this problem. But then right before I was going to take it into my mechanic it started happening and he has no idea what is causing it.

misterjose - I will do that either tomorrow or tuesday

 

[MR2BOY]

Does the car idle's rough when is sitting? Also do u have an aftermarket boost gauge?

 

[LiquidX]

An improperly adjust FIAV will cause idle surge as well which can happen over time.

http://www.dsmtuners.com/forums/articles-intake-exhaust/391977-free-fiav-block.html#post152458783

 

[iguanahotsauce]

The car seems to idle alright. I let it run for about 20 minutes yesterday to see how it idles and it was fine for a while but after about 15 minutes the idle rpms kept going lower and lower until it was at about 500rpm. After thinking about it for a while I realized my throttle body could be dirty because the surge doesn't happen until I step on the gas. I am going to check out some things today and see if I can fix the problem. While I am thinking about it there are a few other questions that I have been wondering about. The first one is that the needle in my equis boost gauge vibrates when I am boosting and I was wondering if this is normal or if I should have the gauge replaced. The second is that I need to get new tires since it has been sitting for five years and I am trying to decide if I want to buy new or used tires. I went to americas tires and the salesman told me with an awd vehicle it is bad to have two different sets of tires because the varying tread height will cause the transfer case to go out in 10000 miles. Is this true or is it just some bs he is making up to sell me tires? My last question is about brakes. My local auto parts shop has two types of brakes and I have no idea which to go with and if it will really make a difference

 

[hereitcomes]

Different sets cause a T-case failure? Oops. I run free tires that I get from work. The sizes are the same, but brands differ. I have never bought a tire before, and have put 20k on just this one DSM.

Match your tire sizes. That is important.

 

[razrman8]

People will tell you anything these days to get you to buy something.

 

[iguanahotsauce]

Yeah that's what I figured

 

[cliffkemp]

if it is an awd, it is not a good idea to run different size tires from front to back that have different diameters.

awd likes same size tires and is best overall set up for a car anyway. awd doesnt like different diameter tires that much and may shorten the life of the awd system over time depending on the difference in diameter. my .02 worth

 

[iguanahotsauce]

I wasn't planning on running tires with different diameters I was just talking about if I had different brands. Because I have two tires that are the correct size for my eagle rims that are still good but I need to buy a second pair since the ones I have now have flat spots on them. Does anyone here who has an aftermarket boost gauge have problems with the needle vibrating when you are boosting?

 

[Absit]

Never mix brands.
Never mix new and used.
Never mix sizes.

All of these matter on varying levels, but each one will contribute to premature driveline failure.

 

[crazycooter]

I would try adjusting the biss!!! Also since you just got the car I'm thinking the gas may be dirty!! You did say it sat for 5 to 6 years!!! Try adding a half bottle of seafoam to a full tank of premium gas!!! Also, it might be a good idea to check your plugs and wires!!! Try a compression check too!!!! These are all basic things that one should do to any used car they get!!! Especially if it has been sitting for so long!! Make sure you use 93 octane if possible too!! None of that cheap gas!!! Might even be the clutch or pedal assembly!!!!!! Check all vacuum connections too!!

 

[cliffkemp]

Never mix brands.
Never mix new and used.
Never mix sizes.

All of these matter on varying levels, but each one will contribute to premature driveline failure.

amen to that

 

[iguanahotsauce]

Never mix brands.
Never mix new and used.
Never mix sizes.

All of these matter on varying levels, but each one will contribute to premature driveline failure.

Really? I don't know what to do. I need this car as it is my daily driver now but there is no way I can afford to buy four new tires and I can't find any shops around here that have a set of four used tires. Will it be really bad for my talon if I mix two different brands of used tires. All of them are the same size. I just don't know what to do because I am pretty much screwed if I don't get tires on it. I would use the ones on it now but they have bad flats spots and I don't know how that would affect the car and they are also two different brands. I am assuming the person I got it from had been driving on two different brand tires every day for as long as he had the car.

 

[crazycooter]

I am definately going to say to try adjusting the idle air control!!! If it was bad when you bought the car and you had to replace it.. I am thinking the previous owner tightened the screw to "stop" the problem because it is obnoxious!!!! If the screw is adjusted too much in it will have this problem I had the same problem when I changed mine... I had the screw almost in all the way and when the car warmed up when i put my foot on the clutch to stop it would die!!! What is the temp in the area the car is stored???? If it is cold it may take about 15 minutes to warm up completely and the EC is designed to idle high until it is warmed up!!! The ECU is also trying to keep the car alive ( this may be the "surge" you are experiencing )... If it is hard to comprehend this because I am terrible at explaining things.... What I am gettin at is if you have your car in gear and "let it almost die" or even die... it will start back up if it is still rolling if you put your foot on the clutch... get it... hope it helps!!

 

[cliffkemp]

Really? I don't know what to do. I need this car as it is my daily driver now but there is no way I can afford to buy four new tires and I can't find any shops around here that have a set of four used tires. Will it be really bad for my talon if I mix two different brands of used tires. All of them are the same size. I just don't know what to do because I am pretty much screwed if I don't get tires on it. I would use the ones on it now but they have bad flats spots and I don't know how that would affect the car and they are also two different brands. I am assuming the person I got it from had been driving on two different brand tires every day for as long as he had the car.

its not good and it may be ok for now but, at the earliest possible time you can, get matching tires. My talon came with 2 different makers and they started wearing funny. Went to stock size rims and replaced the tires with all same size and make and runs good now. I would fix that problem asap and crazycooter seems to have some good ideas for fixing the idle problem as well. there is a proceedure to fix the idle in the shop floor manual or haynes manual as well. I have the Chiltons version and the idle info is on page 1-50 if you want to look it up.

 

[iguanahotsauce]

I am going to get one of those manuals but for now I will try adjusting the idle air control. Does anyone with an aftermarket boost gauge have a problem with the needle vibrating when boosting? I'm not sure if it's because of the location that I put my gauge or it it's just a poorly manufactured gauge and I should swap it out for another one.

 

[jb300zx]

Really? I don't know what to do. I need this car as it is my daily driver now but there is no way I can afford to buy four new tires and I can't find any shops around here that have a set of four used tires. Will it be really bad for my talon if I mix two different brands of used tires. All of them are the same size. I just don't know what to do because I am pretty much screwed if I don't get tires on it. I would use the ones on it now but they have bad flats spots and I don't know how that would affect the car and they are also two different brands. I am assuming the person I got it from had been driving on two different brand tires every day for as long as he had the car.

Okay. I just got my 1992 Eclipse, and it has aftermarket rims and tires. So I don't know what you need. What size rims do you have? Curious as I have a set of brand new tires gathering dust at my house. Never mounted. Never touched the pavement. Sounds like you need a set of tires pretty bad. Thought maybe I could help.

 

[1991BlackTalon]

Boost leak test it, do you still have your biss screw?

 

[iguanahotsauce]

yeah I'm going to order the boost leak test kit and check it when I get a chance and I don't know what a biss screw is. I am still pretty new to working on cars

 

[crazycooter]

Its the big phillips screw that's counter sunk on the throttle body!!