Still having problems with idle

[raybugarin82]

So i bought a rebuilt throttle body but the idle speed control is not included. I used an ISC from a 90 non turbo.....still, the idle is going up and down though its not like before....i asked my friend why its still idling like and was thinking of returning all vacuums to original positions....he said to not do that and the reason why its still looping is because he remove the balance shaft from the engine.....what is a balance shaft and does it affect the engines performance??i am going crazy about this car and i havent driven it for years.....please help

 

[Gavin24]

I dont think balance shaft should cause your idle to loop...

 

[BrokenTsi]

Have you tested the ISC to make sure its good?

 

[Talondvr]

Check that your throttle body is grounded and the closed throttle switch, tps, and throttle cable is adjusted properly too.

 

[92AWDHX40]

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

 

[BrokenTsi]

Start off by checking your base timing with a timing light. Then inspect your ISC according to the link above. Also, do a boost leak test. You can't have any at all or else you will surge.

 

[raybugarin82]

I didnt check the isc tps but i got a new problem, the car will start then dies and wont start again.... It sounded like as if its out of gas......it happened when it was running then i turned on the headlights then it died..i was thinking maybe i tightened the biss screw shut but its not..or maybe some grounded wires....anyway until now the car do the same thing each day.....any ideas what happened??? Could it be the fuel pump or injectors???

Check that your throttle body is grounded and the closed throttle switch, tps, and throttle cable is adjusted properly too.

How do i check if its grounded??are there any wires needed to be connected to it??

 

[Talondvr]

How do i check if its grounded??are there any wires needed to be connected to it??

There should be a little tab going from the TB to the bolt on the intake pipe side. That creates a ground for the closed throttle switch.
Sounds like you got bigger issues tho.

 

[johnovision27]

+1 ISC. They beat me to it.
Also, keep in mind that you can only set the BISS properly if you have a way of measuring the ISC position. ECMlink will do that.
I'm kind of surprised no one has said this yet, but vac leak? Do a test, you never know what you can find.

Not sure if it was already mentioned, but there it is again. I'm tired.....

 

[raybugarin82]

Thanks for the replies i really appreciated it. I followed the Link for terry's Talon troubleshooting..theres one step there that i did.

.............. Disconnect the idle switch and the ISC connector so the engine runs at a steady speed and the ECU can't fiddle with the Isc........

I did this and still the car is looping and sometimes the engine will die.....do you guys think its the isc??? I was thinking maybe fuel injectos or fuel pump....

 

[Talondvr]

Thanks for the replies i really appreciated it. I followed the Link for terry's Talon troubleshooting..theres one step there that i did.

.............. Disconnect the idle switch and the ISC connector so the engine runs at a steady speed and the ECU can't fiddle with the Isc........

I did this and still the car is looping and sometimes the engine will die.....do you guys think its the isc??? I was thinking maybe fuel injectos or fuel pump....

buy a multimeter if you don't have one already.
Check your isc: DSM ISC motor testing & Replacement - YouTube

Just wanna make sure I'm reading that right.. You unplugged the ISC and it still surges? One bad fuel injector and it will run rough, Two bad and it wont run. Fuel pump?.. check your fuel pressure. Test your closed throttle switch. Test and adjust your TPS. Check timing and set biss screw. Make sure the TB and IM are grounded. State what you have tested and the results. With more feedback from testing we can help to better answer or you could just throw parts at it and hope it fixes it.

As the above poster stated: do a boost leak test!

Happy wrenching!

 

[steve]

How did you install the 90 ISC on a 91? The connectors are different.

 

[raybugarin82]

Im confused..im sorry i might not know what im talking about...which one is the closed throttle switch??i thought it was the tps? If it was the tps, it came with the TB that i got refurbished...the ISC fit to the connectors perfectly probably its not from a 90 TB.... I'll put up some pictures to identify things tomorrow..
Also i check the vacuum hoses and follow the route from taboo speed shop for 1g......its a little confusing.....theres 2 nipples from the valve cover....one is breather and the other is the one with a PVC valve that was connected to a nipple below the intake manifold near the injectors......then theres another nippl from the intake manifold to ( i guess as it was connected to tge fue, rail) the fuel pressure regulator and boost gauge.......
What i did is connect the breather hose the pvc valve and block the one from the intake manifold....is this right??i have no ideas what to do anymore....the last resort i will do is take it to my mechanic (my friend who sold me the car) and spend money.....he always say that the idle loop is normal because 1st was the maf and need to upgrade to 2g maf....2nd he said that he eliminated the balance shaft....3rd he said that the ISC/TB needs to be replaced......i feel like hes guessing and he just doesnt care about it.....
im running out of options...that car had been sitting in the garage for almost three years since i bought it.....never had the chance to drive it around.....and keep throwing money at it ....thank you all for the replies and comments...good day

 

[steve]

which one is the closed throttle switch? i thought it was the tps? If it was the tps, it came with the TB that i got refurbished.

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The Idle Position Switch is the closed throttle switch on a 1G. On a 2G it's inside the TPS.

 

[raybugarin82]

Oh okay....so thats te throttle switch.....i thought so too......anyway, i didnt see any signs of the ground wire being there at all actually this is the first time i saw a ground tab and a throttle body stay in a 4g63.....what the minimum wire gauge i can use for the ground?? Can i just inprovise the grounding like i would connect a wire from the tb to the IM or the ground wire behind the throttle body??...ii havent got the chance to take pictures yesterday...have a good day guys

 

[steve]

The ground doesn't carry much current so just about any handy wire will do.

Have you checked to see if the IPS is working? It could be functional and not have anything to do with your current issues.

If your prior ISC was bad in a way that one of more of the coils inside were shorted they will damage the ECU so that a new good ISC won't work. That's why you need to measure the coils on the old one and any replacement.

Have the capacitors been replaced on your ECU?

 

[Junfan]

I am once again fighting idle and surge problems. I have a thread in the tuning area and somehow fixed 2 things and made it worse. Kinda getting frustrated but all will be forgotten the first time I make a real pull. HAHA

 

[skatershawn]

What about This, I too have been dealing with idle surging since i rebuilt my motor and have spent countless hours swapping sensors, vacuum lines, and testing sensors over and over but have yet to solve it! I even sent my ECU to ECMTuning to get checked, cleaned up, and the caps replaced and they said it passed like a charm!

Next thing IM going to try, and what are yalls opinion on this, is Intake Manifold Gasket!
Could that be causing an idle surge??

 

[Talondvr]

What about This, I too have been dealing with idle surging since i rebuilt my motor and have spent countless hours swapping sensors, vacuum lines, and testing sensors over and over but have yet to solve it! I even sent my ECU to ECMTuning to get checked, cleaned up, and the caps replaced and they said it passed like a charm!

Next thing IM going to try, and what are yalls opinion on this, is Intake Manifold Gasket!
Could that be causing an idle surge??

In theory, any boost/vac leak can cause surge. So without thinking about it too much (been a long day) I would say yes. A BLT should be done to find all leaks first.

 

[04bls84]

I had a boost leak at my fuel injector. The o-ring that goes around the fuel injector was cracked and was suckin air into the head. I would have never found it without a boost leak test.

 

[92AWDHX40]

Gott love a bl tester.

 

[badbluething]

Clean or replace your MAF, run a boost leak. Strange fixing your ISC didn't solve the problem. Our idle motors a junk and often go bad and are in need of replacing.

 

[raybugarin82]

Sorry for the late replies ive been so busy this past week...anyway, i got my isc motor and tested the resistance. The reistance are both 30 ohms in both terminal 1-3 and 4-6....measured the volts from the connector......whats the ideal output voltage for the isc connectors.....i already did the ground wire of the TB.....still its surging from 1200 - 1800 rpm, sometimes it will drop to less than 1000 rpm then surge up to 1500....
Im about to replace my maf to 2g maf......
I havent done the boost leak test but i replaced all vcuum hose.....i was thinking of the fuel filter amd pump because my eagle talon dont have the idle surge anymore....also what bout battery?? I put a 95 amp alterntor to my egle talon....i am going to replace the spark plugs and wires as well and have the ECU check.....thanks for the help guys

 

[l314ckhe4rt]

one of your injector is bad