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throttle issues.

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triston2469

10+ Year Contributor
231
0
Sep 15, 2012
Yukon, Oklahoma
So im having a few throttle issues. When I start the car it fights to stay running and pretty much dies right off the bat so to keep it running you have to play with the throttle. Then after it has ran a while and you drive for a little it idles anywhere from 2000-3000 rpm. The other issues I'm having is that when it gets up to 3500 RPM while driving it studders really bad. The car sat for about a year before I bought it and for this to be the only issue I'm having I think its pretty good.

Here is what I have tried so far thinking it would fix the idle issue and studder issue:

Cleaned the air filter cause it was horrible. Luckily it has a K&N.

Checked spark plugs and they looked like they were fouled up with carbon really bad so i changed them.

I have adjusted the throttle cable so that it is not just dangling and not too tight.

I am kinda confused on what the problem is. I'm thinking that the issue could possible be the Throttle Position Sensor, but im not exactly sure.
 
how do you go about testing them with a multimeter?, and where is the iacv at?

well i did a google search and found how to test the TPS and it tests good, so that is a slight piece of mind. Also did a search on how to test the IACV and it took me to some other DSM forum but it didnt explain everything very well. what i got from it is you put your MM leads on pins 2 and 3 and see what that reads then you do the same for 5 and 6 and they should both have a low number. Well pins 2 and 3 dont read any ohms and pins 5 and 6 read 30 ohms. So I am thinking that could be the bad part. Any more info on testing the IACV would be extremely helpful
 
how do you go about testing them with a multimeter?, and where is the iacv at?
(...)
Hi,

There is a possibility to check the ISC, if it works ore not. You have to measure the resistance between
pin 1 and 2 ,
2 and 3 ,
4 and 5 ,
5 and 6 of the ISC.
If only one is 0 or the resistance are not all in the same area ( arround 28 - 33 Ohm) the ISC is damaged.

The location is straight under the intake hose. Directly under the Throttle body.

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Regards
 
Thanks for the help. I tested the ISC last night and found that pins 2 and 3 had no resistance as well as pins 4 and 5. So now i get to wait till i get paid friday to be able to go order a new one. Hopefully they can get it same day or they have one in stock.
 
Any CEL?

Also I've been searching for it again for you but I found a vendor that was selling new ISC for about $130, both kinds for the 1g.

Good luck in finding it in stock. If they have it your lucky. When I was trying to replace mine, O'rielly's had a part number in their system but could no longer order it (discontinued) and autozone never heard of it. Other parts stores had it discontinued.

I was going through them because O'rielly's had it listed with a lifetime warrenty.
 
Well i can get it on the autozone website for $80. It just sux that i cant get i am going to have to wait till ###### monday to be able to fix it.
 
Ok, an update. I changed the IACV. that fixed the idle problem when you first start it, but i cant go over 4k rpm still. and after driving it for a few min it idles at 2k. how far down is the biss screw supposed to be? could this cause the problems i am having. I bought the car from a retard who didnt really know what he was doin with cars i think and im having to fix his problems. I am also wondering if the fuel filter could be causing the problem of not going over 4k rpm

Also there is no Check engine light on.
 
(...) how far down is the biss screw supposed to be? (...)

Hey,

(That´s the strict way)
if you changed the ISC you should disconnect your battery for a few minutes.
(Best way: Disconnect it while you are changing the ISC)
After that, run the engine ~10 min without any appliance in idle speed.
That´s necessary to train the ECU to the new ISC.

setting the idle speed:

- Engine is warm
- Without any appliance

---> steps of the ISC should be between 8-12
---> the idlee speed should be at about 850 rpm (just turn the screw as long as you reach the mark)

You are only able to see the steps with a data logger.

If the problem is still there after this procedure you have to look at all the other stuff which was mentioned.
I really don´t believe in a bad fuel filter BUT it´s always a good decision to change it, especially if you don´t know when it was changed the last.

Good luck!

Regards
 
thanks for the info. I didnt know that you had to let it idle for 10 min after changing it. i guess i will have to unplug my battery and let the ecu reset and go about that again. I also found today that i had a ground wire not connected to my engine so i connected that, but i still had the rev limiter thing going on at 3500 rpm. I then unplugged the TPS and found there was no hesitation at all while in neutral and the car actually idles like it is supposed to, which leads me to think that the TPS is bad, but i could be completely wrong. LOL
 
Hi,
if the idle is still bad after the procedure above and you noticed a change into the right direction after you had disconnected the TPS plug, you should have the reason why ;)
But I thought you already had tested the TPS?
I´m not telling something new, because all the others here told the same before :)

Regards
 
OK so another update. I changed the TPS and found out that I had a bad alternator. I still need to get the battery charged being that i had my daughter on my last set of days off and she is more important than my car. Also i found out that the TB was only being held on by 2 bolts. So I went and got new bolts and a gasket for the TB and put it all back together and was feeling very hopeful that i found the problem.

Anyway took it for a short drive after her mom i dropped her off with her mom and the idle is good, but I am still having the issue of it acting like it is hitting a rev limiter when it gets to 3500 RPM. When I go on days off again I will take the battery out and charge it just to rule out that the battery is low and that is the cause of the problem.

I am slightly confused about what it could be, and I am running out of "cheap" things to change. I really hope its not the ECU. I know alot of people that have had the same issue I am having have had to change the ECU, and being that its a non-turbo I'm pretty sure a boost leak test wouldnt do me any good. LOL.

Any more ideas would be very helpful
 
So another update. I unplugged the MAS and the car runs like its supposed to. So to eliminate any chances of air filter being the cause of this i went ahead and cleaned the filter and reoiled it and cleaned the MAS. I'm pretty sure im going to have to replace my MAS which will end up having to wait 2 weeks for when i get paid again, but in the end im glad i have finally found out what the problem was with my car. Well that is unless there is something wrong with that circuit in the computer, but im keeping my fingers crossed that that is not the case. LOL
 
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