2G im at a loss...

TuJay · Nov 25, 2017

Heres a video link to what my GST has been doing. Itll sputter, backfire and wont idle when cold but when its warm it almost never does it and idles. Once I get in boost it wont misfire at all. I have no idea.. I cleaned my MAP sensor and that helped a little but not much. Skip ahead in the video where I get on the road and you can really see what i mean.

(sorry for belt squeal)

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pauleyman · Nov 26, 2017

TuJay said:
ECU is fine regarding its condition. It’ll still do it when warm but not nearly as bad or often. I can kind of free rev, it’ll rev but every couple times it’ll hesitate and misfire then rev.

Is fine how? Just a quick visual inspection? That may not tell you squat. Easy test may be to try another ECU which you haven't said you tried yet.

Tanro · Nov 26, 2017

Mine does this too. I was having terrible problems with spark for a while. Eventually it got so bad I had to break down and get a new Ignition module (ignitor for the coils). Seemed to help a bit. But I eventually found a burnt wire on my coil pack harness. Rewired that and it helped a lot. But It still does it when cold. Leaning towards a throttle body issue myself as I have known boost leaks that seem to compound it. I really need to get new lower injector seals and see if that helps. Also need to use a scan tool / dsm link / evo scan to set my ISC.

Just some things to consider. If I was working on your car I'd :
1) Do an intake leak test (boost leak test,or smoke test) it can help find vacuum leaks that will go away once the engine is warm (do it cold obviously)
2) Use a scan tool, or other method to ensure that the ISC is properly set
3) Make sure the TPS is properly adjusted

4) Inspect all the wiring for the injectors, ignitor, and coil pack.

TuJay · Nov 26, 2017

Spideydsm99 said:
Test the isc.

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Well I found this after I took the plug off. Will post the resistances shortly

TuJay · Nov 26, 2017

Spideydsm99 said:
Test the isc.

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Pins 3&4 are open. Time for a new one of those. Hopefully that’ll fix it.

Spideydsm99 · Nov 26, 2017

Glad I could help! :thumb:

TuJay · Nov 26, 2017

pauleyman said:
Is fine how? Just a quick visual inspection? That may not tell you squat. Easy test may be to try another ECU which you haven't said you tried yet.

Tanro said:
Mine does this too. I was having terrible problems with spark for a while. Eventually it got so bad I had to break down and get a new Ignition module (ignitor for the coils). Seemed to help a bit. But I eventually found a burnt wire on my coil pack harness. Rewired that and it helped a lot. But It still does it when cold. Leaning towards a throttle body issue myself as I have known boost leaks that seem to compound it. I really need to get new lower injector seals and see if that helps. Also need to use a scan tool / dsm link / evo scan to set my ISC.

Just some things to consider. If I was working on your car I'd :
1) Do an intake leak test (boost leak test,or smoke test) it can help find vacuum leaks that will go away once the engine is warm (do it cold obviously)
2) Use a scan tool, or other method to ensure that the ISC is properly set
3) Make sure the TPS is properly adjusted

4) Inspect all the wiring for the injectors, ignitor, and coil pack.

Here’s a better list to the circumstances and symptoms of it happening if it helps

Spideydsm99 · Nov 26, 2017

Yeah just change out that isc.

chrysler kid · Nov 27, 2017

Jarvis6699 said:
I could be wrong but your idle air control sensor on those can cause the the same out come when I had a 2G that’s what caused mine

Nice. Solved on the first post!

Tanro · Nov 27, 2017

TuJay said:
Here’s a better list to the circumstances and symptoms of it happening if it helps

Yeah. Same problem here.

Anyways, mine was compounded by other issues. Bad injector seals, burnt wires on the fuel pump and coil pack, failing ignitor. I mean its a 20 year old mitsubishi that was owned by a f***ing moron before me.

But yeah, I'd check the IAC. The big rectangular plug at the bottom of your throttle body.

If bad replace, if functional then set it.

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to set the isc refer to

LiquidX said:
If you have ECMLink you set the BISS to allow your IAC to have a value of 30 while maintaining the set idle.

Otherwise you need to ground out the diagnostic pin and set the idle that way. Having it out of adjustment means the IAC motor is out of it's full range of movement (idle control). Opened too far then the motor will be closer to a closed position and vise versa with the BISS screwed in too much.

This is why the BISS isn't to be touched unless you are setting the idle properly.

I would give a rough estimate that it's best spot is about 3 full turns out from the bottom.

The BISS screw is used to set the ISC. It needs to be a specific range to maintain idle.

Spideydsm99 · Nov 27, 2017

@Tanro yeah I showed him that earlier and he said it’s not working so that’s the problem.

Ludachris · Nov 27, 2017

Hats off to all those who chimed in to help the original poster.

93 GSX TURBO · Nov 27, 2017

My car did the same years ago and it turned out to be a bad ISC.

TuJay · Dec 5, 2017

like my old post said to to after determining my ISC was bad to replace it and that would fix my misfire. I replaced it today and the new ISC helped A LOT it doesn’t misfire nearly as much and it’s somewhat driveable LOL

but it still does like to misfire here and there but like I said not as much as it used to though. It does idle better but still low. I don’t suspect my BISS being out of adjustment because when it’s at operating temperature it’ll idle almost exactly where it should give or take a couple hundred RPM’s so it might be a little out. After taking all that into consideration I suspect my MAP, coolant temp sensor, and a possible boost leak but I’m not sure. Here’s another video with the new ISC.

Sorry again for the belt, I really need to adjust the power steering bracket.

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chrysler kid · Dec 5, 2017

What check engine light code are you throwing.

Have you verified the throttle position sensor is correct by using a
.0177 feeler between the throttle stop screw and the tb spring and verified continuity on the top 2 pins?

Have you adjusted your biss screw outwards till you can hear a hiss from the tps area?

TuJay · Dec 5, 2017

chrysler kid said:
What check engine light code are you throwing.

Have you verified the throttle position sensor is correct by using a
.0177 feeler between the throttle stop screw and the tb spring and verified continuity on the top 2 pins?

Have you adjusted your biss screw outwards till you can hear a hiss from the tps area?

CEL is just from emissions delete.
Call me dumb but I have no idea what that 2nd paragraph means
It’ll idle fine when warm though

jinscho · Dec 5, 2017

TuJay said:
CEL is just from emissions delete.
Call me dumb but I have no idea what that 2nd paragraph means
It’ll idle fine when warm though

Second paragraph describes how to properly adjust the TPS.

First post on this thread gives you the basics: http://www.dsmtuners.com/threads/how-to-adjust-the-throttle-position-sensor-tps.324431/

chrysler kid · Dec 5, 2017

The throttle position sensor helps tell the ecu what position the iac valve needs to be in at idle. If your throttle position sensor shows the computer in the car that the throttle body is 3% open and it is really closed, the car could in theory idle very low like yours is doing

TuJay said:
CEL is just from emissions delete.
Call me dumb but I have no idea what that 2nd paragraph means
It’ll idle fine when warm though

Emissions delete is very vague. The only check engine light that could be triggered is from no catalytic converter. All other emissions equipment can be bypassed without triggering a check engine light. You just leave the bypassed sensor plugged in. The ecu in a generic sense is a dumb ecu, it just detects if the sensor is plugged in and using the electricity being sent to it

TuJay · Dec 7, 2017

chrysler kid said:
Emissions delete is very vague. The only check engine light that could be triggered is from no catalytic converter. All other emissions equipment can be bypassed without triggering a check engine light. You just leave the bypassed sensor plugged in. The ecu in a generic sense is a dumb ecu, it just detects if the sensor is plugged in and using the electricity being sent to it

I was gonna put this in another post but, I can’t find the plug for the purge valve, it’s not there. There is a connector behind the brake cylinder reservoir that’s connected to a connector with no wires. Is there a way I could use ECM tuning to get rid of the CEL? I’m tired of seeing it

chrysler kid · Dec 8, 2017

The wire harness for that purge valve should come across the intake manifold. It should go coil plug, injector plugs, a.c. compressor plug and then purge valve and crank sensor.

So follow the plug for the a.c. compressor back up the wire loom to find the plug for that guy.

PlanZero · Dec 8, 2017

chrysler kid said:
Emissions delete is very vague. The only check engine light that could be triggered is from no catalytic converter. All other emissions equipment can be bypassed without triggering a check engine light. You just leave the bypassed sensor plugged in. The ecu in a generic sense is a dumb ecu, it just detects if the sensor is plugged in and using the electricity being sent to it

Actually on two of my dsms (96+97) I always have the CEL for egr valve flow restricted (don't know the code offhand) after installing a block off plate. All solenoids are plugged in and a spacer on the rear o2 eliminates cel for cat delete. And yes you can remove them with link.

OP it's pretty common to have to adjust your TPS after IAC replacement. I've also found it takes a drive or two for the ecu to adjust to a new IAC or TPS. You really need to understand how to calibrate your TPS. Ours are adjustable and can cause a myriad of problems when they're acting up and may need adjustment. Theres quite a few write ups on how to do it easily. Also take 30 secs and tighten the belt. You probably have a bunch of boost leaks. Do a real BLT with soapy water.

Teezy · Dec 8, 2017

Another way to adjust your TPS is to log the voltage. Make sure it's set at .63 volts off the throttle, and 5 volts at WOT. You don't need to turn the car on to do this, just start the datalogger and adjust accordingly.

Read this carefully : https://www.ecmtuning.com/wiki/idlesurge

This is all assuming you have ecmlink since you mentioned it in an earlier post.

TuJay · Dec 8, 2017

Teezy said:
Another way to adjust your TPS is to log the voltage. Make sure it's set at .63 volts off the throttle, and 5 volts at WOT. You don't need to turn the car on to do this, just start the datalogger and adjust accordingly.

Read this carefully : https://www.ecmtuning.com/wiki/idlesurge

This is all assuming you have ecmlink since you mentioned it in an earlier post.

Ah okay, thank you all for the help I’ll update when I can but one quick question, could I get any generic usb to OBD2 cable? Or do I need a specific one?

chrysler kid · Dec 8, 2017

PlanZero said:
Actually on two of my dsms (96+97) I always have the CEL for egr valve flow restricted (don't know the code offhand) after installing a block off plate. All solenoids are plugged in and a spacer on the rear o2 eliminates cel for cat delete. And yes you can remove them with link.

OP it's pretty common to have to adjust your TPS after IAC replacement. I've also found it takes a drive or two for the ecu to adjust to a new IAC or TPS. You really need to understand how to calibrate your TPS. Ours are adjustable and can cause a myriad of problems when they're acting up and may need adjustment. Theres quite a few write ups on how to do it easily. Also take 30 secs and tighten the belt. You probably have a bunch of boost leaks. Do a real BLT with soapy water.

Couldnt tell you for certain on that one. There's thread about 1994 models having an egr flow sensor, and california models only prior to that. My 98 doesnt throw any codes, I bypassed and blocked everything when I was trying to find out why the car was idling high (it was the throttle cable bracket and i had to reset my idle stop screw and reset my tps, then set my biss screw)

Just a generic shout out, mitsubishi was really spotty with model range options and details. Ive had 4 different 1996 model cars and all of them had different cloth interiors. I had a 96gs that by far had the nicest cloth interior of any car ive ever had, and my 96 gst now might as well be called saddle blanket cloth interior, and a 96rs that was just the same generic base cloth seat as all 95-99 cars. The 95 model gsts has some plush 70's style velvet cloth seats.

Teezy said:
Another way to adjust your TPS is to log the voltage. Make sure it's set at .63 volts off the throttle, and 5 volts at WOT. You don't need to turn the car on to do this, just start the datalogger and adjust accordingly.

Read this carefully : https://www.ecmtuning.com/wiki/idlesurge

This is all assuming you have ecmlink since you mentioned it in an earlier post.

That method is really only valid for an analog volt meter

If you can get an obd2 scanner with the ability to view live data you can see tps% and make sure it is set to zero. However this really needs to be done with a .0177 feeler gauge on the stop screw and a volt meter to measure continuity. If your car is an automatic it must be done this way or you will get some crazy shifting going on

TuJay · Dec 8, 2017

chrysler kid said:
Couldnt tell you for certain on that one. There's thread about 1994 models having an egr flow sensor, and california models only prior to that. My 98 doesnt throw any codes, I bypassed and blocked everything when I was trying to find out why the car was idling high (it was the throttle cable bracket and i had to reset my idle stop screw and reset my tps, then set my biss screw)

Just a generic shout out, mitsubishi was really spotty with model range options and details. Ive had 4 different 1996 model cars and all of them had different cloth interiors. I had a 96gs that by far had the nicest cloth interior of any car ive ever had, and my 96 gst now might as well be called saddle blanket cloth interior, and a 96rs that was just the same generic base cloth seat as all 95-99 cars. The 95 model gsts has some plush 70's style velvet cloth seats.

That method is really only valid for an analog volt meter

If you can get an obd2 scanner with the ability to view live data you can see tps% and make sure it is set to zero. However this really needs to be done with a .0177 feeler gauge on the stop screw and a volt meter to measure continuity. If your car is an automatic it must be done this way or you will get some crazy shifting going on

It’s 5 speed, where do I put the feeler gauge? I have read about it but still vague. I’m using ECMLink because i can’t get a scanner that good LOL

, and I want to clear me CEL. And where would I put my multi meter prongs?

PlanZero · Dec 8, 2017

I love the plush my 96 is mint I wouldn't ever trade it for pleather even the door panels are quieter. Never slide around, no power bs.

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