Idle problems...HELP!!!

[Rice Burner]

Ok, this is driving me crazy. I've had this car sitting in a garage for about 7 years and finally started working on it last year. I relined the tank and replaced the non working fuel pump due to the gas going bad and rusting up the tank and pump. I also rewired and replaced the idle stepper motor and just bought a rebuilt ECU from ebay out of an exact car as mine.

The problem is im still having the car not idling correctly. I starts with no problems but it will not idle. I have to give it gas and it revs high and once I let off the gas it drops down past 500 rpm and wants to die, then if I give it a little gas it revs up again and then drops back down. I tried messing with the BISS but didn't make any difference on this problem. I replaced the ISC with one that I tested out to be good and had to do the rewire for it to work (it was from a newer model). The original one use to just vibrate back and forth. I also adjusted the TPS so that should be fine.

I'm really getting pretty frustrated with this car and really need some advice on what to do or check next. I hope someone can point me in the right direction or maybe something I missed.

1990 Eclipse GS-T

Thanks in advance guys!!!!

 

[92AWDHX40]

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

 

[Rice Burner]

Thanks for the quick reply. I printed and went through that post already. Funny I printed that a couple of years ago when I first started trying to get it running correctly. Back then it would just idle up and down. I've since pulled that info back out and gone through it again to get my ISC and ECU problems figured out.

 

[Rice Burner]

Ok, I went and tested and reset the ISC, TPS, ect. and I had it idling steady at about 1200 rpm. No adjusting of the BISS would get it down any lower. I even messed with the timing and that didn't help (at least not with the timing set correctly). From everything I've done and read I'm starting to think I have a bad FIAV in the TB. It's a 1990 and it seems blocking off one of these TB's isn't as easy as the newer versions. I would like to get the TB rebuilt or at least get the FIAV portion rebuilt but not having much luck finding replacement parts or even someone that rebuilds them with the FIAV included as part of the service.

Are the replacements TB's I see on ebay a direct replacement with all the sensor ports to match up with the ECU including the FIAV and are they any decent or knock off junk?

Does anyone have a recommendation on where I can get the FIAV parts or somewhere to get the TB reworked?

I really would like to get this car back to good running condition like it was when I got it and I don't mind spending a reasonable amount to get it running correctly like it should be.

Thanks for any help.

 

[Absit]

Ok, I went and tested and reset the ISC, TPS, ect. and I had it idling steady at about 1200 rpm. No adjusting of the BISS would get it down any lower. I even messed with the timing and that didn't help (at least not with the timing set correctly).

Check throttle cable tension, there should be a bit of slack when at operating temp on a hot day.

Are the replacements TB's I see on ebay a direct replacement with all the sensor ports to match up with the ECU including the FIAV and are they any decent or knock off junk?

That depends on what you're looking at..

Does anyone have a recommendation on where I can get the FIAV parts or somewhere to get the TB reworked?

You can buy a new (rebuilt) TB for less than a new FIAV. throttlebodies.com rebuilds them, and some freelancers here do as well.

 

[milby43]

Your ISC might be bad, and stuck open. So take it out. Close it manually. Then put it back in, screw it down. But DONT plug it in. Start the car, and see if it still idles high. You might have to adjust the BISS to get it to the right idle.

This is just to see if its your ISC being bad, and stuck open.
I dont recommend running with no ISC. I did it for awhile, with no affects. But i heard it can mess up the ECU. Its a good way to test it though.

ALSO, go see if you have vacuum/boost leaks. They can do alot more than you think. Look up how to make a boost leak tester.

 

[Rice Burner]

I had lossened the throttle cable a little so it definitely hits the throttle stop. I also tested all sensors and reset them to factory specs with same result. The BISS will raise the idle but only lower it to about 1000 - 1200. Also, I visually checked for vac leaks and even pulled and twisted the vac lines to see if it made any difference. I also pulled the vac lines and checked for vacum and to see if any changes in idle. So
that's why I'm thinking it is most likely the FIAV according to "Terry's" test procedures and what I've read online. From what I can figure out the FIAV raised the idle at startup until the TB warms up then is supposed to drop it back down. My car stays high all the time no matter how long it sits there idling. Seems like the TB stays stuck on the warm up mode.

I went to throttlebodies.com but I don't see anything about the eclipse TB and it's also looks like a British website. Is this the correct link? I did find a few but looks like they don't actually work on the FIAV when rebuilding, just pretty much everything else.

 

[LV-DSM]

Try here:

DSM THrottle Bodys

This guy does very nice work.

I know another member here that also rebuilds tb's and may be able to help. Let me know.

 

[doayamaha]

do you hear any hissing like a vacume leak, mine would idle hi so i turn the biss almost all the way in to get it to idle right. turned out that the intake mani was leaking from the gasket, fixed it and reset the biss, now it idles rock solid with rock solid a/f ratios.

 

[DJ23GSX]

Not to be a smart ass but are you adjusting the biss correctly? You need to ground the plug on the firewall and one of the pins on the diagnostic port to be able to adjust it correctly. If you aren't adjusting it correctly then every time you move it the isc is going to compensate for the increase or decrease in air intake so it would make it seem like adjusting the biss isn't doing anything like you posted earlier in this thread. Grounding the 2 connections takes the ecu/isc out of the loop. Its just a thought

 

[doayamaha]

Not to be a smart ass but are you adjusting the biss correctly? You need to ground the plug on the firewall and one of the pins on the diagnostic port to be able to adjust it correctly. If you aren't adjusting it correctly then every time you move it the isc is going to compensate for the increase or decrease in air intake so it would make it seem like adjusting the biss isn't doing anything like you posted earlier in this thread. Grounding the 2 connections takes the ecu/isc out of the loop. Its just a thought

there are ways around doing this, like a rev after adjustment, you want it to hang for just a slight second b4 returning to idle. I used to ground those connections he is talking about but got tired of trying to find my grounding leads in my mess of a garage, so devised the method i use now which works well. Also in setting the idle return switch make sure it isn't pressing the throttle blade open.

 

[Rice Burner]

Ok, I was going to try and do the multiple quote thing like you guys are doing but I'm too dumb to figure it out and I've got hit the road

I did contact DSM Throttle bodies and I will probably send it to him this week. I'm going to try cleaning it really good off the engine and see if it makes any difference.

No hissing that I can hear and I did pull and push all the lines I could find, including pulling them and checking for vacum.

Yep, I did adjust the BISS according to VFAQ and my Mitsu shop manual and same result.

The only thing I really haven't done (that I can think of anyway) is to clean the TB off the vehicle. Mind you it is really clean already and no carbon in the plate or in the body that you can see by looking inside. I dont know, maybe I need to really spray it down really good and pull the TPS and the ISC as well as open up the FAIV and spray that out as well and see what happens. I may give it a shot later this evening if I get home early enough. I'll let you guys know what happens if I get a chance to try it out.

Thanks again for all the suggestions by the way

 

[DJ23GSX]

I've seen bad throttle body shaft seals keep the plate from closing all the way causing a high idle. Its pretty common for the dsm shaft seals to go bad. I would def take a look at the fiav. I've owned quite a few dsm's in my day and only one of them had a fiav that actually worked like it was supposed to.

 

[Rice Burner]

I got home and took the TB out and pulled out the sensors and removed the FIAV plate. Inside those areas were a lot of carbon and especially in the ISC hole. In fact I thought I lost a part out of one of those holes because after spraying it out it now had a deeper opening like a plug or something fell out. After checking the bucket I was spraying it over and nothing there I figured it was just a bunch of carbon. I took the spray straw and poked it in there and pulled out some sticky black carbon like stuff. I sprayed it out and also the FIAV area and the vacuum hose ports and got it looking pretty clean.

I pretty much disassembled the entire TB and sprayed it out. I want to go ahead and replace the shaft seals and the FIAV gasket but I'm having a hard time locating them. Anyone know where I can find a rebuilt kit for the 90 TB?? I've seen them on the net but now that I need one I can't find any parts or kits. I cant even find the FIAV gasket. Only ones I'm finding are for the newer 1g models.

Any ideas where I can find the parts...I'm pretty curious to get this back together and see if this will actually solve the problem.

 

[DJ23GSX]

These are the tb shaft seals for a 90 tb

SKF 3030

SKF 3930

I used those seals on my 90 tb so I know they fit.

As for the 90 fiav gasket this is what I found. Part number MD614300

90 FIAV Gasket

 

[Rice Burner]

These are the tb shaft seals for a 90 tb

SKF 3030

SKF 3930

I used those seals on my 90 tb so I know they fit.

As for the 90 fiav gasket this is what I found. Part number MD614300

90 FIAV Gasket

Dude you are a life saver. I spent the better part of my work day (hope my boss isn't a DSM Tuners fan) today searching for those. The ones from chicago-rawhide, which most posts reference for the 1990, were a no-go. Seems like they are no longer produced. I'll get these tomorrow or maybe tonight when I get home.

 

[DJ23GSX]

Dude you are a life saver. I spent the better part of my work day (hope my boss isn't a DSM Tuners fan) today searching for those. The ones from chicago-rawhide, which most posts reference for the 1990, were a no-go. Seems like they are no longer produced. I'll get these tomorrow or maybe tonight when I get home.

No prob. Just so you know I was able to order those SKF seals through a local bearing shop in case you can't find them anywhere else. Even if you can't get the SKF brand the links I posted gives you the dimension of each seal so you now exactly what to order. Luckily my company does a lot of business with the bearing shop so I was able to score both seal for free Also if you have a local Mitsu dealer bring them the part number for the FIAV gasket and it will be cheaper than ordering it online considering you will have to pay shipping and a $7.50 handling fee from extremepsi or jnz tuning.

Good Luck

 

[Rice Burner]

Ok, got my seals ordered from a supplier here in Houston and I may have them by Friday which would be great. Now I should have everything I should need. Then I could get it back together and hopefully running good over the weekend. I appreciate the tip on the seals and everyone's help and advice. I'll post how it turns out once I'm done. Now the fun part will be getting that TB back together correctly. I didn't find all the How To's with all the dismantle advice until I took it appart but I guess they will help me get it back together if I run into any problems.

 

[Rice Burner]

Ok, here's the latest. I got the seals and installed them. They went in ok but the little one was a bi*** to get installed. I put the TB back together and it is pretty much clean as a wistle. The car started up with out any problems as it usually does but I'm still having a hard time getting it to idle correctly. I also ended up ordering a ISC used from ebay because I thought mine was bad but turns out my digital meter isn't giving correct info and I did use another meter to check and test everything again. Anyway, I'm not too pissed about that because I got one of the new ISC (black) and it was a good price.

Ok, back to the current problem. I can get the idle down to about 800rpm but when the fans kick on it wants to drop below 500 and lopes and wants to stall. If I give it a little gas it will shoot up to about 1700 rpm and eventually work its way back down to 500rpm if the fans are still running it will idle ok. Also, it wants to bog when I give it gas like it isn't getting any gas then kicks in and reves. I tried setting the timing with the pins in the car grounded and also the one on the firewall. The problem is when the idle either drops or rises up the timing is off again so I can never seem to get the timing correct with the idle bouncing all over the place .

Would a Datalogger help me diagnose this and future problems? I've seen these on ebay for less than $100 but not sure if this or the software that goes for about $300 would be the way to go for future mods and settings. At this point I would rather not drop $300 on software unless it's really going to pay off right away, especially if I can get a Datalogger for less than a hundred. Anyone have any advice on Datalogging and what I can do with it? Do I need a modded ECU?

Any ideas what the problem could be now??

Here is whats been done so far?replaced & set ISC, replaced ECU with rebuilt unit, fuel filter, set IPS, tried to set timing, checked vacum lines visually, adjusted BISS... My next move is to turn this into a BBQ and try and make back all the money I've put in this thing over the last 6 months Well maybe not since I've had this since 1993 and has some good times with this ride

 

[DJ23GSX]

I tried setting the timing with the pins in the car grounded and also the one on the firewall. The problem is when the idle either drops or rises up the timing is off again so I can never seem to get the timing correct with the idle bouncing all over the place .

When you adjust the timing you only need to ground the pin on the firewall not the one on the diagnostic port inside the car. Its going to be tough to set it correctly until you can get it to idle smoother.

 

[Rice Burner]

I just went out an bought some plugs and wires since these have been on the car for over seven years. Though the car has been sitting up for 7 years since it got wrecked, I don't remember how long before that these were put on the car. I don't think they were very old before that since I was good about keeping it tuned up at the time.

Also, it doesnt have a themostat so I went and bought one. Could not running it with a thermostat have any effect on the idle?? Maybe some temp sensor messing with the computer or something??

Would the O2 sensor effect the idling of the car. I remember the car use to have a gas smell coming from the exhaust back when it was running years ago and I intended to change it but never got around to that. It could have been my fried ECU though which was just changed out. I haven't really smelled that but I also haven't looked for it either so it very well may still have that smell. Do the 1g's have two O2 sensors? Ive been seeing some people talking about 2 sensors but cant narrow it down to if the 90's models have 1 or 2.

I can't believe it's this hard to get this thing idling like it use too. This car use to purr like a kitten and never gave an ounce of trouble. Hopefully I can get it back to that before I get too frustrated.

Thanks for everyones input and putting up with all these questions.

 

[DJ23GSX]

I just went out an bought some plugs and wires since these have been on the car for over seven years. Though the car has been sitting up for 7 years since it got wrecked, I don't remember how long before that these were put on the car. I don't think they were very old before that since I was good about keeping it tuned up at the time.

Also, it doesnt have a themostat so I went and bought one. Could not running it with a thermostat have any effect on the idle?? Maybe some temp sensor messing with the computer or something??

Would the O2 sensor effect the idling of the car. I remember the car use to have a gas smell coming from the exhaust back when it was running years ago and I intended to change it but never got around to that. It could have been my fried ECU though which was just changed out. I haven't really smelled that but I also haven't looked for it either so it very well may still have that smell. Do the 1g's have two O2 sensors? Ive been seeing some people talking about 2 sensors but cant narrow it down to if the 90's models have 1 or 2.

I can't believe it's this hard to get this thing idling like it use too. This car use to purr like a kitten and never gave an ounce of trouble. Hopefully I can get it back to that before I get too frustrated.

Thanks for everyones input and putting up with all these questions.

From my experience when an o2 sensor goes bad it makes the exhaust smell like rotten eggs. All 1g's have only 1 o2 sensor. Your exhaust probly smells like fuel at idle cause I assume according to your profile your running a walbro 255 on the stock fpr and its being overrun causing really high bfp. Have you checked for boost/vacuum leaks yet?

 

[Rice Burner]

No I haven't checked for boost leaks yet. I did visually check for vacum leaks and by pushing and pulling on the vac lines to see if I could detect any change in the idle but no changes were noticed. I use to smell a lot of fuel years ago before it got wrecked but I haven't really checked lately. It may have been the ECU since that was fried pretty badly.

Sorry, but what does "BPF" stand for? Do you think the walbro could be causing an issue with the idle? I was intending on getting a pressure regulator once I got things smoothed out and running good.

 

[92AWDHX40]

First of all do a boost leak test easy to do and cheap, mine solved lots of problems since i added my fmic.

 

[DJ23GSX]

Sorry, but what does "BPF" stand for? Do you think the walbro could be causing an issue with the idle? I was intending on getting a pressure regulator once I got things smoothed out and running good.

BFP= Base Fuel Pressure. I've run the walbro 255 on the stock regulator in the past with no idle issues but if there is a big vacuum leak it might be a problem. When my alternator was on its way out my idle used to drop to around 500rpms and want to die when I turned on the headlights or anything else that drew power from the electrical system.