Please read DSMers, I need help bad!

[joeym4130]

Well I'm just about to drive the car off of a cliff!! . Or sell it.. i just might, i hate idle problems. Sorry if this is long, i just really need your guys' help!
I originally had a idle surge (1000-1500RPM), and diagnosed a bad ISC, the coils were out of spec. So I replaced the ISC and nothing changed so I found an old good ECU from a friend and put the ECU in and now it is idling at about 2500RPMs steady!
Now i had a HIGH idle problem!! ahh! Next I was pointed towards bad TPS, accoording to the logger at idle mine was reading 12%. So today i just put in a new TPS and adjusted it using the ohm meter at the terminals according to the haynes manual. Now im getting 1.96% at idle from the TPS thru the logger. But still have the same high idle!! And now after putting the new TPS i have a beautiful Check engine Light on the dash, but funny thing is its only there when your foot is off the gas. As soon as you give it any gas the CEL disappears. I have no clue.
Another puzzler is the readings from the logger concerning the ISC. Now I thought the ISC should be adjusting itself in idle mode, but mine is at 0%..... This is wrong isnt it? I thought 0% meant it was opened up letting as much air thru as possible?? Maybe the Idle Position Switch is bad? I'm getting continuty when the throttle is closed tho...unless the wire to the boot is bad somewhere...any ideas on this?

Here is an example, note the ISC: Does O2 look right also? Timing?
TIMA O2-R ISC TPS ERPM INJP
29.00º 0.04V 0 1.96% 1781.25rpm 2.05ms
28.00º 0.04V 0 1.96% 1812.50rpm 2.05ms
29.00º 0.04V 0 1.96% 1812.50rpm 2.05ms
29.00º 0.06V 0 1.96% 1843.75rpm 2.05ms
29.00º 0.06V 0 1.96% 1812.50rpm 2.05ms
29.00º 0.04V 0 1.96% 1812.50rpm 2.05ms
29.00º 0.04V 0 1.96% 1812.50rpm 2.05ms
29.00º 0.06V 0 1.96% 1843.75rpm 2.05ms

 

[Tommy31]

From what I can see:

1. Your timing is off, even with the RPM's as high as they are. It should read 8 or 9 degrees at idle of 750-800.

2. It doesn't look like your O2 is cycling, check the wires and connections or replace it with a known good.

3. Your throttle position on idle should read 10%; Either your cable needs adjusting or your TPS is shot (might be you adjusted it wrong). Just because you're idling doesn't mean that the throttle's not going to be open a little.

A high idle could also indicate that your thermostat is shot and you're stuck in warm up mode.

If you've got a logger try and pull the CEL code that you get when your foot's on the gas.

Hope these idea's help.

 

[joeym4130]

Hmm. ok I'll have to check timing some week when i can get to a garage. The logger says 5 degrees when key is on..this is base timing correct? So i probably need to adjust ignition timing right? How do I know good values to turn the timing to? I dont understand this TPS , i adjusted it using resistances and its saying 1.96%....maybe i'll use the logger and get it around 10% closed again....thanks...more ideas anyone?

 

[BISHILVR]

hmm...maybe your fiav(fast idle air valve) is no good or not getting coolant to it?...

 

[joeym4130]

Shoot yeah...FIAV...didnt think of that so much with idle ahh!

ok i have DSM on the brain since this car is new, and i went out in the cold tonight to look at it a bit... Well..the CEL is from the TPS being out of adjustment..have to fix that next weekend. But the idle is still high regardless of how i have my TPS...

Here is something else i dont know how i forgot to mention.... When deaccelrating once it gets around 2k or so if its in 2-3gear...it bucks around a bit like if you tap the gas... and i also noticed it never seems to totally deaccelerate... sometimes i see the RPMs rising if im off the gas...confusing...The throttle cable has slack..dunno...could be unrelated to idle and another problem, but who knows...

 

[steve]

Originally posted by joeym4130
The logger says 5 degrees when key is on..this is base timing correct? So i probably need to adjust ignition timing right? How do I know good values to turn the timing to? I dont understand this TPS , i adjusted it using resistances and its saying 1.96%....maybe i'll use the logger and get it around 10% closed again....thanks...more ideas anyone?

Everything assumes that you have set your base timing to 5 degrees BTDC. The ECU depends on you setting it correctly with a timing light by adjusting the CAS.

The ECU expects the TPS voltage to be about 0.5v at idle. Because the differences in the actual total resistance from one TPS to another and the 5v refference the ECU generates you really should set the TPS by voltage not resistance at idle. Getting the datalogger to read 10% at idle should be close enough.

Did you bother to check and set the BISS base idle speed after you replaced the ISC?

Also make sure your Idle Position Switch works. It's not unusual for the wire to it to break. It should have continuity to ground at idle and go open (infinite resistance) as soon as the throttle starts to open.

Steve

 

[joeym4130]

Ok..i'll go get a timing light and work on that too.

Yeah the BISS and o-ring is all there...with the screw all the way in it wont make a difference either...blah..

And the IPS works...at the switch itself..now if the wire is bad i have no clue on how to check that...when i take the connector off the car runs no differently however..a clue to a shorted wire somewhere perhaps..

 

[steve]

What datalogger are you using. I'm pretty sure the Pocketlogger, TMO and MMCd will all tell you the status of the IPS, you just have to look in the right spot.

If your BISS is bottomed out and you still have a 2500 rpm idle you need to figure out where all the air is coming from. The FIAV is one possibility but various leaks are other possible sources. The PVC, brake booster, and fuel pressure regulator are direct manifold taps as is the EGR valve. Another thing to check is the gasket between the TB and manifold.

Steve

 

[joeym4130]

I'm using MMcd...also have palm'n'stein from tunerstein...but i only used MMcd so far...I will have to look around for a help file to find out what value is the IPS. There is ascreen with a bunch of values i dont know what they are..probably there. thanks...more list of stuff to check hah.

 

[joeym4130]

confused again Ok, i have a ECU in that i got off a guy on the trader thats been remanufactured. With that ECU in, she idles high the way im explaining, the problem im having now. But with the old ECU, it has bad idle surge....from 900-1450RPMs. I dont know what the heck that means...any ideas?? One ECU bad maybe??..but both look like they have good caps ....even swabbed alcohol to check... They are for sure the right ECUs too..checked the #s.... ughhh.

On edit, after more deep thoughts:
I have a feeling the high idling ECU might be good tho... cause on the logger with the surging ECU, my ISC is trying to move while driving, when it should be at 0%. So im guessing the ECU causing the surge is the toasted one...that one tries to move the ISC constantly, even when the key is on the ISC vibrates. But the high idle ECU is not engaging the ISC at all! jeez. haha