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Throttle plate and IPS proper adjustment

PJGross

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Dec 5, 2002
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Lake Orion, MI
While I'm waiting for a USB to Serial connector that will hopefully be recognized by Tunerpro, I should get down to basics and make sure my throttle position is set up.

I was searching VFAQ, and what I want to understand is:

Position of throttle plate vs TPS vs IPS when no throttle engaged.
Should the throttle plate be fully closed?
When should the idle sensor engage? (How far from fully closed)
What should the TPS read when the above two are properly adjusted?

I think if I get the above squared away, then I can start looking at adjusting base idle when connector grounded, etc.
If there is a VFAQ or other good page I am missing for setting the throttle plate and idle switch position, please post a link. I have the idle setting procedure printed out.

-------------------------------------------
Symptoms:
Randomly will settle idle at the set point of 900rpm (keydiver chip) vs slight hunting 800-1100 or so. Not to fuel cut. At clutch in, coming to stops, it will always stall if throttle not heal-toed and blipped. Likely unrelated, any attempt to roll into throttle results in crazy stuttering at 4000rpm but interestingly no knock being generated on the boost to knock gauge (keydiver) with no ability to build boost. (In 2008 when last running, the T3/T04e with 272s and 9:1 compression would start to spool around 3800-4000 rpm IIRC.)

Assuming no obvious boost leaks, I'd like to make a checklist for myself to ensure I have all the TB settings approximately in range and then start checking other symptoms. As I type this, I'm almost thinking I might have a boost leak, but I wouldn't think it would idle at all? I will check for boost leaks and report time to bleed down when at Xpsi start with engine at TDC.
Other things I need to figure out:

Base fuel pressure: I had it at 37psi, but was reading 43psi might be standard so set it there? Anyone? I don't know what Keydiver wanted since I can't find my emails from that time anymore.

Also, the 02 sensor is not cycling at all. I don't think it is reading, is that a sign of fouling? I ordered a new one in case of this. I changed the SAFC to as low as -20 at 1000rpm and never got a cycle on the 02 sensor gauge.


I'm sure there are 1 or 2 very basic issues holding me back from getting this thing sort of squared away, but being out of the game >10 years has made me unable to troubleshoot the very basics without some help. Any suggestions welcome.

I guess I should do a compression test as well, just to make sure I'm at least healthy in that respect?

Thanks for feedback,
PJ
 

PJGross

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Dec 5, 2002
Messages
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Lake Orion, MI
For Throttle stop and TPS, does this sound reasonable:

1. Adjust throttle cable so there is tension on it but just before throttle plate moves.
2. Adjust the TPS so that when at 0% throttle it reads .63V

I think I am missing something, though. How do I know if the throttle stop is set correctly? I may have messed with this in 2008 when adjusting idle. Is there a guide for measuring the throttle blade to TB clearance?

-PJ

EDIT: Will Try this: click
 
Last edited:

PJGross

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Lake Orion, MI
USB cable #3 works! Tuner pro doesn’t see it when tested, but when hooked up to car it scans!

TPS with throttle closed reads 10.2%, goes to 100% at wide open. This is set correctly then, yes? I think I had adjusted it to read .67V so should be at 10% at idle?

The idle position sensor tab was bent over and not making a connection. That could be an issue.. (doh). Need to see if that is adjusted correctly. I wonder if that was causing the stall when coasting issue?

Lots of things to check now that I can see what’s going on!

PJ
 
Last edited:

AllanL

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Aug 4, 2008
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294
Location
NV
This is for a 1G:


Before setting the TPS, the IPS needs to be set.

Screw in the IPS until it has continuity to GND [using a multimeter]. Screw it in 3/4 of a full turn more. Then lock the IPS hold down nut.

TPS voltage range at closed position is 0.48~0.52V.

If you have access to a 2G [4pin TPS], it is better, as you do not have to struggle with the continuity issue of the external IPS.

You'd have to add in 1 wire from the IPS to the TPS connector though.
 

PJGross

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Dec 5, 2002
Messages
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Location
Lake Orion, MI
Well, somewhat success, or starting to:

1. Adjusted throttle cable per faq's.
2. Checked TPS in correct position, think so: 10.6% at idle on Tuner Pro
3. Adjusted BISS so ISC was reading 29 steps at my 900rpm idle set point

Is there a line in tuner pro that tells me if I am in open or closed loop?

I'm thinking still open loop as I have no 02 cycling and all Fuel Trims and O2 trim are reading 99.84, which seems odd and a preset?

But, I have been cutting the battery power as I have a slow drain when connected and am only messing with the car once a week or so.

Hoping my alternator is not toast as I've been having an issue with it squealing on and off. Was thinking just belt stretch but not sure.

-PJ
 

iceman69510

Turn Right Racing
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Mar 5, 2001
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Michigan
I have a rebuilt alternator sitting here (done by an independent shop I have used often, not an Autozone level part) if you determine you need one.
 

CutlassJim

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Jul 17, 2006
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Manchester, NH
Quoting PJGross:
Well, somewhat success, or starting to:

2. Checked TPS in correct position, think so: 10.6% at idle on Tuner Pro


I'm thinking still open loop as I have no 02 cycling and all Fuel Trims and O2 trim are reading 99.84, which seems odd and a preset?


-PJ



10.6%? Like TPS position? It should be at zero at idle. It sounds like you are stuck in open loop and that could be the issue right there.

Not sure if it's an option for you but is there anyone near you that would let you use their DSMLink ECU for a bit?

I've taken my ECU and installed it in other peoples cars to diagnose issues then put their chipped or stock ECU back in after we find the problem.
 
Last edited:

PJGross

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Lake Orion, MI
That's a good suggestion on the borrow link thing.
If it wasn't such a steep learning curve, I would just say screw it and buy Link but I have no clue what I would do with it.

I would love to know someone around greater Detroit that could help me go through my car for a few hours, just to check the basics.
I think I'll put up a post.

For a 1G, I believe 0.62V is equal to 10.X% throtte position at idle.

When I first saw the reading, I was like, "duh, that's wrong", but I think it is actually correct or very close to ballpark.

-Paul G.
 

CutlassJim

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I just grabbed a random log form the forums and used link on my work computer.

Looks like 0.61v is %0 and %10 is over a volt. Also even if that is all correct but your idle switch isn't making it kicks the ECU right out of closed loop.


x4L7ss5l.png


gTHvxX3l.png
 

PJGross

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Location
Lake Orion, MI
Link changes the % to 0. 10% is correct on tuner pro.
Both are .62 v or .6x.
That I did some research on.

But yes, I’m going to check the IPS for continuity and 3/4 turn past context as the set point.
 

AllanL

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Aug 4, 2008
Messages
294
Location
NV
0.5V is 10% 9f 5V. It is the throttle closed voltage.

5V is basically WOT.

You're basically spot on.

And TP is showing it.
 

PJGross

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Joined
Dec 5, 2002
Messages
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Location
Lake Orion, MI
Ok, so my IPS was barely touching. I adjusted it to contact, then 15/16 of a turn per the service manual.

Guess what, NO stalling when pushing in the clutch coming to a stop! Amazing how that works!

I checked timing with plug grounded and I'm at 5 btdc.

I screwed with the BISS at that point, turning it in 3/4 turn to get idle down to 900, but I just ended up having 0 steps on the ISC now with the plug unscrewed..... I saw that at the end of a test drive so I will fix that next time.

At normal idle, TPS position on tunerpro is 12%, but 0% on SAFC. I might back out the IPS 1/4 turn, maybe I opened the blade just a touch with it?

So, now it is running well at idle and part throttle. However, 02 sensor is not cycling or reading anything. Not sure what that is all about. I have a log and will start to go through some troubleshooting with it.

Getting on it a bit, it built PSI to about 12 or so before stumbling. I have it logged so I'll see what is happening there. Want to make sure no other basic things are off prior to making more runs.

-PJ
 
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