High idle when warm
Thread Starter
Instructor
Joined: Jun 2018
Posts: 236
Likes: 17
From: Stockton California
High idle when warm
Ok so I need some help! My dilemma is after I drive my car for a while and it gets warm the idle will raise, sometimes giving in the 2k range... now sometimes at a light after a while at a light it will drop slowly. Now I have the EGR deleted and have (2) o2 sensors turned off/deleted (the rears) Ii believe it’s a vacuum leak of some sort but where should I start looking? And why is it happening only after car is warm. I just swapped a new 383 that chad Golen built and broke in himself so I don’t think it is from the manifold etc but I’m up for all tips tricks and suggestions as I want to install my oil catch can and fix this before I dyno it! Any and all help is highly appreciated
Thread Starter
Instructor
Joined: Jun 2018
Posts: 236
Likes: 17
From: Stockton California
High idle
I don’t... but no check engine light is on. I’m curious if I can find it quick if my tuner plugs in... seeing how it’s a new build and the car had 0 issues before I’m thinking it should be something quick and simple
Le Mans Master
Joined: Sep 2013
Posts: 6,192
Likes: 750
From: near the thumb in the mitten
No O2 sensors? IDK how tune works, with no feedback. You need a scanner or data logger to check TPS and IAC. You could retorque intake possibly a few thermo cycles may have loosen things up.
Thread Starter
Instructor
Joined: Jun 2018
Posts: 236
Likes: 17
From: Stockton California
Warm up issues
the o2 sensors by the cats is deleted/turned off because I’m not running any.. I was thinking of trying to torque everything down but was thinking if it was the intake manifold it would do it constantly.. but I’ll check
Thread Starter
Instructor
Joined: Jun 2018
Posts: 236
Likes: 17
From: Stockton California
Scanner
my my dad has one I might go by and grab it and give it a try... I had one for my car but now have the torqhead system so my obd1 is obsolete lol
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Burning Brakes
Joined: Nov 2017
Posts: 1,060
Likes: 80
From: Fort Mill, SC
Pretty invaluable tool to maintain an LT1. Mine is a 96 with true obdii but im pretty sure it works on all LT1s. You need to download the GM mdi driver to make this work.. through me for awhile until I figured that part out. Since you are now frankensteined Im not sure how much it will help but Id suspect it will You can see your short and long term fuel injector trims which in your case you might need to reset yours to make it work quicker. I think you can do it with this tool. A really good obdii reader will read most of the same PID's but in my experience not all of them and I have 2 obdii readers. I bought the wifi version which is nice for live monitoring while you drive. Ive even worked on my car from in the house.
EDIT: also lets you manually fire relays like the fans, EGR, and ABS bleed.
Last edited by barchetta1; Jan 9, 2020 at 07:10 PM.
Burning Brakes
Joined: Nov 2017
Posts: 1,060
Likes: 80
From: Fort Mill, SC
He's obviously in open loop running some sort of injector/ingnition schedule probably based on the map sensor (if this is an lt1).. If you unplog your o2's the car will run a preprogrammed limp schedule. Assume he has a "tune".
Burning Brakes
Joined: Nov 2017
Posts: 1,060
Likes: 80
From: Fort Mill, SC
One other thought.. You can graph your temp sensors, map, mas, and desired idle speed and you should be able to determine which sensor is making the ECU lower and raise the idle Im guessing there is a PD that is going to tell you why the idle is changing, The tech2 will show you a history along with snapshotted data of each PID
EDIT: sorry I meant PID this whole time lol.. I'll go back and fix..
EDIT: I now see you ave a torqhead which mean you are running a Gen III PCM.. should still work on your car but even better,, more stuff to monkey with.
EDIT: sorry I meant PID this whole time lol.. I'll go back and fix.
.EDIT: I now see you ave a torqhead which mean you are running a Gen III PCM.. should still work on your car but even better,, more stuff to monkey with.
Last edited by barchetta1; Jan 9, 2020 at 07:14 PM.
Team Owner
Joined: Jul 2004
Posts: 28,462
Likes: 3,288
From: Hartford WI
A scanner or a code reader? One is good and the other, not so much. Does torquehead have some sort of feedback? Or did you mean the O2 sensors AFTER the cat? Upstream ones adjust fuel air ratio and the post cat ones USUALLY just report on the cat. Once in a while, it can cause false alarms on the pre cat ones.
Burning Brakes
Joined: Nov 2017
Posts: 1,060
Likes: 80
From: Fort Mill, SC
A scanner or a code reader? One is good and the other, not so much. Does torquehead have some sort of feedback? Or did you mean the O2 sensors AFTER the cat? Upstream ones adjust fuel air ratio and the post cat ones USUALLY just report on the cat. Once in a while, it can cause false alarms on the pre cat ones.
The good news he has tons of scanning options.. I wouldnt mess with the tech2 now that I know this.
Thread Starter
Instructor
Joined: Jun 2018
Posts: 236
Likes: 17
From: Stockton California
Idle
yes it is still a LT1 and has a tune but just a mail order from pcm for less... I had a tuner take a look at it and I’m going back for a retune he said the spark tables seem similar tonones he’s tuned before but said my fuel was a little funky.. the car wasn’t idling high at the time so he wasn’t able to pick anything up
Thread Starter
Instructor
Joined: Jun 2018
Posts: 236
Likes: 17
From: Stockton California
Code reader
A scanner or a code reader? One is good and the other, not so much. Does torquehead have some sort of feedback? Or did you mean the O2 sensors AFTER the cat? Upstream ones adjust fuel air ratio and the post cat ones USUALLY just report on the cat. Once in a while, it can cause false alarms on the pre cat ones.
Thread Starter
Instructor
Joined: Jun 2018
Posts: 236
Likes: 17
From: Stockton California
High idle
One other thought.. You can graph your temp sensors, map, mas, and desired idle speed and you should be able to determine which sensor is making the ECU lower and raise the idle Im guessing there is a PD that is going to tell you why the idle is changing, The tech2 will show you a history along with snapshotted data of each PID
EDIT: sorry I meant PID this whole time lol.. I'll go back and fix..
EDIT: I now see you ave a torqhead which mean you are running a Gen III PCM.. should still work on your car but even better,, more stuff to monkey with.
EDIT: sorry I meant PID this whole time lol.. I'll go back and fix.
.EDIT: I now see you ave a torqhead which mean you are running a Gen III PCM.. should still work on your car but even better,, more stuff to monkey with.