Go Back   Great Lakes 4x4. The largest offroad forum in the Midwest > 4x4 Talk > Chevy Tech
GL4x4 Live! GL4x4 Casino







Search
Reply
 
Thread Tools
Old January 10th, 2014, 06:01 PM   #1
wave_crusher
I'll Direc your TV
 
wave_crusher's Avatar
 
Join Date: 01-20-09
Location: Big Rapids, MI
Posts: 4,653
iTrader: (20)
Engine RPM higher when in gear

1996 5.7L Vortec

I noticed that my truck will rev higher when in gear, around 1100 RPM/1000 RPM, but when in park it will idle at around the right RPM 700/800

What the heck would cause that? Never had it happen nor have I heard of it
wave_crusher is online now   Reply With Quote
Old January 11th, 2014, 09:40 AM   #2
wave_crusher
I'll Direc your TV
 
wave_crusher's Avatar
 
Join Date: 01-20-09
Location: Big Rapids, MI
Posts: 4,653
iTrader: (20)
Nothing?????
wave_crusher is online now   Reply With Quote
Old January 11th, 2014, 09:52 AM   #3
ljense8
Web Wheeler
 
ljense8's Avatar
 
Join Date: 01-16-13
Location: Holland, MI
Posts: 457
iTrader: (2)
Maybe a vacuum leak? That would be my first check.
ljense8 is online now   Reply With Quote
Old January 11th, 2014, 10:44 AM   #4
concreteguy82
Yeah Buddy!!
 
concreteguy82's Avatar
 
Join Date: 03-01-11
Location: Clio, Michigan
Posts: 2,566
iTrader: (3)
Now I honestly have no clue here. However a friend of mine has the same year k2500 with the same motor; and was having the same problem you're having only reversed.... Much higher idle in park. It ended up being the throttle position sensor.
__________________
Quote:
Originally Posted by whiterhino View Post
BTW, I do not hate our country. I love our country, I just hate the way it's trending.
concreteguy82 is offline   Reply With Quote
Old January 12th, 2014, 01:09 PM   #5
Iggy
Senior Member
 
Iggy's Avatar
 
Join Date: 01-02-12
Location: Traverse City, MI
Posts: 111
iTrader: (7)
I had a similar problem years ago with a S10 Blazer with Vortec 4.3 - it was the plenum gasket (between the lower and upper) leaking vacuum. I would first check the TPS and MAP sensors to make sure they are working properly.
Iggy is offline   Reply With Quote
Old January 12th, 2014, 07:37 PM   #6
wave_crusher
I'll Direc your TV
 
wave_crusher's Avatar
 
Join Date: 01-20-09
Location: Big Rapids, MI
Posts: 4,653
iTrader: (20)
Quote:
Originally Posted by Iggy View Post
I had a similar problem years ago with a S10 Blazer with Vortec 4.3 - it was the plenum gasket (between the lower and upper) leaking vacuum. I would first check the TPS and MAP sensors to make sure they are working properly.
Thanks, I will make sure to check those. I haven't messed with it yet; I haven't had to go anywhere beyond walking distance this weekend.

I'm gonna take a can of ether to it first to see if there are any obvious vacuum leaks
wave_crusher is online now   Reply With Quote
Old January 14th, 2014, 08:21 PM   #7
wave_crusher
I'll Direc your TV
 
wave_crusher's Avatar
 
Join Date: 01-20-09
Location: Big Rapids, MI
Posts: 4,653
iTrader: (20)
Took a can of carb cleaner to it, didn't find any vacuum leaks, kept looking up other peoples' issues, and found out that the engine coolant temp sensor is a good cause of that.

I replaced it; it helped, it stays under 1000 rpm now, but still revs up to 15/1600 when I first start it, but now it does go down faster. It still idles to fast.

I'm going to swap out the ecm for the stock one and see if it's a computer issue, it's quick to do. I will also be check/cleaning the IAC; last resort i'll be replacing that and possibly the TPS
wave_crusher is online now   Reply With Quote
Old January 26th, 2014, 02:40 AM   #8
beaterk5
Senior Member
 
beaterk5's Avatar
 
Join Date: 12-21-07
Location: dansville-48819
Posts: 1,068
iTrader: (3)
Send a message via MSN to beaterk5
Possibly brake booster? You say idle in gear I'm assuming your not moving with your foot on the brakes.
beaterk5 is offline   Reply With Quote
Old January 26th, 2014, 08:41 AM   #9
Wehan
'cause wife's Asian.
 
Wehan's Avatar
 
Join Date: 10-07-06
Location: Charlotte, MI
Posts: 2,026
iTrader: (21)
Quote:
Originally Posted by beaterk5 View Post
Possibly brake booster? You say idle in gear I'm assuming your not moving with your foot on the brakes.
Could he use use the E-brake to check? Engage E-brake, put in drive, take foot off brake peddle and then check idle?
__________________
Wehan is online now   Reply With Quote
Old January 31st, 2014, 08:48 AM   #10
wave_crusher
I'll Direc your TV
 
wave_crusher's Avatar
 
Join Date: 01-20-09
Location: Big Rapids, MI
Posts: 4,653
iTrader: (20)
Quote:
Originally Posted by Wehan View Post
Could he use use the E-brake to check? Engage E-brake, put in drive, take foot off brake peddle and then check idle?
I'm actually not sure if my E-brake works lol; I've never used it

The main problem was the engine coolant temp sensor; replaced that and it solved most of the issue. I think it still idles high but I have not checked anything else
wave_crusher is online now   Reply With Quote
Old January 31st, 2014, 11:32 AM   #11
davidkassie
Senior Member
 
davidkassie's Avatar
 
Join Date: 01-29-09
Location: BENTON HARBOR michigan
Posts: 746
iTrader: (6)
my snap on scanner has a "reset iac" feature, has worked for me in the past....
davidkassie is offline   Reply With Quote
Old January 31st, 2014, 11:48 AM   #12
wave_crusher
I'll Direc your TV
 
wave_crusher's Avatar
 
Join Date: 01-20-09
Location: Big Rapids, MI
Posts: 4,653
iTrader: (20)
Quote:
Originally Posted by davidkassie View Post
my snap on scanner has a "reset iac" feature, has worked for me in the past....
I looked at mine for that a while ago, but it didn't have anything like that. I didn't think it would because it was only a cheaper $150 scanner
wave_crusher is online now   Reply With Quote
Old January 31st, 2014, 02:44 PM   #13
davidkassie
Senior Member
 
davidkassie's Avatar
 
Join Date: 01-29-09
Location: BENTON HARBOR michigan
Posts: 746
iTrader: (6)
Our genesis at work doesn't either... my snap on solus does
davidkassie is offline   Reply With Quote
Reply
Great Lakes 4x4. The largest offroad forum in the Midwest > 4x4 Talk > Chevy Tech
Thread Tools

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump



All times are GMT -5. The time now is 10:21 AM.


Powered by: vBulletin, Copyright 2000 - 2012, Jelsoft Enterprises Ltd.
Copyright 2005 - 2012 Cracker Enterprises - Powered by Linux
vB Ad Management by =RedTyger=
Page generated in 0.15061 seconds with 38 queries