325es surging at idle/ driving when motor cold, getting horrible MPG - BMW Forum - BimmerWerkz.com
BMW Forum BMW Forum

Auto Insurance

» Featured Product
Wheel & Tire Center

Go Back   BMW Forum - BimmerWerkz.com > BMW Model Specific Forums > 3-Series (E21, E30)
Register Home Forum Active Topics Gallery / Showroom Auto Loans Garage Search Today's Posts Mark Forums Read Auto EscrowInsurance

3-Series (E21, E30) Chat relating to the BMW 3-Series from 1975-1983 and 1984-1991 line. Specific models: BMW 315, BMW 316, BMW 318, BMW 318i, BMW 320/4, BMW 320i, BMW 320/6, BMW 323i, BMW 320i. E30 Family models include: BMW 325e, BMW 325i, BMW 325is, BMW 325ix.

BimmerWerkz.com is the premier BMW Forum on the internet. Registered Users do not see the above ads.
Reply
 
LinkBack Thread Tools Display Modes
Old 01-01-2007, 07:16 PM   #1 (permalink)
1st Gear Member
 
whitey_E30's Avatar
 
Join Date: Feb 2005
Car:
Posts: 133
Photos:
whitey_E30 is an unknown quantity at this point
325es surging at idle/ driving when motor cold, getting horrible MPG

i was not having this problem before, it started about 2 months ago when the weather started getting cooler. it always surged at idle, but now its doing it while its driving before the engine warms up. also i getting horrible gas mileage. went from about 28-29 mpg down to like 20-21. just wonderd if they were related. i took it to a shop and they said replace the idle control valve. (a few others on the forum said so too in an earlier post) im just wondering if that will fix my mileage problem too.
__________________
this is my
whitey_E30 is offline   Reply With Quote
Sponsored Links
Advertisement
 
Old 01-01-2007, 09:22 PM   #2 (permalink)
Crazy Fabricatin' Admin
 
gotKRAUT's Avatar
 
Join Date: Feb 2004
Location: Elk Grove, CA
Car: '87 325es M50tu Swapped
Posts: 9,355
Photos:
gotKRAUT has a reputation beyond reputegotKRAUT has a reputation beyond reputegotKRAUT has a reputation beyond reputegotKRAUT has a reputation beyond reputegotKRAUT has a reputation beyond reputegotKRAUT has a reputation beyond reputegotKRAUT has a reputation beyond reputegotKRAUT has a reputation beyond reputegotKRAUT has a reputation beyond reputegotKRAUT has a reputation beyond reputegotKRAUT has a reputation beyond repute
Send a message via AIM to gotKRAUT Send a message via MSN to gotKRAUT Send a message via Yahoo to gotKRAUT
i just cleaned my idle control valve for free just remove the idle valve and take a can of brake cleaner and hose it out, usually does the trick and saves you a chunk of cash
__________________
Kyle Sutherland

1995 BMW 540i/6:
The Calypso Beast Vid 0-70ish
1987 BMW 325es: Face & Butt Lifted/M50tu Swapped*Sold*
1985 VW Scirocco: Too many mods, money pit*Sold*
E34 Plate Filler Wanted!
gotKRAUT is offline   Reply With Quote
Old 01-01-2007, 11:13 PM   #3 (permalink)
5th Gear Member
 
Join Date: May 2004
Location: NC
Car: Opening soon:
Posts: 1,118
Photos:
Starmavin is a jewel in the roughStarmavin is a jewel in the roughStarmavin is a jewel in the roughStarmavin is a jewel in the rough
Quote:
Originally Posted by whitey_E30
i was not having this problem before, it started about 2 months ago when the weather started getting cooler. it always surged at idle, but now its doing it while its driving before the engine warms up. also i getting horrible gas mileage. went from about 28-29 mpg down to like 20-21. just wonderd if they were related. i took it to a shop and they said replace the idle control valve. (a few others on the forum said so too in an earlier post) im just wondering if that will fix my mileage problem too.
Like I said before the #1 cause of a screwed up idle and bad mpg is a faulty coolant temp sensor.
Starmavin is offline   Reply With Quote
Old 01-02-2007, 12:38 PM   #4 (permalink)
1st Gear Member
 
whitey_E30's Avatar
 
Join Date: Feb 2005
Car:
Posts: 133
Photos:
whitey_E30 is an unknown quantity at this point
went and got a coolant temp sensor. i thought it mounted right up on the drivers side of the radiator but im not sure. it looks like there are 2 sensors thereand neither of them have connectors like the new sensor i got. maybe he gave me wrong part? the one i just picked up it the pic on the car hood. the one with the nice puke yellow plug. used:
Attached Thumbnails
325es surging at idle/ driving when motor cold, getting horrible MPG-dscf0125.jpg   325es surging at idle/ driving when motor cold, getting horrible MPG-dscf0126.jpg   325es surging at idle/ driving when motor cold, getting horrible MPG-dscf0127.jpg  
__________________
this is my
whitey_E30 is offline   Reply With Quote
Old 01-02-2007, 01:22 PM   #5 (permalink)
1st Gear Member
 
whitey_E30's Avatar
 
Join Date: Feb 2005
Car:
Posts: 133
Photos:
whitey_E30 is an unknown quantity at this point
i think i found where the sensor could go but im not sure. theres only about 12 different places. help?
__________________
this is my
whitey_E30 is offline   Reply With Quote
Old 01-02-2007, 02:51 PM   #6 (permalink)
Crazy Fabricatin' Admin
 
gotKRAUT's Avatar
 
Join Date: Feb 2004
Location: Elk Grove, CA
Car: '87 325es M50tu Swapped
Posts: 9,355
Photos:
gotKRAUT has a reputation beyond reputegotKRAUT has a reputation beyond reputegotKRAUT has a reputation beyond reputegotKRAUT has a reputation beyond reputegotKRAUT has a reputation beyond reputegotKRAUT has a reputation beyond reputegotKRAUT has a reputation beyond reputegotKRAUT has a reputation beyond reputegotKRAUT has a reputation beyond reputegotKRAUT has a reputation beyond reputegotKRAUT has a reputation beyond repute
Send a message via AIM to gotKRAUT Send a message via MSN to gotKRAUT Send a message via Yahoo to gotKRAUT


according to the bentley manual which every E30 owner should have its right there...



BTW love the avatar
__________________
Kyle Sutherland

1995 BMW 540i/6:
The Calypso Beast Vid 0-70ish
1987 BMW 325es: Face & Butt Lifted/M50tu Swapped*Sold*
1985 VW Scirocco: Too many mods, money pit*Sold*
E34 Plate Filler Wanted!
gotKRAUT is offline   Reply With Quote
Old 01-02-2007, 05:47 PM   #7 (permalink)
5th Gear Member
 
Join Date: May 2004
Location: NC
Car: Opening soon:
Posts: 1,118
Photos:
Starmavin is a jewel in the roughStarmavin is a jewel in the roughStarmavin is a jewel in the roughStarmavin is a jewel in the rough
That is the coolant switch, that makes the car fast idle when cold. The yellow sensor is the correct one for the computer and idle module, it'll go right next to the #1 injector. You can get at it from the passenger side just under the air intake. There will be two sensors there, the one above it has one pin and that runs the gauge. The ones in the rad are the high and low speed fan switches.

P.S. The coolant switch is used in 87 and older cars with the idle control module, in 88 and up models the idle module is intergrated with the DME.

Last edited by Starmavin; 01-02-2007 at 05:53 PM.
Starmavin is offline   Reply With Quote
Old 01-02-2007, 06:02 PM   #8 (permalink)
Crazy Fabricatin' Admin
 
gotKRAUT's Avatar
 
Join Date: Feb 2004
Location: Elk Grove, CA
Car: '87 325es M50tu Swapped
Posts: 9,355
Photos:
gotKRAUT has a reputation beyond reputegotKRAUT has a reputation beyond reputegotKRAUT has a reputation beyond reputegotKRAUT has a reputation beyond reputegotKRAUT has a reputation beyond reputegotKRAUT has a reputation beyond reputegotKRAUT has a reputation beyond reputegotKRAUT has a reputation beyond reputegotKRAUT has a reputation beyond reputegotKRAUT has a reputation beyond reputegotKRAUT has a reputation beyond repute
Send a message via AIM to gotKRAUT Send a message via MSN to gotKRAUT Send a message via Yahoo to gotKRAUT
wow i was lookin at the pic in the bentley backwards, you are correct sir, its on the cylinder head, coolant outlet next to the thermo switch
__________________
Kyle Sutherland

1995 BMW 540i/6:
The Calypso Beast Vid 0-70ish
1987 BMW 325es: Face & Butt Lifted/M50tu Swapped*Sold*
1985 VW Scirocco: Too many mods, money pit*Sold*
E34 Plate Filler Wanted!
gotKRAUT is offline   Reply With Quote
Old 01-04-2007, 09:38 AM   #9 (permalink)
Neutral Member
 
jfertita's Avatar
 
Join Date: Aug 2006
Location: Virginia
Car: 86 BMW 325
Posts: 81
Photos:
jfertita is on a distinguished road
so there is the coolant temp sensor and the thermo time switch, what are the differences and do they both contribute to bad mpg and erratic idle?
jfertita is offline   Reply With Quote
Old 01-04-2007, 01:05 PM   #10 (permalink)
Crazy Fabricatin' Admin
 
gotKRAUT's Avatar
 
Join Date: Feb 2004
Location: Elk Grove, CA
Car: '87 325es M50tu Swapped
Posts: 9,355
Photos:
gotKRAUT has a reputation beyond reputegotKRAUT has a reputation beyond reputegotKRAUT has a reputation beyond reputegotKRAUT has a reputation beyond reputegotKRAUT has a reputation beyond reputegotKRAUT has a reputation beyond reputegotKRAUT has a reputation beyond reputegotKRAUT has a reputation beyond reputegotKRAUT has a reputation beyond reputegotKRAUT has a reputation beyond reputegotKRAUT has a reputation beyond repute
Send a message via AIM to gotKRAUT Send a message via MSN to gotKRAUT Send a message via Yahoo to gotKRAUT
ones a sensor(just monitors temp) and one is a switch (sends a ground signal a certain temp) usually used for timing and idle control, but it is rarely the culprit because the only function it has is open or closed...closes below 86*F and open at about 118*F

idle valves get clogged which cause the surge, as i stated above, just take it off and hose it out with brake clean
__________________
Kyle Sutherland

1995 BMW 540i/6:
The Calypso Beast Vid 0-70ish
1987 BMW 325es: Face & Butt Lifted/M50tu Swapped*Sold*
1985 VW Scirocco: Too many mods, money pit*Sold*
E34 Plate Filler Wanted!
gotKRAUT is offline   Reply With Quote
Old 01-04-2007, 06:35 PM   #11 (permalink)
5th Gear Member
 
Join Date: May 2004
Location: NC
Car: Opening soon:
Posts: 1,118
Photos:
Starmavin is a jewel in the roughStarmavin is a jewel in the roughStarmavin is a jewel in the roughStarmavin is a jewel in the rough
Quote:
Originally Posted by jfertita
so there is the coolant temp sensor and the thermo time switch, what are the differences and do they both contribute to bad mpg and erratic idle?
Ok, this should clear everything up. In all you have 6 temp sensors/switches on any 325 that is 87 and older. As mentioned before, the two in the radiator are for high and low auxiliary fan speeds.

The 4 in the motor found in and near the thermostat housing are as follows:

The thermo-time switch, this operates the cold start injector only, this is the larger one closest to the front of the motor.

Coolant temp switch is the next one back, is for cold warm up, this holds an open circuit until the cars coolant reaches the set temp then closes. gotKRAUT posted a pic pointing this one out.

Next one in has one pin and is for the gauge.

Then the last one is the coolant temp sensor, this is the most important sensor, it looks exactly like the sensor for the gauge but with two pins, this sends engine temp signal to both DME and idle control module.

Last edited by Starmavin; 01-04-2007 at 06:41 PM.
Starmavin is offline   Reply With Quote
Old 01-05-2007, 08:54 AM   #12 (permalink)
1st Gear Member
 
whitey_E30's Avatar
 
Join Date: Feb 2005
Car:
Posts: 133
Photos:
whitey_E30 is an unknown quantity at this point
I got the coolant temp sensor in... but im still getting horrible gas milage and car still chugs before it warms up. so it didnt work. any more ideas.
__________________
this is my
whitey_E30 is offline   Reply With Quote
Old 01-05-2007, 05:43 PM   #13 (permalink)
5th Gear Member
 
Join Date: May 2004
Location: NC
Car: Opening soon:
Posts: 1,118
Photos:
Starmavin is a jewel in the roughStarmavin is a jewel in the roughStarmavin is a jewel in the roughStarmavin is a jewel in the rough
When cold remove the cold start injector then plug the hole with your thumb or anything that won't get sucked in, then have someone start the car, see if and how it is sprays fuel, hold a cup up to the injector it should spray a fine mist for 3-4 seconds then stop. While the car is warm, shut it off and remove the cold start injector, plug the hole, then have someone start the car, see if it is sprays fuel again.
Starmavin is offline   Reply With Quote
Old 01-17-2007, 07:18 AM   #14 (permalink)
1st Gear Member
 
whitey_E30's Avatar
 
Join Date: Feb 2005
Car:
Posts: 133
Photos:
whitey_E30 is an unknown quantity at this point
just replaced the ICV, and the car still is showing the same symptoms as before. erratic idle, poor fuel economy. i dont have much time to do work on it. is there anything else that is easily replacable that could possibly be the culprit??? it only does it when its cold. after driving for about 20 mins, it runs fine once it warms up while im crusing down the road.
__________________
this is my
whitey_E30 is offline   Reply With Quote
Old 01-17-2007, 08:07 AM   #15 (permalink)
Neutral Member
 
jfertita's Avatar
 
Join Date: Aug 2006
Location: Virginia
Car: 86 BMW 325
Posts: 81
Photos:
jfertita is on a distinguished road
You can try testing your thermo time switch if you havent done that yet, only other thing i would suggest is vacuum leaks or something with your fuel system
jfertita is offline   Reply With Quote
Sponsored Links
Advertisement
 
Reply

  BMW Forum - BimmerWerkz.com > BMW Model Specific Forums > 3-Series (E21, E30)


Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools
Display Modes

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
Trackbacks are On
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
Erratic Idle / Misfire / Cutting out makdolby 3-Series (E36) 12 02-05-2012 07:57 AM
325es surging in cold weather whitey_E30 3-Series (E21, E30) 3 10-28-2006 11:07 AM

Powered by vBadvanced CMPS v3.2.2

All times are GMT -5. The time now is 04:40 AM.



Powered by vBulletin® Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.
Content Relevant URLs by vBSEO 3.3.2
Garage Plus vBulletin Plugins by Drive Thru Online, Inc.