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Idle issue

Ok im stumped on my idle issue, TB was rebuilt, checked and replaced all vacuum lines, all fmic piping is tight. steve said my ISC is fine.

here is a clip of the idle, now it will idle fine when i start it up and dont press the gas. but as soon as i press the gas it will fall to 500rpms and almost stall.

any suggestions?

Video of idle
 

belize1334

Well-known member
Joined
Nov 18, 2003
Messages
3,316
Location
Bozeman, MT
Disconnect your MAF and make sure that the pins are nice and clean and then plug it in again and make sure the connection is good and tight. A bad MAF or bad MAF connection can cause idle issues. Have you checked your ECU Error Codes? Also, if you have a logger you should check your "closed throttle switch" to make sure it's clicking over when the throttle is opened and also your TPS to make sure that it's varying as you adjust throttle and that it drops to a minimum value of ~16(?) when the throttle is closed. Either of these things could interfere with initial dip in enrichment and cause the issue you're having.
 
Last edited:

Myles

Well-known member
Joined
Aug 8, 2006
Messages
5,264
Location
Skokie, IL
Chris, in case you didn't see this. Hertz posted this in chat. Step by Step to adjust your closed throttle switch.

CLOSED THROTTLE POSITION SWITCH (FIXED SAS) ADJUSTMENT Ml3FIDA NOTE 1. The closed throttle position switch has been precisely adjusted by the manufacturer; it should not, therefore, be moved to another setting.

2. If however, the adjustment is for any reason accidentally disturbed, or the closed throttle position switch is replaced, make the necessary readjustment by following the steps (1) .?%izkntly relax the tension of the accelerator cable. (2) Disconnect the connector of the closed throttle position switch (fixed SAS).

: (3) Loosen the lock nut of the closed throttle position switch (fixed SAS). (4) Turn the closed throttle position switch (fixed SAS) in the counter-clockwise direction until it is sufficiently loosened, and securely close the throttle valve fully.

(5) Connect an ohmmeter between the closed throttle position switch terminal and the body. (6) Begin tightening the closed throttle position switch and locate the point at which the closed throttle position switch is switched ON (conductive with body). (This is the point at which the throttle valve begins to open.) From that point, then tighten the closed throttle position switch 15/16 turn.

(7) Securely tighten the lock nut while holding the closed throttle position switch so that it won’t turn. (8) Adjust the tension of the accelerator cable.

(9) Adjust the basic idling speed (engine speed adjusting screw). (P.13-245.) (lO)Adjust the throttle-position sensor. (P.13-248.)

(1) should be "sufficiently"
 

Dialcaliper

Well-known member
Joined
Jun 22, 2007
Messages
1,287
Location
Mountain View, CA
If none of these things work, pop open your ECU and check the capacitors. If you have already replaced them, check that the none of the current driver chips (IC106, 109 or in that vicinity I think - all are single row ICs) have any burn marks or anything like that on them. One of the chips controls the current output to the ISC.
 
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