Idling Problem.

[Czop418]

Ok guys i have a pretty good question for you. I just recently rebuilt my motor. Its a H/C 95 lt1 with a pcm tune. Now The car seems to run fine during normal drives no excescive accerlation just basic cruising. But whenever I give the car full throttle i notice it seems to be idling at 1500 when i stop or put it in neutral. Now Im throwing a SES light and im going to get that checked out this week. But other than that i also noticed my Low Coolant light is on (sensors bad gotta replace) and it seems to idle high whenever that lights on. I know that low coolant can cause surging to spin the Water Pump faster in other cars and i was wondering if that could be a cause / possibility. Now i Already checked the MAF / MAP. Check for Vaccum Leaks couldnt find any. Im just sort of stumped for now. Until i get it scanned. Anbody have any Input in my Problem. Thanks Alot.

-Rich

[S.J.SLEEPER]

have you checked tps?

[RamAir95TA]

The TPS being bad shouldn't affect the idle speed. The SES scan should be able to give you some good info. Maybe a bad or dirty IAC, sticky throttle body, etc.

[BarneyMobile]

Originally Posted by RamAir95TA

The TPS being bad shouldn't affect the idle speed. The SES scan should be able to give you some good info. Maybe a bad or dirty IAC, sticky throttle body, etc.

Not saying that the TPS is the problem but the TPS has alot to do with the idle. The pcm has to know where the throttle is to calculate how much to open or close the IAC.

[Czop418]

TPS is good , But if the IAC was bad wouldnt it do it non-stop. Not 50-50. Thanks for all the input guys. Anything else maybe.

[Pampered-Z]

What size throttle body are you running what size cam? Could just be the tune needs to be touched up as well.

The low coolant sensor should have no effect on how the engine is running.

[Czop418]

Ok well I just got done scanning it tonite. Well heres the damage. Im Pulling one engine code and one tranny Code.

Engine Code 43: Bad ESC. "Electronic Spark Control Im guessing. Well From what ive done research its a Bad knock sensor and or Module. Well I tried both i Have a LT4 Knock Module And 2 , LT1's and replaced the actual sensor itself. Still Pulling the Code. Does that Mean That the Coil is Bad ?

Tranny Code: 76 System Voltage too high. Now im Guessing that Goes Hand in Hand with code 43. Correct me if Im wrong.

Now guys Do you think if i change the coil , it will stop All my problems ? Thanks Alot.

-Rich

[S.J.SLEEPER]

Originally Posted by BarneyMobile

Not saying that the TPS is the problem but the TPS has alot to do with the idle. The pcm has to know where the throttle is to calculate how much to open or close the IAC.

THANK YOU!

[Pampered-Z]

43 = Knock Sensor (KS) circuit


I find no code 76 for OBDI in any of my reference guides.

[NastyEllEssWon]

in one of the guides i have under the ''gm'' section it says code 76 is egr solenoid failure.....might help point you in the right direction?

[Czop418]

Can't be egr , I had the tuner remove it. Yea I woud have never found out about that code I was just messing with the scanner running through all the possibiltys , then on a test drive I figures I check the diagnostics on the tranny and that popped up I tried googling that code and nothing. But here's the thing if I clear the. ESC code the tranny code disapears and vice versa.

[sweetbmxrider]

clearing the computer clears all the codes on a 95. you can't just clear one code.

air bag light on? code 43 applies to both the pcm and sir system

43

CIRCUIT DESCRIPTION
During normal. non-deployment operation of the SIR system the DERM monitors the voltage supplied through the dual pole arming sensor to the high side of the driver deployment loop at the "Driver Source Sense" terminal "A5." This measured voltage will have a value approximately equal to "Driver 36 VLR." When the voltage measured at "Driver Side Low" terminal "B8" is in its normal operating range, indicating driver deployment loop integrity has been maintained, while simultaneously the voltage measured at Driver Source Sense" is a specified amount below "Driver 36 VLR" for 500 milliseconds DTC 43 is set.

DTC WILL SET WHEN
The voltage measured at "Driver Side Low" terminal "B8" is within a specified percentage of "Driver 36 VLR" while simultaneously the voltage measured at "Driver Source Sense" terminal "A5" is a specified amount below "Driver 36 VLR" for 500 milliseconds. This test is run every 100 milliseconds during the "Continuous Monitoring" tests.

ACTION TAKEN
DERM turns "ON" the "AIR BAG" warning lamp and sets a diagnostic trouble code.

DTC WILL CLEAR WHEN
The voltage measured at "Driver Side Low" terminal "B8" is within a specified percentage of "Driver 36 VLR" while simultaneously the voltage measured at "Driver Source Sense" terminal "A5" is within a specified amount of "Driver 36 VLR" for 500 milliseconds.

DTC CHART TEST DESCRIPTION
Number(s) below refer to circled number(s) on the diagnostic chart.

1. This test checks for an open in "Driver Source Sense" circuit.
2. This test checks for a short from the "Driver Source Sense" circuit to ground.
3. The test determines whether the malfunction is due to increased resistance across the "Driver Source Sense" resistor in the dual pole arming sensor.

DIAGNOSTIC AIDS
An intermittent condition is likely to be caused by a poor connection to the DERM at terminal "A5," a poor connection to the dual pole arming sensor at terminal "D," an open or short to ground in CKT 1400 or a partial open inside the dual pole arming sensor.

43

CIRCUIT DESCRIPTION
The Knock Sensor (KS) system is used to detect engine detonation. The Powertrain Control Module (PCM) will retard the spark timing based on signals from the KS module. The knock sensor produces an AC voltage which is sent to the KS module. The amount of AC voltage produced by the sensor is determined by the amount of knock. The circuitry within the knock sensor causes the PCM's 5 volts to be pulled down so that under a no knock condition, CKT 496 would measure about 2.5 volts.
The internal PCM test run on the KS circuit will determine if it is operating correctly.

DIAGNOSTIC TROUBLE CODE (DTC) 43 WILL SET WHEN
If the PCM detects that any of the following voltage conditions have been met for 5 seconds, DTC 43 will be set:

* Sensor open, (voltage greater than 4.1 volts).
* Sensor grounded (voltage less than 0.78 volts)

ACTION TAKEN (PCM WILL DEFAULT TO)
The Malfunction Indicator Lamp (MIL) will illuminate. The PCM will retard timing to a predetermined maximum based on current RPM and Manifold Absolute Pressure (MAP). Some loss of performance will result.

CHART TEST DESCRIPTION
Number(s) below refer to circled number(s) on the diagnostic chart.

1. If an audible knock is heard from the engine, repair the internal engine problem, as normally no knock should be detected at idle. The PCM supplies 5 volts on CKT 496 which should be present at the knock sensor terminal when the sensor is disconnected.
2. This test determines if the knock sensor is faulty or if the KS module is faulty.
3. CKT 496 shorted to voltage will set DTC 43 and indicate on Tech 1 scanner as sensor open. With the sensor and the PCM disconnected, no voltage should be present on CKT 496.
4. An improperly installed knock sensor can prevent the knock sensor from grounding to the block.
5. If a short to battery voltage is found, additional component damage may have occurred. If DTC 43 resets after the short is repaired, it will be necessary to re-run this chart to locate any additional faults.

DIAGNOSTIC AIDS
The PCM has the ability to diagnose opens and shorts in the KS circuit. The Tech 1 scanner will display if the sensor is open or if it is grounded when the PCM detects these conditions.

* Check CKT 496 for a potential open or short to ground.
* Also, check for proper installation of the KS module.
* KS sensor wire is routed too close to secondary ignition components may be susceptible to EMI interference.
* Refer to Diagnosis by Symptom/Intermittents See: Symptom Related Diagnostic Procedures\Intermittent Condition

76

Circuit Description:
This DTC identifies a solenoid that cannot be energized due to an open in its circuitry, or a solenoid that is always energized due to a short to battery in its circuitry between the driver and the solenoid. An open will not allow proper ABS operation, but the short to battery simply turns "ON" the solenoid. A path for base brakes is still allowed once the motor rehomes and the check ball is lifted off its seat during key "ON" initialization.

DTC Will Set When:
DTC 76 can be set only when the solenoid is commanded "OFF." If the EBCM detects an excessive voltage in the left front solenoid control circuit, a malfunction exists.

Action Taken:
A malfunction DTC is stored, ABS is disabled and the ABS warning lamp is turned "ON."

DTC Chart Test Description:
Number(s) below refer to circled number(s) on the diagnostic chart.

1. Checks for a short to voltage in the control circuitry of the solenoid.
2. Checks for an open in the control circuit of the solenoid.
3. Checks the solenoid coil for proper resistance.
4. Checks for an open in the solenoid ground circuit.
5. Checks for a possible intermittent malfunction in the solenoid circuitry due to poor terminal contact.

Diagnostic Aids:
An "Intermittent" malfunction may be caused by a poor connection, rubbed through wire insulation, or a wire that is broken inside the insulation.

The frequency of the malfunction can be checked by using the enhanced diagnostic function of the Tech 1.

Any circuitry, that is suspected as causing the intermittent complaint, should be thoroughly checked for backed out terminals, improper mating, broken locks, improperly formed or damaged terminals, poor terminal to wiring connections or physical damage to the wiring harness.

post up if you need more help. also i think the idle may be tuned related unless your ECT sensor is getting a mixed reading causing the idle to bump up. only way i'd see that happenin is if you actually were losing coolant though it seems only the sensor is bad in your case?

[Czop418]

Ok code 76 is for the skip shift elimnator haha. Just figured that out. And as for my knock sensor im still working on that i think its faulty wiring somwhere / possible EMI

[Czop418]

Ok guys ive been testing my Knock Senor for volts. And for some reason im not getting ****. In stumped i just got the new pcm from pcm for less. And nothing does that mean my ecm is bad?