Just finished installing the PPC headers on my car. Had a few issues, i.e. the 02 sensor wires were too close to the headers and burned. That sent codes like crazy. Ended up curing that with heat wrap and a new fuse.
Now - I have code - P0118 - coolant temperature sensor. I replaced the sensor with a new one. That solved the problem for a couple days. It's back again. Also, the idle is very rough and varies between 900 - 1200 RPM. and the car is surging. At times it runs up to 3500 RPM on it's own, I can be in gear or at idle and it will rev up on it's own. It feels like it bogs off the line, and is not making the kind of power that an LS1 should. I cleared the codes last night and it came back 4 times in an 8 mile drive. I'll add that it seems to be runnning rich now.
The car has about 14,000 miles on it - and has the usual bolt ons. Hypertech and 4:10's. Granatelli MAF. I changed the plugs with the header install.
Anyone else have this problem before? Any suggestions for a power tuning shop in the Detroit - Windsor area?
I know this should be in "Technical" but there may be others with the same concerns that don't often check there.
Thanks.
Posted by DaddySS (Member # 848) on :
Hawk:
RPMs running up like that, surging is usually a sign of a vacuum leak - do you hear any hisssing? Running rich after headers is normal. Check all of your wires to make sure that you are not cooking any of them. I assume you have auto tap, are you getting any indication of why the rpms are running up and down?
Posted by Hawkeye (Member # 88) on :
Nope, I hear no leaks, I replaced the coolant sensor with a new one. I called the dealer and he said it's possible then new one is defective - but not likely.
I do not have auto tap, just a code reader. I think I'll put the stock prgramming back and make an appointment with the dealer. It could be just a coincidence with the headers and have nothing to do with it.
Posted by DaddySS (Member # 848) on :
Here's the test info - is your voltage too low or too high?
P0118
Schematic
CIRCUIT DESCRIPTION The Engine Coolant Temperature (ECT) sensor contains a semiconductor device which changes the resistance based on the temperature (a thermistor). The ECT sensor is mounted in the left bank cylinder head near the front of the engine. The ECT sensor has a signal circuit and a ground circuit. The PCM applies a voltage (about 5.0 volts ) on the signal circuit to the sensor. The PCM monitors the changes in this voltage caused by changes in the resistance of the sensor in order to determine the coolant temperature.
When the coolant is cold, the sensor (thermistor) resistance is high. The PCMs signal voltage is only pulled down a small amount through the sensor to a ground; therefore, the PCM senses a high signal voltage (low temperature). When the coolant is warm, the sensor resistance is low. The signal voltage is pulled down a greater amount; therefore, the PCM senses a low signal voltage (high temperature). At normal operating temperature, the scan tool should display an ECT value of 1.5-2.0 volts.
When the PCM senses a signal voltage higher than the normal operating range of the sensor, this DTC sets.
The engine coolant temperature information is sent to the instrument panel cluster via the class 2 circuit.
CONDITIONS FOR RUNNING THE DTC The engine run time is more than 60 seconds. OR The engine run time is less than 60 seconds when the IAT is more than 0°C (32°F).
CONDITIONS FOR SETTING THE DTC
The engine coolant temperature is less than -39°C (-38°F). All conditions met for 20 seconds. ACTION TAKEN WHEN THE DTC SETS
The PCM illuminates the Malfunction Indicator Lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails. The PCM records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the PCM stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the PCM records the operating conditions at the time of the failure. The PCM writes the conditions to the Freeze Frame and updates the Failure Records. CONDITIONS FOR CLEARING THE MIL/DTC
The PCM turns the Malfunction Indicator Lamp (MIL) OFF after 3 consecutive ignition cycles that the diagnostic runs and does not fail. A last test failed (current DTC) clears when the diagnostic runs and does not fail. A History DTC clears after 40 consecutive warm-up cycles, if this or any other emission related diagnostic does not report any failures. Use a scan tool in order to clear the MIL/DTC. DIAGNOSTIC AIDS
IMPORTANT:
Remove any debris from the PCM connector surfaces before servicing the PCM. Inspect the PCM connector gaskets when diagnosing/replacing the PCM. Ensure that the gaskets are installed correctly. The gaskets prevent contaminant intrusion into the PCM. For any test that requires probing the PCM or component harness connectors, use the J 35616-A connector test adapter kit. Using this kit prevents any damage to the harness connector terminals. Refer to Using Connector Test Adapters in Diagrams. If the engine has sat overnight, the engine coolant temperature and intake air temperature values should display within a few degrees of each other. If the temperatures are not within 3°C (5°F) , refer to Temperature vs Resistance.
If you determine that the DTC occurs intermittently, performing the P1115 diagnostic table may isolate the cause of the fault.
For an intermittent, refer to Symptoms. See: Diagnostic Information and Procedures\Symptoms
TEST DESCRIPTION
Steps 1 - 8
Steps 9 - 19
The numbers below refer to the step numbers on the diagnostic table.
Hi Brian, sorry to hear the troubles...When I first installed my SLP long tubes, I would get codes, but they were only for rear o2 heat levels...anyways the fix was to reroute the engine wires, even though they were wrapped to protect from heat, the heat of driving was effecting the resistances...No lights at all last year since I did that and still I run all 4 original sensors...Although I didnt have any surging so this may just be what my fix was and also maybe someone else may be having this problem...its just something to check. Good Luck Al
Posted by Hawkeye (Member # 88) on :
Thanks guys. I figured I'd have to check the resistance of the wiring for the coolant sensor.
It's amazing how many things are affected by that small piece. What wires did you have to re-route? I changed the 02 sensor wires and triple insulated them after one burned right through and shorted out against the header.
That blew a fuse and caused the revese solonoid lock out. I could not shift into revese after pulling into a parking space! What a treat!
Posted by 35th_camaro_ss (Member # 1738) on :
I actually rerouted the entire harness, I actually cut all the ones in the harness beside the engine that they give a sleeve to protect spliced,soldered,shrinkwrapped and put new factory type loom. I used larger guage wire to overcome the chance of adding resistance as some of those sensors are very small currents...I prob overdid it, but I have had no problems at all since...ALSO NOTE that when I cut into the harness, the small sensor wires were discolored and almost brittle feeling, I cut that all out and replaced and now looks like never was touched with new factory type loom, esp where I show the car I didnt want anyone to notice...but now my wires run nowhere near any heat source and no more light. Al
Posted by Midlife CrisiSS (Member # 2141) on :
Whoa! Sorry about the problems; I know they can be frustrating.
I had an SES following my PPC install, but it was due to an exhaust leak. I had better recheck all the wire routing again.
Posted by 2002Z4CSS (Member # 1393) on :
Brian,hopefully when that V-ref circuit was shorted out it did not take out a driver in the ECM. Was this code present before the header install?
Livernois Motorsports in Dearborn Heights can do ECM tuning. They have in house chassis dynos and a new portable one. Posted by Hawkeye (Member # 88) on :
No codes ever before the header install. And, I was checking on LS1tech.com and someone there has the same problem that I have - strange!
I may have to make an appointment with Livernois.
Sorry - no Milan last night for me.
Posted by Raven (Member # 1962) on :
When SLP installed my headers They told me that installing them changes a lot of the PCM Paramiters. You should take the car to a shop that does LS1 mods to have the PCM tuned to your changes. It sounds like the PCM does not know what to do!!
[ 09. April 2004, 07:44 AM: Message edited by: Raven ]
Posted by sscamaro (Member # 1330) on :
Sorry to hear of your problem Brian. Thats why I am glad I had a pro install my headers. Never throw any codes and ran like a champ. Hope you get it fixed.
![[Smile]](smile.gif)