crc Posted March 6, 2003 Report Share Posted March 6, 2003 Does the PCV tube run directly from under the plenum on 3.1? I took the manifold off today and now I'm staring at a damn torn tubing sticking out from under the manifold. It must've gave away easy because there was hardly any play there and plus it was aging. The shop manual schematics I've seen show PCV connection for 3.1 in a different configuration. Quote Link to comment Share on other sites More sharing options...
crc Posted March 6, 2003 Author Report Share Posted March 6, 2003 scratch that.. silly question.. it IS the PCV.. *sigh* wonder how much for a new one? Quote Link to comment Share on other sites More sharing options...
crc Posted March 6, 2003 Author Report Share Posted March 6, 2003 BTW, here's a good checklist I've come across on the net for those having rough idle or poor idle problems, something that is fairly common with higher mileage 2.8's and 3.1's ============== If your car is experiencing idle trouble and tip-in hesitation, here's a few ideas for you: 1) Check to see if the Idle Air Control valve is working properly. ** Easy to tell if it's going bad.. terrible idle + no noticeable increase in idle RPM when you turn on heat or a/c 2) Check the fuel pressure at the Schrader fitting on the fuel rail. With the pump running and the engine off, the pressure should be about 40-47 PSI at the fitting. With the engine running, the pressure should drop 3-10 PSI. Snapping the throttle should give momentary increases in pressure corresponding to the throttle cracking. If the pressure is low, suspect the pump in the tank or a fuel filter. If it is high and/or a increase in pressure isn't seen when the throttle is cracked, the throttle body may need cleaning and/or the fuel pressure regulator may be bad. 3) With a voltmeter roached in, check the TPS (Throttle Position Sensor) for its closed-throttle voltage (about 0.50 to 0.60 V or so). With the engine off, *slowly* open the throttle watching the voltmeter; a 3-1/2 digit meter should increase smoothly in about .02 volt increments to at least 4.70 volts. A scan-tool would be handy for this check because then you see what the ECM sees as TPS input. 4) Check to make sure the charging system output is greater than 9 volts and less than 16 volts. 5) If the car has an automatic transmission, have the park/neutral switch checked. 6) Check to make sure the PCV (Positive Crankcase Ventilation) system is okay...specifically, make sure the PCV valve itself isn't stuck causing a vacuum leak. On these engines it's easy to miss this nugget because it's hidden under the intake plenum, in the rear valve cover. If the valve is indeed 3-years old, it may be time for a new one. 7) When was the O2 sensor last replaced? If it is d-e-a-d dead, it'll force a Code 13, but a lazy O2 sensor (one that is slow to react) may cause a goofy idle but no code. Typically, degraded (slow) sensors do cause Code 61 but maybe yours isn't that bad yet. 8) Have the MAP (Manifold Absolute Pressure) sensor and its vacuum hose checked. 9) Have the EGR system checked. On this car is the 3-armature digital EGR...maybe one of the solenoids is stuck open. 10) Check the spark plug *wires*. 11) Have a trusted mechanic put a scan tool on it (ALDL port) and observe some critical numbers with the engine hot and idling: - Integrator.............................should not be too far from 128 - Block Learn Multiplier.................should not be too far from 128 - O2 volts................should be active anywhere from 100mV to 1.00V - cross counts.............should increase and roll over at 255 rapidly - CTS.........................varies but if engine is hot, at least 85C - MAP......about 10-20kPa at idle; voltage should be around 1 - 2 volts - TPS..............................should read about 0.5 to 0.6 at idle - MAT....................varies, but somewhat over ambient if hood open - BARO................depends on atmospherics, but should be 95-103 kPa - fuel pump voltage..........engine running should be about 13.5V or so - spark advance.................varies, but about 12-18 degrees at idle - knock retard.........................................should read zero - closed loop indicator...depends, but it'd be nice if it read "closed" - RPM...........pretty smooth around 900 or so (depends on alot though) Quote Link to comment Share on other sites More sharing options...
Redfox340 Posted March 6, 2003 Report Share Posted March 6, 2003 For the valve: couple bucks... For the hose: less than that... Any auto parts store has rubber hose and the valve to replace it. Just grab the diameter of the tube, and snap a couple extra inches to be on the safe side. I know the pain of those... my 2.8L L-Body did that in the winter 2 years ago; pain when it's -10 degrees out. - RedFox340 Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted March 6, 2003 Report Share Posted March 6, 2003 Make sure you get hose that will take the heat. The hose on my TGP broke last summer. I got one at the dealer. Cost me about $8.00. Went to put it on and discovered the n/a 3.1's are setup different. The hose has a 90* angle in it also. If you use straight hose you will need a 90* plastic elbow from another PCV valve. Here's a pic of how the TGP is setup. on the n/a 3.1's the angled end of the hose goes on the PCV valve. The other end goes onto a metal tube. The TGP plenum has a nipple on the bottom of the plenum that the PCV valve hose connects too. I just turned the hose around and used the angled end on the plenum and put an elbow from another pcv valve on my valve. Quote Link to comment Share on other sites More sharing options...
mfewtrail Posted March 7, 2003 Report Share Posted March 7, 2003 Make sure you get hose that will take the heat. The hose on my TGP broke last summer. I got one at the dealer. Cost me about $8.00. Went to put it on and discovered the n/a 3.1's are setup different. The hose has a 90* angle in it also. If you use straight hose you will need a 90* plastic elbow from another PCV valve. Here's a pic of how the TGP is setup. on the n/a 3.1's the angled end of the hose goes on the PCV valve. The other end goes onto a metal tube. The TGP plenum has a nipple on the bottom of the plenum that the PCV valve hose connects too. I just turned the hose around and used the angled end on the plenum and put an elbow from another pcv valve on my valve. not to be an ass or to hijack a thread(which I'm partially doing), but did you take a picture of your plenum up against a christmas tree? Quote Link to comment Share on other sites More sharing options...
Guest Posted March 7, 2003 Report Share Posted March 7, 2003 well it does preduce a nice background for contrasting the parts. Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted March 7, 2003 Report Share Posted March 7, 2003 That tree is growing in my front yard... well it does preduce a nice background for contrasting the parts. That's what I thought. Quote Link to comment Share on other sites More sharing options...
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