Toxie Posted August 11, 2010 Author Report Share Posted August 11, 2010 Thanks again for the support guys, I do appreciate it. Jonpro03, you mentioned to check the sensor grounds on the back of the engine... I never knew about those before, where exactly would those be located on the back? And are they all together in one bunch? Thanks again everyone!! Quote Link to comment Share on other sites More sharing options...
Toxie Posted September 11, 2010 Author Report Share Posted September 11, 2010 (edited) Today I replaced all the injectors and still it runs bad. I took this to the local Pontiac dealer and they said ECM needed replaced so I did that and that did not fix it. I took it to a local mechanic and he said that there is not much left to do that I already have done... After I replaced the injectors today and started the idle re-learn, it ran ok for about 5 minutes then started running rich again. When I had the plenum off I saw where #5 intake was wet with what looked like exhaust and gas. The one next to it (#3) was sort of wet and the first one (#1) only very slightly. The back bank looked fine... that is why I replace the EGR earlier thinking the extra exhaust gas was coming into the motor... What am I missing here guys? What is left? When I pull a line off the fuel regulator I have vacuum. This is what i have replaced so far... Ignition Control Module (ICM) Ignition Coil Packs (3) Spark Plugs Plug Wires EGR Valve Idle Air Control Valve (IAC) Oxygen Sensor Coolant Temp Sensor Throttle Postion Sensor PCV Valve Air Charge Temp Sensor (MAT) ECM (Computer) Fuel Injectors Tested ok... MAP Sensor I sure hope somebody can help... Thanks. Edited September 18, 2010 by Toxie Quote Link to comment Share on other sites More sharing options...
Night Fury Posted September 11, 2010 Report Share Posted September 11, 2010 Test compression? Quote Link to comment Share on other sites More sharing options...
Toxie Posted September 11, 2010 Author Report Share Posted September 11, 2010 Not yet. But if there was bad compression, would it run fine sometimes and others not? I have driven this for 20-25 miles when its in the "run ok" mode and it ran fine...it was as smoother as ever. Then for no apparent reason it starts acting up again. Thanks Quote Link to comment Share on other sites More sharing options...
Night Fury Posted September 11, 2010 Report Share Posted September 11, 2010 True, but with as many things you've ruled out, you don't have much else to check. Lol Fuel filter new? Do you have good fuel pressure? Quote Link to comment Share on other sites More sharing options...
ruktosk Posted September 11, 2010 Report Share Posted September 11, 2010 Have you verified that the ECM is sending the correct reference for each of the sensors? Quote Link to comment Share on other sites More sharing options...
Toxie Posted September 12, 2010 Author Report Share Posted September 12, 2010 Have you verified that the ECM is sending the correct reference for each of the sensors? In post #15 I listed my ECM output when the car was running bad... other than the rich indicator, all seemed inline. Is this what you were referring to? Thanks Quote Link to comment Share on other sites More sharing options...
mra32 Posted September 12, 2010 Report Share Posted September 12, 2010 Might be a long shot, but debris in your fuel return line for the front bank? Weirdly failing fuel pressure regulator? It would be nice to get a readout of the fuel pressure when this is happening. Quote Link to comment Share on other sites More sharing options...
spiderw31 Posted September 12, 2010 Report Share Posted September 12, 2010 Not yet. But if there was bad compression, would it run fine sometimes and others not? I have driven this for 20-25 miles when its in the "run ok" mode and it ran fine...it was as smoother as ever. Then for no apparent reason it starts acting up again. Thanks I used to have a Pontiac 6000 with the 2.8 that acted exactly as you describe. I also stared testing, replacing, and trying to diagnose exactly as you are. After much headache, trial and lots of error I finally found that I had gotten either a bad spark plug or wire in a recent tuneup. The plug was all brown around the outside, and the wire boot was hardened and cracking. After replacing just that one plug and wire, the car ran wonderful again. Moral of the story? Check the simple stuff again, and don't assume that the parts you got are good. Whatever the issue is though, hopefully you can pin it down. Good luck! Quote Link to comment Share on other sites More sharing options...
ruktosk Posted September 12, 2010 Report Share Posted September 12, 2010 In post #15 I listed my ECM output when the car was running bad... other than the rich indicator, all seemed inline. Is this what you were referring to? Thanks No. Grab a multimeter and verify that the reference signal from the ECM to each sensor is within spec for that sensor. If one or more are not, then the affected sensors will be sending incorrect information to the ECM which can mess up your AFR. When checking, try using the chassis as the ground. This will also verify if any sensors are improperly grounded. Quote Link to comment Share on other sites More sharing options...
AL Posted September 13, 2010 Report Share Posted September 13, 2010 I didnt see the ICM on that list... Try replacing that, the Ignition Control Module which the coils mount to Quote Link to comment Share on other sites More sharing options...
Toxie Posted September 18, 2010 Author Report Share Posted September 18, 2010 I didnt see the ICM on that list... Try replacing that, the Ignition Control Module which the coils mount to Yea, sorry that was not on the list but on the first page.. It was replaced and then checked also later... Thanks Quote Link to comment Share on other sites More sharing options...
AL Posted September 18, 2010 Report Share Posted September 18, 2010 Wow, I read everything again, I have no idea how I missed you having the ICM tested multiple times... I honestly dont know what else to check... And the fact its intermittent is blowing my mind also Quote Link to comment Share on other sites More sharing options...
Toxie Posted September 30, 2010 Author Report Share Posted September 30, 2010 OK guys, I finally found out the reason for the problem. I tested the fuel pressure at the rail and that was fine. Then I tested the compression and noticed that #5 cylinder went from the same psi as all the other cylinders to half of that to 0 psi and back to full pressure... I have an intake valve that sticks open sometimes. When it sticks open I can smell fuel and it runs bad, as soon as the valve closes it runs perfect. I put Seafoam in the oil, gas, and the brake boosters vac line. I ran 50 miles and it did not miss a beat but then today and yesterday it ran 1/3 of the time bad with a stuck open intake valve and the rest of the time perfect when the valve finally unstuck. Is there anything else I can try before tearing down to get to the heads? I may try Marvel Mystery Oil too to see if that helps. Thanks again for all your help. I'm just relieved that finally I know what the problem is... Now I just need to fix it... -Toxie Quote Link to comment Share on other sites More sharing options...
Night Fury Posted September 30, 2010 Report Share Posted September 30, 2010 Run trans fluid in the oil for a while? Not sure on the amount/duration it should be done, but I know it has worked for several people Quote Link to comment Share on other sites More sharing options...
tornado_735 Posted October 1, 2010 Report Share Posted October 1, 2010 Marvel is great stuff, I would give it a shot. Quote Link to comment Share on other sites More sharing options...
AL Posted October 1, 2010 Report Share Posted October 1, 2010 I'm not sure if the trans fluid in the oil would work or not for your problem... What you do though is put a quart of trans fluid in with your oil after an oil change (don't over fill your engine though) and run it for about an hour or so just cruising around town... Then change the oil again... You don't necessarily have to change the filter again though but I always do Quote Link to comment Share on other sites More sharing options...
Garrett Powered Posted October 1, 2010 Report Share Posted October 1, 2010 damn, I am going to run compression tests on my cars. Quote Link to comment Share on other sites More sharing options...
slick Posted October 1, 2010 Report Share Posted October 1, 2010 Tear it down and fix it correctly. There's no magical fluid that fixes mechanical issues. Quote Link to comment Share on other sites More sharing options...
Toxie Posted October 1, 2010 Author Report Share Posted October 1, 2010 (edited) Yep, I totally agree... I never had any luck with additives. I just thought I would give it a shot until I found the time to tear it down. Thanks again to everyone for all your help on this. Edited October 2, 2010 by Toxie Quote Link to comment Share on other sites More sharing options...
Garrett Powered Posted October 4, 2010 Report Share Posted October 4, 2010 yeah, if the bottle it comes in is shaped like a beaker. and it is covered by a million mile policy with all kinds of disclaimers, it has to fix it. fix it with chem-tools! I cant stand those "air compressor and tool box in a bottle" products. Quote Link to comment Share on other sites More sharing options...
virtuetovice Posted October 6, 2010 Report Share Posted October 6, 2010 Yeah like those head gasket repair bottles.... Quote Link to comment Share on other sites More sharing options...
Toxie Posted October 24, 2010 Author Report Share Posted October 24, 2010 Well guys... I finally found time to tear it down this weekend...this is what I found. I'm going to have the valves seated and get all new springs and valve seals too. Anything else I should have done to the heads? Quote Link to comment Share on other sites More sharing options...
tornado_735 Posted October 24, 2010 Report Share Posted October 24, 2010 Sweet Jesus! How in the shit did that happen? As for the heads, I think you're doing everything I would. You could top swap it since you're going to have the heads off, but that's up to you. Quote Link to comment Share on other sites More sharing options...
mra32 Posted October 24, 2010 Report Share Posted October 24, 2010 GOOD JOB. I posted in your thread earlier about a somewhat similar, but less severe problem i was having. I ended up fixing it last night too! Quote Link to comment Share on other sites More sharing options...
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