Frank Posted March 31, 2012 Report Share Posted March 31, 2012 I have a issue with my V6 with hot wire air mass. The adjust screw just spends without any adjustment,seems stripped out,not sure! It looks like the screw makes a electric connection , Factory repair manual says it a air bleed screw, it sure does not look like it from the inside near the hot wire. Any way I had no vacuum leaks good fuel pressure,wires and good plugs. Have a lean misfire with injection good. Also i set the throttle to put her in the run mode. My o2 sensor works ok. The idle valve works. Without hurting fuel milage does any one know a trick? I was thinking putting a restrictor in the air boot side of the idle valve. I have enough RPM to do this. My friend said the Volvo model 89 V6 runs to lean at idle also. I have the same fuel pump as knew she was new. Thinking a Pump and O2 will be the next parts she will get! Thanks for the read. Frank in the bay area Quote Link to comment Share on other sites More sharing options...
Bean Posted April 1, 2012 Report Share Posted April 1, 2012 Hi Frank, What kind of plugs are you using? And how's the distributor cap and rotor condition? I find troubleshooting with used parts to be iffy at best, so when ever I encounter this kind of situation it's usually an excuse to give it a complete tune up so that all the parts are known good and ruled out of the troubleshooting. I also think the only way you can diagnose a lean misfire is with a wideband O2 sensor. I'd bet the misfire is something more simple. I once had some Bosch platinum plugs start arcing spark to the inside of the tube - I only noticed it when troubleshooting a misfire in a dark garage. Totally stumped me until that moment - been using NGK's ever since. Rabin Quote Link to comment Share on other sites More sharing options...
model1911 Posted April 4, 2012 Report Share Posted April 4, 2012 I would also check your gaps on all the spark plugs and if you can get a vacuum gauge on it and see if there is any erratic bouncing should be uniform through out the fire order if needed i will try to get you some views of what it should look Quote Link to comment Share on other sites More sharing options...
Frank Posted April 8, 2012 Author Report Share Posted April 8, 2012 I would also check your gaps on all the spark plugs and if you can get a vacuum gauge on it and see if there is any erratic bouncing should be uniform through out the fire order if needed i will try to get you some views of what it should look That 's a good idea, to check valves with the vacuum gauge. But it is running so rough at idle that I will get the rough reading in the vacuum gauge. I should check at cranking with no fuel injection. I think I will run a leak down . Compression test was around 150 lbs each cylinder.I will enrich with propane and see it she smooth out. The spark plug gap is stock 30 thousands. What should work better? Quote Link to comment Share on other sites More sharing options...
Frank Posted April 8, 2012 Author Report Share Posted April 8, 2012 Hi Frank, What kind of plugs are you using? And how's the distributor cap and rotor condition? I find troubleshooting with used parts to be iffy at best, so when ever I encounter this kind of situation it's usually an excuse to give it a complete tune up so that all the parts are known good and ruled out of the troubleshooting. I also think the only way you can diagnose a lean misfire is with a wideband O2 sensor. I'd bet the misfire is something more simple. I once had some Bosch platinum plugs start arcing spark to the inside of the tube - I only noticed it when troubleshooting a misfire in a dark garage. Totally stumped me until that moment - been using NGK's ever since. Rabin Thanks Rabin, I have new French wire set and new NGK plugs. see runs great except at idle. Do U think a new O2 sensor would help. It is lazy on my scope. Cap and rotor good! Thanks again for u thoughts. Frank Rabin do u now anyone how needs a good Turbo GAS head? Quote Link to comment Share on other sites More sharing options...
model1911 Posted April 8, 2012 Report Share Posted April 8, 2012 Well the compression sounds good for an old engine and the gap sounds good on the plugs the o2 being lazy shouldn't be the cause if the mass air is like GMs then if you un plug it at idle it should smooth out but as far as i know only the GMs did it so i dont know if it will work on your car but you can always try it and as for checking with vacuum with the injectors killed and cranking the engine is just fine and if you have egr system on the car still i would check it out and make sure its not dumping exhaust gas into the intake at idle Quote Link to comment Share on other sites More sharing options...
Bean Posted April 9, 2012 Report Share Posted April 9, 2012 I'd unplug the O2 and see if it smooths out - it should default to a rich map without the signal. If that doesn't solve your problem - by next guess would be a slight vacuum leak is causing the rough running / misfire. And no Frank - I don't know anyone that needs a Turbo head. I've got lots myself - but I do know that when someone needs one - they need it NOW. If I were you I'd just post up an advert and wait. If I come across anyone needed one - I can send them a link to your advert. Rabin Quote Link to comment Share on other sites More sharing options...
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