Hi guys, still having problems with the idle with my car. Had the car and transmission scanned three times for codes now (all different scanners) and nothing comes up. I recieved a print out of the diagnostic report. I was wondering if anyone can spot anything that's wrong: _________________________________________ Data Stream - Value/Status Engine Speed - 731 RPM Desired Idle - 737 RPM ECT Sensor Volts - 2.64 V ENG Coolant Temp - 73°C IAT Sensor Volts - 2.09V IAT - 57°C MAP Voltage - 1.19V MAP - 32 KPA Baro Pressure - 101 KPA TPS Voltage - 0.51V TPS Angle - 0% 02 Ready - YES Fueling Mode - Open Loop 02 Sensor Signal - 853 MV 02 Cross Counts - 0 INJ Pulse Time - 3.51 MS Injector Voltage - 13.8V Air/Fuel Ratio - 13.4 02 Sensor Status - RICH Battery Voltage - 13.6V Reference Volts - 4.98V Idle RPM Varint - 11 UNIT CAM Signal - Present INJ A FDBK - Open INJ B FDBK - Open IAC Position - 17 Step Spark Mode - EST Spark Advance - 34 BTDC Knock Signal - NO Prom id - 5068 _________________________________________ The only thing that I was told is that the 02 sensor is ready rich. The o2 sensor is less than 10,000kms old and does not throw a code. Any ideas? Thanks, Chris.
id say o2 sensor first, sitting rich, doesn't need a to throw a code to be stuffed, pretty much has to be sitting at extremes or totally dead to throw a code, 10,000km if it's a cheap o2 is about all you'l get. Make sure it's bosch or delphi for a good one. the IAC sitting at 17 steps doesn't give alot of room, should be around 30 steps. Prom id 5068 is fairly old as well, get an updated memcal it has alot of fixes and tranny updates. Can help you with that if you wish.
how much for a updated memcal for my 94 vr v6 acclaim because i have been having some of the same problems
Hi The1, thanks for your help. The Oxygen sensor was replaced with a NGK unit I believe, I will buy a new one over the next few weeks and try that. What do you mean by 17 steps from the IAC? The IAC itself is less than 2000km old, most sensors got replaced when I put the recon engine in. Have sent a PM regarding an updated memcal.
Looks like new O2 sensor is the go next week. How can I adjust the stop screw? Is that the throttle cable?
to get o2 to ready status it only has to dip to 200mv once and back up, so id say it's very slow and sitting at 800mv most of the time which is keep the fuel coming in!! it would be in open loop as id say it would have only been started and scantool plugged in, need to go for a drive to get closed loop back on.
well o2 sensor normally fluctuates rich to lean 800mv to 200mv in normal closed loop learn mode operation, when it's not warmed up it sits static at 450mv.
I would think this is worth a look if idle is not good and IAC is clean and cable has slack...remember though v6 idle is not great anyway......as said below IAC should be at least 30 (more like 40) at idle. I do not see anything which indicates a crook O2. Car was idling in open loop and if it had just been started to get the scan and not driven then O2 reading just confirms this. If it had been driven and then left running at idle to get the scan then there is a O2 problem. If you did just start the car to get the scan without driving then o2 is just confirming rich idle as computed by ECU. Voltages, pulse widths, rpm etc all look pretty normal for VR V6. (except IAC as said and idle variation slightly high at 11)
unless it's a cold morning start, which it isn't as coolant is 73c and o2 has had time to get to ready status, then it shouldn't be that rich.
What is the bias voltage applied to the O2 when its offline? I was going to say the 450mV is the bias but it seems too high.
They will idle in open loop. It's only the first few (maybe 20-30) seconds of idle that are closed loop. I wouldn't say that it is overly rich for idling in closed loop, especially at lower than operating temp.. Nor would I say that the IAC steps are out if it's in neutral or a manual. It's not super critical but 10-30 steps seems to be normal. As long as it's not 0 (or 255!) at any point it's OK. I would like to see what it is doing at operating temp. - 101-103C - (assuming that it will get there; if it doesn't that's likely to be a problem right there and yes, a colder than standard thermostat is a "problem") before making any judgement about what's going on. It would also be interesting to match what the IAC steps are saying with what the engine idle is doing i.e. does a change in steps produce a noticeable change in idle or not, what does it do when you create a vacuum leak and artificially raise the idle speed.
It's an auto and I believe it was idling in park. I wasn't there when the work was done, dropped it off to auto elec. I dropped the car off at 9am, after about a 15-20 minute drive, according to the time on the scan sheet the car wasn't scanned till about 12pm. Thermostat is standard replacement. My idle does fluctuate, it can be anywhere from 750 to under 700. The car is quite shaky under 700rpm. If I'm stopped at traffic lights and the fan kicks in, the revs drop and the car shakes then they pick back up. Battery is new, alternator and battery were tested and they both passed. I was thinking about booking the car into another shop and checking for vaccum leaks, started the car the other morning when it was cold with the belt off, sounded like a hissing noise coming from the throttle body area. I sprayed some WD-40 all around the seals, sensors and hoses and there was no change in idle. Could be totally unrelated to this problem - but the car struggles to start when it is hot. CAS is new. Starter motor drags but it does fire up every time, I'm assuming it just needs a new starter. Starters prefectly fine when cold.
Installed new Oxygen sensor, put in the tune I got from The1, and also installed a new throttle body today. Car runs 100% better, the vibration and rough idle is pretty much gone. There is a very slight vibration, which I have heard happens with the buick engines, but it is hardly noticable. Pretty ####ing stoked right now. Oxygen sensor was very black and sooty.
