Quote:
Originally Posted by ksa8907
More oxygen means incomplete burn, more co means incomplete burn, more hydrocarbons means fuel in the exhaust. Running rich has destroyed your cat. I think you know the general problem, just need to diagnose why its running rich. The oxy sensor should be correcting it... unless it is sending bad data. Edit: i see you replaced that.
Any news on compression test? Are you burning oil? Is the timing in spec? Ignition coil? Idk...
Map sensor? Those are pretty typical for failing.
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Xposted on another forum, DannoXYZ seems to answer why the O2 can only correct so much bad info from other sensors. (thread here:
Breakin' [California smog test limits] 2: Electric Boogaloo. - Toyota Nation Forum : Toyota Car and Truck Forums )
Got the car up on a lift (friend owns a lift) and found a chunk of substrate blocking the exhaust.
Front face of rear cat with chunks of precat littering it. Has sounded that way for ages.
Blockage.
Front face of rear cat.
Not shown: Melted down precat and chunk of wayward substrate liberated from exhaust.
Think this may have been part of my problem?
I'll check compression and sensors tomorrow, it was 105F today.
NEXT BIT OF DIAGNOSTIC INFO
Okay, did a compression check and a shallow sensor test (I can't get to the backside of the ECU so I'll have to rig something up to test the MAP. I'm an EE major, shouldn't be an issue [famous last words].
TPS:
VC-E2: 3.42k
VTA-E2
WOT: 2.75k
67*: 2.3k
45* 1.7k
23* 1k
0* .5k
IDL-E2: within specs
Coolant temp sensor: 1300 at 35C, 480 at 67C. Will revisit when I have a gasket for it.
IAT: Meter reads it as being in spec. I'll have to check again because I didn't write down the reading.
Compression test. Written as first 3 puffs and then about where I ended the test. First time running a compression test so I may not have cranked long enough, I only cranked ~5-6 times instead of the 7 my hayes said to do.
#1 : 120, 150, 180, 205
#2 : 120, 150, 180, 205
#3 : 120, 150, 180, 205
#4 : 120, 150, 180, 210
Spark plug wires:
#1 : 3.41k
#2 : 3.08k
#3 : 2.44k
#4 : 2.15k
Rear catalyst surface temps at idle:
Front was something like 130C, outlet was 160C. Couldn't get close enough to get a better reading but the exhaust seems hotter now that it used to be so it seems like my cat may be working now that that exhaust blockage isn't making the exhaust cool down before the cat.
I have some boroscope pics on another computer, I'll post them later.
NEXT diagnostic info:
Do you know what the mechanical limit for the ignition advance is? I'm thinking that if my timing belt jumped a tooth (unlikely, but possible) my maximum ignition advance with TE1 shorted to E1 will not be the same as an engine that hasn't jumped time.
Did more data gathering:
MAP voltage from sensor pin to ground:
24.5" HG: 1.48 (initially read at 1.2v but then all my readings seemed to have shifted up .3v)
22.5" HG: 1.65
22" HG: 1.69
21"HG: 1.8v
engine off~ 3.56v.
Idle: needle vibrating at around 24.5" HG.
I drove around with a multi meter watching the oxygen sensor, as it cooled down outside the engine seemed to be on the rich side of .5v more and more.
I need to find somewhere that has enough vac line that I can watch the MAP from the cabin.
I am doing some looking and it looks like I should be idling at 1.2V and not 1.48. Would this be a likely culprit?
EDIT: Okay, double checked the vacuum readings and it seems that I'm still .3v high. I'm guessing that my MAP sensor is a POS.
Readings are taken by putting a sewing pin into the signal pin of the connector and the same for the ground pin on the connector.
I'm suspecting that the MAP may be erratic about readings. It initially read out at 3.4v then suddenly went to 3.56v.
I think I'll go to the scrapyard tomorrow and try to find a working sensor.
EDIT: IF the limit is 17 degrees or thereabout, that is about what I can set my timing to as max. I'll double check it, it may be closer to 20. I remember looking at another thread and it looks like that a jumped tooth will throw off camshaft timing by 7.5 degrees.
Oil burn rate looks to be low.