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And i thought maybe some of the OG's around here (is that what we are now? ) could help me brainstorm. I have been chasing CEL's for the past 3 months. It started with lean codes. I would replace one thing and clear it and then A week later the CEL comes back with a different code.
After Its all said and done, i have replaced (with OE parts):
-Denso IRIDIUM plugs (gapped correctly)
-6 coils
-front bank air fuel sensor
-Rear bank air/fuel sensor
-4 vacuum lines on top of engine
-MAF (2x, got a bad one out of the box first go- second one fixed lean codes)
-valve cover gasket (weeping)
-TB screen
-Alternator (went bad in july, fixed that then)
-Air filter
-Gas cap.
there might be more but its been awhile. Here is a video of what the car is doing:
Things Sewell checked but did not replace:
-front bank cat (tested good)
-rear bank cat (ditto)
-charcoal canister and evap system (smoke test was good)
It really is a shame because it truly is a pleasure to drive otherwise.
When you got these codes, did you just replace the part indicated, or actually consult the Service Manual for that car and go through each specific test or step the Manual indicated for that specific code? Pat Goss, Motorweek's lead Technician (who owns his own repair shop) gives a good explanation on how to deal with codes.
You are missing the codes. You didn't mention what the codes were.
Also, was the video supposed to illustrate something? It just appears to be someone revving a car with the CEL illuminated.
codes were:
This last time i got a Random cyl misfire detected code: p0300
the video is me driving the car at 70ish mph. The car drives normal for a bit, then, as i begin climbing a rather steep grade, the car downshifts 2 gears, and the RPMs become erratic.
Originally Posted by mmarshall
When you got these codes, did you just replace the part indicated, or actually consult the Service Manual for that car and go through each specific test or step the Manual indicated for that specific code? Pat Goss, Motorweek's lead Technician (who owns his own repair shop) gives a good explanation on how to deal with codes.
I did what i could with my limited access to tools and computers at the time. I was staying with family while waiting for our new house to be finished. When i couldnt pin it down i took it to sewell. They couldnt figure it out either. After a month in the shop and nearly a grand in diagnosing time paid for, they called me and told me they couldnt figure it out and to come pick it up.
OK, now that I understand the video, it all makes more sense and I have some thoughts.
If this were an older GM/Volvo and many other makes, you'd suspect immediately the (transmission) vacuum modulator and/or hoses. It senses engine load by tapping off the manifold and then passes that on to command shifts. A leak there would create the air ratio issues and explain a single-point failure for all this. But these don't work that way, so we think how it does that. But as a check point, t's worth making sure all manifold take-offs are sealed/connected and the hoses run down fully for leaks. I see the egr system was smoke tested, but checking the intake that way would be good to do (and cheap to do at home).
Parallel to the transmission vacuum modulator, on these cars that's handled by the MAF sensor. It could also be a single-point failure for all this, with incorrect air ratio values being passed, and also air flow (translated later into load data by the ECM). I know you now have a working one, but it might not mean it's 100%. A fault could lie in the harness or sensor circuit and I can't recall right now how this one is built/designed as I have not had mine apart in a while. Perhaps there's a ground in that harness that is at fault, or the harness itself fails intermittently, like when hot. This has to be checked fully. But if all that is solid, it still leaves another wrt to the MAF sensor line of diagnosis...
Alternator. From what I can piece together, this is all post-alternator (last 3 months vs. that in July)? How did the alternator fail? A bad bearing, brushes wore out, or diode shorted? If the latter, did it go for a while with the battery draining down overnight and occasional flickering lights? A bad diode could have passed AC voltage long enough to damage an electrical component elsewhere (hopefully not the ecm).
OK, now that I understand the video, it all makes more sense and I have some thoughts.
If this were an older GM/Volvo and many other makes, you'd suspect immediately the (transmission) vacuum modulator and/or hoses. It senses engine load by tapping off the manifold and then passes that on to command shifts. A leak there would create the air ratio issues and explain a single-point failure for all this. But these don't work that way, so we think how it does that. But as a check point, t's worth making sure all manifold take-offs are sealed/connected and the hoses run down fully for leaks. I see the egr system was smoke tested, but checking the intake that way would be good to do (and cheap to do at home).
Parallel to the transmission vacuum modulator, on these cars that's handled by the MAF sensor. It could also be a single-point failure for all this, with incorrect air ratio values being passed, and also air flow (translated later into load data by the ECM). I know you now have a working one, but it might not mean it's 100%. A fault could lie in the harness or sensor circuit and I can't recall right now how this one is built/designed as I have not had mine apart in a while. Perhaps there's a ground in that harness that is at fault, or the harness itself fails intermittently, like when hot. This has to be checked fully. But if all that is solid, it still leaves another wrt to the MAF sensor line of diagnosis...
Alternator. From what I can piece together, this is all post-alternator (last 3 months vs. that in July)? How did the alternator fail? A bad bearing, brushes wore out, or diode shorted? If the latter, did it go for a while with the battery draining down overnight and occasional flickering lights? A bad diode could have passed AC voltage long enough to damage an electrical component elsewhere (hopefully not the ecm).
The alternator:
it was running fine, no issues at all. One day I went to go get pizza for dinner. I drove there with my headlights on as i always do. When i got there I turned them off and then shut off the car (like I always do). When I came out 10 mins later it would not start. Wouldnt even crank. I called my wife who came and gave me a jump. I got home, left it running and tested with my fluke multimeter. It was charging 12.6 with headlights off. Turn the headlights on and the charge instantly dropped to 11.7 and continued to fall slowly.
As a result i replaced the alternator. Now charging at a pleasant 13.2v.
Also, sewell smoke tested the intake, vacuum and egr. Found a leak somewhere and replaced that hose. The MAF was also faulty and was replaced, and that was the 2nd one. First one was a no-name brand (walker or something) and was not good when i put it on. The new one is a Toyota part.
i replaced the alternator myself. I also replaced the air/fuel sensors (2x, once with off brand, and once with denso) myself, the front VCG and the coils and plugs, all at the same time. At that time I did the MAF as well, as it was 160,000 miles old, and parts were cheap. But the one i got was bad. Then, when i got more lean codes, i changed the air/fuel sensors from off brand to denso.
it was running fine, no issues at all. One day I went to go get pizza for dinner. I drove there with my headlights on as i always do. When i got there I turned them off and then shut off the car (like I always do). When I came out 10 mins later it would not start. Wouldnt even crank. I called my wife who came and gave me a jump. I got home, left it running and tested with my fluke multimeter. It was charging 12.6 with headlights off. Turn the headlights on and the charge instantly dropped to 11.7 and continued to fall slowly.
As a result i replaced the alternator. Now charging at a pleasant 13.2v.
Ok, the alternator is indeed the first place to start. You need to find out why it is not making adequate voltage. 13.2 is “sick,” not happy. Is that in fact the output voltage at idle and what is the voltage at higher rpms?
Ok, the alternator is indeed the first place to start. You need to find out why it is not making adequate voltage. 13.2 is “sick,” not happy. Is that in fact the output voltage at idle and what is the voltage at higher rpms?
how is 13.2 sick? Its adequate. Under revs it makes 14.4 or so. 13.2 with headlights on at idle should be just fine?
Originally Posted by speedkar9
A system that's too lean still indicates a vacuum leak to me.
At higher RPM's it could cause a bigger issue since airflow is higher.
Have you replaced the throttle body and intake plenum gaskets when changing the spark plugs?
I did not replace the intake plenum gaskets bc they werent bad. They looked almost new, still plenty of flex.
how is 13.2 sick? Its adequate. Under revs it makes 14.4 or so. 13.2 with headlights on at idle should be just fine?.
No, that means the car is drawing from the battery at idle most likely. That is not a healthy alternator. A healthy battery new is 12.8 and with internal resistance, takes over 2.2/cell or so to even begin to charge. 13.2 is break-even and way out of norm for a new alternator.
Since you have an airflow or electrical sensor/air metering issue, and it all started after installing a bad alternator, fix the alternator first. It may not be related, but you need a baseline of known good parameters to work from.
The foreign junk alternators in auto parts stores these days run a huge failure rate. If you can, take it to a local auto electric shop for a correct rebuild or at least diagnostic.
No, that means the car is drawing from the battery at idle most likely. That is not a healthy alternator. A healthy battery new is 12.8 and with internal resistance, takes over 2.2/cell or so to even begin to charge. 13.2 is break-even and way out of norm for a new alternator.
Since you have an airflow or electrical sensor/air metering issue, and it all started after installing a bad alternator, fix the alternator first. It may not be related, but you need a baseline of known good parameters to work from.
The foreign junk alternators in auto parts stores these days run a huge failure rate. If you can, take it to a local auto electric shop for a correct rebuild or at least diagnostic.
I put a Toyota (denso) alternator in it. I will double check the voltage reading tomorrow.
took the ES to JP Euro (formerly JP Importz) in Dallas. Jason has been my go-to guy for all things automotive that seem to be not figure-outable for 15 years.
He called me this morning to tell me some good news and some not good news.
good news: the problem with the car originally started as a MAF sensor. Sewell couldnt figure it out because they didnt test the cars fuel trims under load. They were hooking it to the computer, putting it in neutral and revving the engine. Jason put it on his dyno, and ran it with the scan-tool hooked up and it was barely getting any fuel above 4500 rpm. Then, at 5500, it was dumping tons of fuel into the system. This was causing the cats to deteriorate.
there's the bad news. As soon as he replaced the MAF with a denso part, it through codes for bank 1 and bank 2 cats.
11-01-17, 12:09 AM
Having some trouble with my 02 ES
) could help me brainstorm. I have been chasing CEL's for the past 3 months. It started with lean codes. I would replace one thing and clear it and then A week later the CEL comes back with a different code.
