Help us help you. By posting the year, make, model and engine near the beginning of your help request, followed by the symptoms (no start, high idle, misfire etc.) Along with any prevalent Diagnostic Trouble Codes, aka DTCs, other forum members will be able to help you get to a solution more quickly and easily!
Ohm tests are not reliable and to assure whether or not bidirectional led test is reliable, you must know injector circuit (some have a weak bias voltage signal which can confuse you).
I suggest you to follow scannerdanner test procedures.
Let's suposse you are suspecting a bad injector driver and assuming also this system has an injector driver for each injector. You can just unplug one injector at a time and watch if exhaust gases improve.
Wyeth wrote: Had a bit of time now, and stuck a bi directional led across the injector leads while disconnected from the injectors with the ignition in position 2 and engine not running, and the led lights up. Not very bright, but it lights up. is that normal?
That may be the drivers leaking a couple milliamps, which isn't that unusual for semiconductors. Since the LED was dim I wouldn't worry about it personally. You could repeat the test with an incandescent test light if you want to be 100% sure.
Wyeth wrote: Found this on the site, describes exactly what Im having
Are you getting noticeable misfires and clouds of white smoke?
Best way to get some direction here is to hook up your scan tool and get O2 sensor, fuel trim and loop status data. That's if the vehicle even has O2 feedback. Beginning to wonder since you're in RSA and there isn't anything in the data you posted earlier related to it....
No misfires at all, and yes, startup I get greyish white smoke and when I rev it up there is also that same smoke, not just as much. When I rev it up, it doesnt come down as quickly as I think it should. Gosh I need to get this sorted
Will see if I can do live data tomorrow and post here.
Wyeth wrote: I just noticed, according to Autodata, at idle, injector time should be 3.5ms
That's about right. It sounds like your PCM is overfuelling the engine for some reason. Before you fire the engine up to get O2 data grab the temperature PIDs KOEO. They should be around ambient with the engine cold.
can def see an increase in injector pulse time as well as air mass air flow. But honestly cannot say I understand what Im looking at. BTW, I cannot view O2 sensor data
Wyeth wrote: can def see an increase in injector pulse time as well as air mass air flow. But honestly cannot say I understand what Im looking at. BTW, I cannot view O2 sensor data
The PCM appears to have substituted a MAF value which is too high. That appears to be what has driven your injector pulse higher. Your ECT is also lower than the data you posted earlier, and IAT is unplugged and defaulted to -60*, which could also have increased the injector pulse.
Regards O2 data have you confirmed the vehicle has O2 sensors?
Let me know if i´m wrong, but i´m afraid we don´t have any direction yet. These tests were not conclussive.
With Maf unplugged, scanner is still reporting something about 1.4 tons of air per hour (did exhaust gases improve?). Target for this test is to check whether or not pcm is reading Maf correctly.
Pulse width about 13ms, but coolant temp now at about 20 celcius. That tells me ECT is changing but not whether is catching or not actual temp.
Air temp now at -60 celcius? ok, IAT is inside Maf, but air temp doesn´t change that bad pulse width (not from 4ms to 10ms). Corrections of pulse width due to air temp are up to 20%
We have to know if scanner is lying. We need a base line. We need to check with another tool
The obd port is behind the knee pad under steering column you might have to remove pad to get to it. Should be next to hood release and may have a cap or flip out cover on it. Also when plugging into the obd 2 port reinstall cap for diagnostic port under hood otherwise you might/ will get a no com as there are jumpers in the cap to allow use of other port. Fyi
Let me know if i´m wrong, but i´m afraid we don´t have any direction yet. These tests were not conclussive.
With Maf unplugged, scanner is still reporting something about 1.4 tons of air per hour (did exhaust gases improve?). Target for this test is to check whether or not pcm is reading Maf correctly.
Pulse width about 13ms, but coolant temp now at about 20 celcius. That tells me ECT is changing but not whether is catching or not actual temp.
Air temp now at -60 celcius? ok, IAT is inside Maf, but air temp doesn´t change that bad pulse width (not from 4ms to 10ms). Corrections of pulse width due to air temp are up to 20%
We have to know if scanner is lying. We need a base line. We need to check with another tool
You're not wrong. Only direction we have at this point is ECT might be reading low and holding the vehicle in open loop. That's if you believe the scanner.
Without reliable scan data that also includes O2 feedback PIDs it's gonna be tough to diag..........
For the life of me I cannot figure out where on the scanenr I saw O2 sensor ampere draw. If I recall, the one was pulling something like 43 amps while the other 13 amps. And im positive these where pre cat readings. Im going to spend soem time with the scanner tonight adn let you guys know.
For what its worth, engine coolent temp sensor aint that exspensive, so might as well replace it. I was getting different readings on the scanenr and the dash temp. Scanenr was reporting about 10deg lower than dash reading
