26
votes
Accepted
How does the car's ECU detect a misfire?
This comes directly from this web site:
http://www.obdii.com/articles/Onboard_Diagnostics_Demystified.html
What it says, is that early OBD-II systems could not detect misfires, but since then a few ...
- 9,326
16
votes
Accepted
Sharp cornering is turning my Service light on for a second
It could be that you are cornering so hard that you're pushing the oil in the sump to one side, away from the pickup pipe. This temporarily means you're oil pump is sucking up air and you are ...
- 23.5k
15
votes
LTFT and STFT values are off and don't make sense
I think I have an answer
But bear in mind that this is my assessment with the limited information at my disposal.
I'll walk through my reasoning here. If someone finds a flaw in my logic then I'm ...
- 39.1k
12
votes
How does the car's ECU detect a misfire?
Engine misfire can also be detected by looking at the coil voltage just after the plug is fired. When the fuel/air mixture actually ignites there are lots of ions and radicals floating around. This ...
- 2,083
8
votes
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ECM vs. PCM vs. ECU?
From my personal experience with this particular subject you have many variables that come into play.
My shop specializes in computer systems on some of the newer vehicles (Mostly Japanese), but we do ...
- 3,343
8
votes
Accepted
Is there a way to use a PC as an ECU for testing CANBUS Sniffer devices?
Sadly you are not going to be able to do what you want simply connecting CAN-H and CAN-L to a serial port. Here is a pointer to the physical interface layer for CANBUS.
CANBUS Physical layer ISO ...
- 9,326
8
votes
Accepted
Can a car operate without a catalytic converter?
Most vehicles which are OBD-II compliant (newer vehicles are a little different) use just the O2 sensors located before the cat to adjust the air/fuel ratios. The in-cat or after-cat O2 sensors are ...
- 153k
7
votes
Accepted
How do I pull error codes from my Kawasaki motorcycle?
How do I pull error codes from my Kawasaki motorcycle?
Here are the instructions to pull error codes from your 2001 or later Kawasaki street motorcycle.
Step 1
Pull off your seat and near the battery ...
- 33k
7
votes
Accepted
Will disconnecting battery lead to remaps being reset?
No, it shouldn't. During a remap, there are tables which the ECU reads to know what/when/how fueling and other events should occur. This is in non-volatile memory. There are other parts of the ECU ...
- 153k
6
votes
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What is the cost/benefit for reprogramming an ECU for a non-enthusiast?
You can't necessarily re-program an ECU that is stock from factory. There are a few aftermarket ECUs that you can buy though.
On that particular vehicle it won't make too much difference. You can ...
- 3,343
6
votes
Accepted
Keep Alive Memory (KAM)
KAM remains powered when the ignition is off due to the fact it receives power from the battery. It is the same as RAM in the sense that it is a volatile form of memory and will lose its data if power ...
- 316
6
votes
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Could a modern car be modded enough to work without ECUs?
Yes, it is possible
Albeit with some trade-offs.
A modern-day road car is an amalgamation of several sub-systems, and electronics usually have an important role to play in them. The nice thing is ...
- 39.1k
6
votes
Determining active gear from OBD2 for Ford Fiesta
You can determine the gear by comparing the engine RPM and the vehicle speed. Most cars that have a shift light though do not actually know what gear they are in, they use engine RPM, engine load and ...
- 16k
6
votes
Accepted
How is barometric pressure related to emissions testing?
The federal test procedures for vehicle emission certification(FTP) is run on a dynamometer. It starts with the vehicle at an exact temperature and barometric pressure and humidity. It is run in a lab ...
- 11.6k
6
votes
How does the car's ECU detect a misfire?
Variations in current drawn by the "high-tension" (HT) coils can also identify misfires to the engine ECU.
This is one reference that I found to back this up
AutoTap: Analyzing Ignition Misfires (...
- 24.9k
6
votes
Accepted
Bike currently running rich due to aftermarket exhaust, will adding an aftermarket air filter without any ecu work fix it
If anything, your bike should be running lean
Thoughts
You put an aftermarket non-restrictive exhaust on your MV, that increases the flow of gasses which requires more fuel to compensate for the ...
- 33k
6
votes
Accepted
Tapping into the on-board computer
You cannot easily "tap" into any ECU/PCM. Depending on what year your vehicle is, it could be a simple set of analog gauges which you could tap into the signal line, but you'll need to do some ...
- 761
5
votes
A most intriguing cold-start misfire mystery
Root Cause: probably a couple of things
Sadly, I feel that there isn't enough data here to uncover the smoking gun, but I have realized some things upon reflection that can indicate what is probably ...
- 39.1k
5
votes
ECU replacing procedures
I have replaced he old ECU ( SIRIUS 32N ) with another one ( SIRIUS 32 ) which is used before, the car has not started the first two tries but have started normally the third time, the immobilizer ...
- 363
5
votes
Accepted
How is Dodge Spark Advance Controlled by the PCM if there is a Distributor?
While the vehicles are equipped with a distributor the innards of that distributor have changed quite a bit. The distributor no longer contains flyweights or any mechanical timing controls, instead it ...
- 16k
5
votes
Accepted
Need urgent help - car cut out and instruments frozen and will not start
I found the problem. I purchased breakdown cover and called the AA out on Sunday afternoon. They were very fast and the guy was incredibly helpful. He said that a fuse had blown, and checked the fuses....
- 6,555
5
votes
Tapping into the on-board computer
If your car has a OBD2/ODBII port then it is achievable. I'd imaging the simplest way would be to use a ELM327 type cable or even a bluetooth adapter to provide the interface between the pi and the ...
- 341
5
votes
Cause of limp mode in Vauxhall Astra which ECU code is relevant?
Essentially you have put 10 milliliters of oil in your gastank
I have done this before with more oil than that on accident into my truck.
My solution was to fill the tank to the top and dilute it as ...
- 33k
5
votes
Shouldn't my post-cat O2 sensors (lambda probes) be reporting varying numbers?
Here's how to decipher INPA
lambdaintegrator
Short-term fuel trim. Both banks have a short-term correction of 28%.
This should settle down to 0% fairly quickly, so the fact that it stays red ...
- 39.1k
5
votes
Accepted
Cannot Access ABS-control-unit with ODB2-adapter
To my knowledge, access to the ABS module will not be possible through a generic OBDII adapter.
The most commonly available option for VW's of this era is a VAG-COM cable with RossTech software on a ...
- 39.1k
5
votes
Can I replace my ignition coil with a ECU?
There are a number of ways to go solid-state ignition and there are a few open source projects that allow you to build your own ECU and loom and utilize an ignition system from something else.
One ...
- 23.5k
5
votes
Accepted
Why buy an ECU with the highest version alphabet?
As a general rule, you should buy the part number specified for your car. Later (higher version alphabet) may not be compatible. If it is compatible it is unlikely you will notice a difference since ...
- 306
5
votes
Can't detect Proton GEN2 ECU
When a scantool is unable to connect to a vehicles ECU:
Make sure you have power to the OBDII connector under the dash. (Since the adapter lights up, it means you have power)
Try connecting to a ...
- 634
5
votes
Accepted
Considerations for a successful VW 2004 Jetta 2.0L engine swap in place of a 1.6L engine
It would help if we had the engine codes and the two ecu types (EDC15/16, Med7/9 ect) and the fault codes that are present but here goes:
It sounds like the engine was swapped complete with the ...
- 2,781
5
votes
When doing an engine swap , do you have to have a matching ecu
GM engine management software (from your old Impala ECM) is not going to be able to run a Honda engine. If you managed to flash the Honda software onto your GM ECM, you'd likely brick the device.
A ...
- 3,149
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