Is it possible to bypass the computer box on a car?

Mars

Mars

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I am having such trouble with my Mazda. :(

I have finally gotten someone who knows what they are doing with the engine and he sorted it out, but he told me it was over fueling (whatever that means) an I should take it to an Auto electrician.
So now they tell me that the computer box has blown and had been bypassed sometime in the past. I thought that if the computer did not work the car wouldn't work either? :confused:



Public service notice: STAY AWAY FROM AUTOMATE!
 
What computer box?
Sounds like this guy is full of it, but i am not all that sharp with these things
 
yes you can bypass the computer but bear in mind, depending on which car it is, you may need to replace a lot of sensors and control valves with manual devices. For one, you'll need to a find a new way to regulate fuel & air into the fuel injection - so you'll basically go back to how carburetors worked. Bottom line is, it's simply not worth it, unless you're swapping the engine out with something totally different, which already has an ECU or doesn't need one, generally when building a dragster / hotrod.

If "the computer box was bypassed sometime in the past", then it could have been one or two minor functions that was faulty and bypassed.

Best bet is to goto some scrapyards and see if you can pickup one 2nd hand
 
I'll phone around. Apparently the car is running perfectly as is tho.

I am damn sue that nothing major had been done in regards to the computer box. :mad:
 
Bypassing the ECU entirely would typically require an after market ECU to be installed to continue to manage the engine (ignition timing and fuel metering at the minimum) so I highly doubt it has been bypassed.

It is however possible that some sensors have been bypassed which could cause problems.
For example it is usually possible to bypass the O2 sensor in the exhaust. Most ECU's will automatically go into "limp mode" and will run with a very rich mixture instead of just stranding you on the side of the road.
 
Paul_S said:
Bypassing the ECU entirely would typically require an after market ECU to be installed to continue to manage the engine (ignition timing and fuel metering at the minimum) so I highly doubt it has been bypassed.

It is however possible that some sensors have been bypassed which could cause problems.
For example it is usually possible to bypass the O2 sensor in the exhaust. Most ECU's will automatically go into "limp mode" and will run with a very rich mixture instead of just stranding you on the side of the road.
Click to expand...

Maybe its that.. I hope.
 
I am having a similar problem with my mercedes...it just switches of while driving. mechanics cant find the fault. could it be the ECU was swapped?
 
Camerong said:
I am having a similar problem with my mercedes...it just switches of while driving. mechanics cant find the fault. could it be the ECU was swapped?
Click to expand...
Is it an A Class? We have seen PLENTY of issues with the A Class that all end up being battery related. We have seen engine management faults, braking faults, limp mode, random errors and more.

It comes out with a 646 size battery, but its specced much higher than your normal 646 so you need to replace it with a 652. It actually needs an AGM battery but we usually put a 652 EFB in there because the AGM is so much more expensive and it seems to be ok but we always recommend the AGM. Plenty of people replace the battery with a normal 646 and it starts to give all these random errors within a year or so.
 
the Role of an ECU can be huge, "bypassing" or have it sorta work doesnt sound right. Its the brain of a car. Unless its an older car where it plays limited roles. Take what the mechanic says with a pinch of salt and get a second opinion.
 
If you've ever hooked up an OBD II device to your car and looked at all the sensors and what not that are being monitored, you'd understand why a correct ECU and Management is so important. I was quite shocked to see how many sensors are at work when I first drove with an OBD II connected. Surely if someone hooks one of these up to your car they would be able to tell what is or isn't working. If your car is overfueling it's very possibly because sensors aren't doing their job and telling the engine what mixture etc to use?
***Just thinking out loud here
 
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