Car Wont Start Computer not waking up.

Starting in the spring my 07 Swift started not starting on occasion. It always turns over strong, just no fire. After doing some research it looks like it is the ECU not waking up. The solution being to replace it. It always starts eventually, and its not a huge deal right now being summer. But come winter I do not want to be stuck for 15 minutes waiting for my computer to decide to cooperate. It gets bloody cold here in Ottawa. I have looked online, and there are used ECU's available but I don't want to end up going threw the hassle and expense of changing it and end up in the same situation. And I defiantly don't want to pay $700 for a new one from the dealership. I guess my real question is how much is involved in changing to a stand alone system. I have seen that there are a fair number of people on here and deawootech that have done it. Rewiring is not an issue for me. I am more concerned about the compatibility of parts. What will work, what wont, what would I need?

Any help is greatly appreciated.

A standalone system like a megasquirt would run you probably close to 700$ in parts and a lot of time, sweat and more than likely tears too. Other systems will run in the thousands.

Check ebay for 07-08 ecu... I'm they're pretty cheap. I would also make sure you don't have a corroded wire going to the ecu... happened to me on an old 1990 Olds.

Plus standalone does not necessarily include a warm up circuit, nor emissions controls you may/may not need, etc..

A new ecu might be needed, but did you check all the ECU fuses? maybe the memory or something is blown?

it could also be the ignition switch.

If I buy a used unit from ebay is it just plug and play or will I have to take it in so that it can be flashed or whatever? Is there a difference between the standard and auto ECU? When I called for a quote they asked me which it was.

there are enough listed you should get a match to yours. also look on your ecu for the numbers, and match that.

get the right tranny, get about the same year (06-08) and it can be out of a swift, g3, aveo, or wave..

It still starts and runs fine. I just have intermittent issues where it wont fire. I have to wait 5-10 minutes then try again.

Alright thanks alot. I will take a look at that tommorow.

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Originally Posted by smiller

It still starts and runs fine. I just have intermittent issues where it wont fire. I have to wait 5-10 minutes then try again.

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that is "potentially" classic ignition switch issue.

how did you diagnose the ecu? you are sure it is not sparking versus no fuel?

does it start ok first thing in the morning versus multiple stops throughout the day?

did you check the fuel pump relay?

I worked for an Auto Electrician in the '90s, many ignition issues were caused by too much weight (too many keys) on the key. Since then I only have the starter key and a tag on the key ring.

I do not recommend going standalone and i speak from personnal experience!

Swapping the ecu is as simple as unplugging the current one which is located under the hood just to the right of the battery (if you dont know already) and pluggin in the new one.

Theres a chance you will get a check engine light with the new ecu, if that happens a simple reflash at your local dealer for like 60-70 bux should do the trick.

It could be something else than the ecu tho, when its cranking do you smell fuel? Is there spark? Injectors not firing? Imo if you have spark or the injectors are firing when cranking than your ecu is working, it's a different problem. It could be a bunch of things here, sometimes much simpler than you think.

The Reason I think it is a bad ECU is that when it does it, the check engine light does not come on before it fires. I don't smell any gas like there is no spark. It just cranks and cranks and cranks. From what I have read on other GM forums that is just the ECU not waking up. I don't know if that sounds right to you.

the cel wont come on in start mode? or do you mean when you turn the key to the on position there is no engine light?

if you dont smell gas after that much cranking, then your probably not getting gas.

spark and gas are two of the three "opposites" (third being compression) in order for the car to run.
so not smelling gas most likely means no gas, not lack of spark. Lack of spark would mean you smell gas.

When I am turning the key and the car is turning over there is no check engine light

does the check engine light come on in the on position (before you start the car?)


the check engine light does not illuminate in start.