limp home mode ecu

[veegeeta]

ok guys have looked around and come up with nothing on this as my car is now manual have a ecu that is in limp mode like you descibe in threads doesnt rev past 3000 rpm and does hurt your back when it does it i tried everything from changing all sensors air flow meter every thing that basicly had a sensor attached to it nothing worked! the last thing i did was get a second hand ecu pluged in and problem was solved car is a rocket again now im trying to reflash and rewrite the limp ecu with no luck in comming out of limp mode so my conclusion is ecu is screwed any ideas in fixing this ecu so can have for a spare

[Patryn999]

My first suggestion would be to pop case open, and look for any dry joints on the plug terminals -> PCB. (Google dry joint - looks like solders cracked around where leg goes through). TBH this will be most likely.

Second look for any electrolytic caps that have bulges (For pics look at wikipedia article Capacitor Plague). And you can try replacing these, as it'll be a dollar or two so cheap gamble.

Otherwise it'll take someone with fairly heavy electrical knowledge as my next guess would be a blown driver or input buffer. Which unless you have a friend who will do it for free will cost you as much as a second hand ECU is worth, and I cannot guarantee that it'll even be fixable.

[veegeeta]

any ideas on what caused it?

[Patryn999]

Dry joint - Vibration, bending/overuse of connectors, poor solder join from factory. (movement).
Capacitor - Bad cap from factory, heat (life expectancy of elec caps halves every +10 degrees).
Input/Output - Output shorted to ground at some stage, input walloped with high voltage somehow. ESD damage. Plethora of things.

If it is a dry joint, add a bit of solder when reheating as you need the flux in the added solder to clean out the oxidation in facets of broken join. Most solders a flux-cored (aka have flux inside of solder).

[veegeeta]

thanks for your imput have sent ecu away to see whats going on with it ill let you know how it goes

[veegeeta]

ok verdict came back on my ecu seems to have droped a injector driver. so ecu is stuffed. reads and writes fine even idels but as soon as you put load on it ,it all goes to **** like no fuel, have dumped this one. got another second hand and now have had a tune and re-flash and car is perfect no problems now i can enjoy the finener things in life again.

[Nick Mann]

Congrats on working it out. Are you running standard injectors?

[veegeeta]

yes at moment i am running standard injectors.
Congrats on working it out. Are you running standard injectors?