ECU GETTING VERY HOT - CORRECT OR NOT

B18FT - LOVER · Post by **B18FT - LOVER** » Sat Jun 06, 2009 7:03 am

Morning all...

I had my project volvo running yesterday for about 20 minz, every thing ran perfect, reved perfect and idle's perfect too..

I swithched it off and went tp put all the ecu's back into there correct posistion where they are mounted and noticed that the fuel ecu the bigger one of the 2 is really hot, so hot you could barley touch the case of the ecu...

Asked a few people and they all say it's normal and that all ecu's get hot whilst in use ???

Would it be possible for some one to run there car around for 20 mins then grab hold of the ecu (one above drivers feet on rhd car) and tell me if it's warm or not...

Dont want to burn the ecu out, so some real help and advice is needed here please boys...

Rob.......

B18FT - LOVER · Post by **B18FT - LOVER** » Sun Jun 07, 2009 7:47 am

Some one help me please - only a simple check...

pol · Post by **pol** » Sun Jun 07, 2009 8:02 am

Hi, where is this ecu? Are you talking about the black plastic box that would normally live in the centre console? Mine is exposed at the moment if so. If its the other metal one then i;m not sure where that is!

pol

B18FT - LOVER · Post by **B18FT - LOVER** » Sun Jun 07, 2009 8:11 am

Its the other metal one mate..

When you are sat in the drivers seat its above your feet in the rh side kick panel, get your head down by the pedals and look up you will see it screwed to the side of the car..

If ou could just run the car at idle for 15 mins and put you hand on it see if it get's hot... Be proper job if you could do this check so i know whats what

pol · Post by **pol** » Sun Jun 07, 2009 8:28 am

I'll be outside in the next 30 minutes or so, so i'll give it a go for you.

pol

pol · Post by **pol** » Sun Jun 07, 2009 9:15 am

Well mine has been idling up to full temp and the ecu is stone cold.

Pol

B18FT - LOVER · Post by **B18FT - LOVER** » Sun Jun 07, 2009 2:07 pm

Hmm, thats strange mine gets soo hot u cant hold it the front face is boiling yet it seams to run fine with no faults. Dunno wat too do ! Thanks alot foe trying any how i mite try dissconnect the rev counter as that was the last wire i joined up...

Any other ideas welcome

pol · Post by **pol** » Sun Jun 07, 2009 3:27 pm

I'm afraid my knowledge of ecu's is pretty slim but getting that hot doesn't sound good to me!

I'll let you know if it gets hot after an actual drive but I wouldn't have thought it'd make that much difference?

pol

ted clutch · Post by **ted clutch** » Sun Jun 07, 2009 8:58 pm

i would definately try disconecting your tach wire.experience has told me to check the last thing i did before the problem started,they are usually related if things have been done.also open up the case and check for visible heat damage. capacitors are a common failure with age quality and voltage,if they short they will connect to ground with low resistance causing a lot of heat.look around the bottom of them for crap and debris.this happened in my info board and smelled of burning.i was astonished to find they were only rated at 15v . not much margin for error especially when you consider voltage spikes.i replaced them with 25v rated and works good.im a mild electronics hobbyist.

B18FT - LOVER · Post by **B18FT - LOVER** » Sun Jun 07, 2009 9:01 pm

To be honest i never noticed it before but then i never had it removed whislt it was running... Tacho was the last wire i joined up but it goes direct to the rev counter so cant see theres a issue there ?

Derek · Post by **Derek** » Mon Jun 08, 2009 5:36 pm

you said its the first time you have ran it with the ecu removed. maybe the casing is earthed when it is bolted to the body work? just an idea.

B18FT - LOVER · Post by **B18FT - LOVER** » Mon Jun 08, 2009 10:37 pm

Perhaps pol will be so kind as to remove his ecu from the retaining clips and see if it gets hot with out being bolted to the car...

Only other thing is my loom ran orange colour ecu's and i swapped them for later style red ones, wonder if there is a difference... and that's why its getting hot

dave r5 · Post by **dave r5** » Tue Jun 09, 2009 10:21 am

mine get warm too not excesivly hot but hot anuf to notice, mine are bolted and earthed

B18FT - LOVER · Post by **B18FT - LOVER** » Thu Jun 11, 2009 6:33 am

So when ur car been running for say half hour, been reving it and all that, then if you touch the big ecu can u hold it for long, mine gets so hot you cant really hold the case for long..

Was wondering if it is becasue my car runs orange ecus, but i swapped them for the later type red (maroon) colour ecu's.....

glasgowjim · Post by **glasgowjim** » Thu Jun 11, 2009 6:51 am

Rob the overheating of ecus has to my knowledge never been reported and certainly not inrelation to overheating only ruff running.

B18FT - LOVER · Post by **B18FT - LOVER** » Thu Jun 18, 2009 6:15 am

**UPDATE**

I dissconnected the rev counter fed wire and it still got hot...

I re-fitted my old orange ecu's and they also got hot with in 20 minz of running..

So i refitted the maroon (red) ones but this time i bolted them to the body throught the mounting holes and it seams to have nearly cured the problem they just get very slighty warm...

I was thinking it could be the fuel pump feed i took off the loom to the fuel pump, but then that has a relay built into the circuit so the relay should take the load so the ecu doesnt have to...

Stumpped... lol

bbf · Post by **bbf** » Thu Jun 18, 2009 7:49 am

does your idle valve work? i.e. if it is stuck, ecu tries to correct the idle setting all the time, warming itself up. another heat source are the transistors for injector opening. i doubt the problem would be there, unless you have fitted wrong injectors.

B18FT - LOVER · Post by **B18FT - LOVER** » Thu Jun 18, 2009 6:21 pm

bbf wrote:does your idle valve work? i.e. if it is stuck, ecu tries to correct the idle setting all the time, warming itself up. another heat source are the transistors for injector opening. i doubt the problem would be there, unless you have fitted wrong injectors.

Yes mate it idles a treat never stalls... And the injectors are the ones that came with the engine from new, never been replaced...

Every one else claims there ecu's are stone cold, now mine is bolted to the body its luke warm where as before you couldn't touch it... Running out of ideas...