fuel pump constantly priming

[mathew_colville]

Have a look in my profile. Im pretty sure the wiring for fuel pumps is in there. Ie the factory diagrams.

I think the ecu will earth the red/white wire through one of the driver ic. Maybe one of these is damaged inside the ecu.
The drivers are the same as described in my evo1-3 sticky on idle control issues.

If the red/white wire goes to the ecu (I think it does) check its connected and continuous. If so pop the cover on the ecu and look for corrosion under the caps and/or a burnt ic driver.

thanks ill look into it

 

[rvrftw]

I'm guessing this is why they earthed it, rather than fix the issue that stopped the fuel pump from working originally

 

[mathew_colville]

I'm guessing this is why they earthed it, rather than fix the issue that stopped the fuel pump from working originally

yeah i think thats the case

so i found this diagram of a 4g91t (it was something like that) anyway the wires look the same as what mine are


i think im reading it correctly but i want someone to confirm this for me

this is what i got from it:
mpi control relay- white/red wire - mpi control unit (ecu im guessing) so as jack of all said it seems like it might be the ecu?

 

[khubner1]

wht/red goes to pin 8 on an evo/gsr

 

[mathew_colville]

yeah i noticed that but im presuming that the white/red will still be a mpi control relay in the ecu? the blue/black one in this diagram which is in pin 8 is still a mpi control relay

anyway it seems pretty certain that its between the mpi control relay and the ecu so ill see where the red white wire goes into the ecu, pull out ecu and check the ics(?)
see if i can see anything that looks suspect

 

[4piknup]

Thats it mat. Check your ic like in the ones postrd in idle speed issues. The ics are like double relays in a little black box (pretty similar to a mfi relay). They are a 'twin darlington pair'. Pics to follow.

Here is one.

 

[MDK87]

Oh oh, Jacks gonna bust out his electronics knowledge.

 

[mathew_colville]

Sorry guys went a little camera happy, the front looked like it was in good condition but when i turned it over it doesnt look right (even though i got no idea what im looking for)


















The back is looking a bit suspect to me








does anyone know what that stuff is, can i wipe it off or is it something more sinister :wacko:

 

[mathew_colville]

i was just looking at pictures of ecus in google image trying to figure out what is going on, on the back and noticed mine seems to be missing a couple of those black things (ic driver maybe) is this true or is my ecu just a little different?

 

[4piknup]

Its just clear paint. No biggie. You can clean it off with stuff but its just messy to do it. You can just put some more clear gloss over the top.
Board looks ok.

The ic are the 5 the same in the second pic.
If you have a multimeter, just compare the pin combinations on each ic. Set your meter to diode check.

I think evooox put his results in the idle control thread.

Bit you are just looking for one side of one of the ic having different results to the other ics.

 

[4piknup]

Oh oh, Jacks gonna bust out his electronics knowledge.

I hope it fixes itself.

 

[4piknup]

http://www.4gtuner.com/gallery/image/79-pge153jpg/

Thats the pic, I cant read the ecu pin nos or the wire colours. As im on phone.
Does that work?

Can you just borrow and pop another ecu in it for 10min?

 

[mathew_colville]

Sorry, you don't have permission for that!


[#10744.1]
Sorry, but that does not appear to be a valid image. If you arrived at this screen by following a link on this site, please notify a system administrator

 

[mathew_colville]

the closest people to me that i know of (evo-00x and evl20t) are at least 2hrs drive away, dont think there is anyone closer

 

[EVOCPE]

I have a GSR ECU, but its chipped to run EVO mods

Will still start the car just wont run properly, regardless of that we will see if the pump still primes constantly

 

[mathew_colville]

thanks for the offer evl20t, ill see if i can get a multimeter and try that first, otherwise i might have to come and visit

is anyone else able to access this picture or is it just me who cant?

http://www.4gtuner.c...e/79-pge153jpg/

 

[EVOCPE]

Nope, pic wont work

 

[khubner1]

jack has linked page 156 of the manual direct access via page 153 in adobe. by printing the series of pages you can lay them out to get the how diagram rather than just snippets

https://www.dropbox.com/s/ixx2eldfjeqtepv/CC%20Lancer%20Coupe%20%26%20Mirage%20General%20Electrical%2092-96.pdf

 

[khubner1]

from looking at it the white with red goes to pin 8 on the ecu and is earthed by the ecu so either your loom or ecu had an issue between the MFI relay and pin 8 on the ecu and they just earthed to by pass.

if it was me i would do a continuity check between the cut section of r-w and pin 8 and see if you have cont (if you do rejoin the two parts and see if the pump works) if not you have confimed a ecu issue. on pin 8 what kind of ecu are you running? i'll have an evo 1 ecu up for sale soon

 

[MDK87]

The ECU is covered in conformal coating to protect it from corrosion and moisture.
It's starting to peel off but it's no big deal.
You could if you had a lot of time and patience, take to it with some acetone and a toothbrush but you just need to be careful you don't damage anything on the 20+yo board while you're doing it (only do the underside).
Just so you know, the whole board is covered in it... I would probably just concentrate on the areas in the last 4 pics and leave it at that.
If you want to recoat, idk if you can just use clear paint but Jack has obviously tested it out.