starting problem plus missfire and overfuelling.

[shifty biscuits]

i have a 97 ls400 1uz fitted into a 91 toyota gx81 mark II. ecu is the 34/22/16/28 pin pt no 89661-50350
my mate and i have wired it into the car and got it running. i have been over and triple checked the wiring we have done and according to all the info and diagrams i have managed to get hold of it should be right. the relay set up is as the ls400 diagrams, efi relay turns on from ignition, powers up the cir open relay then that powers up the fuel pump relay.... in the diagrams there is a control wire "fc" from pin 4 of the 16 pin ecu plug, its green with black stripe. this should from what i can gather trigger the circuit open relay by being an ecu switched earth? the wire has no signal and this relay is not operating, therefore the fuel pump relay is not operating either. could the ecu be damaged? im sure this wire used to earth out on ign, the relays all worked a few weeks ago although one of them clicked loads when the car was running...

on to the starting prob/missfire.
we have been running the fuel pump with a switch to get it going. the car has never been able to idle from cold start, it takes a while before it will hold idle on its own. in the ls400 it was fine. this problem has now got worse, starting the car is a bitch and it pops and coughs through the intake then when you get it running with the throttle, when running its missing loads and wont rev properly, tending to cut out when you poke at the throttle. after a while it used to sort its self out then it would rev fine and idle smoothly, then it would start fine when warm. today i tried it an the missfire was more persistant and the car was overfuelling loads. so much so i had to give up and shut it off as the fumes filled the unit. its very cold at the moment which i thought might be making it worse. i tested the ecu temp sensor and i think its working ok. problem was the same with this unplugged too.

i have run the car up to temperature twice (a couple of weeks ago) both times it was running fine after the initial cold starting complaints, it would rev and idle perfectly, after 10 or 15 mins the revs would start to drop off and if you held the throttle it was ok but if you left it it would cut off.
could these the fact i dont have any lambda sensors wired up or installed yet be causing me problems? i will be getting some bosses so i can weld them on to my exhausts soon but at the mo they are off.

i have a warlbro 255 lph pump installed but im using the stock fpr. could this cause overfuelling?

im not sure what to try next with these so if anyone can suggest what i could do or try i would be much obliged.
cheers.

 

[sideshow]

efi relay is wired wrong
gets turned on by ecu
fuel pump wire doesnt work a relay but a fuel pump ecu
have u got power to idle motor
check for skark on every cylinder and also pulse to all injectors
make sure all injectiors work as they get stuck over time when not working
very common
otherwise might have to learn voltages and start diagnosing sensors

was loom complete or cut at firewall and u joined it

 

[gloverman]

Hey Jim the UCF20 series ecu dont run the fuel pump ECU but a fuel pump and circuit opening relay. You are correct that the EFI relay sounds like it is wired up wrong.

Also I recommend wiring up a diagnostic socket and plug in a scanner do you can get some live data.

Cheers

 

[sideshow]

Ok cool kelvin
I know the looms better once I see them
I don't normally relate them to the models
My home made diagrams tell me what I need to know hehe
Just thought wire is different since he can't get fuel pump to work
But he must just have wired it wrong

 

[gloverman]

The Toyota trick of not priming can catch people out too. Cheers

 

[sideshow]

yes that's y I like the tacho relays

 

[shifty biscuits]

whats a tacho relay?

ok i f***d up a bit in my first post, like you said the efi relay is triggered by the b/o wire from the ecu then it kind of daisy chains power to the other relays when they are closed. the signal wire that should close the circuit open relay looks like it should be an ecu controlled earth but i get no ground or live from it with ignition on.

sorry i got a bit muddled as i dont have the car here with me haha.
basically its wired up as it appears in the diagrams.

i had a complete donor car so i removed the whole loom in case i needed bits of it.

i do have power to the idle motor....
um... i ordered a new ecu temp sensor so im gonna try that first when it shows up.
is there a simple test for injectors?
i'll check spark tomorrow, gonna get new plugs too as they look a bit coked...

so the lack of o2 sensors not looking like a cause of any of the symptoms then?

cheers for the replys so far.

 

[Bushwhacker]

The missing O2 sensors is the most likely cause of all the problems, especially the fuelling. The ECU can't figure out what the hell is going on!

 

[shifty biscuits]

yeah i hope its that. i forgot to get some bosses today but i will be fitting the o2's soon. when i wire them up i was planning to use the wires for the sub o2 sensors then link the signal wires into the primary o2 sensor pins in the ecu as i read it can fool the ecu to thinking it has all 4 sensors to remove the codes and possible base map? it would think the the cats are stuffed which is supposedly not as much of a problem. is that right?

 

[Bushwhacker]

You only need the main O2 sensors, the ECU won't notice the sub sensors are missing. Just snip off the sub sensor wires and tape/seal them up.


I've wired nine 1UZs into Hiluxes this way without problems.

 

[shifty biscuits]

ok cool will do. thanks.

 

[sideshow]

I even doubt the missing front o2s will cause that much headaches
but I could be wrong
also y bloody change the temp sensor
y not learn how to test voltages
no wonder no one on here learns anything
everyone these days even mechanical workshops
are all parts replacement guys
they know fk all about diagnosing and testing
and all they know what to do is unbolt and replace parts

anyway temp sensor wire on ecu is a
called "thw" find it
test voltage about 4 volts cold and slowly down to 2 or 1.5 volts
when hot or running
get a long flat blade screw driver use it as stethoscope to
listen if injectors are pulsing when running
if u have miss remove spark lead off one at a time and see if engine
doesn't change note
if it drops revs means cylinder is working
if it doesn't drop cylinder is dead so see if it's injector
or spark or compression in that cylinder
also look at spark plugs see if one is black or all are black
so if rich all over or just one cylinder

 

[shifty biscuits]

ok the temp sensor was 7 quid so thought why not give it a go. i did attempt to test it but getting it to -20 degrees then 20 degrees then 80 degrees and checking the ohms was a bit dificult so i couldnt really trust the results. im a welder fabricator not a mechanic or sparky, this whole thing has been about me learning new tricks, electronics and wiring has always been my most hated subject so its taking a while to get to grips with it so bare with me im trying haha!
i will check the injectors and spark next time using these methods. cheers for the help so far.

 

[shifty biscuits]

update, fitted primary o2 sensors, no effect, not had time to check spark or injectors yet. checked ecu flash codes, got all 4 o2 sensor codes, air mass sensor code and egr code. still starting/running like a pig, not warmed it up as it stank out the unit...

 

[ihiryu]

tried unplugging the MAF and seeing how she idles?

 

[shifty biscuits]

right just done new plugs, wired up a missing power for afm, egr etc that had a broken join, changed the iacv. seems to be sorted but idle is high now. think the replacement iacv might be stuck open...

 

[redrocco]

If you have the iacv that is held togeather with screws carefully take it apart and give it a good cleaning. I had to do that to mine a few years back. I had finished my swap and had been driveing the car for a year and then one day it just started idleing very high then low then would stall. Cleened the iacv and all was well.