1JZ starting issue - starts then stalls - also need TPS calibration specs

[Bananaman]

Morning,

So for the past few weeks my cressida has been having issues, i'm at a loss as to what's causing it exactly, so here goes:

The problem:

-When starting the car, it will fire up perfectly, you put the key back to the ON position, it idles up as per normal cold start, but then when this sequence stops and the revs start to drop, it stalls. You cannot save it with the accelerator.

-Ran the codes, is showing 25 which according to http://www.cygnusx1.net/Supra/TechTi...ror_codes.aspx and http://mkiv.supras.org.nz/articles/engine_2_25.htm is telling me its run lean for 90 seconds. That said, it had this code when i did it 6 months ago - so i don't think it is related
-If you leave the starter motor engaged, it runs perfectly (yes, realise this isn't good for the starter). The problem only occurs after going back to ON.
-If you persist, it may take 5 times or 20, but once it does finally idle it is fine
-My ISCV is working fine, and if it wasn't some accelerator would stop it stalling anyway
-The car now has a big single and emanage blue piggyback. Its been running fine for months with this, and its worth noting that the last time i ran the codes and got that code 25 was PRE turbo and ecu swap.


I'm letting the ECU reset now that i've pulled the codes, but i'm wondering if my fuel pump is stopping running for some reason, i'll check that shortly.

Unrelated - changed my TPS yesterday and i need the calibration values - feeler gauge thickness / resistance / what to measure. Can't find them anywhere

Thanks all
Bardin

[Bananaman]

So just now i was fiddling with it again, and i couldn't hear the fuel pump priming at all, let alone staying running. But if it isn't priming, then it shouldn't be firing up at all....?

For now though i have a flat battery, will carry on later with a newly charged battery

[pandaah]

bridge FP and B+ in the diagnostic connector with a paper clip, see if you can rule out the fuel pump

[Bananaman]

bridge FP and B+ in the diagnostic connector with a paper clip, see if you can rule out the fuel pump

Thanks, yeah I'm just about to do this as it happens, just came in to get a paper clip.. it IS the fuel pump not turning on, it just decided to start working then, and the car ran... to prove the point, it started cutting in and out in time with the car. So, i've got dodgy wiring somewhere methinks - i'll see how it goes bridged, whether it is intermittent that way as well or not

Pump is a walbro, only about 6mths old

[Bananaman]

So, the car decided it didn't want to turn the fuel pump on again just now, so i bridged the terminals - pump comes on without a problem. So it seems that whatever normally tells the pump to turn on isn't doing its job?

[Bananaman]

Ok, so i just switched relays with something else and tested - the EFI MAIN relay is definitely switching on with ignition, but the pump does not come on. Bridge the Fp and B+ terminals, and it DOES come on no problems.

Assuming there isn't another relay in the picture somewhere that bridging the terminals bypasses, i'm stumped?

[pandaah]

wilbo would know much about this, i think the part your having trouble with is the circuit opening relay,,unless anyone else has any info?

[wilbo666]

My ears are burning

If bringing Fp in the diagbox fixed your issue the stalling just after starting then it sounds like a Fuel Pump ECU system problem....

FYI, I don't think the fuel pump 'primes' when you switch ignition on...

Cheers
Wilbo

[pandaah]

is it a jza70 ecu?.. might be time to crack her open and look for faulty caps

[pandaah]

actually just had a look on ebay.. i didnt realise the fuel pump had its own little control unit

[wilbo666]

Woops, yeah if it's JZA70 then it has a Circuit Opening Relay... (JZZ30 and others had the Fuel Pump ECU setup, but not jza70).

Sound like ECU trigger for the Circuit Opening relay or the COR is suspect?

That's the direction I'd be looking in anyway.

Cheers
Wilbo

[Bananaman]

Found some info here in a thread where someone describes my exact symptoms

http://jzxproject.com/bbs/lofiversio...php/t2175.html

Fuel pump does definitely prime when you turn the ignition to on (well.. when its working normally) - you here it buzzing for a sec until (i assume) it gets up to pressure.

I was told the ecu was jza70 when i bought the car, but when i went to wire up the emanage discovered it was in fact jzx90. Yeah it sounds like the COR is what i should be heading for (unless jzx90 has this fuel pump ecu you speak of), i guess i'll have to get under the passenger side of the dash again and check it out. Thanks for the help

[Bananaman]

Ok, so I grabbed 3 spare circuit opening relays today, tried two - car is still the same, so i'm pretty confident this is not the problem. Any more ideas?

[Bananaman]

Woops, yeah if it's JZA70 then it has a Circuit Opening Relay... (JZZ30 and others had the Fuel Pump ECU setup, but not jza70).

Sound like ECU trigger for the Circuit Opening relay or the COR is suspect?

That's the direction I'd be looking in anyway.

Cheers
Wilbo

How can i check the ECU trigger for the COR? I'll try and find the pinout for it, i assume i can check it in the plug for the relay itself?

[Bananaman]

Oh, and JZX90 is the same ecu plug as JZZ30, so does this mean i'll have this fuel pump ECU you speak of? My ECU part number is 89661-22470.

I'm tempted to just get my hands on a spare ECU if i can get one cheaply enough, so that i can rule that out, a jzz30 one can't be too hard to find / expensive..?