1JZ strange problem please help

[postfach]

I've recently put a 1JZ-GTE into a z20 soarer and it goes fine....until it's warm. As soon as it warms up a little, giving it any gas at all causes it to splutter and with a little more gas it goes silent (stalled perhaps?) but upon letting off if will return to a fairly normal idle.

So far i've replaced:
spark plugs
water temp sensor
map sensor

none of the above seem to make any difference at all.... i suspect it may be something in the wiring but i'm open to pretty much any suggestion at this point.

please help!

[MrOizo]

have you done anything like taking off and replacing anything in the cambelt region at all?

[postfach]

no haven't done anything like that yet

[edwagon]

The jzz30 soarers do a similar thing when the fuel pump ecu starts failing. You probably won't have retrofitted one of those, so it won't be that exactly, but thats the sort of thing that it sounds like. How warm does it need to be? like just off fast idle (like 1 min) or 5 or 10 mins to warm up fully?
Can you extract any codes from it? Is it going into limp mode? Is it packing a sad because it thinks its missing the auto, or any other part of the wiring? is all the wiring in good cond? have you made really sure that all the connectors are clean, dry and connected firmly? (check them!) all earths good etc?

[postfach]

usually happens after 2 or 3 minutes of running. It's not giving any codes, ill have a look at the connectors and earths tomorrow but everything should be dry. How can i tell if it's in limp mode? i would assume it would stop me from revving past a certain point but it doesn't really want to rev at all.

[Malcolm]

do all 1jzs run coil over plug? I've heard of the 1jz coils cracking due to heat/vibration, so maybe go through removing them one at a time and see if removing one makes no difference to how the engine runs.

[StuartM]

my 3s-ge celica had identical symptoms and it was the fuel pump
test its pressure with your fingers, but from memory you'll need to see if theres 50psi or more there

[postfach]

fuel pump should be fine tho, probably should have mentioned before, its a bosch in tank unit, meant to be good for up to 450-500hp, although maybe the wiring isnt thick enough to supply a decent current? (i used the standard wires) but yeah ill check the fuel pressure tomorrow as well (provided i can find the required equipment)

[StuartM]

the only other thing that comes to mind would be an ignition coil thats not up-to-task

[StuartM]

can you smell fuel out the exhaust when it sputters?

[postfach]

any idea how to check the coils?

[postfach]

hmm i dont remember, tho im guessing what you're getting at is if i can smell fuel i should look at the coils, if not, check fuel supply?

[StuartM]

yep spot on.
use an ohmmeter to measure the resistance of the primary coil (between + and -) and you should see 1 ohm or less
then measure the resistance of the secondary coil (between + and the high voltage output) and it should be ~10k ohms

the figures might not be exact because they come from an 87 supra manual. but measure the resistances when the coil is cold. then run your engine and see if there is much difference when its hot. also check or replace your spark plug leads

[postfach]

it has individual coils, does this still apply?

[StuartM]

im already out of my depth tryin to help online
it surely cant hurt to check the difference in resistance in the coils when cold and hot though.

[Si]

how old is the engine?
what ecu are you using with it?
when did the problem start occuring?

[postfach]

im already out of my depth tryin to help online
it surely cant hurt to check the difference in resistance in the coils when cold and hot though.

true, no harm in checking

how old is the engine?
what ecu are you using with it?
when did the problem start occuring?

its from a 1995 jzx90, done 92000km, im using the ecu that came with it, it was an auto, and as far as i know it's always had the problem (i never saw the engine running before i bought it as it came as a half cut)