1JZ Starts Up Then Stalls/Dies - Post Conversion Teething Issues..

[hamgatan]

OK just a forenote here,

I've just finished up the 1JZ conversion from my old Soarer into my new one.. and there's still some teething issues.

I am quite sure I've done all the Vacuum lines properly (I checked each one off in the EPC), and the only one I disconnected from the old car was the one that goes from the last port in the Intake Manifold around to the back of the head, and eventually into the factory BOV.

Now here's the thing.

With this little twat, if I leave him vented to the air, I can start the car and It'll idle fine.. air will escape obviously.. but it will still idle fine.



However if i bung him up, or plug my boost gauge into him, the revs will drop right off and the engine will stall. (PS This image isn't my 1J, Can't recall the source to credit it either..)

Before anyone asks -

1. I'm 99% sure the vacuum lines are perfect
2. There is no rags stuffed anywhere in the intake or cooler piping.

Ideas?

[triptek]

Sounds like a idle control valve problem. Have you checked if it's getting 12v.

[hamgatan]

negative. i might have to pull the ISCV out tomorrow and have a looksy when its light out..

[xistant]

i lol'd at rag cos ive left one pre intercooler lmao

[hamgatan]

not sure which pins to test on ISCV for 12v feed.. so i tested a few and got 0.05v in some areas..

If i start it now with the boost gauge unplugged it'll stall and die.

If i start it with the ISCV unplugged... interestingly enough the car starts first go, idles beautifully but then goes up to 2100rpm, and drops to 1100rpm, then repeats that process over and over.. 2100, 1100, 2100, 1100...

what do you reckon it might be Mark?

[triptek]

The two black/red wires should be getting 12v with the ignition on.

[hamgatan]

what do i ground the multimeter to when checking?

[triptek]

Just use the strut tower bolts.

[wilbo666]

what do i ground the multimeter to when checking?

Battery Negative is also a good spot


Also pins 2 and 5 - the middle two are the ones that should have power.



As to the reason why the engine revs up/down/up/down, that is because with the ISCV unplugged and fully open there is enough air to bring the engine revs up above the 'deceleration fuel cut' RPM limit....

If the throttle is closed (Sensed by Throttle Position Sensor) and the RPM is above ~2000 RPM (I don't recall the exact number) then the ECU will cut fuel until the RPM drops to the lower limit (~1100RPM) where fuel is then added again. This usually happens under deceleration. In your case the sequence then repeats

Cheers
Wilbo

[hamgatan]

so i changed the ISCV with the one off my JZX90 and adjusted the idle screw up.. so now i have a happy 800rpm idle.. (thereabouts)

Went for a spin down the road.. got boost, boost gauge is reading 0.9 bar... still popping like mad (as if im bouncing off the limiter) off the back of the dump pipe.

Noticed my power steering is noisy as too. I bled it with the old drag the wheel to full lock on each side technique.. but shes still noisy as hell when turning... suggestions?

[tomo1ggte]

so i changed the ISCV with the one off my JZX90 and adjusted the idle screw up.. so now i have a happy 800rpm idle.. (thereabouts)

Went for a spin down the road.. got boost, boost gauge is reading 0.9 bar... still popping like mad (as if im bouncing off the limiter) off the back of the dump pipe.

Noticed my power steering is noisy as too. I bled it with the old drag the wheel to full lock on each side technique.. but shes still noisy as hell when turning... suggestions?

did you jack up the front tyres when you did this and check the fluid level?

[hamgatan]

no i didn't but i re-bled the rack again and filled it up.. seems okay now. might have not been enough fluid sucked through. brakes are still spongy as though. will have to try bleed again.

had my nice shiny new centrepipe tigged up this morning and exhaust bolted up finally.. but as for the engine side of things.. engine purrs beautifully at the moment.. starts to hit boost and im sitting there thinking good.. here we go.. starts to kick in and then as it starts to go, i get a lot of popping going back through the exhaust instead of boost. pa-pa-pa-pa that kind of sound. S-AFC is disabled. i might take it out of the equation just to test.. but other than that im stumped as to what it could be?

interestingly enough i switched the BOV with the one from my JZX90 and found that on the JZA70 one the inside of the outlet port was sealed shut wheras the JZX90 one was open?! wtf...? Identical Part numbers... I'm assuming someones bunged up the JZA70 themselves.

[hamgatan]

OK this is officially frustrating me.

I have swapped plugs with working ones.
I have swapped coilpacks with working ones.
I have swapped map sensor with working ones.

no difference. still pops and backfires like shit under boost load. I'm really at a loss as to what it could be now..

I took it for a very gentle drive for 25-30 min... when i was coming home I noticed I could give it a bit more throttle and it would accept boost without popping like mad.. it actually kind of behaved itself.

Then when I got home i decided to comp test it.

Cylinder 1 - 172psi
Cylinder 2 - 159psi
Cylinder 3 - 160psi
Cylinder 4 - 164psi
Cylinder 5 - 168psi
Cylinder 6 - 158psi.

So its not great.. but theres a relatively large difference between 1 and 6.. But not anything that should be causing me major concerns.

Then i took it out again today and back to the popping/backfiring again on boost... GRRRRR

[88cameron88]

getting too much fuel for some reason?

[hamgatan]

possibly. its running a GTR pump now (which is pretty close to the walbro) in spec (253lph vs 255lph)... definitely sounds like its overfuelling... but stock FPR shouldnt be letting more than what the engine needs through right?