Part help PLEASE!!!!

impulsive · Post by **impulsive** » Wed Jul 23, 2014 7:48 am

Hi all,

I'm wondering if anyone out there with spare parts for their 4ZC1-T can help me out. I am desperately trying to find this part:

Does anyone have one of these they would be willing to sell me?

Thanks!

Bart

IZU069 · Post by **IZU069** » Wed Jul 23, 2014 11:46 am

FYI until replaced - IMO it can be bypassed. It's a circuit that blocks coolant to the turbo until warm.

impulsive · Post by **impulsive** » Wed Jul 23, 2014 12:01 pm

IZU069 wrote:FYI until replaced - IMO it can be bypassed. It's a circuit that blocks coolant to the turbo until warm.

Yes, mine has been gone since I bought the car. But my local SMOG (emissions testing facility) is telling me that it is part of the air injection system, even though I told them a million times it is for coolant to the turbo. They look at the vacuum chart on the hood an assume shit.

I know I shouldn't complain, as you boys in Oz and Nz probably have worse road regs, but over here in the States, at least where I live, they seem to be cracking down on this SMOG horseshit.

Thanks - Bart

Post by **Piazza_man** » Wed Jul 23, 2014 12:29 pm

Can you not show them the part via a workshop manual? Sounds silly to me.

impulsive · Post by **impulsive** » Wed Jul 23, 2014 1:24 pm

eyecon wrote:Can you not show them the part via a workshop manual? Sounds silly to me.

Oh my shop manual will be coming with me next time.

Bart

archangel62 · Post by **archangel62** » Wed Jul 23, 2014 11:01 pm

No luck from me, mine's missing it too! Elky maybe?

IZU069 · Post by **IZU069** » Thu Jul 24, 2014 1:25 pm

There is a one-pager I wrote on that circuit... https://imageshack.com/i/jwpiazzaturbowatervalveopg.

As I recall, a coolant temp sensor operates an air (vacuum) valve.
The air valve (vacuum) operates a coolant (water) valve.

I don't see why the pneumatics can't be omitted - ie, temp sensor controls electric coolant/water valve. IMO that will reduce emissions since IMO taping airflows causes step changes or changes air balance etc...)
I'm not sure if the latter was considered in my writings... Probably not in the original since it was a mere quick analysis for a mate.

My conclusion was that it was a pedantic add-on to increase the (cold) turbo temperature quicker - ie, prevent cold coolant from cooling the exhaust-gas warmed turbo - and probably to reduce turbo wear (bearings & seals).

IMO if bypassed the emissions impact should be negligible. The slightly cooler turbo housing (until then engine coolant approaches normal operating temperature) does not impact combustion mixes & temps and is unlikely to alter exhaust temperature (eg, to effect the O2 sensor).
Plus the cat converter takes time to heat up (it's not a pre-heated type - at least not here; nor for any 1980's vehicle). Maybe that coolant valve is open before the cat reaches its operating temperature? (Not that it should matter...)

My other consideration - AFAIK no other vehicles at that time or soon thereafter had any similar circuit.
And Isuzu engines are clean burners as proven by the stringent Tokyo requirements. (Yeah ok, that refers to diesels, but Isuzu were the only diesels allowed and that was way before the regulations took effect re nano-particulate emission etc.)

Not that I'm an expert on the above, nor (may) remember details (accurately).
But if they are suggesting that an initially cooler turbo body effects emissions (and a still-cold cat doesn't?)....
Of course, if it is a Regulation, then it's a regulation - ie, the onus is on you to provide the proof.

It would be interesting to replace with a normal electric valve and removing/blocking the vacuum lines. Surely anyone can see that has no negative impact (even if it does require an Engineering Certificate - at least testing should not be required).