First engine run in 18 months (Page 1/2)
gregr75 JAN 27, 07:26 PM
I had the first fire of the engine today. It ran for 10 seconds at high idle and then died… No surprise I knew it wouldn't be perfect. I poked around and what alarmed me was to see coolant in the throttle body. I had drained most of the coolant from the car during restoration and only planned to run for a very short time. Im pretty sure all the hoses are hooked up not sure with this could be?

The engine was running fine 18 months ago and i didnt do any engine work other than removing and replacing the top plenum.

[This message has been edited by gregr75 (edited 01-27-2024).]

PhatMax JAN 27, 07:32 PM
Could be the TB coolant passages are cracked internally ?
gregr75 JAN 27, 07:34 PM
.... I had also change spark plugs…

Yeah something bad is going on, I took off the upper Plenum and there's coolant in it the EGR tube was dripping coolant out of it

[This message has been edited by gregr75 (edited 01-27-2024).]

fierogt28 JAN 27, 09:17 PM
I’d remove the TB off the plenum. Removed the TB coolant lines first. (Front and rear)
Take off all accessories. But do not fiddle with or destroy the cap on top. That is there for a reason. It’s the idle screw that is preset at the factory. It’s perfectly set for the throttle plate at idle.
Everything else you can remove to inspect.
I never heard of a cracked TB or housing.
You’ll need to run a colouring with water to see if it’s only coming out of the opposite end only. If you water coming out internally or somewhere else.
Check the TB mounting gasket on the condition.
That’s a gasket that must be replaced once the TB is removed. Some overlook that because it may look in good shape or reusable.
To be honest, I noticed passages on the mounting surface on the TB before, but never noticed if there was coolant coming out from there.
I’ll get a pic of the inner surface of the TB for reference.

------------------
fierogt28

88 GT, Loaded, 5-speed.
88 GT, 5-speed. Beechwood interior, All original.

fierogt28 JAN 27, 09:24 PM


So, after taking this picture. The coolant definitely passes and touches the gasket upon sealing to the TB / plenum surface.

I suspect you have a bad gasket. The coolant will run into the intake and drain down into the EGR tube.
Because the EGR port is at its lowest point.

Take it off, and report back on your findings.
The TB gasket might or will rip off or need to be destroyed to get it all off with a sharp blade.

Be prepared to buy a new gasket.

------------------
fierogt28

88 GT, Loaded, 5-speed.
88 GT, 5-speed. Beechwood interior, All original.

Patrick JAN 27, 10:26 PM

quote
Originally posted by fierogt28:

The coolant definitely passes and touches the gasket upon sealing to the TB / plenum surface.



All the more reason IMO to remove the coolant lines that go to the TB.
gregr75 JAN 28, 01:18 PM
thanks fierogt for the tips on removing the TB. The 2 torx bolts holding it on are seized, im gonna have to soak in pb blaster and maybe apply some heat.

i have another theory too, i dont think i hooked up the hose indicated. i cant tell what if this is a coolant hose but it runs vertically down behind the AC lines and goes into the firewall right above where the sending unit wire/fuel vent line pass thru the hole.

I'm thinking if this is a coolant hose, it may have sprayed whatver coolant i had left directly at my Plenum gaket interface which was just torqued by feel and not to spec. And coolant entered the intake that way,? I think this because all six channels of the plenum were wet with coolant. I removed the spark plugs and they had drops of liquid on them but I can't tell if it was gas or coolant.

Does anyone know what this hose is for?
82-T/A [At Work] JAN 28, 01:56 PM

quote
Originally posted by gregr75:

thanks fierogt for the tips on removing the TB. The 2 torx bolts holding it on are seized, im gonna have to soak in pb blaster and maybe apply some heat.

i have another theory too, i dont think i hooked up the hose indicated. i cant tell what if this is a coolant hose but it runs vertically down behind the AC lines and goes into the firewall right above where the sending unit wire/fuel vent line pass thru the hole.

I'm thinking if this is a coolant hose, it may have sprayed whatver coolant i had left directly at my Plenum gaket interface which was just torqued by feel and not to spec. And coolant entered the intake that way,? I think this because all six channels of the plenum were wet with coolant. I removed the spark plugs and they had drops of liquid on them but I can't tell if it was gas or coolant.

Does anyone know what this hose is for?





I "think" this is one of the deleted (edit: vacuum) hoses from one of the recalls. It should go to a large black tube that's located on the firewall. But I'm not sure. I don't have a V6 Fiero in front of me to look. There should be only two coolant lines that go to the intake plenum (via the throttle body). These are the ones that attach at the back of the engine (passenger side) that connect to the two steel lines that run along the underside and then connect to the throttle body.

Personally, I think it's worthwhile having them, so long as everything is functioning properly. They help the engine warm up a little, and unless you live in a Southern State... it will probably do more good than harm. But it can't hurt to just loop them off at the filler neck until you get everything else situated. You definitely don't want coolant going into your intake.

[This message has been edited by 82-T/A [At Work] (edited 01-28-2024).]

PhatMax JAN 28, 02:11 PM
Hope this helps. This is a firewall pic with the hoses still there…..your pic looks like it may be the brake booster vacuum..

[This message has been edited by PhatMax (edited 01-28-2024).]

gregr75 JAN 28, 03:22 PM
Ok dumb question so i do I need to hook the open end of thats hose somewhere?