86 L98

Ok here is the project I just finished that created the problem. I replaced the ORings in the fuel injectors since one was leaking. Got everything needed off, put back on, and torqued correctly. I cranked the car and it ran fine for about 5 seconds and then quit. I cranked again and kept my foot on the pedal and idled it while a buddy listened to the motor.

You could hear a distinct hiss and I immediately knew it was a vaccum issue. I connected all the vaccum lines back up correctly however during the removal process, I snapped a few of the 20 year old lines. I went to a parts house and and got some small diameter rubber hose and patched up the lines.

It still does the same thing.

I then took the plenum off again and retorqued the runner bolts in case I didn't do it right the first time.

Still hisses and cutts off at idle

I am thinking I may have

1)Crissed crossed a vac line
2)Didn't hook a line up (I doubt this since I went through everything twice)
3) Do I need to go through the whole vac system and replace lines?

I guess since none of you guys can actually look at my engine, could someone send me a vac diagram? I want to track down a diagram and go through each connection one by one, and make sure I have every thing together.

Here is what I think is the problem

I contorted the little black vac tree by the thermostat to get the the bolt to remove it and mave have cracked the rubber assembly and it is losing vac as a result?

Or is the gold circular part under the plenum (I don't know it's name) damaged? Is that part where the vac originates? The hissing is coming from somewhere around the underside of the plenum.

I know this is a major vac leak since the car won't run without my foot on the gas. Is someone in the Raleigh/Durham area able to come look at the engine (thought I'd throw it out there) Or could someone send me a vac diagram and some advice! Please help!

PS The car ran perfectly fine before I began the ORing project

 

You can use some carb cleaner carb cleaner and spray around suspect areas while the engines running and when it smooths out temporarily, you'll know you've found the area. Some people use starting fluid too, but it's extremely volatile and a stray spark from a plug wire or something could cause it to ignite. I don't recommend it. Even with carb cleaner be careful, keep your face away and wear eye protection.

 

I really think it is that black rubber tree near the TB. I twisted that thing all around getting it off. What does that piece actually do? What does the gold circular piece do attached to the intake mani?

 

If you look undeer yesterdays C4 general threads you will find a nice vacuum diagram. Also for checking vacuum leaks instead of starting fluid or carb cleaner try a hand held propane torch. That way you can best control the gas and pinpoint right around any fitting. Still have to be carefull though.

 

If you are talking about the one on the water neck it is for EGR. Here is the diagram I posted yesterday.

 

Good News guys, I found the problem. My buddy must not have seated the left runner to the manifold correctly. I had someone hold the pedal at idle and shot carb cleaner on all flanges. I shot it on the front left intake/runner connection and it smoothed out and ran fine for a few minutes.

I guess I am going to have to take the whole thing apart again and retorque again. My manual gives me a vauge range of torque. How many ft lbs should I torque the runner flanges to the intake manifold? Also I changed the gaskets, should I make the surfaces perfectly (no old gasket residue) clean? Thx