Help with intake manifold 91 b2600i

Having trouble removing the intake manifold on my 91 b2600i to replace a leaking gasket that is causing my engine to idle low and occasionally die. Also figured I'd clean injectors and fuel rail (which were pretty gunked up from the leak, and my frequent use of ethanol I've been told). I removed the top half and have all nuts and bolts removed from the bottom. I pretty much just need to slide it off to get to the gasket now, only there's a motor mount in the way. It's bolted to the frame below the engine in a spot that, no matter what combo of extensions I use, I can't seem to remove it. I am an amateur mechanic at best, so I was hoping someone who's done this before could tell me what the trick is to getting it off? I can post a pic if that would help...

Can you get a closed end wrench on it?
Is it behind the starter? Remove starter!



My '93 does not have anything but the nine bolts holding the lower intake on. Double check the entire lower side of the intake with fingers and/or mirror. There are: five on bottom, four across top.

The injectors are not exposed to the combustion, so, exhaust can not clog them, fuel residue or debris in the fuel can.
The gasket is not likely to be the problem, unless you found it with a mechanic's stethoscope or intake manifold vacumn was low.
Hope this helps, keep us breast of the situation.

Hey thanks for your reply.

I for sure had all the nuts and bolts removed, just had to get that support arm off, which I eventually did after removing the front passenger side wheel and using some creative ratchet extensions.

The intake manifold gasket was most definitely the problem, it was totally ruined and there was clearly fuel or coolant or some combination of the two leaking out. I think the injectors got gunked up because the o-rings on them were bad, lots of debris and junk found in the intake chamber. The gasket was sort of melted to my engine block so I'm going to get that cleaned up, soaking the whole intake manifold as we speak and hopefully when it's all cleaned up and the new gaskets are installed with freshly cleaned injectors, she will run like a top!

Be careful with the injectors, the nose on them is fragile plastic. Don't drop or bang them around.
You'll be b-ing in no time.

Congrats on getting it apart.

Now that you have the manifold off, now is the time to inspect and replace those small coolant lines that are largely hidden underneath the manifold. It's not uncommon for people to replace the radiator hoses and heater hoses, but these little bypass lines and oil cooler lines rarely get replaced. If and when they spring a leak, you'll loose coolant just the same as if a radiator hose when out. Also, if you go with OEM, you'll get top quality hoses AND they are molded for a perfect fit. Also, the one that comes out of the back of the IAC valve (top of the throttle body) will be 8mm on one end and 10mm on the other. So generic auto-parts store hose will be stretched pretty tight on the larger fitting. Also, don't be surprised if you find some of this metal coolant pipe rusting, not only on the inside, but also on the outside underneath the hose.

Here is a shot of all the hoses.



As for cleaning the injectors, the best way to clean them has have them sent to an injector shop and ultrasonically cleaned. When they come back, you'll have a report and know exactly what the flow rate is on each - always best to have them closely matched. They'll also come back with new o-rings, spacers, and pintle caps; your original ones are probably a little brittle.

Thanks, I did send the injectors to a shop to get cleaned, said they are real good now but he didn't give me new o-rings, had to pick those up myself. Is there somewhere I can order that whole package of coolant lines you're showing there?

I'd get them all at the dealer. the hose quality is definitely better than the big box stores.