cracked intake manifold 1994

[Mark S]

I recently purchased a 1994 with 8500 miles from the estate of a customer. It had been sitting for 15 years. I had to replace fuel pump to get it running. Once I got it running the RH exhaust had raw fuel coming out the pipe. The last injector on the LH side had a slight fuel leak at the top of the injector. I figured that maybe from sitting the injectors were gummed up so I bought a reconditioned set from a Viper specific parts source.
I replaced all 10 injectors and started it again. Still fuel coming out of the RH exhaust but I did not let it run very long. There was also still a leak at the last injector on the LH side. I removed all of the injectors again and I see that the injector that was leaking at the top has a crack as shown in the intake manifold. Is this a common problem? is the only fix a used manifold? what is a good Source for that?
Do you think that is why there is raw fuel out of the exhaust? Does the exhaust have a crossover pipe or are the pipes for each bank of cylinders? or can someone suggest something else I should be looking for?

Thank You very much for any help!

 

[MoparMap]

Wow, never seen anything like that before. I would guess that could have something to do with the exhaust issue. Those are side fed injectors, and by the look of it the crack joins the feed port and the nozzle port, so when that system is under pressure it could be dumping fuel straight from the "rail" (it's cast into the intake, so not exactly a rail, but same idea) into the cylinder. Thinking that would be a tough thing to fix, but guessing someone might be able to do it if you looked around hard enough. Would take some welding and new machining at minimum, but with how that is recessed down in there I think it would be pretty tough to get to. A replacement intake probably makes more sense in the long run.

 

[GTS Dean]

That's apparently one of the early-style 4-rib manifolds with the pressed-in runner tubes like my '93 had. They were discontinued early in the '94 M.Y. run. I think they are better looking, but not as robust as the 3-rib fully cast replacements.

To fix that problem is going to be a real challenge because of how tight the confines are - and there's still some likelihood that the fix isn't going to hold. The later 3-ribs are a straight bolt-on and they are plentiful and fairly inexpensive.

 

[Mark S]

I agree fixing this one would not be money well spent. It looks like an easy part to find but just want to make sure it was not a common problem and the used intake I buy has the same issue.

So yes, this is a 4 rib manifold. Is the 3 rib is a direct replacement and all parts will bolt to it then?
I am hoping this is why the fuel was coming out the exhaust but it was on the other bank of cylinders so I was not sure if that was possible.

 

[GTS Dean]

I'm 98% certain it is a direct interchange.

 

[99RT10GTS]

Not a direct interchange. The IAC has to be relocated to the front and re-wired. I have a good 4 rib if you need one, but not cheap. I would try to fix yours first. I believe the early manifolds were Magnesium too.

 

[GTS Dean]

I also thought that G1 valve covers and intakes were magnesium, but one of the original Team Viper engine managers said that was not true of production units. If true, then perhaps the bad injector well can be drilled out and a new sleeve machined and pressed/welded in for a reliable repair.

 

[Mark S]

well thats a bummer the 3 rib is not a direct swap......I found several at a place in WI. Called them Friday but Viper guy went home early and was calling them back tomorrow. How expensive is a 4 rib?
I hate to spend money trying to fix only to fail and have to buy one anyway.

 

[GTS Dean]

Lengthening the IAC connector pigtail is not rocket science.