bagger

When replacing the three fuel lines in the engine compartment on a 3.2 Carrera, how much does it help to remove the intake manifold?

I'm planning on doing this work while the engine is in the car. And I'm asking because Peter Z. recommends removing the intake manifold in his book. But everything that I've read here only talks about removing relatively minor stuff like: the airbox, airflow meter, heater blower ducting, and heater blower.

I recognize that this is a bit of a vague question, but I'll appreciate input from anybody that has done this work before.

The three fuel lines are the ones in the picture below (thanks for the picture and descriptions imcarthur!):

ron mcatee

I changed mine by removing the right side manifold. All you need is room to remove the hard line and it won't manuever around the othe hardware unless the rubber boot is removed or one of the manifolds is taken off. Be sure you have new gaskets prior to reinstallation. Plug the holes so nothing drop in the intake of the heads.

Ed Hughes

A partial drop (oil lines, rear motor mounts) lowers the motor enough to easily do this, IMO. But, you can do it in situ. Taking an engine out for refreshing cooler seals, breather gasket, clutch, cleaning, and several other things is also a wise idea.

rusnak

I also think an engine drop makes sense, but I'd probably advocate a full engine removal because the extra access makes doing a good job much easier. Depending on budget, there are a lot of things that probably need changing. Removing the engine is itself not a beginner project, so that also depends on experience level.

Ed Hughes

But many HAVE begun with an engine removal. One can make a party of it to have extra hands. As I mentioned, there are many other sidejobs that can be done with the engine removed.

Droops83

I have done several with the intake in place to make the job go faster (after verifying that there were no intake manifold/gasket leaks!). But, I also have worked on these engines a lot and know what is what on the backside of the engine by feel. Also the hard line of the new fuel line gets bent a tad when you do it this way and you have to bend it back a bit after it is slipped under the intake so that all the brackets line up.

In other words, if you have never done this before, remove the intake. It will make the job easier, and you can replace the intake gaskets, among other things, while you are in there.

bagger

I may be too ignorant to know what I'm getting into, but removing the manifolds seems like it would not be too difficult. And it would probably be a good idea to replace those gaskets anyway. The thing that worries me about removing them is, as Peter says in his book, you should plan on setting the idle mixture control and idle speed. Since I don't have an analyzer to do that, it means going to a good mechanic. And the closest one that I know of is 4 hours away.

Ed Hughes

You can replace it all and then get it dialed in. 3.2's are not tempermental

rusnak

I would agree. The CO% is a baseline anyway, and the DME will adjust the fuel pulses to keep the mixture correct once the O2 sensor has warmed up. In other words, changing the gaskets and fuel lines won't make it miles out of spec. If you feel that you have to, you can rent a CO% meter.

Steve Weiner-Rennsport Systems

Thats really true wisdom,....

rusnak

I just re-read my last post, and I want to clarify. I checked the f/a ratio with an LM-1, and fuel pressure with a pressure gauge, and there was no change after replacing gaskets and fuel lines. I do plan to re-check a second time now that there are miles on it, and to re-check bolt torque.

bagger

rusnak,

Where have you seen CO% meter rental?

bagger

Assuming that I'm going the intake removal route:

1. What else do you recommend that I replace?

2. Should cooler seals and breather gasket be on the list?

3. For the intake removal, should I just replace the gaskets or the Intermediate Flange (930-110-459-00) too?

4. Do all the seals related to replacing the fuel lines come with the Porsche original parts (the three in my original post)?

rusnak

Bagger, just call around, and you should find one in your area. When I began to really study the L Jetronic, I realized that you need a dedicated test bung and a wideband O2 sensor to really see what was going on. I then got a cat bypass and installed a second bung, and got an LM-1 tester on Ebay. I like the fact that a wideband sensor shows you the fuel air ratio, rather than co%.

You need 12 gaskets. Consider buying some Curil-T just in case you end up puting a scratch somewhere (ouch). No need to replace the block spacers. Zims has a nice alternative to the factory fuel line. The factory lines bolt right in. Be sure that the lines do not touch anything. Use all brackets.

bagger

Thanks for the recommendations rusnak. I'll probably have more questions about analyzers but I'll read the other threads on that subject first. BTW: Thanks too for your video you posted of your Zims fuel lines.