Somebody

Well, I'm going to try and be as informative of the situation as I can...

The reason I checked the vacuum lines was cause the car was overboosting, a common problem which gets the common response of checking over the vacuum lines. I have had this problem ever since the mechanic replaced the waste-gate with a tial. So I found a helpful chart off of rennlist

and went to work checking over my mechanics work.

I started out with finding the vacuum line out of the top of the blow off valve was connected to the two "things" on the fuel rail and nothing else (in the diagram it shows them tying into the manifold). After a while of following lines I discovered many other errors


So immediately I started to set things right. Or so I believe. I think I have everything going to the right place, but I have a few further questions I need to get cleared.

First: for the fuel vapor purge system. On the car there is a bell shaped brass "thing" and a huge, plastic round thing that looks like the far right "thing" in the diagram. Which vacuum line goes to the manifold? the brass bell "thing" correct?

Second: can I connect the two fuel line "things" together with the brass bell "thing" then finally connect it to the manifold. Now by looks I'd call it a banjo bolt connected to the manifold with two "ports" on it. I have the two fuel lines and brass bell "thing" going into one port and have a yellowish looking clear line going to the klr. Is this alright? I did not want to cut into that line really and thought that this would be alright. on the diagram it shows that the two fuel rail "things" do Not connect to each other, and infact both connect to the two different spots on the same banjo bolt.

Third: From the cycling valve port that goes to the waste gate I have a t connector going to the mbc (I got it at the same time I got the wastegate and have the overboosting so it never has worked). then on the second port of the wastegate it goes straight to the mbc. Now, in the instructions I heard that tial was backwards with their ports, and has to be switched around. Could this be done at the mbc? Just switching the lines there instead of having to get underneath the car.

Finally: The last things that concerned me with the car was that the brake reservoir (I believe) cap that has two wires coming off of it that go no where. I checked on the other 944 I got and I saw where it tied into the wiring. Would this cause the car to not start up? I don't know if it was like this before I started to work on the vacuum lines or if I might have somehow broke them loose while working on the car.

The car's starter sounds good, the useless a/f ratio gauge I have shows some movement. I'm at a loss of what to do next.


hope this doesn't end up like last time I went to try and fix a simple problem...

it started with a burnt out tail light....

j/k


Any help is appreciated.

KuHL 951

Don't know if it will help or not but I would check the sensor connectors at the bracket at the rear of the camtower. If you just bumped one they connection can be bad enogh to prevent start-up. The connectors on my 83 gave me fits until I finally Ty-Rapped them bith to keep them from jiggling and dying at the worst possible times. It's worth a look.

Charlotte944

First: The 'Bell" thing is one of the control valves for the evaporative emissions and should NOT be connected to the intake manifold. If you follow the diagram that is on the passenger side shock tower you will see that the control vacuum comes from the throttle body, goes to a temperature switch under the intake, and then goes to the control valve. If you connect this valve to the intake, the valve will always be open and the charcoal cannister will always be purging, which amounts to a huge vacuum leak.

Second: The Fuel Pressure Regulator and the Fuel Pressure Damper (the "things" on the fuel rail) should be connected directly to the intake. I've seen this done with a single line from the banjo bolt. From there the line goes into either a metal 'T' or a rubber 'Y' adapter. One side of this first adapter is connected to a second adapter, and the other side of this first adapter feeds the Blow Off Valve. The second adapter feeds the Fuel PPressure Regulator and Fuel Pressure Damper.

Third: Your MBC/Cycling valve plumbing is wrong. If you are using an MBC you do not need the cycling valve. The proper routing is from the banjo bolt on the Intercooler, then to the MBC, and finally to the control port on the Waste Gate.

Fourth: The wires at the Brake Reservior cap are for the low brake fluid warning light and have nothing to do with a no start.

Fifth: Your no start could be caused by the fuel pressure being too high. This can happen when there is no vacuum going to the FPR and damper. Under this condition the fuel pressure will prevent the injectors from opening.

Somebody

well, I spent some more time under the hood today going over the diagram and reviewing the both posts.

KuHL :: I'm very ignorant when it comes to cars, especially porsches, and was unable to exactly locate the connection you might be talking about. I applied some pressure to the cycling valve connectors but to no avail. There is a sensor with a cap on it that is just dangling by the cam tower. I didn't think much of it until I started writing this post...

Tomorrow I'll try zip-tying that connector onto the cam tower bracket.

Charlotte944 :: Thank you for your elaborate response.

With regards to the evaporative emissions control valves. I have the Bell looking control valve going to the throttle body (through the temperature switch). And the other one I have going to the intake manifold. In the diagram, there is a green line that goes from the vapor purge system to the intake.

However, you did not mention this happening in your paragraph about the Fuel Pressure Regulator and Damper. So where does this vacuum line end up at? (the one off of the plastic piece on the fuel vapor purge system, it's indicated in green on the diagram going to the intake)

As for the MBC, I have found some diagrams out on the net about how to hook it up correct, but I have one problem. Having to bypass the cycling valve. What do I do with the third line coming from the cycling valve which goes into the intake boot? do I just cap it off then? To take out the cycling valve after I bypass it, could I remove it with the intake manifold on? What about the metal lines for the banjo bolt and intake boot line. temporarily I can bypass the system, but now that I'm working on the car myself, I'd like to make sure things are done right (to the best of my ability).

Are there any tests i should perform to troubleshoot the reason for the car not starting?

michaelathome

"Somebody" needs to post something about the year and model of their car and post a pic of the engine and lines as best they can.

Michael

Somebody

1986 944t

Somebody

Well, still no digital camera to take pictures, but I'd be ashamed of how the vacuum lines look at the moment. Once I find the configuration to get it started, I'll bust out the good line and really route it in nicely. I have been looking over a lot of engine bay pictures lately and seeing some good ideas.

As an update on how things are going, still no start. I have been looking over and re checking the way the lines are connected. I've even tried to put it back to the wrong way the mechanic had them. I have gone through and worked on the idle, TPS sensor, etc using Lindsey's tech section.

I have found another diagram that was based off of the first one.

I have the tee's and lines going exactly like this one for the fuel rail section. I have yet to bypass the cycling valve still since it was starting with it intact. Also with the idle stabilizer, I haven't bypassed those two "Y"pieces.

I have pulled the plugs out to check them and they looked fairly clean.

Checked fuses, etc.

Is there a way I could have jammed some of the valves open or closed when the vacuum lines were run wrong?

Could this be some bad relay at awkward timing? (as I try and fix another part of the car)

Any help is appreciated as I want to get this car back on the road.

Rock

is the J boot on all the way...

schnellfahrer

Overboosting after installing Tial WG? Sounds like it is installed backwards.

Does the tach bounce when you run the starter?

Somebody

Rock:: Just checked the j boot and it is all the way on.

schnellfahrer:: As I'm cranking on the car the tach does not bounce at all. An odd thing I noticed though was that if I tapped the gas when I start cranking on it, the oil pressure gauge starts to climb.

schnellfahrer

Do a search on speed and reference sensors.

Somebody

Yep you are correct, it was one of the sensors male connectors that was the problem. But I didn't find the mistake myself...

I gave in an had my mechanic stop by to find the problem. He found the problem in about 5 minutes but that just comes with experience. He used a tool to check for spark and found that it was not firing. I'm just glad the problem was located cause I was going crazy thinking it was how I set up the vacuum lines.

What had happened was the male connector dry rotted and broke off into the female connector when I was messing around with the vacuum lines. I was not familiar with those lines and didn't really ever check that location of the engine bay as the connecters were not placed in the bracket they should have been in, they were further down into the engine bay.

Long story short, I have replaced all the temporary vacuum lines with lindsey racing's vacuum line kit and have them tucked away pretty well.

The sensor that broke off has yet to be replaced correctly due to the amount of a pain it is to replace. Instead I just used some electrical tape to keep the connectors together. I have been trying to remove that sensor on my parts car porsche to get a feel for how hard it is but I have yet to budge it...

Here's a picture of the engine bay...


it's no where near what some of the engine bays look like, but if you would have seen a before picture, you would really notice a difference.

KuHL 951

This is the 3rd time now that I've posted about this same thing happening and still the car had to go to a shop. As far as I'm concerned it's one of the first and easiest things to check after the DME relay if the car just stpos running or won't start. We really should have a simple laminated troubleshooting guide and DME relay test wire we all carry in the glove box with the more basic things that always seem to happen on the 944.

ibkevin

"dry rotted and broke off into the female", it doesn't get much worse than that!