help help help

[bholmes]

Ok, here's how it was...
I was at school waitin to meet w/ one of my buddies, while I waited I decided to tinker (always a bad idea). My Wife, Mom, Dad and Grandpa all have compained about a slight fuel odor around the car, so I decided to track it down in my spare time. I checked the small 1/8th inch lines coming from the two fuel regulators to start with. The rubber "T" where the two return lines from the two fuel pressure regulators come together looked like it may be a little old, so I tried to slip it off and look at it under the light (it was dusk). However, instead I just broke the "T". So I tried to pull the small return line that runs to the vaccum/tank so I could go get a new "T" when my buddy got there, instead I broke a peice of the 1/8th inch tubing. So by the time I got done it was pretty ratty (needless to say all those peices were in need of repair due to cracking). So I ran to Autozone and got some* parts to fix it, they didn't have everything I needed, and were closing. So I got what I could and tried to coble it. I ran the two regulator return lines into a "T" that then went solely to the tank return unit on the fender and left the vaccum hook up open because of lack of parts. This caused way to much back pressure on the line, I had a fitting blow off and then had to redo it and wire it so I could make it home. This however made it load up on pressure and made it start to run VERY rough for some reason (not sure how the regulators work). So I instead put my return to the vaccum port and left my return unit on my fender open. This made it run fine and I drove it home without a hitch, ran like it always has. But when I got home I parked it for about 15 minutes and then It wouldn't start and stay running. It would start and then die, so I switched it back to the return on the fender thinking it was getting to much fuel, this didn't help either though. So now it won't start I thought it's possible it could be flooded, so I'm going to try it here in an hour or so. Does anyone have any answers or ideas? Thanks so much for your help!
~bholmes

[nynor]

what car do you have?

[bholmes]

86 944, not S or turbo, plain 944

[bholmes]

I just went and tried to start it again, it started and ran fine for a just long enough to make me happy and then I reved it up and put it in gear to go for a drive and then the same problem as before. Seems to me like it's not gettin the fuel, could it be possible I messed up my regulators witht he back pressure? You'd think a little rubber fitting would blow off before the regulators got messed up. So that's where I'm at now...where I started at.
~bholmes

[nynor]

could be a ruptured diaphragm or something in one of the regulators.

i'd start by making sure it is back together properly, then i'd test the fuel pressure at the rail and the flow rate.

[bholmes]

That's along the lines of what I was thinking...where can I pick up a fuel pressure gauge? I'm not seeing any at autozone.com or partsamerica.com, will I probobly have to order it? Thanks for the help. I'll kee you posted.
~bholmes

[bholmes]

An after thought. Once I do get things back to original how do I know which regulator is bad (if one/both are bad).
~bholme

[nynor]

when mine went, they both went.

you can blow into the vacuum line and if it allow the air in, they are done. you can test them separately.

[bholmes]

Sounds quite likely, I think I've got the procedure down between you and clarks garage, I'll give them the once over tomorrow and see what I need to do. Thanks again.
~bholmes

[Razorback1980]

Are you saying the vacuum lines from the regulator and dampner go to the fender somewhere? IIRC, they are suppose to go to a vacuum fitting on the intake manifold.

[SoCal Driver]

There have been diagrams posted here on both the early and late 944's vacuum line layouts. Search for them. Also use the diagram that should be on the fender well.

[bholmes]

I'll search for the diagrams, to be honest, I think it was a factory return line, or had been a factory replacement item (I'm not sure if those fuel lines can stand 20yrs of service). The way it was run was from both the regulators into a T then it was a single tube for a little bit, then another T that went to the manifold vaccum port and the other branch of the T went to the diaphram on the fender well. That is how I intend to run my replacement lines as well unless someone has a legitament reason for doing it otherwise. I'll probobly do them tonight as soon as I can get a baby sitter! (wife has school, 6 month old isn't too good with cars...yet). What is the diaphram on the fender for? Is it like a check valve for the fuel return, or is it something else that requires vaccum and just gets it from the same source as the return line? Also I ordered two new regulators, they should be in tomorow, the way I have it figured is if the regulators aren't the problem, it never hurts to have parts on hand since I intend to own the car for quite some time. Thanks for the input.
~bholmes

[SoCal Driver]

Stop guessing and get the diagrams. You can buy the rubber tees and elbows from Pelican or a dealer. The hard plastic line comes in three foot lengths from Pep Boys or Kragen or whom ever.

[bholmes]

Already got the parts and just got the diagrams, they help alot, thanks SoCal. I'm just itchin to get out and work...babysitting is a ROUGH job sometimes! Since I can't work on it I am just insecently BSing.

[SoCal Driver]

Rerouting/replacing vacuum lines is hands on just like trying to find an electrical problem. You just have to do it.

[bholmes]

Finally the wife got back so I could get started. I got my vacuum lines taken care of, no biggie. However it seems it's not my regulator that's giving me problems but my fuel pump. I'm getting ready to go back out and test the fuel pump and check the fuse block to make sure it's nothing that simple. I'll keep you posted.

[SoCal Driver]

What is your fuel pressure?

[bholmes]

My fuel pressure is none. None at all, so I checked the fuel pump/O2 sensor fuse and it was OK, so I jumped the DME (wire across 30 and 87b) and tried to see if I could collect any fuel in a container from the front end of the fuel rail and I got nothing. I tried turning the switch to the run position as well as even cranking the motor and neither produced fuel. Naturally I thought it was the fuel pump so I pulled the pump and tested it with a 12v source and it worked fine. So I reconnected it to the wiring on the car and just left it lay and turned the switch to the run position and the pump did not do anything. Now I'm a little baffled. I've owned the car two or three weeks, so I'm still not to familiar with them. I thought there maybe a fusible link in the wiring, but it seems that the 15amp fuse in the fuse box is the fuse for that line. Looking at the schematics the only things I see that could be wrong it the DME, the Fuse, the wiring itself or most probably the connection to the power souce for the DME. What would the car do/not do if the DME didn't have power? The car will crank over, which it looks to me that the starter has nothing to do with the DME, so that makes sense. Any light you could shed on this problem would be a great help.

[SoCal Driver]

The fuel pump does not run unless the engine is cranking or running. When cranking (as has been pointed out before) the signal to the starter is also sent to the DME and the DME closes the second set of contacts in the DME relay to run the fuel pump.

Once the engine starts the signal from the speed sensor on the flywheel (reads the teeth on the starter ring and is not in any way related to what the tach indicates) keeps the second set of contacts in the DME relay (fuel pump) closed and thus the fuel pump running.

[bholmes]

Ok, I did not know that, thank you. None the less, I was not getting fuel when I jumped the DME and cranked the motor. Could it be I didn't have a good connection when I jumped the DME? I'll have to try it again with the pump out of the car today and see if it runs when someone cranks it. It sounds to me like what people describe as the DME when it fails. I really don't know to much more that it could be. Well thanks for the help, I'll look into things some more today and let you know my findings.