91 tsi fuel pressure solenoid chattering and the dsm dies

[freebird_43]

I have searched several threads here pertaining to the fuel pressure solenoid on the 91 tsi but havent found a way out of this problem. this sol. chatters and the car dies, as long as it is chattering it wont start. if it stops chattering it will start. not sure if the sol. is the problem or whats controlling it. Ive read in this forum that this sol is not even needed! any guidance would be great!

 

[SmoochDarling]

I think you are referring to the fuel pump relay, which you do need. The solenoid is part of the whole vacuum line/evap system which most people toss.

 

[freebird_43]

the fuel pump relay would make sense, however I chased this chattering noise to the bank of sol. on the driverside fire wall it has the egr sol. fuel pressure sol. and evap emission purge sol. I isolated it by unplugging each sol. and ended up at what is called the fuel pressure sol. in the manual, its vacuum operated from the fuel regulator but electricly controlled by something, I cant seem to find a schematic on how this sol is controlled. it is very intermittant but becomming more frequent.

 

[DSMReviver]

it might be something entirely different. fuel relay "mpi" is on the passenger side at least on 2g. where is the noise coming from? top, bottom, timing side?

 

[freebird_43]

I chased this chattering noise to the bank of sol. on the driverside fire wall it has the egr sol. fuel pressure sol. and evap emission purge sol. I isolated it by unplugging each sol. and ended up at what is called the fuel pressure sol.

The noise (chattering ,buzzing or vibrating) is being emitted from this sol. I looked at it today and the car starts fine and no (chattering ,buzzing or vibrating) is comming from this device. I doubt that the sol is the root cause of the car not starting and also dying, this condition may be affecting something upstream on the vacuum circuit or perhaps on the electrical side. it may also be associated with the large amount of rain that has came down in the area of late. The DSM' S all seem to be plagued with the same problems I was hoping someone had seen this before and could get me out of this problem. I will keep an eye on it and hope it doesnt fail as Im pulling out in front of a mac truck!

 

[Spoolin92GSX]

I can't speak on removing the solenoid, as I'm just about to remove mine, but I can give you an idea of how it works.. It is electronically controlled by the ECU, to block vacuum "flow" to the Fuel Pressure Regulator (on the passenger-side end of the fuel rail) during hot starts. So, obviously there are a chain of components that could affect how this solenoid functions (or if it does at all). Everything I've read says that eliminating the solenoid has no ill effects, but I can't confirm that *yet*. The worst "possible" effect is that a hot start takes a few more cranks to fire up. Give it a try removing the solenoid if it's still acting up, just make sure you keep a direct vac/boost source to the fuel pressure regulator.

 

[freebird_43]

Thanks for the info, I was able to download the service manual with schamatics and found that the FPS is controlled by the TCU, I swapped out the FPS with a used one and the same thing, the coil is chattering and either the DSM wont start or it will die if its running. very intermitant problem, one day its ok and the next it wont start or stay running to even get out of the driveway! I had both the TCU and ECU rebuilt or replaced approxamatly two years ago. I think I will chech the connectors on the TCU and make sure everything is tight. I can hear relays switching in the ECU or TCU when this FPS coil is chattering. I will post what I find

 

[nmarcy]

I just removed all 3 of those sensors that ate on the firewall. They can be removed. I used taboo emissions delete diagram to figure out what to do with the vacuum lines.

Taboo speed shop vacuum diagram and removal for 1g and 2g - Mitsu-Media

This is the Link if you wanted to remove all 3 of the sensors on the firewall.

 

[Laggg]

Deleting the emissions system is the best mod ive made to my dsm so far haha. Clears the bay and eliminates issues that could arise.

 

[freebird_43]

it appears to be the ECM, I took it out and sent it to crites core here in Indiana and just got a call from the guy that rebuilt the ECM and he told me its worn out! however it was rebuilt 3 yrs ago. so 130 bones and I should be able to get the DSM back into the wind! This car is pretty much stock and hoping to keep it this way for awhile, she perfomes well when she runs, and is very dependable. she has 130K on the clock and has been taken care of, I purchase the car for 1600 bones 3 yrs ago, but she was stuck in safe mode, and blowing oil past the turbin, so had to put 300 bones into the ECM and TCU and I replaced the turbo with a stock 14B another 150 bones for it. all in all she is a runner for sure!

 

[o0GuitarKid0o]

Mines squished like the vac line completely closed can it cause issues?