850 dying "solved" Topic is solved

Post by **Clemens** » 03 Feb 2016, 03:35

The temp sensor sounds reasonable to me. Why did you put in larger injectors? Were you having problems already?
Is the fuel pressure known to be good? a dying fuel pump / clogged filter could cause fuel starvation. Try removing the spark plugs after it dies. If the plugs are wet from fuel then you have an ignition Problem, if not maybe it just doesn´t get enough fuel. The filter could Clog from driving, as soon as the Motor and pump are off the filter unclogs itself because the pressure is gone. This is a wild speculation, but I´d seen that happen before.

jantt · Post by **jantt** » 03 Feb 2016, 04:24

Someone says it not the temp.sensor when it just die. They say it`s fuelpump maybe.

My car is born with 200 cc injectors and they can max deliver 200 hp.
I am at about 200 hp so to get more power I want larger injectors.
I have made larger air intake to get more air and want now more fuel.
Have a chipbox, but get not more power and think it could be because of the small injectors.

Post by **Clemens** » 03 Feb 2016, 04:31

yeah, but now it´s a different story. Without being a mod Guru, I´d say the mechanical changes (like the larger air intake) could be responsible for your problem. Especially at idle. The basic idea of the larger injectors to compensate for the bigger air flow is correct, but since this is a quite modern car (compared to old school carburetted motors) you might need to remap the ECU according to your new hardware.
Also, give the IAC (idle control actuator) and the throttle body a good inspection/cleaning. And of course, an air leak around the injector seats could be the source of problems as well. Did you put new o-ring onto the injectors?

Post by **rspi** » 03 Feb 2016, 04:36

Check fuel pressure.

jantt · Post by **jantt** » 03 Feb 2016, 04:55

No has ordered new O-ring, but not got then yet.

Idle is perfect.

Now they talk about and yes I remember now that we have changed a lot of fuelpumpe relays.

jantt · Post by **jantt** » 03 Feb 2016, 09:08

Have checked temp.sensor and it`s ok. Changed fuelpump relay and it`s not that.
Just drove 6 km home and it didn`t die, but lost rpm sometimes when I hold for red light. Rpm went up and down.
Could it be some vacuumtube leeking ?

Post by **erikv11** » 03 Feb 2016, 10:49

erikv11 wrote: ... Since you were just working on it, I would look carefully for any vacuum leaks.

Stumbling at low RPMs is a common symptom of a vacuum leak.

Stumbling at a particular throttle position could be a throttle position sensor (TPS) problem, but it seems unlikely to show up right after you were working on it. Unless did you clean the throttle body, and some solvent got into the TPS?

jantt · Post by **jantt** » 03 Feb 2016, 11:19

No did not clean throttlebody.
Will check all tubes again tomorrow.
It came after I changed the injectors, so I changed the injectors back because I thought that was the problem.

jantt · Post by **jantt** » 03 Feb 2016, 21:50

Have now ckecked all vacuumtubes and they are ok.

Guess it`s now only fuelfilter or pump that could be the problem ?

jantt · Post by **jantt** » 03 Feb 2016, 23:40

How about the potentiometer on the throttlehouse ? Could it be that ?