94 850 Turbo doesn't want to start

greenacarina · Post by **greenacarina** » 31 Mar 2014, 12:26

Hey all. Finally got my 94 850 turbo back together after swapping in a manual trans. Re-connected all my wiring and vacuum lines and this thing does NOT want to start on it's own. A good blast of starting fluid will get it started, then it runs normally...idles correctly, gets up to operating temp, will not restart without the starting fluid. I haven't driven the car yet, so not sure how it does under load.
Not sure where to start here...guessing I may have connected a vacuum line incorrectly?
Here's what I have-
Vacuum "tree" - fuel pressure reg, solenoid valve, long black tube that goes toward the battery then heads toward the passenger compartment (cruise control?).
Manifold vacuum fittings (larger one and smaller one that are below the plastic vacuum tree)- Larger one to the turbo nipple that is not the wastegate, smaller one to the fuel vapor canister purge valve.

Any suggestions?

Thanks
Chris

Post by **erikv11** » 31 Mar 2014, 12:41

Did you hook up the big vacuum line to the brake booster?

That third one on the tree doesn't sound right. All the 850s I've ever seen (all 95+), the cruise works entirely on a separate vacuum pump under the battery.

greenacarina · Post by **greenacarina** » 31 Mar 2014, 14:40

Ah! Forgot about the little pump gizmo under the battery. That is intact and working. Still not sure what that other tube is for, but I am pretty certain it attaches to the tree.
BUT...I did some more testing and it appears my injectors aren't bring triggered. Double checked my crank pos sensor and the connector for the ECU, both are plugged in correctly and snug. Going to take a closer look at the crank sensor and make sure I didn't muck it up somehow.

Any other suggestions?

Post by **erikv11** » 31 Mar 2014, 14:51

Fuel injector relay up under the radiator shroud? That's assuming fuel pressure (fuel pump and its relay) is ok.

greenacarina · Post by **greenacarina** » 31 Mar 2014, 15:00

Yep, it's getting plenty of fuel at the rail. I tested the injector plug with a noid light...got nothing. EXCEPT...it did fire up once, randomly, and got the blinky light like it was supposed to. Then I shut it off, no restart, no blinky light.

Post by **erikv11** » 31 Mar 2014, 15:17

Well then that could be the fuel injector relay, although I won't know how to test that one. Or ECU, good call. I remember someone posted a problem like this once and it turned out to be frayed wiring somewhere between the relay and the ECU, or something like that ...

Post by **Volvofan94** » 31 Mar 2014, 20:26

I tested the fuel injector relay on my 850 Turbo when it had a rough idle. Here is a good link on how to jump/test the fuel injector (titled Noise Suppression in the link) relay. Jumping the relay will cause the IAC valve to pulse with the key in Position 0. The pulsing will go away when the key is in Position II.

http://www.davebarton.com/volvorelays.html

greenacarina · Post by **greenacarina** » 01 Apr 2014, 10:08

AH!!! I have heard a lot of people use the terms "fuel injection relay" and "fuel pump relay" interchangeably. If there is a relay that controls the injectors....I think I'm in business!
Will chase that one down today.

Thanks!!
Chris

Post by **jose456891** » 01 Apr 2014, 11:09

Expendable parts are commonly overlooked. What is your fuel pressure when sitting w/ key on, idling, under load?

Perhaps the fuel filter is clogged or the fuel pump relay its on its way, or the fuel pressure regulator is hooked up wrong.

greenacarina · Post by **greenacarina** » 01 Apr 2014, 16:34

OK. Found the relay attached to the fan shroud. It appears to be functioning correctly, but still no signal to the injectors. AND....I dug out my test light and it appears that I also have no signal at the coil. Starting to think more and more that my crank sensor is TU, as that is certainly a common link between those 2 problems. Also haven't ruled out the ECU yet. Is there a pinout diagram somewhere for the ECU?

Thanks,
Chris