Been awhile since I have been here but I have a continuing problem I am hoping that someone here may be able to help me with.

I have a 1995 850 Turbo Wagon that simply will not start (basically it will turn over just fine, but it will not even attempt to fire).

Background: The car ran perfectly the day I parked it (about 18 months ago). Now it will not start. The battery had been disconnected about a week after parking it for the long period of time. Upon charging the battery and reconnecting it, it has not started up, nor even once attempted to fire when cranking.

Here is what I have done so far:

1: Bought an OBD-II reader and scanned the system. The only problem code it presents is P0120, which is a malfunctioning Throttle Position Sensor.

2: I replaced the TPS and the code remains still saying it has the P0120 code (I have also reset this code and it continues to show up, even with the new sensor installed.

3: Replaced the battery with a brand new Interstate battery

4: Checked and rechecked as best I can to make sure the built in alarm system is not causing the car to be unable to start. I do not think this is the problem.

5: Replaced the spark plugs with new platinum ones (old ones removed were also platinum)

6: Syphoned out all the old gas and drained the lines. Replaced with new high octane gas.

7: checked to make sure the fuel pump is pumping and building pressure (it is). Also just replaced the fuel pump relay shortly before it was parked for the long duration (the new relay worked great, no issues there). Have since tried a new fuel pump relay as well just to make sure.

Possible problem is a situation with the coil. I have the 12V running to the plug that plugs into the power stage of the coil, however I am not reading any power on the wires connecting directly to the coil. The connector itself has a third wire, which I assume is a control wire that tells the power stage to turn on/off (and thus supply power to the coil itself). I do not know for sure that this is what the 3rd wire is, nor do I know what to look for or check in regards to voltages and such to see if possible the power stage is malfunctioning, or possibly something else is keeping the system from turning on power to the coil. Any help here or explanation on how this part works would be helpful.

Aside from that I am open to any possible ideas on what else to look at the help figure out why the car simply will not start or fire. I am on a budget and cannot afford to keep replacing part after part in this, but dont mind going thru the processes of testing things to try to determine whether parts are good or not. What other possible electrical problems could be causing this? any specific sensors to inspect and test to make sure they are good or not (and hopefully some instruction on how to test them).

Anything would be helpful, thanks.

 

How long was it sitting before you tried to start it... the full 18 months?

Do you have compression?
Have you checked/replaced the CPS?
Have you tested your injector pressure? (clogged injectors from dried up e10)
Do you have solid spark?
Have you sprayed anything into the intake manifold to see if the motor pops?
Have you looked at the connections for the main relay?

 

Yes it had been sitting unused for that long or longer.

Compression: I believe so, no official checking of that though.

CPS: I have no checked but plan to, unsure of proper method to do so, any pointers would help

Injector Pressure: Not sure, I know I have pressure to the distribution manifold that the injectors connect to but have no checked the injectors directly (pointers on how to safely do so would be helpful). I have used the small valve on the end of the manifold, and the pump does rebuild pressure each time I bleed it off to check.

Solid Spark: Not seeing one. Appears the coil is not getting power. Power is present at the plug into the power stage module next to the coil, but no power is being sent to the coil that I can read with my meter.

I have sprayed some starting fluid into t he intake manifold today. Actually it did pop only once (as if only a single cylinder fired only once). I have not been able to get it to do so again though. This happened the 2nd attempt at using starting fluid.

Main Relay Connections: Which relay specifically? I have checked all the relays I could find and checked them and removed/reseated each one. These include all the ones next to the fuse box in the engine compartment (where the fuel pump relay is) and the ones underneath the dash on the drover's side. Nothing looked bad and reseating them did not change anything.

Side note, even with the new TP sensor, the ODB-II is still giving me the code that the TPS is malfunctioning. Could this cause the engine not to fire at all? I am beginning to think that the TPS isnt the problem (or if so, only one part of it, but the new one is installed).

I know there are several sensors that could cause this, but at approx $100 each I cant afford to just buy em all and replace em, so finding out the proper method to test each first would be helpful.

Thanks again

 

CPS would cut out your spark, but if the engine popped with the starting fluid you should have spark.
The main relay is above the radiator..
The tps code gets thrown alot whenever the motor doesnt have the propper components to start, it compression, fuel.

I pull the injectors and see if they are fuzzed up with the green gunk that sitting dried ethanol causes.


These are out of a motorcycle that was sitting for 4 years..

 

I will check the main relay when I get the chance tomorrow I think (might be Friday).

I dont mind pulling the injectors (was coming up soon on my list anyways to inspect and possibly clean). However, prior to doing so I have a couple of questions regarding the injectors:

1. Anything specific to keep in mind when removing them (or special process needed to do so)?
2. Do you know of any place selling the o-ring kits that would also include the small filter inside the injector (I assume they have one). All the kits I have seen are only for the o-rings).
3. Anything specific I need to make sure I do not do to the injectors (specific parts to be very careful with, certain cleaning solvents not to use (or ones you suggest that work well), etc)?

Aside from the injectors. I have been working on and cranking the engine ALOT, and only that one time, with the starting fluid) did it ever sound like it even attempted to fire and even then it sounded like only one cylinder partially tried to fire). After which I began inspecting the coil. Any way that you know of to test the signal that is supposed to tell the coil it can charge up? Specific voltage to test for maybe?

I am guessing that this signal would be sort of feint and very quick, so my Multi-Meter may not be able to pick it up quick enough to really be able to read it properly, but any means to help diagnose the coil and power stage would also help. I am trying to rule out individual parts so I am not left with just having to keep buying and trying things, since most electronic parts cannot be returned. I dont mind if later I have to come back to it, but anything to help me better test things would be handy. If not, no biggie, any assistance or info you may have is always appreciated.

Thanks again.

 

Should see 12V at red wire on coil referenced to ground. If you don't, and you've got 12V at blu/red wire going to pwr stage, then it's probably the pwr stage unit; get another one from junkyard; rarely see those fail.

 

it probably might be the fuel injectors. but check the fuel pump also. as well as the timing belt makesure its not broken and check the distributor cap as well ur ignition iming might be off. oh and also makesure there no moisture or damge to an of the ignition parts

 

oh and deos the engine rotate slowly??

 

If you are getting fuel pressure but no spark, I would replace the cam shaft sensor.

 

I'll answer the questioned mentioned by the last couple of posts in one shot here.

- I've been wondering about the power stage unit, as I've had this issue on 2 cars in the past, each time it was something that rarely goes out (at least before the coil or other parts), and of course both times previously, that little unit is kinda pricey, but it's actually cheaper for the Volvo than the previous 2 times
As best I can tell, the coil isnt getting power from the power stage. There is a third wire going into the power stage that I assume is a control wire that the computer tells it when it can come on, but I dont know how this control voltage (if it is) actually works, whether it is a constant signal or one that cycles with the coil. If it cycles, my meter might not be able to read it properly or quickly enough. This is all speculation of course as I'm really not sure what that third wire is for.

- The fuel pump is pumping, although I can never actually hear it kick on. The tests I have done are as follows:
1. When I drained the gas tank I initially disconnected the fuel filter (the one by the gas tank), and cycled the ignition. Each time it spewed gas out.
2. During cranking attempts, to bleed out potentially old gas, I would bleed out the pressure via the small fetzer valve on the fuel rail by the injectors. Each time I would crank it I would check the valve and it had built up pressure again.
I do not know if the fuel pump is building up proper pressure, but it is continuing to build pressure. And yes, as best I can tell at this point it is not firing. It has never attempted to fire with gas, and it only ever once attempted to fire one time with starting fluid, but even then it may have been something else, it sounded rough but was only a split second.

- Does the engine rotate slowly? I am guessing you are refering to when I crank the engine over? If so, it sounds just like it always has when cranking (just that it never fires). It doesnt sound like it is struggling to crank and sounds quite smooth with no hiccups or varying cranking speed.

- I havent checked the timing belt yet and the cam shaft sensor I think is my next item to consider replacing anyways, since it can cause such problems and has a tendency to go out anyways. The distributor is also next to be checked as well. Just got swamped with last minute work to be done and havent had a chance to check anything else just yet.

Is is common or anything to have such electrical parts (such as sensors) to just quit working because a vehicle has been sitting? I can understand that the timing belt could just be old and lack of use could cause it to break, but I wasnt sure if just sitting could cause a car to get out of timing and such. basically just wondering for future reference really, I will still be checking everything you all have mentioned.

Thanks a bunch,