I have a 1995 850 T5r saloon which I have owned for nearly 25 years and for the first time ever I can’t get it to start let alone run smoothly.
I have to admit that I think my problem is at least in part down to the fact that I don’t use it nearly enough and although under a breathable cover she hadn’t seen light of day for nearly a year when it started playing up.
I know I need shooting!
So, the build up to the ‘not-starting’ – the symptoms were a drop in performance and very poor mpg (down from c. 26 to sub 20 on a long run. But it started and ran. I read the fault codes and variously read 121 (MAF) and 231 (Long term fuel mixture too lean or rich in part load stage). All cleared and haven’t recurred.
I then experienced significant hesitation on acceleration and loss of power generally but still ran. Then I struggled to get home – lumpy running, cutting out etc.
So into my garage for some Stage 0 tuning stuff (although missed a couple of things-later).

What I have done:
- New MAF sensor (not Bosch! But really, would this stop the car from running at all?)
- Tried starting with MAF unplugged (default mode?) and would not start
- All new vacuum hoses
- New distributor cap and rotor arm
- Cleaned plugs and leads
- New O2 sensor (Bosch) – there’s only one pre-cat
- New fuel pump
- Checked fuel pressure and c. 40 psi – ok
- Cleaned and serviced injectors (new seals and filters)
- Changed oil, filter and air filter

What I haven’t done (yet):
- Changed plugs and leads (leads are a pain to source and the plugs looked ok)
- Changed TCV (turbo control valve) or FPR (fuel pressure regulator), both cited on line as potential issues but not for an inability to start the car!

So just tried to start it and it fires for about a couple of seconds, really rough and dies. Also strange squeak – never had before!
I opened up the oil filler to check for obvious signs of head gasket failure i.e. milky oil and nothing but it did look like there was a lot of misty vapour in there!

Sorry for the lengthy post but if anyone has any ideas I would love to hear them.
Thanks.
Pete

Forgot to mention - PCV done too.

 

Did you check the injector relay? look for a gray box up front by the fan... There should be Youtube vids to check as well

 

Thanks for the thought and I haven't yet. I only found out about it from RobertDIY's Youtube video this morning!
I have shifted focus onto the Camshaft position sensor as it seems to be a common issue and creates some of the symptoms I have. A new one is on order - not so expensive here in old Blighty as for you in the US!
It was a little oily around the seal when I took it off but not too bad. But the lower bolts was only hand tight - odd.
Thanks again for your suggestion.
Pete

 

I am not certain a cam position sensor will cause a no start - but a failed crank sensor certainly would so Id that to the list of suspects :-) Did you try reading the fault codes? There's a good write up on volvotips.com on how to use the diagnostics jumper/LED on the 95s

 

Thank you, I will do that. Apparently, cam position sensors can gradually fail and send wrong info to the ECU on fuel, air, spark and whatnot such that the car can run rough and then stop when it completely fails.
Codes 121 (MAF) and 231 (Long term fuel mixture too lean or rich in part load stage) came up hence why I changed the MAF and O2 sensors but now I get nothing - apparently she is running fine! Lol

 

The engine has to run a while to set those codes (unless the air mass meter is disconnected.)

You need to try to determine if it's spark or fuel that's not working.

Spark - test light on the flashing side of the coil?

Or - spray starting fluid in the intake - it if runs you have spark and no fuel. (or incorrect fuel metering)

It is true the cam sensors on those cars (1993-1998) fail. Whenever I saw a cam sensor code with that style sensor - it was replaced. Before the car was towed in for a cam sensor!

But instead of throwing parts at it - figure out if it's spark or fuel - that's much easier to do on a 98 than a newer car (that has one ECU controlling both)

 

Cheers hoonk. Good advice.
I have gone some way with both spark and fuel having removed the coil lead and seeing a spark but admit I still have to check for a spark at the plugs.
With regard to fuel, I had poor pressure at the rail which prompted a new pump and filter resulting in an increase of some 10 psi but no cure.
My rationale for the cam sensor change, which was relatively small money for a pukka Bosch unit (Ł55 / $67), was that if failing was sending all the wrong information for both spark and fuel timing etc. to the ECU. Hopefully it will arrive tomorrow so we'll see.
But thanks again for your input.

 

Changing the camshaft position sensor has made no difference I am afraid.
I have spark at the plugs and 40psi at the fuel rail.
It tries to fire and dies.
I will check the injector solenoids are receiving power but other than changing the crankshaft position sensor, I am at a loss!

 

I suspect your real problem is a big leak in the plumbing between the MAF and the throttle. That's very common on T5's and it disconnects the MAF from reality. The rubber mitten right at the throttle body is the worst offender, but once in a while one of the simpler rubber elbows will simply slip off the hard pipe. I've had a couple of failures in the idle air bypass hose.

All these big leaks have the potential to make a squeak, but I don't think that is too common.

 

Thanks Firebirdparts. I have had all of the hoses off, both vacuum, throttle to MAF, intercooler etc. etc and they were ok when I took them off and are now back on securely. Always worth another look so thanks again.
I'm waiting for a crankshaft position sensor and fuel injector relay - yup, I am throwing parts at it since i confirmed spark, fuel and air were ok!
I read elsewhere that a dirty idle air control valve can cause problems so that's now on the list too!
Fast running out of options though so any further thoughts are gratefully received!

 

Forgot to mention that when I checked power to the injectors I got a continuous 12 volts when cranking which didn't sound right. I was expecting on / off pulsing to reflect intermittent demand over the engine's cycle. Anyone have any thoughts on this? This is one reason why I thought it might be fuel injector relay / crankshaft position sensor / camshaft position sensor.

 

The ground side is the part that's timed

 

I know I'm being a bit dim but could you put that another way for a simpleton like me please?

 

On the diagram follow a red highlighted wire from the battery 1/1 labled 5R to 2/32 relay. When that relay is energized power is sent thru the green wire (GN) to all the injectors (and a few other things) So you will find +12v at the injectors all the time (with relay turned on)

The injectors fire when the control unit 4/46 provides a ground connection - follow the other wire from each injector back to the Control unit and note the little ground symbol - at connection A10 for example. .

 

That’s really helpful, thanks.

I am getting 12v when the test leads are on both injector pins, not on one pin and the other to earth. So if one of those pins is ground, shouldn’t the meter be showing a pulse when turning over the engine?

 

Your meter does not have a fast enough sampling rate to detect a voltage change. You need a simple noid light (that fits your wiring) if you want to verify the injector pulse.

 

Got it. Thanks again hoonk. Just need to source one in the UK now!

 

That is how it should be. You need to look elsewhere. The pulses exist, but they're really short.

If you want to poke at this area, then they make something called a "Noid light" that you would plug in place of the injector and it will flash when the injector is told to turn on. if you're interested in that sort of thing. Oh, sorry, you already got that. I'm behind, ha ha.

 

Thanks firebirdparts. This is where I am now!
Hurrah! She's started after fitting a new crankshaft position sensor - thanks to you guys for the suggestion. But it sounds like I have a misfire. I have got electrical pulses at all injectors after testing with a noid light and spark at the plugs. But if I remove the plugs from the injectors on two of the five cylinders and/or the HT plugs from the same cylinders there is no difference to the engine note / misfire! I have switched spark plugs between cylinders and the same cylinders have the problems.
I have good fuel pressure at the rail and cleaned all the injectors.
Also cleaned the Idle air control valve for good measure.
What with all the other stuff I have done and replaced I am at a loss again - sticky valves maybe? I have had and still have an on/off ticking noise.
Although I'm not looking a gift horse in the mouth with regard to getting her started, I would just like her back to her old self!
Any suggestions will be gratefully received.

 

Just ordered some new HT leads and genuine Volvo spark plugs. Once fitted I will report back. Hoping it's not a valve issue!