Engine 850: B5234T/2.3/20v/T5: Starting issue

WOW - I can't believe it!!! EXACTLY WHAT MY CAR IS DOING!!!

Check this out........

http://www.vpcuk.org/forums/t14434-i...or-my-car.html

Anyways again everything replaced. However I have not had a new engine fitted, so I don't think it is this cleaning between engine and gearbox that is the problem.

NOW THE AMAZING BIT...... The last fault code read and cleared on my car was... you guessed it The RPM Sensor. I even did the same as stuart and replaced the switch behind the barrel. It is so frustrating. I think my RPM sensor may have been knocked or damaged in the garage when I had all that work done. Anyways I have ordered a new one from Volvo and I am picking it up as soon as I wake up Friday morning.

I will be fitting the new one and cleaning everything near it and checking all wires and earths nr there. I hope this is the fix.

STUART ILL LET YOU KNOW FRIDAY!! LETS HOPE AND PRAY!!

Bison

No Joy, It's definately not the RPM sensor, this has been replaced with a new one today. my local Volvo specialist had a look at it this morning. He thinks it's fuelling, there are no fault codes recorded suggesting nothing electrical.

Anyways back to the drawing board. I will be keeping an eye on this thread. Car is booked in for 1sr Nov for full diagnostics. Won't be cheap by the sounds of it. Hope we can come up with a fix before then.

Bison

[pault5]

i had the same fault some time ago, it turned out to be the fuel pump.
paul

[BlackBeast]

Good time to upgrade to a Walbro pump if it is the fuel pump. Much cheaper than a Volvo one too.

[imac]

Originally Posted by Bison

No Joy, It's definately not the RPM sensor, this has been replaced with a new one today. my local Volvo specialist had a look at it this morning. He thinks it's fuelling, there are no fault codes recorded suggesting nothing electrical.

Anyways back to the drawing board. I will be keeping an eye on this thread. Car is booked in for 1sr Nov for full diagnostics. Won't be cheap by the sounds of it. Hope we can come up with a fix before then.

Bison

Have you swapped ECU's with another automatic T5?

Would only take a few minutes to do and your specialist probably has one or two spare to try!

Have you swapped ECU's with another automatic T5?

Mine is a RICA'd ECU and my car is manual. Standard ECU is making no difference, problem still occurs.

[liuleichan]

Originally Posted by pault5

i had the same fault some time ago, it turned out to be the fuel pump.
paul

I've had a problem with a fuel pump to - it wasn't actually my original fuel pump, it was a used one replaced previously, to chase an unrelated problem.

When I first had the problem with the fuel pump, it wouldn't start - there was spark, but no fuelling. It was recovered to my local garage, as the recovery people couldn't get it going.

It was dead like that for a while - good few hours, 'til the next day. Then at some point, it just started. Then it worked for a while, stopped working for a while (ie all whilst it was still at the garage), and working again.

So totally dead for a good few hours at first, then intermittently on-and-off working.

Had the original fuel pump put back in (which just so happened was still in the boot!) and it's been fine where that's concerned ever since.

[Mark_in_Conwy]

Hello everyone, I'm another T5 owner with a frustrating problem like Stuart's Intermittent failure to start when hot. (My engine has been separated from the gearbox to fix an oil seal, but my problem began well after this. I have not had a change in engine). I have a wild alternative idea - an engine oil additive - that might help for £14 or so.

My list of attempted fixes since February must be in the running for some sort of prize, and please can we all agree not to compare the money spent with the value of my 220,000 mile T5 (!!)

I have replaced HT leads, coil, ignition switch, battery and fuel pump relay. I have replaced the crankshaft position sensor, fixed a dodgy electrical feed from the battery, replaced coolant temperature and camshaft position sensors. I have even had the ECU refurbished and then swapped the ECU itself (though I have now reverted to the original).

The good news is as follows, and I'd appreciate any thoughts. A local Volvo specialist advised that the hydraulic valve lifters may be sticking when the engine is hot. He claimed this was a common fault leading to the intermittent hot starting failure. Parts are north of £350 with several hours of labour to replace them. HOWEVER - in Halfords I saw a product in the oil additive department that is designed to free "sticky or rattling" hydraulic lifters. WYNNS HYDRAULIC VALVE LIFTER (£6.99 for 350ml). I bought a bottle and put it in the engine. I have since put in two more bottles (2 bottles is about the right dose for the oil volume but I'll be doing an oil change soon). My car has not failed to start for over a month. I am beginning to think that I have solved the problem (but am still "touching wood").

I freely admit that I can not figure out the logic of why sticky valves would cause ALL the symptoms. Perhaps we are dealing with several factors combining together. It is plausible that the easy bump-start (I try to park mine facing downhill, Stuart!) is because the engine is whacked round more brutally than with the starter motor (though mine fires immediately even if I bump at about 2mph). At some stage we did have a dodgy spark (hence replacement of all the ECU and HT parts) but I don't know whether I have any problem now because it is behaving so well. I've put tools in my car to test the spark if it fails on me again.

Is your spark now reliable, Stuart?

The comment about interference and dodgy earthing is interesting. I'm pretty sure my volvo mechanic tried and discounted this on my car but I could be wrong.

I would be really keen to know from the experts the location of the most significant earth connections. It seems there is one on the starter motor and there is one next to the battery, but the one I'm particularly keen to find are the earth connection points for the ECU itself. My ECU refurbisher said that the unit was earthed remotely, and I have the details of which ECU terminals should be earthed, but I don't know where the other end of the connection is located. These may be through certain of the sensors but I really don't know. I reckon it must be worthwhile to ensure all these earthing connections are clean and free of corrosion.

Time to sign off - I'm hoping the oil additive has done the trick, and may put another dose in my fresh oil. If the problem comes back I'll test my spark and then try to find as many earth connections to clean as possible.

Best regards to you all!
Mark

[Mark_in_Conwy]

I know few of you will be surprised. Do you remember what I said about "still touching wood"...?

So my beloved T5 failed a hot start again yesterday (i.e. 12h after my previous message and the first time in over a month). Why didn't I keep my big mouth shut... Seriously, I do believe the oil additive does help to give the engine the best possible chance at starting with a dodgy (but not completely absent) spark.

I connected a strobe, when the engine was failing to start. For the first three to five seconds of cranking there was no spark at all. Then there was an irregular spark every few turns (but, since it was irregular, I think it was only sparking every third or fourth time). Sometimes, after about 20 seconds there was a series of good sparks and the engine would fire up and run smoothly.

I guess this is abnormal behaviour, and something is messing up the ECU. So, I'll be following this thread if anyone has any better ideas than mine! I'm still dead keen to hear advice regarding earthing connections or possible causes of interference to the ECU circuitry.

Yours Sheepishly,
Mark

[pookie]

I've been away for the weekend and have only just come across this thread. Did the voltage at the coil + terminal (hot cranking) get measured? if so what was it ? Secondly, but I don't think that it has anything to do with the hot starting problem, fuel pressure at 3bar or whatever is good, but what volume of fuel is the pump delivering , I've seen many instances of enough fuel pressure but after 30secs or so the engihe stops until the pump ups the pressure.

Pookie