v70 2.5 tdi 1998 cold start problem - electrical

shahidocean · Post by **shahidocean** » 18 Dec 2009, 06:13

guys,
i've had this v70 for a few years now, started first time every time like a trusty old workhorse. anyway went to pick up the kids and someone in a small nippy car shot in front of me forcing me to emergency stop! the next day i had a cold start problem, cranked for about 5 mins before it fired but ran fine after that.
called aa they said glowplugs, i got some off ebay and they fitted them, same problem, took it to nationwide under aa breakdown warranty, they said glowplug voltage too low on start, they sent to volvo dealer who said, ecu need replacing and maybe other things, i bought the car back home drove it!
i think its a wiring issue, when i braked hard i think one of the wires or plugs in the loom has been stretched. can anyone help me and give me some pointers, which connections should i check and where they would be, also where can i find the information on this diesel version d5252t engine. thanks in advance, i am looking forward to hearing that sweet sound of firing on first turn. have a brilliant christmas!

everitt · Post by **everitt** » 20 Dec 2009, 15:07

Hi, is your check engine light on? if so can you get the code read?

z28chuck400hp · Post by **z28chuck400hp** » 29 Dec 2009, 09:45

during the hard stop you may have kicked up some "slop" from the bottom of your fuel tank.May have plugged up your fuel filter, causing hard start...may be a cheap fix... good luck, let me know how you make out.

shahidocean · Post by **shahidocean** » 06 Jan 2010, 03:04

hello guys,
thanks for the replies it is very much appreciated,
haven't done anything with the car yet because of the weather and holidays, i posted on another forum as well and i now have a circuit diagram of the 15.7 msa starting system, i need to go and get a t30 socket, to get the engine cover off. I will check the fuel filter, how can i check that?

I want to assume that its a wiring harness problem, because the volvo guys would have found a code on their scan, i will ask them but i dont want to take the car to them again, i think this problem is beyond their capability anyways ...

I have a meter, whats the best way to start diagnosing the problem. I find that in these problems, finding the real source of the problem is the whole battle, so i am looking for clues, the big one is this ...

When the aa guy replaced the glow plugs when i started it, it fired first time then it stopped starting again on the second firing, so i think the breaks in the wiring system are close to the glow plugs, it also was misfiring on a few cylinders starting up, now this is what i don't understand, i thought that the glowplugs are only used in under 5degrees and that they don't operate like spark plugs, so when the compression happens, the injectors squirt a mix into the cylinders and this happens later if its colder, I want to check that circuit path make sure the that voltage is getting there, and also check the voltage at the plugs and follow the wiring back to source.
is there anything obvious that i should check. best regards

shahidocean · Post by **shahidocean** » 12 Jan 2010, 08:13

ok guys checked from the relay pin 3 to the glowplugs and there is continuity,
checked the voltage at the glowplugs, when i turned the key, i got 12 volts
coz the glowplugs come on for about 10 seconds in the cold, when i started,
i got 12 volts during the cranking and it started in about a minute, then i ran it took it for a run, when it was hot i started it first time three times. nothing wrong with it! so i will try starting it in the morning. i can see fuel coming in to the injectors, i think through a clear pipe so i am assuming fuel system is working, glowplugs work, ecu works, relay works, and there is continuity. what to test next?

shahidocean · Post by **shahidocean** » 13 Jan 2010, 03:09

my lambda light is on in the dash is that telling me something?

shahidocean · Post by **shahidocean** » 26 Jan 2010, 17:31

guys flipping brilliant news ! shes alive !!!!

my car's working again, pump timing and some air leaks
63.45 and worth every penny, the car is roaring along, nay purring along, and that sweetesst of all sound, whirrrr brroooom started! first time every time, from cold from hot ! and that tdi 2.5 boost perfect firing optimum performance and sipping at that 46-60 mp...gsss god bless [ bugsy's autos bucklesham ( can i put this here?)] , the flipping experts ! Diesel kevins your man !

thanks all you guys !!!! back on the road again !

oracleminded · Post by **oracleminded** » 01 May 2010, 08:57

Can you tell me what the problem was? What did you fix?

shahidocean · Post by **shahidocean** » 01 May 2010, 13:39

it was the vaccuum hoses were leaking that go into the egr valve / controller and around there,
my egr valve is stuck open too i am waiting for a gasket and i will remove that and clean it and that should fix it completely ...

shahidocean · Post by **shahidocean** » 17 May 2010, 12:24

update,
cleaned the EGR valve, replaced it with new gaskets,
the lambda light went out ! but i still have a cold start problem
engine usually starts after the first firing runs for about 20 seconds
and then i get white smoke and it stalls.

if i switch off the engine and restart it and give it some gas and let it warm up,
then it runs fine, could this be a bad mass air flow meter?

thanks