Starting problems some progress but PLEASE HELP !!

From CEM to VEM, from LED to lightbulb and more. If you have an electrical problem, like a broken info-centre, search for answers in this category. This is also the place to be when you expect the problem to be of an electrical nature...

Moderators: jifflemon, coyote1980, Rachel

r5b18ft
Knows where Volvo is from
Posts: 190
Joined: Wed Nov 05, 2008 10:04 am

Re: Starting problems -- PLEASE HELP !!

Post by r5b18ft » Wed Jun 01, 2011 5:35 pm

I replaced both ECU's and problem still there.

Injectors are fine as car starts after a veryyyy long while left untouch.

So, this is exactly whats happening :

1. Car starts fine & leave it to warm up
2. Turn off and try to start it again immediatley - starts OK.
3. Turn off and leave it for 15min/20min - NO START
4. Leave it for a long while , say 5hrs, try to start again - starts OK.

I am thinking some electrical / electronic component is warming up and failing when it comes to start and needs alottttt of time to cool down and work again !

NOTE : engine works flawlessly when started ! No knocking, perfect 850-900rpm idle, no smoking, etc


ITS DRIVING ME CRAZY !!!!! :cry: :cry: :cry:

r5b18ft
Knows where Volvo is from
Posts: 190
Joined: Wed Nov 05, 2008 10:04 am

Re: Starting problems -- PLEASE HELP !!

Post by r5b18ft » Thu Jun 02, 2011 1:15 pm

So.... a little bit of progress today !

I started the car as usual & waited for it to warm up.

Turned it off and left it to rest for 15min.

Tried to start again - NO start.

Unplugged the temperature sensor and tried again! BANGGGG ... off it goes :D thought it was the temperature sensor so I went to the local BOSCH agent and bought a new sensor. Removed the old one, put in the new, plugged the wiring and tried to start again -- NO START !!! :angry:

When the the temperature sensor is removed or when to car is COMPLETELY COLD ! Not a single degree more ! it starts OK -- when hot it does not start, despite the brand new temperature sensor!

What other electronic component relies on the temperature sensor readings ???

NOTE: As I said in my previous posts, I already have tried a couple of spare ECU's, and still with same problem.

User avatar
glasgowjim
480 Is my middle name
Posts: 4827
Joined: Sun Oct 01, 2006 5:28 pm
Location: GLASGOW SCOTLAND

Re: Starting problems -- PLEASE HELP !!

Post by glasgowjim » Thu Jun 02, 2011 4:41 pm

there are 2 engine type sensors for the 480 engine

the turbo one which has black plastic casing round the socket

the NA one which has a blue plastic casing round the socket which one have you got?

r5b18ft
Knows where Volvo is from
Posts: 190
Joined: Wed Nov 05, 2008 10:04 am

Re: Starting problems -- PLEASE HELP !!

Post by r5b18ft » Thu Jun 02, 2011 5:41 pm

glasgowjim wrote:there are 2 engine type sensors for the 480 engine

the turbo one which has black plastic casing round the socket

the NA one which has a blue plastic casing round the socket which one have you got?
Black one -- same part number (also looks exactly the same) as the original one.

User avatar
grafi
Knows an Aerodeck isn't a 480
Posts: 225
Joined: Wed Jun 17, 2009 9:12 am
Location: Budapest, Hungary

Re: Starting problems -- PLEASE HELP !!

Post by grafi » Fri Jun 03, 2011 6:19 am

So, you say that the engine always starts when its cold, or warm but the temp sensor is unplugged. If you unplug the temp sensor, it switches to cold mode... Sooo, the engine start in cold mode. Otherwise dont. Fuel problem maybe?
2002 Volvo C70 Cabriolet B5204T4
1995 Volvo 480 'Modell 95' + B18FT + Richmod (sold)

r5b18ft
Knows where Volvo is from
Posts: 190
Joined: Wed Nov 05, 2008 10:04 am

Re: Starting problems -- PLEASE HELP !!

Post by r5b18ft » Fri Jun 03, 2011 10:40 am

grafi wrote:So, you say that the engine always starts when its cold, or warm but the temp sensor is unplugged. If you unplug the temp sensor, it switches to cold mode... Sooo, the engine start in cold mode. Otherwise dont. Fuel problem maybe?
Exactly !

Obviously it is a fueling problem as when the engine is warm, the injectors do not spray! But when cold (or with no temp sensor) they work OK.

Spark is always OK.

Already tried to replace the fuel ECU but still same problem. Also tried to replace other ECU, but still the same.

What other electrical / electronic components have to do with the fueling system ??

Iroll480
Can tell where the 480 was built
Posts: 332
Joined: Sat Aug 23, 2008 7:33 am

Re: Starting problems -- PLEASE HELP !!

Post by Iroll480 » Fri Jun 03, 2011 12:20 pm

Did you check the wiring/connector from the coldstartsensor? Looks to me something is wrong with it, seems that the ecu isn't getting the info from the sensor when the engine is hot. The coldstartsensor from a turbo is different from a N/A engine as it provides a signal to both ecu's.

r5b18ft
Knows where Volvo is from
Posts: 190
Joined: Wed Nov 05, 2008 10:04 am

Re: Starting problems -- PLEASE HELP !!

Post by r5b18ft » Fri Jun 03, 2011 1:47 pm

Iroll480 wrote:Did you check the wiring/connector from the coldstartsensor? Looks to me something is wrong with it, seems that the ecu isn't getting the info from the sensor when the engine is hot. The coldstartsensor from a turbo is different from a N/A engine as it provides a signal to both ecu's.
That is not the case.

Because right after I start the car without the sensor, then I plug it again so it can work correctly, because when hot and without the senor it works really rough, obviously.

User avatar
glasgowjim
480 Is my middle name
Posts: 4827
Joined: Sun Oct 01, 2006 5:28 pm
Location: GLASGOW SCOTLAND

Re: Starting problems -- PLEASE HELP !!

Post by glasgowjim » Fri Jun 03, 2011 2:49 pm

Just an outside chance check the wiring to the cold start sensor for continuity . Eliminates 1 possibility.

Iroll480
Can tell where the 480 was built
Posts: 332
Joined: Sat Aug 23, 2008 7:33 am

Re: Starting problems -- PLEASE HELP !!

Post by Iroll480 » Fri Jun 03, 2011 4:11 pm

glasgowjim wrote:Just an outside chance check the wiring to the cold start sensor for continuity . Eliminates 1 possibility.
Exactly, why wouldn´t you want to check it? Start eliminating everything.

r5b18ft
Knows where Volvo is from
Posts: 190
Joined: Wed Nov 05, 2008 10:04 am

Re: Starting problems -- PLEASE HELP !!

Post by r5b18ft » Fri Jun 03, 2011 4:41 pm

Yes i can. And i will.

But what i mean is that if the wiring is cut, then the engine would not make any difference (when hot) when i plug the sensor again once its started.

When hot i start it without sensor, and it works very rich and high idle. Then i plug sensor again, with engine still running, and it corrects idle and fuel. So the temp sensor is sure to work.

BUT will check still !

r5b18ft
Knows where Volvo is from
Posts: 190
Joined: Wed Nov 05, 2008 10:04 am

Re: Starting problems -- PLEASE HELP !!

Post by r5b18ft » Fri Jun 03, 2011 5:35 pm

I was also thinking, if the wiring for the temp sensor is cut, then the ECU(s) would think that the engine is cold.

Now, with temperature sensor unplugged, simulating a cold engine, it starts immediatley. So, if the wiring is incorrect, it should start anyways, but work rough and on a high idle once the engine is warmed up.

Just a thought, still will check the wiring when I have time. Pin 2 on both ECUs, right ?

User avatar
grafi
Knows an Aerodeck isn't a 480
Posts: 225
Joined: Wed Jun 17, 2009 9:12 am
Location: Budapest, Hungary

Re: Starting problems -- PLEASE HELP !!

Post by grafi » Fri Jun 03, 2011 7:58 pm

According to your informations (replug the sensor corrects the fuel amount) the wiring should be ok, because it corrects the cold mode (too much fuel).
Obviously during the start only in cold mode gets the engine the right amount of fuel. Somehow the injectors dont work properly during start.

(Tomorrow will be the 15th Hungarian Volvo Gathering, I will ask around about your problem, maybe someone met something like this before. :) )
2002 Volvo C70 Cabriolet B5204T4
1995 Volvo 480 'Modell 95' + B18FT + Richmod (sold)

r5b18ft
Knows where Volvo is from
Posts: 190
Joined: Wed Nov 05, 2008 10:04 am

Re: Starting problems -- PLEASE HELP !!

Post by r5b18ft » Fri Jun 03, 2011 11:14 pm

grafi wrote:According to your informations (replug the sensor corrects the fuel amount) the wiring should be ok, because it corrects the cold mode (too much fuel).
Obviously during the start only in cold mode gets the engine the right amount of fuel. Somehow the injectors dont work properly during start.

(Tomorrow will be the 15th Hungarian Volvo Gathering, I will ask around about your problem, maybe someone met something like this before. :) )
Exactly !

Ok, thanks a lot :)

Iroll480
Can tell where the 480 was built
Posts: 332
Joined: Sat Aug 23, 2008 7:33 am

Re: Starting problems -- PLEASE HELP !!

Post by Iroll480 » Sat Jun 04, 2011 10:53 am

Maybe a too high resistance in the wiring, this will feed the ecu with the wrong info. Would explain that the sensor is influencing the idle, but not right enbough to start it when hot.
I haven't read the whole topic, but did you also checked the MAF sensor and the airintake temp sensor?

r5b18ft
Knows where Volvo is from
Posts: 190
Joined: Wed Nov 05, 2008 10:04 am

Re: Starting problems -- PLEASE HELP !!

Post by r5b18ft » Sat Jun 04, 2011 11:34 am

Iroll480 wrote:Maybe a too high resistance in the wiring, this will feed the ecu with the wrong info. Would explain that the sensor is influencing the idle, but not right enbough to start it when hot.
I haven't read the whole topic, but did you also checked the MAF sensor and the airintake temp sensor?
How can I check the MAF sensor ?

and is the air intake temp sensor plugged just before the turbo ? on the rubber elbow..

Iroll480
Can tell where the 480 was built
Posts: 332
Joined: Sat Aug 23, 2008 7:33 am

Re: Starting problems -- PLEASE HELP !!

Post by Iroll480 » Sat Jun 04, 2011 2:20 pm

Here is a drawing at which pins you have to measure the resistance from the MAF (luftmengenmesser). I only have it available in German, but the pics and resistance values speak for themselve I hope! The 382 ohms is just a starting point, most turbo's have the resistance set higher for better power and more economical driving. Inside the maf there's an CO adjusting screw for the settings, so best is to change the settings and check them with later with a CO meter to prevent it from running too lean.

Image

r5b18ft
Knows where Volvo is from
Posts: 190
Joined: Wed Nov 05, 2008 10:04 am

Re: Starting problems -- PLEASE HELP !!

Post by r5b18ft » Sat Jun 04, 2011 2:39 pm

Cant understand where I need to check for the resistance tho :?

Can you explain to me the procedure in some simple terms please ?

I am more of a mechanical person then electrical :lol:

User avatar
glasgowjim
480 Is my middle name
Posts: 4827
Joined: Sun Oct 01, 2006 5:28 pm
Location: GLASGOW SCOTLAND

Re: Starting problems -- PLEASE HELP !!

Post by glasgowjim » Sat Jun 04, 2011 7:14 pm

Iroll
even zooming up you cant read the diagram as the numbers are too small to read

r5b18ft
Knows where Volvo is from
Posts: 190
Joined: Wed Nov 05, 2008 10:04 am

Re: Starting problems -- PLEASE HELP !!

Post by r5b18ft » Sun Jun 05, 2011 10:28 am

Temp. sensor wiring is OK, just checked it!

Post Reply