S40 power loss

Mandla · Jan 13th, 2008, 10:22

Driving home last night, in my 1998 S40 T4 when it wouldn't take any throttle and a sudden loss of power. i managed to coast into a layby where it wasn't idling properly and was trying to stall, so i switched it off and left it for a minute and tried to restart it. After a few turns it started but was still the same , idling wrong and just stalled when you gave it throttle, i got it towed home and looked under the bonnet for air pipes off or vacuum pipes because it felt like it was getting no air or it couldn't get rid of the exhaust gases, seized turbo or maybe the cat had collapsed blocking the system, i could hear the fuel pump working, I took off the air filter and looked into the mass air flow meter to see if it was dirty, but it looked ok. I started the car, it seems to be idling normal again. When in the car the engine malfunction light was on which would be right enough but the DSA light was on as well. When i let it run for a while it started vibrating violently and stalled. Then i removed the key and the radiator fan started and wouldn't go off until i put the ignition back on again so i pulled the fuse. Tried it this morning and the fuse back in (no fan) and it started perfectly didn't run it for long removed key fan back on, so i pulled the fuse again, Can someone help!!

Enigma666 · Jan 13th, 2008, 13:43

What is happenening tot eh temp of the car when you turn it over? Does it soar up high (faulty thermostat perhaps)
There are a few people on here with the idling issue where the car seems to want to cut out and you have to keep the revs up to stop it (one of the blessings of an x40)
Not sure about the juddering though.
Check all the pipes again for any obvious signs of leaks or splits and if possible take a piccy of the engine bay witht he covers removed

wa666ou · Jan 18th, 2008, 00:28

Have you checked for error codes?

manoman48 · Jan 18th, 2008, 06:29

I would put my money on the fuel pump. Same year as mine and I have just had to replace mine after the same problems. That said it doesn't explain the strange fan behaviour. As already mentioned, what does the coolant temperature guage read?

If it happens again, but then after an hour or so it works fine again, this is exactly the same as what happened to mine. Be warned though - the distance you can drive before it cuts out gets shorter and shorter.

edit - have a read of this thread => here <= as one of the posters mentioned the fan acting strangely when there was a fuel pump problem.

Enigma666 · Jan 18th, 2008, 10:16

I'm intrigued to know how a fuel pump can activate the fans I must admit...
The fans are driven on temperature sensors alone, my guess would be any fans staying on would either be a faulty thermostat or a temp sensor

manoman48 · Jan 18th, 2008, 11:03

I agree.. it certainly doesn't seem logical to me, but may be a bug in the ECU software?

spyda · Jan 18th, 2008, 11:34

Sounds like a similar thing that happened to me - which turned out to be a major misfire, resolved in the most part by a change of spark plugs.

Only difference really is that I had no issues with the fan. The rest of it all sounds very familiar.

Jan 13th, 2008, 10:22	#1
Mandla New Member Last Online: Mar 12th, 2008 06:48 Join Date: Dec 2007 Location: Johannesburg	S40 power loss Driving home last night, in my 1998 S40 T4 when it wouldn't take any throttle and a sudden loss of power. i managed to coast into a layby where it wasn't idling properly and was trying to stall, so i switched it off and left it for a minute and tried to restart it. After a few turns it started but was still the same , idling wrong and just stalled when you gave it throttle, i got it towed home and looked under the bonnet for air pipes off or vacuum pipes because it felt like it was getting no air or it couldn't get rid of the exhaust gases, seized turbo or maybe the cat had collapsed blocking the system, i could hear the fuel pump working, I took off the air filter and looked into the mass air flow meter to see if it was dirty, but it looked ok. I started the car, it seems to be idling normal again. When in the car the engine malfunction light was on which would be right enough but the DSA light was on as well. When i let it run for a while it started vibrating violently and stalled. Then i removed the key and the radiator fan started and wouldn't go off until i put the ignition back on again so i pulled the fuse. Tried it this morning and the fuse back in (no fan) and it started perfectly didn't run it for long removed key fan back on, so i pulled the fuse again, Can someone help!!

Jan 18th, 2008, 06:29	#4
manoman48 Master Member Last Online: Apr 28th, 2023 11:20 Join Date: Mar 2007 Location: Sc.unthorpe	I would put my money on the fuel pump. Same year as mine and I have just had to replace mine after the same problems. That said it doesn't explain the strange fan behaviour. As already mentioned, what does the coolant temperature guage read? If it happens again, but then after an hour or so it works fine again, this is exactly the same as what happened to mine. Be warned though - the distance you can drive before it cuts out gets shorter and shorter. edit - have a read of this thread => here <= as one of the posters mentioned the fan acting strangely when there was a fuel pump problem. Last edited by manoman48; Jan 18th, 2008 at 06:36.

Jan 13th, 2008, 13:43	#2
Enigma666 Master Member Last Online: Apr 16th, 2021 11:32 Join Date: Aug 2006 Location: Chester	What is happenening tot eh temp of the car when you turn it over? Does it soar up high (faulty thermostat perhaps) There are a few people on here with the idling issue where the car seems to want to cut out and you have to keep the revs up to stop it (one of the blessings of an x40) Not sure about the juddering though. Check all the pipes again for any obvious signs of leaks or splits and if possible take a piccy of the engine bay witht he covers removed

Jan 18th, 2008, 00:28	#3
wa666ou Junior Member Last Online: Jan 26th, 2016 08:34 Join Date: Jun 2006 Location: Kermarne	Have you checked for error codes?

Jan 18th, 2008, 10:16	#5
Enigma666 Master Member Last Online: Apr 16th, 2021 11:32 Join Date: Aug 2006 Location: Chester	I'm intrigued to know how a fuel pump can activate the fans I must admit... The fans are driven on temperature sensors alone, my guess would be any fans staying on would either be a faulty thermostat or a temp sensor

Jan 18th, 2008, 11:03	#6
manoman48 Master Member Last Online: Apr 28th, 2023 11:20 Join Date: Mar 2007 Location: Sc.unthorpe	I agree.. it certainly doesn't seem logical to me, but may be a bug in the ECU software?

Jan 18th, 2008, 11:34	#7
spyda Member Last Online: Jun 20th, 2009 23:53 Join Date: Jul 2007 Location: Sheffield	Sounds like a similar thing that happened to me - which turned out to be a major misfire, resolved in the most part by a change of spark plugs. Only difference really is that I had no issues with the fan. The rest of it all sounds very familiar.

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