440 idle problem

[Leighton_s]

Hi

I have a 1995 440 1.8 SI (B18U) which has an idle speed problem and was hoping someone might be able to help. Bought the car two years ago and its been reliable with only an occasional problem with the idle that would rise to 1500 rpm but would then settle down after a while. Searched online and hearing of other owners having this problem changed the idle motor soon after having had the car. This did not cure the problem and it did not bother me much so did not take this any further.

Recently on starting the engine would idle at just over 2000rpm and would rise to 3000rpm when it warmed up. To be able to drive the car I disconnected the four pin plug to the idle control motor and the revs went no further than 2000rpm. After doing some research I found it is possible to control the motor manually by applying 12 volts across the top two pins of the motor and set rpm at 1200 when warm, which is ok in this weather but is going to be a problem when the weather starts getting colder.

To try to repair this problem I have to date tried:

• Changing plugs and air filter as part of service
• Changing idle motor back to original
• Looked for vacuum leeks and changed one rubber pipe which was starting to break up
• Renewed coolant temperature sensor (was noticing an unusually low reading on the gauge)
• Cleaned flywheel sensor
• Managed to get cheap spare ECU on ebay to try
• Renewed exhaust\inlet manifold gasket while on holiday recently (engine runs better, but did cure idle problem)

Might be time to get rid of it now perhaps as the water pump is starting to make some noise and the rear end is getting creaky.

[owenski]

I know this thread is 5 years old but I would like to resurrect for my problem. I also have a 1996 1.8 volvo 440 with a B18U engine and it has the exact same problems as the first posters did.

Like him when you start the car in the morning it would idle ok but after about 10 minutes of driving the idle would jump to 2000 and then on to 3000 and stick.

Like him I have also done the following to try and cure the problem.

Changed plugs and air filter
Changed oil filter and new oil
Renewed front engine temperature sensor
Changed idle stepper motor the new Bosch one I got from local Bosch dealer.
Changed some rubber ends on the vacuum pipes and on the charcoal filter, which where starting to break up.
Managed to get a cheap ECU unit from Breakeryard website as the back of my original one had some corrosion on the circuit board.

Also took it up to my local Smw Volvo dealership for a £75 diagnostic test

Their diagnostic test showed up these three faults below

Number 1 vacuum air pipe split
Number 1 vacuum air pipe valve missing
Manifold gasket needs replaced

I got Volvo to replace the number 1 vacuum air pipe and put in a new vacuum air pipe valve, as it was only an extra £35 to do this on top of the diagnostic price.

I got the manifold inlet gasket from Volvo parts when I was there that day and I am going to get my own local garage mechanic to fit it, as he is a lot cheaper than Smw Volvo.

Now my question to other members is should I also get my own mechanic to replace the exhaust manifold gasket when he is doing the inlet manifold gasket and does anyone know if this is likely to cure my idle problem?

Also I have noticed if I disconnect the air vacuum rubber hose from the bottom of the MAP sensor when the high idle problem happens it lowers the idle to normal but does make the engine run rough and smell bad.

Any help on this problem would be greatly appreciated as its been driving me nuts

[GTMaster]

Exhaust manifold gasket failure doesn't effect the idle (haven't experienced it ever), it just makes the car noisy and the engine bay gets filled with smoke (if it's really bad then some may get into the cabin) but since it's directly under the inlet manifold you can have it replaced as there's more room there if the inlet manifold is removed (the exhaust manifold can be examined as well for cracks etc. in the process). After the repairs check for fault codes again... but when the idle stepper motor was changed was the throttle cable adjusted?

[GTMaster]

Also found this for the B18U engine (don't have this in mine so it was new to me ), might be worth having a look at:
You mentioned that it's alright when cold but as it warms up the revs rise. Could be that the flap is always closed and is sucking in cold air for a longer amount of time (would also mean that the engine might not warm up fast enough). Just a thought...

2_23_B18_35.JPG

[GTMaster]

Throttle cable adjustment... (fault code above picture is for auto gearbox and crank position sensor...).

2_23_B18_13.JPG

[owenski]

Thanks for the quick replys guys.Yes when I put the new bosch stepper motor in I did adjust the throttle cable to take the slack out of it.

Yes the idle fault only happens after about 10 -15 minutes of driving and I think I know that air flap valve with the two rubber pipes running into the bottom of that big pastic air pipe from air filter to injector head.

for a matter of interest do you know which way the 2 rubber hoses go in that air hose hot cold flap valve??

I have it booked in next week to the local garage for them to change to inlet manifold gasket I bought from volvo so if the faults still there after that I will be stuck as I am running out of ideas on this problem

[davejm]

Hey sorry to butt in but got same prob with a 1995 si changed everything i can think of but no joy mine is affected by the weather if its damp it almost stalls when you loose off throttle was thinking about running wires from stepper motor into car and fitting a switch so i can turn it off without lifting bonnet everytime

[owenski]

Originally Posted by davejm

Hey sorry to butt in but got same prob with a 1995 si changed everything i can think of but no joy mine is affected by the weather if its damp it almost stalls when you loose off throttle was thinking about running wires from stepper motor into car and fitting a switch so i can turn it off without lifting bonnet everytime

Interesting that problem. If I where you I would check the ECU under the drivers side footwall cover as that sounds like a damp problem getting into it.

I would take out the ecu unit and dry it on a warm radiator overnight then try and rap a pastic bag over the multiplug and around the ecu and stick it back in to see if that stops the problem.

if it works then water is getting into your ecu unit when its very damp

PS/ If any members from Northern Ireland know of a good mechanic that knows everything about volvo 440,s let me know as I am stuck with my own now

[davejm]

i will look to see if the ecu is getting damp just had the fuel injector refurbed goes well now loads more power shame revs still sticking though

[owenski]

At last I have worked out what this very annoying Idle problem was down too and I have even fixed it myself.

Here is what I did to discover and Fix the problem myself,

I took the drivers side foot wall pastic panel off so I could get at the ECU unit and then I let the car run and idle for about 30 minutes as it was parked to let the problem happen again.

Once the high idle problem started to happen I gave the the long black Ecu multiplug a good wriggle with my hand and sure enough the problem stopped and the idle went back to 900 revs as normal.

I knew then It had to be a bad contact joint somewhere around the black long multiplug or inside the ecu so then the next thing I did was turn the car off and disconnected the positive battery terminal and then unclipped the multiplug from the bottom of the ecu unit and then I used the smallest jewellers screwdriver I had and squezzed all the lose looking multiplug contacts together.

I put the multiplug black on the ecu unit and took the car for a 20 mile drive that sunday. I noticed the problem was still there as I was driving and I pulled in to a layby and wriggled the multiplug again and the problem disappeared again.

When I got home I took all the Torx screws out to open the Ecu unit and I discovered there was cracked solder joints in the ECU board where the multiplug pins join onto the Ecu circuit board

So with my trusty £8 soldering Iron I got from my local Maplin Electronics store I soldered up all the contact pins and put the ecu back together and then I test drove the call all week and its driving great and I am all happy again