High emissions
 

My Volvo 440 1.7si auto 1993 failed on emissions. The mechanic said this can be adjusted using the c.o. potentiometer. But he couldnt find it. He looked through the Haynes manual and it's not where it says it should be. He then said he thinks my engine has been replaced with a 2lt version. I looked for the engine number; when I got home; where it says to look in my owners manual. On my ownership papers my engine number has 1 letter then 12 numbers. Where I looked it had 1 letter and 6 numbers. Is this right? Is the Mechanic right?

Have a look on the front of the engine block, next to where the dipstick tube goes into the block, there may be a small metal plate about 1 inch x 2 inch with the engine series code stamped on it,

mine says B20F, if yours does it is the 2.0i engine.

If yours has a cat converter and Lambda sensor then yours doesn't have the pot. meter on top of the air filter (or around there). If it's a 1.7i then the engine code for the catless version is B18EP while the cat. Lambda version is B18FP (basically same engines, just the latter has a cat converter and lambda sensor fitted, power is 102hp instead of 106hp.)
Why did it fail on emissions? Too high CO/HC (running rich) or high NOx (running lean)? Was it good on idle or was it bad in the whole rev range?

Emissions results
 

Thanx for your replies. Fast Idle Test. CO failed. Max Limit 0.300, mine 0.552. HC passed. Lambda passed. Second Fast Idle Test. CO failed. mine 0.624. Passed the other two. Natural Idle Test. CO failed. Max limit 0.500, mine 0.585.
Looked by the dipstick, which is where i looked last time. The number began with what looked like a P then had 598441 after it. Not quite the B18!

You can check it on the V(ehilcle)I(dentification)N(umber) plate as follows:

Example: XLBEX313ESC593307

Position Example Purpose
1-3 XLB Manufacturer code
4 E Car type
5 X Safety standard
6-7 31 Engine type
8 3 Transmission type
9 E Verification
10 S Modelyear
11 C Factory
12-17 593307 Chassisnumber

Engine type:
01 = B18K-102
02 = B18KP-111
03 = B18E(S)-105
04 = B18E(D)-104
05 = B18FT(M)-107
06 = B18FT(M)-107
07 = B18K(D)-102
14 = B18E-104
17 = B16F-109
18 = B18F-106
19 = B18FT-107
31 = B20F-208

even easier way to read the VIN go to volvo 480 club europe homepage ( only the forum is goosed) and click on vin reader type in your vin and it will tell you what your engine is .

Thanx for the help with the VIN number. Any-one have any idea on the high emissions? Dont want to spends loads trying to work out what it could be.

If the air filter and spark plugs haven't been changed then best to start with those. If that doesn't help then best to check the lambda sond to see if it's working properly. After taking the car out for a spin check the spark plugs and see what colour they are, they should be light brownish. Have you noticed an increase in fuel consumption and is the engine temp gauge working properly? Have you tried checking any fault codes?

Will check air filter and spark plugs tomorrow. Cant take car out as its out of MOT. So cant take it anywhere for any-one to test/check anything. Has always been heavy on fuel consumption. About a month ago the temp shot up into the red. the oil light flickered and the petrol guage went down. Had plenty of oil water and petrol. Its done this a few times since. Asked at garage. They'd never heard of it before.

(Just my opinion on what possible problems there may be):
If engine temp sensor is giving a false reading then that may cause high fuel consumption (also if the temp gauge doesn't show that the engine reaches running temp then the thermostat might always be open and that too can cause higher fuel consumption). If the lambda sond isn't working properly, then that too. If the spark plugs are worn or dist. cap and rotor then that as well. A dirty air filter can cause similar effects. If alls well and the engine runs fine yet the emission reading isn't good then it may be the cat. converter.
There the things i can think of, hope you're able to find out what the problem is.