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Greg, Technician
Category: Car
Satisfied Customers: 1097
Experience:  Automotive diagnostic tech
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Problem with high emissions

Customer Question

Have a Peugeot talbot 1971 cc petrol motorhome. Reg in 1994. Failed the mot test because it registered .91% CO. the limit is.3% . It was at 1.45 at the first test . I then put in additive and changed the filter and drove it for about 75 mls. The engine was purposely hot on arrival for the second test. What is the manufacturers specs for this engine with regards XXXXX XXXXX CO emissions ?.. The engine no is CGAE 0000 809.What further things might be done to address the CO issue before I get it retested.?
Submitted: 3 years ago.
Category: Car
Expert:  Rob replied 3 years ago.
Hi and welcome to Just Answer.
I am sorry you have been waiting a long time for a response.
Could you supply me with the other two readings on the emissions sheet.
regards rob
Customer: replied 3 years ago.
I went to test centre three times in oct. the following are the readings
At high idle -2830 deg C - and oil temp of 98 deg C

1st test. Lambda limit of not between1.03 and 0 .97. Read .974. Pass
CO vol%. Max limit of .3%. Read 1.22 %.Fail
HC ppm. Limit of 200. Read 39. Pass
2nd test. Lambda. Read 1.206. Fail
CO. Read 1.45%. Fail
HC. Read 57. Pass
3rd test. Lambda. Read .987. Pass
CO. Read .91%. Fail
HC. Read .43. Pass

A local mechanic adjusted a carburettor after 1st test. I fitted a new air filter after the 2nd test

Customer: replied 3 years ago.
At low idle of 950 Deg c and oil temp 98deg c the three readings were
1st test read .25%
2nd test. .25
3rdtest. .17
The limit is up to .5 %
So it passed this element on all three occasions
Expert:  Rob replied 3 years ago.
Hi John.
I am a bit concerned that the correct test procedures are not being performed.
this engine was fitted from 1986 to 1994 and they were never fitted with catalyst or oxygen sensors as there were fitted with carbs .
The test says vehicles from 1992 to 2002 have too have a cat test but there were a few engines that were exempt for a couple of years .
you can check this by examining whether you have a catalyst ,oxygen sensor fitted.
the test station has a manual issued by the testing authorities that will tell them if this is exempt I know this as I have been testing for many a year and come across this once in a blue moon.
IF you can get back to me on the cat and sensor is fitted or not.
regards rob
Customer: replied 3 years ago.
I can confirm that a cat converter and oxygen sensor is not fitted. My local small garage man confirmed this . I know the person well who I bought it from and he did not get anything fitted to the engine while they had it for 15 years before I bought it from them..
I noted that my carb specs are as follows:-

Type is Solex 34 PBISA. 16.
Another part of the specs say :-
PSA 315. 1C10

Inote in the Peter Russek Pocket mechanic book (1998) on page76 that carb " PEU A 315 is fitted to engine types 169B and 170B. WhilecarbPSA 425 is fitted to engine type 170 C . The combination re my carb (iePSA 315 is not referred to. The same page refers to the CO content as follows :-
169 B and170B engines. Range is .5% - 2.5%.
The 170C engine range in 1% - 2%.
Which engine do you think I have going on the carb specs.
Also is the measurement technique/system to the above CO content and the ranges stated the same as that used by the test centre and max of .3% allowed. Because if it is then is it impossible for my vehicle to reach the level of .3 or lower?
Expert:  Rob replied 3 years ago.
Hi John.
The only way of knowing what engine you have fitted is to refer the engine code on the engine block.
The test center should be testing the c/o on a max of 4.5 as your vehicle is not equipped with a catalyst and it should only be tested at idle with oil temp at 60 c .
Do you have a governing body that controls the mot testing standards?
regards rob

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