Hi everyone just had my dreaded mot, and no suprises it failed!

 

Nearside + Offside rear brake pipes excessively corroded!!

Nearside headlamp aim too high and too far to the right. (adjuster fault)

Carbon monoxide emission content excessiive. (Both sides)

 

Wasnt as bad as i thought it would be. To be honest though i didnt think it would fail on emissions!!

 

What can i do to sort these failures out though!?

Can the brake pipes be done easily? As i know there are expensive to do in garages etc.

 

Please help!

what a suprise, seems most mot test stations are obsessed with bloody headlights. Did they say the actual adjuster is knackered, you can repair these to a certain extent its usually the plastic pinion thats had it. How high was the carbon monoxide???? you can remove a pipe from the balance tube to aid emmisions just while they test it. Depends where the corrosion on the pipes is, i'm affraid it could be a subframe down job to replace those, get underneath and have a look, you could "tart" them up abit, but be aware there is a safety factor here.

I always take my cars to the guy so he isnt too bad. He adjusted the other light there but said the pinion has broke so might need a new headlight! Also said get some emory on the pipes.

Wot pipe can you remove?

6.32% Left

5.65% Right

What year is your car ?. I didn;t think the 300zx qualified for an emmisions test ?

 

Pull a vaccum pipe off the back right of the plenum this should reduce your emmissions a little (or so I've been told).

Its 1990, all cars have to be tested for emissions just not with cats.

What can i do about the emissions, not really sure how to solve this?!

what a suprise, seems most mot test stations are obsessed with bloody headlights.

 

It's because they can now charge you halfthe fee again when you go back for the re test. Because they have to put it on the ramp for the re test. It is also something most people can't check.

 

You may be able to get the metal cogs from Danny at DTA (see the traders section) to fix the adjustment problem.

 

Not sure about the emmissions, sure they have to test it, but what is the failure level?

 

Good luck getting it sorted.

Co2 emissions on a petrol car are 3.5% max mine were as stated above which was twice that.

 

I dont know if i should try and tackle the brake pipes myself though! is there a guide or anybody who lives close that could give me some advise?!!?

you want to drive it hard for a while before you put it in for mot that brings the emissions right down! if its been standing around for a month or so the emissions will be high anyway and wont pass.

Oh yeah the back break pipes are nightmare you have to drop the rear axle to get to them.

hmmmmmmm, maybe you have an 02 sensor fault. I'm not sure i agree with this 3.5% CO2 business, at the end of the day, the higher the value of C02 the better combustion your getting up to a point of around 15%. Anyway, here just a few little pointers on what can cause emmisions problems.

 

Excessive HC

 

Ignition System Failures

Lean A/F Mix

Excessive EGR dillution

Plugged fuel injectors

leaking exhaust valves

incorrect timing

 

Carbon Monoxide

 

Excessive Fuel Pressure @ injector

Leaky Injector

FPR diaphragm knackered

Crankcase fuel contamination

PCV valves

 

Excessive NOx

 

Cooling system faults (Radiator restricted, thermostat, low level coolant etc...)

Lean A/F mix

o2 sensor fault, slow switching

EGR valve stuck, blocked etc...

Improper spark advance

Carbon deposits on intake valves

well i put some redex in before i took it down and gave it a hard run on the motorway its my daily driver too. He had the car running most of the mot and the emission test was one of the last things he did.

right it seems that for cars used pre 07/92 then its only a meter test carried out for CO which is carbon monoxide not CO2 which is carbon dioxide. And hydrocarbons @ 1200ppm limit. Now look at what ive put up for CO emissions problems, forgot to put down rich A/F mix, Where the O2 and HC levels elevated aswell????? If so i would consider checking the O2 sensors by self ecu diagnostic, or by voltmeter or oscillascope to check the waveform switching from rich to lean. Also check you havent got a blown joint in the exhaust downpipes. You could purposely run lean, removing vac tube or delibrately run on 5 cylinders by disconecting a coil pack, but then you may way fail on HC's

ok think ill have to check the other readings etc. There shouldnt be a blow anywhere in the exhaust as the mot tester would have picked that up. Would it be possible that the cats are knackered?

If a vehicle fails for high CO at idle and /or fast idle then.... if Lambda is too low, the mixture is too rich. This can be caused either by a misfire or by a faulty Lambda sensor. If it's running very rich, the 02 and HC will be higher than normal.

If it has a high Lambda and high 02 (0.5 to 1.5%), the "CAT" could be faulty. Before condemning it make sure its hot enough to work, the Lambda and other sensors are working as they should.If the vehicle fails for high HC then ...if the CO passes, the vehicle is probably misfiring. Or if the CO fails and the Lambda reading is too low, the mixture is probably too rich and it may also be misfiring. If the CO fails, the Lambda reading is high and the O2 reading is high (0.5 to 1.5%) the "CAT" could be faulty. Again check out the simple measures above before condemning it. If the Lambda fails then...if its too high the Lambda sensor may be faulty, the mixture may be too weak or there may be a hole in the exhaust downpipe. If Lambda is too low the sensor may be faulty, the mixture may be rich or the vehicle may be misfiring.