14 replies to this topic

[Hot MPI]

I am sitting here anxiously awaiting the results of my MPI's MOT. I predict a catastrophic failure!

[clubman katie B.F]

don't worry too much, you should be ok with an mpi. when you have a 1971 1275gt then you REALLY worry. good luck

[Hot MPI]

The results are in......FAILED!! The fails were as follows;

No. plate light out,
o/s & n/s track rod ends,
o/s & n/s front subrame mounts broken away!
Excessive play in n/s/f wheel bearings,
o/s lower ball joint worn,
o/s/r footbrake inopperative,
exhaust emissions high.

Plenty to keep me busy this weekend in the snow (

Anyone else out there with a modified MPI who has had trouble passing the emissions test?

[CharlieBrown]

Thats a fairly big list.

Hope you get it all sorted.

[Jordie]

Things like lights and balljoints you could have checked before hand....saving you afew jobs and £30 mot charge......you got a re-test free?

[Jammy]

Part of being an MOT testing garage is that you offer a re-test for free within 14 days (I think its 14 days), I don't know how garages get out of that!

[Hot MPI]

I've got a free retest if I take it back within two weeks, which is why I didn't bother to go over it before I took it in. It's a bit cold out and I'm very nesh! Still, not too bad. I was aware of some of the stuff so I'd already ordered the parts beforehand. It's the emissions that I'm a bit worried about. It's got quite a lumpy idle and is pretty rough below 1500 rpm due to the cam and big valve head. I'm not sure if I can do anything about it. Interestingly, the number plate light is working!? I guess it must be an intermitant fault?

[P91MER]

I have a reasonably standard MPI and i struggle to get it through the emissions! Had to let my mechanic take it in for the re-test because he knows the tester :wink:

Ball joints- mine fail on every year, 1 side bearings were gone aswel.

subframe mounts sound a bit daunting tho!!!

[Lora222]

thank gawd for carbs, and a mini thats registration is 1970 = less harsh mot :grin:

[998dave]

I've got a free retest if I take it back within two weeks, which is why I didn't bother to go over it before I took it in. It's a bit cold out and I'm very nesh! Still, not too bad. I was aware of some of the stuff so I'd already ordered the parts beforehand. It's the emissions that I'm a bit worried about. It's got quite a lumpy idle and is pretty rough below 1500 rpm due to the cam and big valve head. I'm not sure if I can do anything about it. Interestingly, the number plate light is working!? I guess it must be an intermitant fault?

Do what I do, ask them to tweak it in, oh, hang on, no carb...
Dunno if they can tweak it in with an MPi....

[Dan]

Did they rev it to try to get it through the emissions? There's some rule about reving it to two and a half thousand and if the emissions come down to the right level in less than twenty seconds and stay there for long enough it'll pass anyway. That's the only way me mum's old man's Rover gets through!

My '84 car sailed through first time again last week, as ever!

[Hot MPI]

I don't know how the test was conducted, I wasn't present at the time. Looking at the printout, the co was over by 0.75 vol at idle and 0.30 vol over on the 2nd fast idle test. There is also a third symbol, like an upside down y. Does anyone know what this is? It would seem that the tolerance for this is 0.950-1.090 at fast idle. My car was recording 5042.538 ! I don't know what it is, but it doesn't look good :sad:

[Dan]

It's the lambda symbol (it's a Greek letter). It is what the lambda sensor in your exhaust is for. When Lambda is 1 all the oxygen in the air is being burned off with fuel, so the lambda sensor detects oxygen in your exhaust as close to the exhaust ports as possible. It detects if all the oxygen is burned off inside the engine and not in the exhaust, which is a (slightly misguided) government recommendation about how to make an engine clean and efficient. It does sound like there is something wrong, what else is up with it that might give a clue to the problem?

[Hot MPI]

Thanks Dan, I should have known what that symbol meant. Doh!

The engine is quite heavily modified; 1380, big vavle head, high lift rocker, longer duration cam, etc. The fuel pressure regulator has been uprated to a 3.5 bar item to provide the necessary additional fueling at high revs, the trouble is, it causes very rich running at idle. In fact, when it has been idling for a while, such as in traffic, it starts to choke itself on unburnt fuel. I usually have to blip the throttle a couple of times before pulling away again. I have an Emerald ECU which I am in the process of wiring up to the car, but it's not ready yet. I suppose if all else fails I will have to hurry and get it finished, but then it will need mapping, or I could become good friends with an MOT tester I haven't had a chance to familairise myself with the injection models yet, but there must be a way of adjusting the idle co, surely? I have a lambda reading of 5042.538, about 5042 times more than what it should be, you won't be surprised to learn that the fuel consumption is worse than my Volvo T4 ! OH my poor baby! I've got another 11 days left on the current MOT certificate, and I don't use it everyday at the moment, until I sell the T4, so I've got time to sort it out. I now see why nobody bothers to tune the injection models. My GT is a lot easier to deal with, a quick twiddle with a screwdriver and it sails through the emissions test. The old 'uns are the best.

[Teapot]

SLIGHTLY MODIFIED

A quick twiddle with a screwdriver and he sails through the emissions test. The old 'uns are the best.

Recognition at last