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[Martin_1962]

I think the evaporator is on last legs

I wonder though if it is related to the cams and porting?

Irrelevant as its a closed loop system.....

Perhaps the cam changes mean that the car cannot richen the mixture enough?

Car is closed loop, no Lambda connection to the LPG kit.

I will try a day on petrol and see if the emmisions light goes out.

[Marks DTM Calib]

Consider the system operation.....the ecu measures the air mass going in and adds a quantity of fuel related to this mass......it then checks to see how far out it was by looking at the lambda.

All you do by porting and increasing the cam duration and lift is increase the ability to get measured air in....

So the code you get is because the ecu's calculated the fuel required and the lambda correction values have gone out of range....this is either because the mass of air is being measured wrong or the mixture is weak (would only apply to your lpg setup and only likely to happen near the red line on full throttle)

[Martin_1962]

The kit I have was borderline enough gas as standard I am wondering if it simply cannot get enough LPG in at higher revs.

I wonder how much for a newer front end?

[feeutfo]

So its that dodgy cheepo maf then Martin. If so i believe, possibly wrongly, the bosch item can be had on gay bay for 35 to 55 sobs.

Thanks for info Lee, i'd never urd of em...

[Kevin Wood]

The kit I have was borderline enough gas as standard I am wondering if it simply cannot get enough LPG in at higher revs.

I wonder how much for a newer front end?

It would be open loop at higher levels of load so the engine ECU wouldn't know it was lean.

Is the vapour pressure correct and still where it was when the system was calibrated? If so, and the calibration hasn't changed, there's no LPG problem. The issue would have to be present during conditions of light load to raise these codes.

Kevin

[Martin_1962]

Current codes are

0302
0306
0170
0173
0130
0300
0300

I understand the 030n ones

So what is a good MAF on say Ebay then?

[Kevin Wood]

Where are the misfire codes coming from? Does it misfire from startup?

Do you have anything that can display live data?

Kevin

[Martin_1962]

Where are the misfire codes coming from? Does it misfire from startup?

Do you have anything that can display live data?

Kevin

It hiccuped a few days ago going from LPG to petrol - that sometimes sets off a 030n

Unfortunately no live read but a code reader owner works opposite me in the TVR place.

One thing though my test place where a 2.0 scored 25, a 3.0 and 2.6 score 29, tonight the 2.6 on petrol scored 29.6.

These figures are of relative performane

[Martin_1962]

Errr

I pressed the fuel change button unter full throttle got a short misfire lost a couple of pots so rebooted restarted the car and it ran fine.

[Kevin Wood]

Does it normally stumble when switching fuels? Just wondering if it's having to dial in fuel trim on LPG? Mine is seamless, but it does switch one pot at a time.

Kevin

[Martin_1962]

Does it normally stumble when switching fuels? Just wondering if it's having to dial in fuel trim on LPG? Mine is seamless, but it does switch one pot at a time.

Kevin

I think it is varying the fuel trim, I never set it up properly, just adjusted it to run right, I didn't think about the injector timing, just that it ran right. I basically used the instant consumption.  :-[I concentrated on high RPM where the kit suppliers recommended leaning off.

Since it ran well I left it at that

However the kit is now over 4 years old, been on this car for 3 years 8 months, the vapouriser has been striped and stuck back together - and I want to replace.

The injectors are all plastic but are known to have a long service life and to be quiet, but do not like high gas pressures.

I really ought to replace the vapouriser and redo the settings for the new cams

As to MAF, I do not know if it is OK or not £120 is a lot on a hunch.

I think I might call AGWW about the vapouriser and ask them how much for a new one.

My boss wiped the software off his laptop .

[Martin_1962]

Oh stumble - just a little a bit more than it used to but not a lot.

The injectors are said to not reqiure a filter

[Kevin Wood]

Well, I wouldn't replace the vapouriser on a hunch. First thing to try is see if the codes clear when running it on petrol for a while.

When setting up LPG I switch to and from petrol and watch the injector duration on the outputs of the main ECU. This way you can see if the fuel trim is moving. Failing that get a cheap ELM327 cable and watch the fuel trims in the live data.

Sounds like you could do with the LPG tuning software either way - should tell you what your vapour pressure is doing too.

Kevin

[Martin_1962]

The vapouriser is bodged together and doesn't shut off on the overrun anymore - worn valve lever, so it is a candidate.

Looks like a trip with a laptop is necessary - I'll try to pinch my bosses again.

What is your feeling on the MAF?

[Kevin Wood]

First I've heard of a vap. shutting off on the overrun on a SGI system? It should just maintain a constant vapour pressure relative to the manifold. The injectors don't get triggered on the overrun anyway. It's built into the petrol ECU.

If it's the MAF you would have the same problem on petrol.

Kevin