RoverGauge - overfueling problem

[Green King]

Hi

I have recently encountered a problem with my 4.0 Chim over-fueling. I took it out for a long run recently and it ran fine. However once I got home and tried to start it to put it away in the garage it instantly flooded - lots of white smoke out the exhausts and strong smell of fuel. the engine was still hot so I can only assume that for some reason the ECU has decided to over-fuel the engine. I managed to get it in the garage but it ran really badly (and then would not start at all).

I got it out the following weekend and it started fine from cold, but once up to temperature would not restart. Whilst it was ticking over I connected it to a recently purchased RoverGauge to see if that would give me any indication of what was going on. Everything seemed ok except the Airflow reading was sitting a 4% even when the car was fully up to temperature. Is it possible the air flow meter has failed?

I am running a standard unmodified 1993 4.0 pre-serp.

Any suggestion would be gratefully received.

[blaze_away]

Hi Richard

I have been through this recently and now resolved.
I am near Daventry and willing to help check stuff over with you if you wish. We can methodically test a swap key bits to see if we can narrow it down.
Temp sensors lambdas and AFM are the places to start.

[Chimp871]

I had the same problem recently and a change of AFM appears to have fixed it. Use the kind offer above or buy a used one of fleabay - I got a used Jag one part DBC10852 same as err5198

[blitzracing]

The Airflow reading at idle should be about 32 to 35% on the direct setting at idle, and this will jump up when you rev the car. Failed AFM tend to have a very long stabilising period of a few seconds and the overall voltage will be to high, so the car over fuels, although it may not be far enough out to trip a fault code.

Manual testing is here about 1/3 of the way down the page.

http://www.g33.co.uk/pages/technical-fuel-injectio...

[Green King]

Hi all

Thanks for the info. It sounds like the AFM may be the problem.

Blaze_away, thanks for the offer to come over and take a look, I really appreciate that. Let me know when it would be convenient for you as i could use the help. How is it best to get in touch?

[blaze_away]

Green King said:

Hi all

Thanks for the info. It sounds like the AFM may be the problem.

Blaze_away, thanks for the offer to come over and take a look, I really appreciate that. Let me know when it would be convenient for you as i could use the help. How is it best to get in touch?

I will send you pm

[blaze_away]

PMs exchanged. Will update thread when we've haf a look at it.

[Green King]

Hi all

After a very helpful discussion with blaze_away I tested the AFM. It has a good 12v supply, however when I tested the signal and turned on the ignition the multimeter spiked at just over 1 volt and took about 5 seconds to settle back at 0.4.

I assume that this means the AFM is shot. I did test it again and got the same result.

Is my thinking correct? Is it now time for a new AFM?

Thanks.

[Zeb74]

Hi,
Recently I have encountered something similar, the car was smelling and smoking. With RoverGauge I saw also the long term lambda trim at 100%. I've done the same test as you with a multi-meter plugged on AFM connector and all symptoms were here.
I have changed the AFM and it's like night and day.
Mine is a 96 model with 60,000 miles.

[Green King]

Thanks for that, it sounds like we have the same issue. Where did you get your new AFM? I have tried the usual places but they are either out of stock or exchange reconditioned (which I am not sure about).

[QBee]

Have you tried Rimmers? I think it’s a Landy part from memory.

[Zeb74]

Mine is coming from TVR Parts, they have some available from time to time.

[Chimp871]

Refurb afm with a warranty should be fine, not cheap though. It is a landy part and was used in other cars besides LR/Tvr but with different part numbers and without trim screw which blitz says you won't need if you have cats.

My used jag afm (same lucas 5am) is going good 1 month in.

[Green King]

Thanks all, I have tried TVR Carparts but currently out of stock. Will try Rimmers or possibly go with refurb (although it is nearly £100 more than a new one from TVR!).

Cheers.

[blaze_away]

I was offered a clone version 5am recently that came off a griff converting to Megasquirt. Said to be a "good un" that had been running fine for 4 years. It might still be available as by that time I had already got one. Might do you until you can source another one.
I will pm you their details

[blitzracing]

Here you go guys- sensible money- id rather have a rebuild by ATP than any clone!

https://www.atpelectronics.co.uk/p/land-rover-rang...

[Green King]

All sorted. I was offered a secondhand original AFM from a fellow Pistonheader at little money. Dropped it in and all is good again.

Thanks everyone for your help and advice.