Air Flow Meter.....what part number????

[GAVC]

My AFM is giving out irregular signals and keeps resetting itself to running rich, issue is this causes stalling and it's drivin me nuts!!

Problem is new one at Racing Green is £377

Scrapie wants £125 plus carriage

eBay has one for £60 for a landie - Rover 3.9 part number ERR 5198, I've looked at my Chimaera 1998 4.5 and can I see a part number!!!!!

Anyone help, as I'm stuffed right now

Any idea what the part number is, all I see is 5AM and a bar code!

[cornish pasty]

GAVC said:

My AFM is giving out irregular signals and keeps resetting itself to running rich, issue is this causes stalling and it's drivin me nuts!!

Problem is new one at Racing Green is £377

Scrapie wants £125 plus carriage

eBay has one for £60 for a landie - Rover 3.9 part number ERR 5198, I've looked at my Chimaera 1998 4.5 and can I see a part number!!!!!

Anyone help, as I'm stuffed right now

Any idea what the part number is, all I see is 5AM and a bar code!

Hi GAVC C/P here ,bought one the other day from TVR Power Part no E2036 cost Total inc VAT and post was £156.87 For part no's you could try www.parkersteve.dsl.pipex.com/chimeraparts.html not to sure if this will work, will try now have typed off bit of paper. cheers matey C/P

[cornish pasty]

cornish pasty said:

GAVC said:

My AFM is giving out irregular signals and keeps resetting itself to running rich, issue is this causes stalling and it's drivin me nuts!!

Problem is new one at Racing Green is £377

Scrapie wants £125 plus carriage

eBay has one for £60 for a landie - Rover 3.9 part number ERR 5198, I've looked at my Chimaera 1998 4.5 and can I see a part number!!!!!

Anyone help, as I'm stuffed right now

Any idea what the part number is, all I see is 5AM and a bar code!

Sorry got it wrong try http://www.parkersteve.dsl.pipex.com/chimaeraparts...

Hi GAVC C/P here ,bought one the other day from TVR Power Part no E2036 cost Total inc VAT and post was £156.87 For part no's you could try www.parkersteve.dsl.pipex.com/chimeraparts.html not to sure if this will work, will try now have typed off bit of paper. cheers matey C/P Sorry got it wrong try http://www.parkersteve.dsl.pipex.com/chimaeraparts...

[dhf]

Taking one off my 5 litre first week in october if that is any use to you.make me an offer.

[Cider Andy]

ERR5198 is the correct part number. Jaguar DBC10852 also works (and is generally cheaper) but it doesn't have the trimmer pot available (port is blanked off). But wait for 'blitzracing' to come along; I've a feeling he'll tell you the ECU ignores it anyway.

[GAVC]

Many thanks for your help, just bought the one off eBay as can't wait till October as its my daily driver, thanks for the offer though.

[That Daddy]

Cider Andy said:

ERR5198 is the correct part number. Jaguar DBC10852 also works (and is generally cheaper) but it doesn't have the trimmer pot available (port is blanked off). But wait for 'blitzracing' to come along; I've a feeling he'll tell you the ECU ignores it anyway.

[griffter]

Cider Andy said:

Jaguar DBC10852 also works (and is generally cheaper) but it doesn't have the trimmer pot available (port is blanked off).

It does - you just have to remove the blanking plug with a pair of pliers. AFAIK TVR didn't do anything to the AFM other than adjust the trim (if they even did that).
Also, apparently, 3AM and 5AM are interchangeable.

[blitzracing]

Cider Andy said:

ERR5198 is the correct part number. Jaguar DBC10852 also works (and is generally cheaper) but it doesn't have the trimmer pot available (port is blanked off). But wait for 'blitzracing' to come along; I've a feeling he'll tell you the ECU ignores it anyway.

How right he is !!

The trimmer pot only manualy adjusts the low RPM mixture setting on NON catalyst cars. All cars fitted with cat's do this automatically, so the adjustements not needed, hence its ignored anyway on anything post 1992. Its not even part of the AFM really, its just a variable resistance between the trim wire and ground. You could just put an extra varable resistance between these wires if you needed this function. (I think its 1k ohms from memory but dont quote me.) As for compatability, Ive found no electrical differenced between the 3AM and 5AM units, although one has an extra pin on the connector thats not used.

Mark

[GAVC]

Many thanks to all for their quick responses and advice.

[wargriff]

Is this the same air flow meeter that is on the precat 4 litre engine ?

or is it completely diff ?

[FlipFlopGriff]

wargriff said:

Is this the same air flow meeter that is on the precat 4 litre engine ?

or is it completely diff ?

I think yours is a 3AM and the 500's are 5AM. Not sure what the difference is but there must be as they'd both be either 3 or 5. You can interchange them though - I've done it on ours.
FFG

[blitzracing]

wargriff said:

Is this the same air flow meeter that is on the precat 4 litre engine ?

or is it completely diff ?

Electrically they are much the same. Castings are a bit different, and I think the only difference is who made it: Hitachi or Lucas.

[wargriff]

blitzracing said:

wargriff said:

Is this the same air flow meeter that is on the precat 4 litre engine ?

or is it completely diff ?

Electrically they are much the same. Castings are a bit different, and I think the only difference is who made it: Hitachi or Lucas.

thanks, on another point..if i change my AFM will my car start fueling correctly again?

[blitzracing]

The internal electronics are identical, so the only way to alter the outputs is either alter the casting that bolts on the front, so affecting the airflow through the hot wire port, or frig' the electronics. Having said that, these units are getting older now, and dirt builds up on the hot wire (it really cooks on there), so the calibration changes over time, as the dirt changes the cooling effect of the air over the wire. I think this accounts for the majority of why some work and some dont. Also being analogue devices, I dont think the extreme heat in a TVR engine bay helps the component life.

Mark

[GAVC]

Still having problems with the setup on my Chim 450 1998, albeit minor!

Story is, cam was worn and decided pre-cats should come out as well, so put the Chim into a good indie to have the work done.

MC1 cam from V8D installed, took car away, ran really smoothly, but started stalling immediately. Took it back and AFM diagnosed as problematic causing rich running, AFM would not adjust the CO2 reading below 4% (should be 0.2%).

Bought AFM took it back had it fitted, still had problems in setup, tested lambda's and not only was one the wrong part number, but they were both sooted up and shagged - not working. Don't know how that happened.

So with new lambda's fitted took the car away and it's running perfectly on any amount of acceleration, no hesitation just smooth and easy pull. However on standard throttle while cruising, say holding it at a steady 30, 40 or 50mph at anything from 1400 revs or through to 2000, the engine feels hesitant, it constantly feels like its going, but pulling back at the same time and it shunts at lower speeds and worse when cold. I'd suggest its running weak.

Took it back again to check setup and AFM was set at 1.7 volts with 0.2% CO2, so adjusted it to 1.8 volts as the main cat is left in and the reading was zero CO2, no reading at all..... and no change to the car, still hesitant at constant revs and shunting.

Next step is change the tune resistor... any other advice apart from the std lucas setup can be frustrating?

[GreenV8S]

GAVC said:

Next step is change the tune resistor... any other advice apart from the std lucas setup can be frustrating?

Why on earth???

You've changed the spec of the cam. If you were running carbs, you'd need to rejet them or change the needle or whatever. With EFI you need to change the map. The 14CUX hotwire setup requires specialised equipment to change the map and very few people in the country are able to do this. Mark Adams is probably the best known although I expect that TVR specialists around the country will have their own local favorites.

Sorting out the faulty components and getting the engine management system back in working condition is a useful first step, but you still need to get it remapped. That is not a DIY job and changing the tune resister will not solve the problem and could make things a lot worse.

Edited by GreenV8S on Saturday 11th October 12:51

[V6Alfisti]

Based on the part number given above, you can get a replacement for £46 delivered!

Don't blame me if it doesn't work :P

http://cgi.ebay.co.uk/NEW-air-flow-mass-meter-sens...

EDIT: Just noticed your last post, guess it may be of use for others though

Edited by V6Alfisti on Saturday 11th October 12:55

[blitzracing]

As Green says, a remap is possibly one answer albeit very expensive. On some set ups the lack of airflow at low revs causes the ECU to think it needs less fuel, so the engine runs lean. The ECU realises this from its lambda feedback, and applies the maximum enrichment it can, but its right on the limit of its range, so the car shunts as the ECU tries to control it. Its very maginal, as some cars do it and some dont (A friend of mine runs the MC1 with the TVR chip just fine). Cheaper alternatives to try is to boost the fuel pressure a bit, so the ecu can have a bit less correction to do, or try a .8 to 1 ohm resistor in the AFM earth wire. This alters (lifts) the AFM voltage the ecu sees by a few hundred millivolts, so the ecu puts in a bit more fuel. The actual value is pretty critical, as its possible to go to far the other way and overfuel the engine, so you need to check the lambda probes are still switching. The addition voltage added has less effect as the airflow rises so it makes the biggest change at tickover and just above. There is a problem that the ECU sets the overall mixture (long term fuel trim)at tickover, so this destorts the process somewhat, so its a case of try different values and see the effect. The limits are .5 - 1.5 ohms. A crude way of going about it, but it costs about 30p !

Mark

[M@H]

FlipFlopGriff said:

wargriff said:

Is this the same air flow meeter that is on the precat 4 litre engine ?

or is it completely diff ?

I think yours is a 3AM and the 500's are 5AM.

I think I've got a 5AM on my 400.... knowing TVR it will be whatever was on the shelf at the time