Air Flow Meter Gone?

[debaron]

Hi Everyone. Was leafing through the 'Powertuning Rover V8's' book and it describes how to test the 5AM to make sure it's serviceable.

Carried out the tests today and looks like mine is on the way out:





The voltage on my DVM jumped to 0.9 V and then took about 4 seconds to come back down - just like the test says indicates failing.

Should I be paying any attention to this test? I don't want to spend a ton on a new AFM if these results aren't relevant to the TVR V8.

Mine's a '96 400 Serp by the way...




Cheers


Ryan

[debaron]

I've been plagued by rough running for ages - it's intermittent though. Some days worse than others. Doing Injectors, Fuel pressure regulator and dizzy next week to try and cure it so in a word, no - it doesn't run properly!

[debaron]

Thanks Blitz, was hoping you would post!

Mark's advice seems to back up what the test was saying in that namely, my initial voltage does overshoot and thus the AFM is considered faulty. New one on the way!!



Thanks for the advice all.


Ryan

[debaron]

Blitz,

maybe you can help, Just fitted new AFM but idle is all over the place. Revs keep dropping out when clutching in on the slow down to a junction and when starting cold.

What voltage values should I have the CO idle set to - currently at 1.80 V as per factory spec.

Old one was 1.88 V



Would go back to old one but engine seems to be a bit more free to rev over 3000 and my rough running seems to have gone so think the new one is doing something right!


Ryan

[debaron]

Actually, might well be an electrical intermittent connection. Will check where the AFM wires join the loom and plug end tomorrow.

[debaron]

Blitz, thanks for the advice:


Here's what I've done so far


Started up from cold this morning - gave it no throttle and let the ECU take control

revs unstable as follows:

spluttering at 400 revs for a few seconds then up to 1500 and slowly comes down to 1200 then splutters again and repeat. Added some manual throttle to stabilize as engine was shaking around and didn't like the noises it was making! After a minute or so of this, tickover smooth at 950.

Engine nice to drive and seems a lot more free and good power. Has alleviated my rough running - only thing of note is where I had a slight 'ticking' from the top left of the engine, it's now somewhat louder.

Will check Lambda's tonight. I've checked them before and relocated the lead to up near bonnet stay on Off Side and similar on Near Side so they are easier to get to!!

From memory, readings cycled between .8 and 1.4 V so may have been running very rich for ages!!

Adjusted CO idle reading from AFM to 1.9 V


Also - How do I safely reset the ECU!?!



Cheers


Ryan