The V8 Owners Forum -

Hi. TVR 350i with flapper AFM. was running fine then one day misfiring and undrivable. Definitely got sparks and all plugs wet with fuel after repeated attempts to start. Replaced or tested by substitution the plugs, ignition amplifier, coil, ecu, HT leads. Cleaned out plenum and checked all hoses for leaks but will not fire up. Very occasionally will start but runs incredibly rich chucking out black smoke and not at all smooth. Any ideas please?

if the plugs are flooded, bin them and fit new ones.

Have you confirmed good strong spark available at all cylinders ?

has the airflow meter been tampered with at all ? anything could have disturbed it or its wiring ?

Hi. Will be third set of plugs in 6 months!
All ht leads arc a spark when rested on engine metal but how do you define a strong spark.
Did take top of afm to have a look but all looks very clean like new.
I have also replaced cts

Download
http://www.cowdery.org.uk/downloads/FlapperManual.zip
work through it methodically.

Chris.

biltonwilson wrote: ↑

Sun Oct 15, 2023 9:17 pm

Hi. Will be third set of plugs in 6 months!
All ht leads arc a spark when rested on engine metal but how do you define a strong spark.
Did take top of afm to have a look but all looks very clean like new.
I have also replaced cts

If the plugs are flooded, bin them. Doesn't matter if it's 6 seconds, or 6 months. Perhaps at a later date when things are running good, starting good, you might be able to try and re-use them. But in a non start case....it's pissing in the wind.

You define a strong spark with either a spark tester, or experience from a good visual.

And are those sparks at the correct time ?

biltonwilson wrote: ↑

Sun Oct 15, 2023 9:17 pm

Hi. Will be third set of plugs in 6 months!

Humm, third set of plugs in 6 months? That sounds like you've either done a heck of a lot of miles or it wasn't running quite as fine as you first said.
Could it be something has been working badly and has not progressed?

If you're getting a good spark then I'd suspect the fuelling, particularly as a flapper system is going to be a fair age now. Sadly it's not possible to plug in a diagnostic to this system and check what it thinks is happening.
Presumably this system takes a signal from the ignition simlar to the later Hotwire, this would be worth checking but if you are getting fuel (even the fuel pump running) this is probably OK.

A good day. Went through ignition system yet again making sure everything spot on even put some old but perfectly good plugs in. Unplugged cold start injector. Decided to swap ecu to an old one that hasn't been used for 10 years. Car fired up immediately!
Chucked out a lot of smoke until fully warmed up then settled. Went for quick test drive to wake up the neighbours and it was great. Was even popping on overrun like it used to!
Will check a plug colour in the morning but hopefully now sorted.