cossy 24v not running correctly - advice needed

[magpies]

Hi I have a TVR S1 with a cosy BOA 24v. I completed the build in May and took it to Spa that month - 1000 untroubled miles. Done another 500 miles without problems until last month. I drove 100 miles to Chesterfield when it just cut out when pulling away from standstill in traffic at a junction. Wouldn't restart. I couldn't hear the fuel pump prime. (fuel pump bought new a couple of years ago for the build). The breakdown chap crawled under the car and checked that the pump had 12v which it did. He tapped it a few times and it sprung into life. I drove for another 10 miles and it died again. I tapped the pump several times and it started after a number of attempts then drove fine for 150 miles home. I then fitted a new Sytec filter and a new fuel pump. Started fine and ran for 3 miles only to die again, basically sometimes it will start and idle but will not pull away. Some times it runs for 200 metres. The tank was checked and found clean during the build, has new pipes throughout and the injectors sent away for o/h and spray pattern check. The only part still original (1990) is the fuel pressure regulator. Is it worth getting an adjustable one with gauge? What pressure should it be adjusted to?

[Boosted LS1]

Have you set the idle properly, ie the idle air bypass valve? If this is wrong the engine will stall at junctions etc. Not sure if this is your fault though.

[N7GTX]

If it tends to die out more under load when fuel demand is highest then a fuel pressure check at the engine might be helpful. Expect a minimum of 45 psi.
Also check for water in the fuel by pumping some into a clean container.

[glenrobbo]

A long time ago, I had those exact symptoms on a car that proved to be a real test of patience.
Long story short, the cause turned out to be bits of sellotape in the fuel tank!

When the pump was running, soggy strips of the transparent tape would be sucked onto the pickup strainer and block the fuel supply. After stopping at the roadside for a while, messing around with various components & wires, etc, the tape would float off away from the strainer and the engine could be started again and run perfectly, sometimes for many miles, until inevitably the whole thing would repeat causing the engine to die again.
I had a lot of fun sorting this one out, especially considering I had already inspected the tank interior ( via the tank sender access panel ) and found it spotless in there! ( Except for the unseen invisible sellotape hiding in the petrol! )

How it got in there is a mystery, probably the previous owner's little kids had thought it was a good idea. A locking fuel cap would have saved a lot of grief and tearing out of hair!

Just goes to show you should never rule out even the most unlikely scenario.

Good luck Mick!

[KKson]

After spending 3 months tracking down a misfire on my 350i, only to find that THREE brand new components had all failed (distributor hall effect pickup, HT leads and coil), never automatically assume that just because something is new it's okay. Assuming that the pump is running okay and has constant power feed and a good earth then certainly fuel pressure would be the next item to look at. An adjustable regulator with gauge is an easy swap but alternatively if you can temporarily plumb in a gauge (remembering it's high pressure petrol in the line!) at least you can double check that the pressure is correct and not dropping unexpectedly.

If fuel feed and pressure is good then look at the ignition side of things. Could a component be breaking down as the under bonnet temperature rises? The 350i started from cold without a problem but as the temperature rose the insulation on both coil and HT leads broke down. Engine cooled and then all was well again.

[FarmyardPants]

Is the petrol cap vented?