545svk

I need some help on this one, please.
Mostly my '87 auto start first twist of the key - except sometimes. Then, when I turn the key it will spin over energetically, and sort of go "Vroop" but not catch.
When this happens, it won't start for about 24 hrs.
After a vroop it still turns over but gives no indication of wanting to start. I can hear the fuel pump going.
Can it flood for some reason?
When it did it a few weeks ago, I changed the plugs and air filter. I also checked that the fuel flows by removing the return pipe at the tank and turning the starter. All good there.
I also smelled the vacuum lines at the fuel pressure and damper valves. No petrol smell.
What I haven't been able to do is hook up a noid light immediately after a Vroop. That is my next goal.
Any thoughts or experience on something like this will be appreciated.
Cheers
ps - cold start here is shorts and t-shirt weather. And the car doesn't have an alarm or immobiliser.

The Forgotten On

I had a similar issue in my 89. Changed the Temp II sensor and it has been fine since.

You should really change them with every timing belt/ 6 years.

Mrmerlin

Has an intake refresh been done post a picture of your engine
have the computers been rebuilt same for the maf

SeanR

Also check and make sure the wires under the boot are not frayed and touching.

545svk

Thanks guys. Temp 11 is on order. Hope it solves my problem as well.
I'll do a deep dive for frayed cables this weekend.
As for the top end refresh - that should have been my December project. All the parts are waiting in the garage. May be a good idea to actually fit it to the car.
As for MAF and computer - I've had the car 7 years and they haven't been done in that time. The K&N filter was removed 7 years ago but the sticker remain.

545svk

Cleaned the connector on the Temp 11 and car started immediately - but it was also 48 hrs since the previous attempt - so looking forward to the new sensor and time.