Droo recommends reading by mature audiences.
Previously on Droo's Roadster Adventure:
Over the past two months since my rebuild, i've travelled now just over 7000km, Bendigo to Orange (1700km travelled total) and a few other shorter trips to melbourne and back (350km+ over weekends) and have noticed that on the longer trips that the tacho and oil pressure needle would hiccup every 20-50km or so travelled - both needles would dip off randomly for an instant and resume back where they were.
I've only ever noticed this on highway driving where my attention can wander a bit more safely with no other traffic on straight roads..
There would be no hesitation in power delivery, nothing that i could perceive. I couldn't tell if the tach was cutting out on city driving or on my favourite windy back roads near home as i'd be too engaged on the road.
Also in this past two months, i've washed my engine bay twice.
Immediately the following morning, starting the car, the engine would idle mostly ok but on putting a load on it to reverse out my drive way, it would hesitate and splutter. Big loss in power but wouldn't stall.
I'd gently plant my foot and the hesitation restricted the engine, so i'd try to drive lightly but any load on the engine would result in more hesitation.
Leave the car idle for 1-2 minutes and then all is fine as if nothing was ever wrong..
This hesitation condition would be prevalent for 3-4 days after i'd washed the engine. I'd figure that water had gotten into the coil pack and causing a short condition. What didn't make sense of that was that even tho i'd dríven 850km straight back from Orange to Bendigo (several detours and stops) the car started perfectly at that point. Only when it was first started the following days (and not just in the coolness of mornings) the problem remained..
It eventually went away after the 4th day.
Washed the engine again 2 weeks back and the problem, same conditions happened again. Its definitely not as if water is still in there, evaporates when the car's hot for hours then magically reappear the following day in the electrical sockets..
I also noticed several periods of missfire/odd ignition. Some cruising conditions and some light acceleration made the exhaust sound fluttery, like one cylinder/plug wasn't firing fully. This would come and go and i figured and confirmed that one of my plug leads had slightly de-seated itself from the coil pack.. Pressed back in the problem vanished after extended driving but would reappear subtley on the first drive of the following days.
I figured i'd do the COPS mod sooner then later.
Today, on the way back to work from lunch, on giving my car stick on a nice corner, the engine cut out for nearly 1/4 of a second, enough to scare poopies out of me shifting the car's weight in the middle of the corner. I backed off and made sure my underwear was clean.. Arrived at work and carried on glad i didn't become zen with the nearby trees by that corner.
On the way home, driving normally through traffic, the cut out happened again. Over 4 km travelled mostly down a slight decline i was able to experiment with various engine loads. WOT and hesitation and sudden random cutouts. Light cruising throttle, same. Off throttle in gear the engine was off then on again. Turn the engine off (please dont tell me off for that, it was straight road) and revs would drop to 300-400rpm but not stall.
The cutouts became more frequent about a minute later and for longer until the car did cut out and not restart..
I managed to coast to a free parking area, parked, and got a lift home from my partner. Just in time for valentines day. : )
..And now, the conclusion:
After dinner, read online here and other forums, and happily all of the useful information i was able to get researched was via MX5Cartalk : )
4 hours since i'd broken down and parked, i tried to restart. No go.
All that happened was the engine would crank over for half a second (sometimes more, sometimes less) firing initially then failing. I really hoped it would start cold, enough to get me home (5 minutes drive away), but it didn't.
I pulled out my spare coil pack (which i knew had issues but keeping it as a spare because it's kinda pretty in a HR Giger art work sort of way) as well as my spare CAS from the temp spare engine (anyone want a 1.8L block and head?
)25 minutes later, i'd tested that the spare coil pack didnt work any differently to the standard one, but the replacement CAS fixed the problem completely. Yay.
I'll be ordering a brand new one now to replace it and keep my spare as a spare.
Todays Question:
Of all this event i figure age and engine heat would have caused the failure. I cant blame an 18 year old engine component for failing under the conditions it has to live but the engine bay heat wouldnt be helpful to electronic component life- specifically the coil pack, cas and temp sensors at the back of the block. Granted they are made to a specification which would allow for those temperatures, but i'd like to ask if anyone has bonnet venting on the roadsters, not so much for cold air in, but for heat dissipation out of the engine bay?
I ask this as my previous hatch back, had plenty of airflow into the engine bay from a wide mouthed bodykit, after 140km travelled my exhaust manifold was easily grabable 15 minutes after engine off. In over 200,000km travelled, i also never once had a failed sensor. Perhaps i was lucky, but the engine bay wasn't an oven when you opened the bonnet.
