I've been owning a '96 s50b30 for the last four years and love its simplicity and performance. Its has been a hardy daily driver and trouble free.
The car is well maintained, regularly serviced and never over-revved.
Lately (the last few months); i've noticed 2 problems that i have, to date, not been able to trouble-shoot, so would appreciate some advice:
1) Morning cold starts.
On cranking (3 out of 5 times on average) the car would not start at the usual point it usually should (usually by 2 seconds or so). The engine sounds like it is about to start but then holds back and instead it would take an extended (3-4 seconds in all) before firing up. Once it fires up, idling is fine and driving is smooth throughout.
2) If i drive the car without the air-con on throughout, everthting is smooth and fine. With the air con on, driving is still smooth and regular, but after driving for 10 minutes or so onwards, when i stop at the lights or after parking for example, the idling would then get very erratic. It would be searching, dipping and rising from 600+rpm to just above 1000rpm. This would last for as the car is stationary. Once i drive off, throttling is alright while on the move.
Initially before turning the engine (air con off) the idling will still remain erratic. I would have to rev the engine a few times before the idling eventually settles to normal. However just today revving did not seem to work at all. It continued to hunt erratically throughout. I turned the engine off for a couple of minutes and when i started again, the idling became more erratic this time dipping so low that the engine stalled. Starting up was alright thereafter, but the idling and engine stalling remained.
Pissed off initially with the cold-start issue, i changed the following parts (3 months back):
1) Fuel filter and fuel pump
2) Idle valve
3) Battery (Amaron Pro)
4) O2 sensors (long & short)
5) Fuel regulator
6) Ignition Coils
7) Reverted to stock (OEM) Evo 2 air box(ditched the gruppe-M)
8) Denso IXU-22s plugs
In addition, about less than a year back, all engine sensors were replaced as well as the air-flow sensor.
I am determined to solve this bug. What i think remains to be checked are the DME and air con compressor. The air conditioning is cold but makes hell of a lot of noise, so i'm wondering if any electricals connected to it is the cause. I'm not sure if the air-flow sensor could be the cause.
A point to note is that the engine block itself is stock, no mods. I've basically kept the car in OEM form, avoiding any mods to it because the stock power in itself is impressive enough. The previous owner had an Orbit piggy-back which i got rid of.
Also i have, in the last year or so, only been driving the car 3 days or so out of the week. When the car is not in use, it is left in shelter and i do not start the engine. However I don't think this could be a cause. In addition, the weather in Asia is usually warm to hot, cold weather being rather rare.
The time & $$ spent has been rather trying and irritating because the problems remain. i still believe the problem is minor, but tracking it down is the major piss-off for me. So any advice from the gurus out there will be greatly appreciated.
many thanks in advance!