CoxyNZ 2 Report post Posted October 22, 2019 When blipping throttle (even smallest amount) revs drop suddenly down to 200-300 (occasionally dies). When cold it idles super rough at around 600rpm. Replaced intake boot and cleaned maf and no intake leaks as far as I am aware (have thoroughly checked). I'm thinking idle control valve? Also car runs super rich almost sickening standing next to the exhaust especially when cold. Any common easy things to check? Any help appreciated thanks Quote Share this post Link to post Share on other sites
Allanw 1071 Report post Posted October 23, 2019 Idle control valve is common issue. Clean it with CRC or similar, and if that doesn't work, borrow a good one to try. It will be stinky alright - especially cold - if it doesn't have a catalytic converter... Dads E30 was a 1990 NZ new version and there was zero emissions stuff on it - not even a charcoal cannister. Quote Share this post Link to post Share on other sites
CoxyNZ 2 Report post Posted October 24, 2019 Thanks I'll look for a new one and give it a go ? Quote Share this post Link to post Share on other sites
C-130 Hercules 571 Report post Posted October 24, 2019 Is it an Eta engine? Quote Share this post Link to post Share on other sites
CoxyNZ 2 Report post Posted October 28, 2019 ETA? Quote Share this post Link to post Share on other sites
C-130 Hercules 571 Report post Posted October 28, 2019 (edited) 51 minutes ago, CoxyNZ said: ETA? M20b27 - the low revving fuel efficient version of the m20. They are particularly prone to this problem. But of a tune and some maf adjustment usually makes that managable. Edited October 28, 2019 by C-130 Hercules Quote Share this post Link to post Share on other sites
CoxyNZ 2 Report post Posted October 31, 2019 It's a m20b27 with the 2.5 head. I think I have narrowed down the problem to replacing the spark plug wires and the new ones not coming with a pulse sensor. Would this be the cause of the issue? Thanks Quote Share this post Link to post Share on other sites
C-130 Hercules 571 Report post Posted October 31, 2019 Have you done a tune / remap? I suggest you to consider. Talk to Gav at Bellars. Quote Share this post Link to post Share on other sites
CoxyNZ 2 Report post Posted November 5, 2019 Unsure if previous owner has done. After replacing the pulse wire still having the issue. Last thing I haven't checked would be throttle position sensor. Are they easy to adjust? Thanks Quote Share this post Link to post Share on other sites
C-130 Hercules 571 Report post Posted November 6, 2019 16 hours ago, CoxyNZ said: Last thing I haven't checked would be throttle position sensor. Are they easy to adjust? You can try, I haven't had to go down that track. Have you had a go withe MAF adjustment screw? Only adjust by small amount. Quote Share this post Link to post Share on other sites
Fraser 0 Report post Posted December 11, 2019 I've been having the same issue the past months - exactly the same symptoms plus the RPM dipping every few seconds (and stalling when cold) Did you get it sorted? What I've done: Smoke test (no significant vac leaks), clean out the ICV with carb cleaner, replace throttle position sensor (mine was bad, easy to test), pulled apart the AFM and adjusted the slider thingo All of this did not much at all unfortunately, I ended up swapping the ignition coil which was bad and causing the idle to dip so now I just have the symptoms above. What I would recommend to do if you haven't already: Test AFM with a known working one if you can Failing that - check out the TPS with a multimeter Quote Share this post Link to post Share on other sites
Allanw 1071 Report post Posted December 11, 2019 On later cars, there is an round connector under the intake manifold, it can cause bizarre misfires, or the occasional hiccup. Worth spraying the terminals with a decent contact spray. Dads old E30 would VERY occasionally have what felt like a single misfire - cleaning that plug solved it.. Quote Share this post Link to post Share on other sites
