ThreePointFive Posted February 4, 2023 Share Posted February 4, 2023 I have just fitted a PWM exactly as per the instructions in the MS Manual but I'm getting no indication it's actually done anything. It seems just as unwilling to start without throttle applied. Is there a more recent version of Nige's manual than Sept 2014 which would have fuller/different instructions? I have a switched ignition feed going to the PWM and an 'earth' (I guess) going back to the appropriate wire on the ECU. Is it possible to have the wires on the PWM back to front or does it not matter? I have the ECU wire on the side the 90 degree pipe comes off and the live on the side the straight pipe is on. Should the idle screw be wound fully in or otherwise changed to let the PWM take full control? Does Tuner Studio show anything to indicate it's working? Quote Link to comment Share on other sites More sharing options...
Hybrid_From_Hell Posted February 4, 2023 Share Posted February 4, 2023 Hiya Open tunder studio Right click on any gauge and select Gauge templates 2 - look for Idle DC (thats PWM) Power on should show say 60-80% open then drop down as engine warms up ? Nige Quote Link to comment Share on other sites More sharing options...
ThreePointFive Posted February 4, 2023 Author Share Posted February 4, 2023 Nige, that helped immensely. I can now see what's going on. It's starting at 90% and going down to 50% where it stops. It's idling at 1800rpm though, which is not good. I assume there's a target idle speed I'm meant to tell it. Quote Link to comment Share on other sites More sharing options...
Bowie69 Posted February 4, 2023 Share Posted February 4, 2023 You need to block the pipes off, and set base idle with the allen screw, approx 600rpm, then the PWM should be able to bring it up from there to something sensible. 1 Quote Link to comment Share on other sites More sharing options...
ThreePointFive Posted February 4, 2023 Author Share Posted February 4, 2023 Damn. I wish I'd done that before drilling holes in everything. At the moment I've got the base idle screw all the way in so the PWM is doing all the work. I'm just confused why it would stay open when it's clearly over the target RPM (which I've now found). Further question, should it operae in closed loop only or warmup only? Quote Link to comment Share on other sites More sharing options...
ThreePointFive Posted February 5, 2023 Author Share Posted February 5, 2023 It's staring me in the face in that table. Closed DC is set to 50. I just need to adjust that until it is actually closed, which should be lower but not zero or it starts to open again - or so the internets tell me. That also means I can keep the idle screw closed and use this figure to always keep it open by that amount. There might not be any advantage to that but at least I'm only dealing with the variable of the PWM. The internets also keep mentioning a diode is used in a lot of setups to avoid problems. I don't see anything about that in the instructions. And of course it should be in closed loop, not just warm up. I need it to act all the time to smooth out the idle. 830rpm seems a little high for the default slow idle to me, though. Quote Link to comment Share on other sites More sharing options...
Bowie69 Posted February 5, 2023 Share Posted February 5, 2023 So much to add to this.... but on phone at mo, will reply properly later. Quote Link to comment Share on other sites More sharing options...
Hybrid_From_Hell Posted February 5, 2023 Share Posted February 5, 2023 With the engine ticking over adjusting the plenum screw it won't work ! In simple terms with the PWM connected up as you try to adjust tick over............. the PWM undoes what you are doing And no, you don't disconnect the PWM plug - ITS POWERED CLOSED !! What you need to do to adjust the plenum screw is when warm and ticking over Mole grips - Clamp off the PWM pip so no air can go in or out Make sure the Throttle has a bit of slack....... THEN............ adjust the plenum to see if you can get tick over all lovely and cuddly set to what your heart desires and report back Nige Quote Link to comment Share on other sites More sharing options...
ThreePointFive Posted February 5, 2023 Author Share Posted February 5, 2023 8 hours ago, ThreePointFive said: It's staring me in the face in that table. Closed DC is set to 50. I just need to adjust that until it is actually closed, which should be lower but not zero or it starts to open again - or so the internets tell me. That also means I can keep the idle screw closed and use this figure to always keep it open by that amount. There might not be any advantage to that but at least I'm only dealing with the variable of the PWM. The internets also keep mentioning a diode is used in a lot of setups to avoid problems. I don't see anything about that in the instructions. And of course it should be in closed loop, not just warm up. I need it to act all the time to smooth out the idle. 830rpm seems a little high for the default slow idle to me, though. It all sounded so simple when I typed it out, but I failed to account for INFE*. I tried the settings in my post above and it's going straight to 2,000 rpm, sometimes more. Nothing changed in the PWM settings changes the idle. I blocked the pipes off as I thought I'd introduced a huge vacuum leak and but it returns to slow lumpy idle normality, so the issue is in the PWM side. I set the idle screw to 600-ish while I had it isolated. *(It. Never. F##king. Ends.) Quote Link to comment Share on other sites More sharing options...
ThreePointFive Posted February 5, 2023 Author Share Posted February 5, 2023 9 minutes ago, Hybrid_From_Hell said: With the engine ticking over adjusting the plenum screw it won't work ! In simple terms with the PWM connected up as you try to adjust tick over............. the PWM undoes what you are doing And no, you don't disconnect the PWM plug - ITS POWERED CLOSED !! What you need to do to adjust the plenum screw is when warm and ticking over Mole grips - Clamp off the PWM pip so no air can go in or out Make sure the Throttle has a bit of slack....... THEN............ adjust the plenum to see if you can get tick over all lovely and cuddly set to what your heart desires and report back Nige We posted at the same time...! I can't get the idle to come down from 2000, seems like the PWM is stuck open to me. Is there any way to bench test it? Should changes made in the PWM settings update to the unit itself without the engine running? I.e. on the ignition only. I am hearing/feeling nothing going on with it when changing values with the engine off. Quote Link to comment Share on other sites More sharing options...
Hybrid_From_Hell Posted February 5, 2023 Share Posted February 5, 2023 Normally on ignition in engine not stated PWM will show 60 maybe even as high as 80 on start up PWM should drop according to engine temp if warm should drop to virtually nothing if memory serves - if it’s showing high then it either the setting asking it to set tickover high or badly adjusted mechanical / plenum / cable or air leak or PWM is sticking ?? Quote Link to comment Share on other sites More sharing options...
ThreePointFive Posted February 5, 2023 Author Share Posted February 5, 2023 I think the PWM has to be stuck given the engine went back to normal revs when I blocked it off. The question is whether it's stuck due to malfunction or because it's not getting told to move. Would having the live/earth the wrong way around cause it to do nothing? Quote Link to comment Share on other sites More sharing options...
Hybrid_From_Hell Posted February 5, 2023 Share Posted February 5, 2023 No 😂 Quote Link to comment Share on other sites More sharing options...
FridgeFreezer Posted February 5, 2023 Share Posted February 5, 2023 1 hour ago, ThreePointFive said: I think the PWM has to be stuck given the engine went back to normal revs when I blocked it off. The question is whether it's stuck due to malfunction or because it's not getting told to move. Is the PWM number in TunerStudio dropping (so the ECU is trying to close the valve) or not? Quote Link to comment Share on other sites More sharing options...
ThreePointFive Posted February 5, 2023 Author Share Posted February 5, 2023 Yes it is, starts at 90 and will decrease quite rapdily to whatever I have set as the closed value once it sees it's above the target RPMs. Quote Link to comment Share on other sites More sharing options...
Hybrid_From_Hell Posted February 6, 2023 Share Posted February 6, 2023 11 hours ago, ThreePointFive said: Yes it is, starts at 90 and will decrease quite rapdily to whatever I have set as the closed value once it sees it's above the target RPMs. Run that by us again ? Quote Link to comment Share on other sites More sharing options...
FridgeFreezer Posted February 6, 2023 Share Posted February 6, 2023 11 hours ago, ThreePointFive said: Yes it is, starts at 90 and will decrease quite rapdily to whatever I have set as the closed value once it sees it's above the target RPMs. OK so the ECU thinks it's controlling the valve, but the revs aren't doing what you want then. Quote Link to comment Share on other sites More sharing options...
elbekko Posted February 6, 2023 Share Posted February 6, 2023 It still sounds like you need to get the idle screw right. Are you entirely sure it's actually closed? Is the throttle butterfly closing properly? Have you sprayed some brake cleaner around things to detect vacuum leaks? Electronics can't fix mechanical issues. 1 Quote Link to comment Share on other sites More sharing options...
Hybrid_From_Hell Posted February 6, 2023 Share Posted February 6, 2023 try these settings - if no good swap back to yours and we can have a thinky Quote Link to comment Share on other sites More sharing options...
Hybrid_From_Hell Posted February 6, 2023 Share Posted February 6, 2023 Quote Link to comment Share on other sites More sharing options...
FridgeFreezer Posted February 6, 2023 Share Posted February 6, 2023 I've only skimmed this & your other threads but is the old GEMS idle valve blocked off? Nothing else on the plenum that could be letting air in? Quote Link to comment Share on other sites More sharing options...
Bowie69 Posted February 6, 2023 Share Posted February 6, 2023 Setting base idle You must set base idle with hose(s) blocked off, to around 600 rpm. To rely solely on the PWM valve means you may not get enough air flow for really cold weather or high loads (AC/winch) to get the idle up high enough -you need this base level of air *plus* the PWM valve. Closed loop/warm up only Unless I'm mistaken you don't have any heavy loads on your engine, e.g. winch, AC, PTO etc, so you will gain little if anything at all by going closed loop. It is also notoriously hard to get working in closed loop without hunting around the map in every condition you haven't mapped it specifically for. The issue is compounded by the fact your engine is still not really tuned quite right yet, and may well loop around the map as it is, and by adding the closed loop stuff you will be adding yet another variable that you don't really want to be introducing at this point. Put simply, I don't think you need closed loop at all, I don't normally use it even with vehicles with high loads and it is without problems. As I've shown you before we can tweak the idle up with timing under < 700rpm which is more reliable and no chance of looping. It hugely simplifies things by going warm up only. Closed value You need to determine this for your particular valve (they vary), so stick a charger on your battery (so you have 14V rather than the 12.6V battery voltage), then adjust the cranking DC until you can physically see the valve is fully closed. This is then your 'Closed DC', set it. Reset your cranking DC to what it was before (this isn't that critical, and will likely work with the original setting absolutely fine). This is a great way to know if the valve is working, if it won't close then you know you have an issue. Tuning warm up only Well, there's not much to it really, you have four values you are really interested in: Idle duty at lower temp: How open the valve is when starting from cold Idle duty at higher temp: How open the valve is when fully warmed up Fast idle (lower) temp: The temperature that MS defines as 'cold' for the idle vale purposes Slow idle (upper) temp: The temperature that MS defines as full warmed up, normally 88C or so. Between the two temperatures defined in the last two bullets the idle valve DC will ramp down linearly as the engine warms up. Start it from cold and wait a few seconds for the after-start stuff to finish (10-15 secs or so) and then adjust the 'Idle duty at lower temp(dc) until the engine idles smoothly and about the right speed. Then wait for the engine to full warm up and set the 'Idle duty at upper temp(dc)' to give you ~700rpm. These aren't my values! I use a stepper and MS2, just a screenshot so you know where you should be in TS. 1 Quote Link to comment Share on other sites More sharing options...
Bowie69 Posted February 6, 2023 Share Posted February 6, 2023 12 minutes ago, FridgeFreezer said: I've only skimmed this & your other threads but is the old GEMS idle valve blocked off? Nothing else on the plenum that could be letting air in? It is blocked off yes, and I tested it for vacuum leaks when I saw it last year, only a very small one on the throttle shaft spindle seal, which may have been sorted now. Quote Link to comment Share on other sites More sharing options...
Bowie69 Posted February 6, 2023 Share Posted February 6, 2023 15 hours ago, ThreePointFive said: Would having the live/earth the wrong way around cause it to do nothing? No, should work either way round, it is opened/closed by current flow, nothing else. Quote Link to comment Share on other sites More sharing options...
Bowie69 Posted February 6, 2023 Share Posted February 6, 2023 It does beg the question, now I think about it, I assume the ECU has the modification to control the PWM valve? Quote Link to comment Share on other sites More sharing options...
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