Tricky-Ricky Posted March 26, 2009 Share Posted March 26, 2009 OK carrying on from my "EMU Injector Adaptor 2 Info?" post. I am now starting to wonder about the implications of this, as for some time now i have had an irritating miss on idle, and i'm wondering if it is linked to the injector loadings. So i need to ask those of you who log or monitor injector duty cycle, just what their DCs are at idle, can be any injector, just need some comparisons? Quote Link to comment Share on other sites More sharing options...
Ian C Posted March 26, 2009 Share Posted March 26, 2009 From experience, 1.9 to 2.6ms on warm idle, depending on injector size. My 720's idle at 2.1 to 2.2ms, around 950 to 1000rpm, -0.58 to -0.60 kg/cm2 at the plenum. You really need to get an oscilloscope on them if you want to really know whats going on but that's not an easy bit of kit to get ones mitts on. Quote Link to comment Share on other sites More sharing options...
Tricky-Ricky Posted March 26, 2009 Author Share Posted March 26, 2009 Did a log on the EMU software and got durations of 1.3 to 2.0 ms on warm idle, which is not a long way off your figures, however mine are 540cc so do you think its likely to be the cause of my miss? its more apparent on warm idle, cold start is OK, and after a drive it can take time to manifest again, but it always comes back. I am going to make up a resistor pack anyway, cant hurt, and if it corrects it great, just hope i haven't been overloading the EMU/ECU for too long and contributed to an imminent failure, but i guess its a testament to its toughness lasting so long. Now where is the fingers crossed smiley. Quote Link to comment Share on other sites More sharing options...
JustGav Posted March 26, 2009 Share Posted March 26, 2009 Anybody know what drivers the EMU uses? I look up the datasheet and see what the maximum current capabilities are. Quote Link to comment Share on other sites More sharing options...
Ian C Posted March 26, 2009 Share Posted March 26, 2009 Did a log on the EMU software and got durations of 1.3 to 2.0 ms on warm idle, which is not a long way off your figures, however mine are 540cc so do you think its likely to be the cause of my miss? its more apparent on warm idle, cold start is OK, and after a drive it can take time to manifest again, but it always comes back. I am going to make up a resistor pack anyway, cant hurt, and if it corrects it great, just hope i haven't been overloading the EMU/ECU for too long and contributed to an imminent failure, but i guess its a testament to its toughness lasting so long. Now where is the fingers crossed smiley. Those numbers sound way too low to be honest, 440's should be about 2.6 to 2.8, so 540 should be about 2.4. I only saw 1.8 on 880cc injectors so 1.3 is ludicrously low. It could well cause a miss as the lean mix won't ignite - AFR readings aren't much of a help as the misfire makes things look artificially rich with a lot of unburnt fuel present in the exhaust. Ah, wait, static fuel pressure would affect this, if yours is higher than 36psi it'll mean less duration is required for the same amount of fuel. Still it's quite a wild swing of 0.7ms, something isn't right. The idle on mine is a bit lumpy due ot the cams and thats still steady on 2.1/2.2 for extended idle periods... -Ian Quote Link to comment Share on other sites More sharing options...
Ian C Posted March 26, 2009 Share Posted March 26, 2009 Anybody know what drivers the EMU uses? I look up the datasheet and see what the maximum current capabilities are. Mohd has photos of the board on his site if you can get a part number off that - I don't have any reference piccies to hand. Quote Link to comment Share on other sites More sharing options...
JustGav Posted March 26, 2009 Share Posted March 26, 2009 Mohd has photos of the board on his site if you can get a part number off that - I don't have any reference piccies to hand. Hmmm, me neither I just checked... will have to look around. I've still got mohd's AIM address somewhere, might have to buzz him *pops off to search* If you can list the injector resistance ratings we can work out the current draw... I have a sneaky feeling though that the ECU will have the weaker drivers, the EMU would be designed to handle pretty much any configuration... (But not confirmed) Quote Link to comment Share on other sites More sharing options...
Tricky-Ricky Posted March 26, 2009 Author Share Posted March 26, 2009 My fuel pressure is set to 34psi idle, but thinking about it, the fact that the ECU is hunting up and down during idle anyway, it must make things even harder if there is unburnt fuel present, so it trying to switch the injector duration/dc to keep control, and so compounding the problem. Unfortunately Mhodparts site has gone like the EMU forums:( unless anyone knows different? Quote Link to comment Share on other sites More sharing options...
JustGav Posted March 26, 2009 Share Posted March 26, 2009 My fuel pressure is set to 34psi idle, but thinking about it, the fact that the ECU is hunting up and down during idle anyway, it must make things even harder if there is unburnt fuel present, so it trying to switch the injector duration/dc to keep control, and so compounding the problem. Unfortunately Mhodparts site has gone like the EMU forums:( unless anyone knows different? Yeah, I've just found that as well, I've just buzzed him via AIM... so see how that goes. Quote Link to comment Share on other sites More sharing options...
JustGav Posted March 26, 2009 Share Posted March 26, 2009 http://www.mys15.org/S15_Tech/imgaes/PA291260.JPG Balls, can't read it off... there is a 0.47 resistor, which I would assume is there as a current limiter... Quote Link to comment Share on other sites More sharing options...
Ian C Posted March 26, 2009 Share Posted March 26, 2009 Have you tried adding more fuel at idle to see if it smooths out? Injector control may be an issue if your impedances are all wrong. It's not that you'll burn them out per se it's just that they open sluggishly or too fast and bounce the pintle. I think with low impedance it'd be too fast. -Ian Quote Link to comment Share on other sites More sharing options...
Ian C Posted March 26, 2009 Share Posted March 26, 2009 Which bit we looking at Gav? Quote Link to comment Share on other sites More sharing options...
JustGav Posted March 26, 2009 Share Posted March 26, 2009 Which bit we looking at Gav? Without actually seeing the circuit diagram, I'd hazard a guess at the 8 chips along the bottom of the pic with the BIG resistors just above. (Labelled Q7, Q13...) Quote Link to comment Share on other sites More sharing options...
Tricky-Ricky Posted March 26, 2009 Author Share Posted March 26, 2009 Have you tried adding more fuel at idle to see if it smooths out? Injector control may be an issue if your impedances are all wrong. It's not that you'll burn them out per se it's just that they open sluggishly or too fast and bounce the pintle. I think with low impedance it'd be too fast. -Ian Yes i have tried, and yes it does smooth out if it idles at about 11.0 AFR or lower, and it has a natural tendency to run rich if no adjustments are made, and the std ECU idle control cant compensate for, which i'm guessing is down to the low duration being applied? As it gets or is adjusted richer, the duration climbs. Quote Link to comment Share on other sites More sharing options...
Tricky-Ricky Posted March 26, 2009 Author Share Posted March 26, 2009 Without actually seeing the circuit diagram, I'd hazard a guess at the 8 chips along the bottom of the pic with the BIG resistors just above. (Labelled Q7, Q13...) Yes they are the injector driver transistors, i know that from the early units being made too close to the edge of the board, and where being knocked when people pushed the board back int place after setting the jumpers. Quote Link to comment Share on other sites More sharing options...
JustGav Posted March 26, 2009 Share Posted March 26, 2009 Yes they are the injector driver transistors, i know that from the early units being made too close to the edge of the board, and where being knocked when people pushed the board back int place after setting the jumpers. Yes, I remember that Don't suppose you could read the number off on yours? Quote Link to comment Share on other sites More sharing options...
Tricky-Ricky Posted March 26, 2009 Author Share Posted March 26, 2009 Yes, I remember that Don't suppose you could read the number off on yours? Might get a chance to have a look tomorrow, got a lot of clutter in my glove box, sitting over the top of the EMU, data logger, boost controller brain etc, the only place i could cram it all in and still stand a chance of getting to the wiring:blink: Quote Link to comment Share on other sites More sharing options...
Ian C Posted March 26, 2009 Share Posted March 26, 2009 Without actually seeing the circuit diagram, I'd hazard a guess at the 8 chips along the bottom of the pic with the BIG resistors just above. (Labelled Q7, Q13...) Are they ignition or injector stuff? I can't recall which... Yes they are the injector driver transistors, i know that from the early units being made too close to the edge of the board, and where being knocked when people pushed the board back int place after setting the jumpers. The chip that got knocked off was a dinky little IC wasn't it? Next to those things somewhere. Wasn't that the EMB that suffered from it though? Argh I can't remember Quote Link to comment Share on other sites More sharing options...
Tricky-Ricky Posted March 26, 2009 Author Share Posted March 26, 2009 Are they ignition or injector stuff? I can't recall which... The chip that got knocked off was a dinky little IC wasn't it? Next to those things somewhere. Wasn't that the EMB that suffered from it though? Argh I can't remember Actually now i think about it you're right Ian, i think its on the opposite side of the board on the EMU, where the tape is, i had one of the first batch on my old S14 and it caused a misfire, so i think it was the ignition stage. getting old and forgetful, well thats my excuse anyway:senile: Quote Link to comment Share on other sites More sharing options...
JustGav Posted March 26, 2009 Share Posted March 26, 2009 If you get a chance, take a picture of top and bottom and hopefully we can see the circuit tracers. Quote Link to comment Share on other sites More sharing options...
Tricky-Ricky Posted March 28, 2009 Author Share Posted March 28, 2009 Still haven't got around to taking a pic, but i have got the resistors i ordered through, and have made up i lead to wire then in, just cant seem to locate no three injector + feed:blink: Quote Link to comment Share on other sites More sharing options...
Ian C Posted March 29, 2009 Share Posted March 29, 2009 Still haven't got around to taking a pic, but i have got the resistors i ordered through, and have made up i lead to wire then in, just cant seem to locate no three injector + feed:blink: I don't follow, you can't find Injector 3, or its wire from the ECU or the wire from the EMU? Quote Link to comment Share on other sites More sharing options...
Tricky-Ricky Posted March 29, 2009 Author Share Posted March 29, 2009 No i can't locate the last black-orange stripe positive feed wire, can't find any continuity from no 3 injector to where i'm going to splice the resistor pack in, most odd, but the light was going so i'll have another look in the morning. Quote Link to comment Share on other sites More sharing options...
Ian C Posted March 29, 2009 Share Posted March 29, 2009 Ohhh right you're up to your elbow in the main wiring loom somewhere. Yeah, they are all over the shop, good luck Quote Link to comment Share on other sites More sharing options...
Tricky-Ricky Posted March 29, 2009 Author Share Posted March 29, 2009 Finally sorted the wiring and the resistor pack is installed, there is a slight improvement in duration times on idle, but not markedly, idle is more stable but occasionally get a slight pop, but its a lot better than before:) I did manage a quick drive and lodged on both EMU and innovate LW3, and will have to do a little tweaking of the map, however now i have used the EMU logging a bit more, it would be nice if i could log the AFRs on the EMU and have them match up with the Innovate. I have never been able to do this, despite the innovate feeding both the EMU and the std ECU, the EMU is set to the default Innovate setting and innovates own software is also setup for the simulated narrowband output. Have you any ideas on why they wont match Ian? i'm presuming you have something like AEM wideband? Quote Link to comment Share on other sites More sharing options...
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