FridgeFreezer Posted February 17, 2008 Share Posted February 17, 2008 TBH my cranking pulsewidth is probably way off as mine doesn't currently start perfectly. Quote Link to comment Share on other sites More sharing options...
V8 Freak Posted February 17, 2008 Author Share Posted February 17, 2008 Sorry FF.... I actually used Ian's start pulse information and your ASR info... (I've edited the original to show the same..) Neil Quote Link to comment Share on other sites More sharing options...
Hybrid_From_Hell Posted February 17, 2008 Share Posted February 17, 2008 Do you mean ASE (After start Enrichment ?) I'll have a peek later, but I think the true answer will be as with mibne to fit (as Ian has done) a Cold start type valve PWM jobbie, so it can have the extra air to help it start and hold the rpm whilst decay / warm up is in progress, without a PWM I think the starting is always going to be a bit of a bodge however nicely 'tuned' the bodge may be ? Nige Quote Link to comment Share on other sites More sharing options...
V8 Freak Posted February 17, 2008 Author Share Posted February 17, 2008 Ah yeah.. ArSE or something like that ! Not familiar with MS terminology yet ! LOL Whatever it is, my system runs pants right when cold if I use the Omex equivalent to add the sort of fuel you guys are adding.... Have to hold it on throttle while it chugs away for 10 seconds or so and then it settles down on the throttle and runs sweet.. Drop the throttle and it pretty much runs, or has done today with new calibration, regardless of how cold it is !! I'm guessing the diference would be that once running and using the main maps I'm adding fuel via throttle and then the ASE is adding fuel too. With your systems you are adding fuel and the valve is letting in more air... Not adding more fuel again ! Neil Quote Link to comment Share on other sites More sharing options...
Bull Bar Cowboy Posted February 17, 2008 Share Posted February 17, 2008 Hmmmmmmmmmmm If it fires to start then the one shot pulse is OK, and I guess the cranking pulse is adequate…….. but the reality is that the tolerance of the pulses that will do the job is huge. So, once it’s fired and began to run then the clock starts ticking for the decay timer. The start fuel decay timer is (I think) the same as MS ASE……….if this is wrong, or the coolant temp correction table is wrong then it will not run correctly, and I feel the trouble is in this area…………can you post up your coolant correction table ? OK........... here is my ASE table (After Start Enrichment)........ You can see that I have it fixed for 8 Seconds and then decays for 4 seconds, but only when the coolant temp is below 24C. ....... other wise it just decays for 12 seconds. The % are an % increase to the main fuel table.................... To help you understand the table a little more ................ this is the MS help file, It's been found that during winter the cranking and after start enrichments need tweeking in order to get the engine to start and run without restarting it several times from cold. The reason is felt that the after start and cranking enrichments dont follow temperature in a linear format. So if you find this is the case you can use this table to tweek areas where it is difficult to start. It has been found that the areas for concern are around 32F (0C) After Start Enrich Counter is the length of time in Seconds or engine cycles that the after start enrich runs for. The percentage added is decayed down to zero as the time expires Set ASE Mode to FIXED for a timed period of ASE that does not decay, after the timer the ASE will then decay as usual during the TOTAL ASE time period thats left. This has a temp setpoint as it should only be needed when the coolant temperatures are fairly low. Setting MAP to a fixed value helps to maintain a constant PW during the initial start where the map drops quickly from around 100KPa to the tickover KPa. This is held during the FIXED time period. The FIXED period is a period of time at the start of the TOTAL ASE time. FIXED must be less than TOTAL To help you ( or really annoy you ) to understand MS a little better, the following is what we use to setup the cold start / warmup. It is called the warmup wizard.......... the arrow against the coolant temp tells you exactly where the coolant temp is (real time) , and the values on the right are real time values taken from all the various sources........ this way we get to see the big picture all on one page as a snapshot against engine coolant temp.......... Ian Quote Link to comment Share on other sites More sharing options...
V8 Freak Posted February 17, 2008 Author Share Posted February 17, 2008 It's in the excel sheet I posted earlier... "Coolant Table %" row.... Do you want me to send over the Excel sheet ? And are my assumptions about air wrong ? You are putting in more air while using ASE, I'm not ! Quote Link to comment Share on other sites More sharing options...
Hybrid_From_Hell Posted February 17, 2008 Share Posted February 17, 2008 Ian is shoving more air in as he has a bosch 2 wire PWM which pops in more air diminshing as the temp increases to closed I don't (yet ) and mine will fire, start and only run providing I hold the throttle open a tad (more air and RPM held up), I am 99% sure that with a PWM mine will fire start and run without my "Temporary" PWM - a coke bottle jammed in the throttle pedal Nige Quote Link to comment Share on other sites More sharing options...
V8 Freak Posted February 17, 2008 Author Share Posted February 17, 2008 "Temporary" PWM - a coke bottle jammed in the throttle pedal Nige Is that Coke bottle calibrated in any way ? Does it require Coke in the bottle and can you use Full Fat Coke if required? Just had a chat with Ian and I'll be calling Omex again tomorrow to see if I can get one or two more truths from them about their book of lies. (The manual) Good news is, with only about 15 seconds investment on the loud pedal it's running and looking after itself ! Neil Quote Link to comment Share on other sites More sharing options...
Hybrid_From_Hell Posted February 17, 2008 Share Posted February 17, 2008 Is that Coke bottle calibrated in any way ? Does it require Coke in the bottle and can you use Full Fat Coke if required?Neil Neil, Your over compliacting things A Diet Coke bottle suffices, ..............a Full Fat jobbie is plain overkill Nige Quote Link to comment Share on other sites More sharing options...
FridgeFreezer Posted February 17, 2008 Share Posted February 17, 2008 Yeah but who buys diet coke? That's like buying low-fat cyanide Quote Link to comment Share on other sites More sharing options...
V8 Freak Posted February 18, 2008 Author Share Posted February 18, 2008 Ok. I had a pleasant chat with Andy at Omex today. He conformed that the Start Fuel Decay is NOT like ASE in MS. It only adds from the time cranking starts to when the timer runs out. It calculates fuel pulses from the Throttle position (VE) and Start Fuel Coolant entries. If you have it set for 5 seconds, and crank for 4 seconds and the engine gets into normal running maps, you will have 1 sec of additional fuelling. So effectively you only have to have it for as long as your average crank ends up being... He quoted me from some tables from a different engine but basically massive amounts of fuel when sub-zero (+500%) down to +100% around 40 degrees. He also told me about their standard throttle settings for cranking. Baseline at 100 VE for zero throttle input. (Effectively gives you a start point for calculations.) Based on what he told me today the cells would look like the following. He also added that without extra air at the start the system couldn't start the car, so I will have to manage the throttle for a few seconds, but no need to splash out on a coke bottle as I won't need it for too long. Used the settings above today and I was able to leave the car to run after 15 secs or so at 10% throttle. Now I believe I know what interracts with what, I will amend the table a little.... The standard throttle map Omex recommend isn't a flatline throttle map so I'll continue to use the flat version I built so I can add air without adding to the fuel going in under cranking. Start fuel colant number look scary for sub-xero, but those days are rare. As least I can play with condfence in knowing what I'm affecting now. Neil (Ok Nige... I can officially be the Omex expert on the Forums now!) Quote Link to comment Share on other sites More sharing options...
Bull Bar Cowboy Posted February 18, 2008 Share Posted February 18, 2008 Ok. I had a pleasant chat with Andy at Omex today.He conformed that the Start Fuel Decay is NOT like ASE in MS. It only adds from the time cranking starts to when the timer runs out. It calculates fuel pulses from the Throttle position (VE) and Start Fuel Coolant entries. If you have it set for 5 seconds, and crank for 4 seconds and the engine gets into normal running maps, you will have 1 sec of additional fuelling. So effectively you only have to have it for as long as your average crank ends up being... So, what you are saying is that the timer starts from the moment you start cranking and finishes at time out, regardless of an engine start of not. So, if you set it at 20 seconds and the engine started after 10 seconds , then you would have 10 seconds of additional fueling during the engine run time ?.......... If so that's like ASE with a subtle twist. He quoted me from some tables from a different engine but basically massive amounts of fuel when sub-zero (+500%) down to +100% around 40 degrees. He also told me about their standard throttle settings for cranking. Baseline at 100 VE for zero throttle input. (Effectively gives you a start point for calculations.)Based on what he told me today the cells would look like the following. The pulse widths in the yellow row are pretty much what I would expect to see for a RV8 ........... He also added that without extra air at the start the system couldn't start the car, so I will have to manage the throttle for a few seconds, but no need to splash out on a coke bottle as I won't need it for too long. That applies to any engine ............... carbs not only provide a mechanical richer mixture, but they also mechanically open up the throttle or a secondary air device.............EFI is the same............ extra fuel is easy to provide, but we must also have some device for extra air. Used the settings above today and I was able to leave the car to run after 15 secs or so at 10% throttle. Good ............. looks like the above setting will probably do the trick.............. it also looks like we may get a few cold nights this week due to a HP area over us. Start fuel colant number look scary for sub-xero, but those days are rare. As least I can play with condfence in knowing what I'm affecting now. Not really ............ its like I tell my boss at salary rise time ......... "whats 10% of FA" !!!! ........ same applies here.............. as long as the final pulse widths look sensible, then the coolant adder % is purely academic...... Ian Quote Link to comment Share on other sites More sharing options...
V8 Freak Posted February 18, 2008 Author Share Posted February 18, 2008 So, what you are saying is that the timer starts from the moment you start cranking and finishes at time out, regardless of an engine start of not. So, if you set it at 20 seconds and the engine started after 10 seconds , then you would have 10 seconds of additional fueling during the engine run time ?.......... If so that's like ASE with a subtle twist. Yeah but the percentages are way too high for ASE.... (Maybe a coke bottle for those really cold days.... Nige, you got one spare ?) The pulse widths in the yellow row are pretty much what I would expect to see for a RV8 ........... These remain unchanged and are based on your cold start settings. (They appear to be working so why change eh ! ) extra fuel is easy to provide, but we must also have some device for extra air. I still have a choke cable from way back when... Maybe a manual valve ! it also looks like we may get a few cold nights this week due to a HP area over us. Bring it on.. Any snow forecast ? Would love to go out and play now it's starting as well as running... Now the front axle is in tip top condition thanks to Mr. Ashcroft for the diff and Sir Les of Hensonshire for the expert application of loads of other new parts including swivel balls, CV's, bearings, gaskets etc. No more of that slap and clunk and bounce back and forth when I lift off now.. Behaves more like a normal car ! I'll tweak more this week but I'm pretty happy for now. Thanks for your ongoing assistance Ian.. (And words of wisdom Nige.) Neil Quote Link to comment Share on other sites More sharing options...
V8 Freak Posted February 25, 2008 Author Share Posted February 25, 2008 Bit of an update, probably the last for this thread....With BBC, FF and HFH helping me out I've become very familiar with Omex and engine management in general. I took the plenum apart for a good cleaning recently, reset the butterfly etc. and decided to move the coil packs to the front of the engine.... Needless to say, when I got it all back together it ran like pants with a big HFH misfire at tickover. Checking and re-checking stuff finally revealed my soldering was up to scratch but the Omex loom had a loose connector on one of the coil pack plugs. Soon sorted that out. With a few tweaks today on the cold fuel settings I appear to have an engine that starts with a tweak on the throttle, settles down straight away to a nice tickover and runs / purrs nicely unless there is liberal use of the loud pedal.... In case anyone is interested, these are the current settings we have been discussing recently... I've still got to fit the hugemongous air filter to the rear of the engine and plumb in the snorkel, but other than that I'm extremely happy with how things have worked out. I've still got an adventure in tuning to come at some point just to make sure I'm getting the best out of the engine but no idea when that will be yet... Thanks to everyone who's contributed to this thread and special thanks to Nige and Ian who have helped on specifics right from the start. Neil Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.