I'm continuing to struggle with my cold starts. From what I can tell I've got sufficient cranking pulse widths, but as I transition into after start and warm up enrichments it just won't idle without me giving some extra input on the throttle. For cold starts (about 50 deg F right now in the SF Bay Area) I'm at a about 177% from warmup enrichment (Warmup Wizard) and an additional 50% from After start enrichment, for a total of 225%. Even at this level, the motor won't idle. However, if I give a stab at the throttle to raise the rpms, this seems to work against me unless I get the timing and amount just right. As you can see on my log from this morning, I was unable to save it with some additional throttle input. And, strangely (on line 306) I always seem to get a period where many functions go to zero or drop dramatically.
So my questions are these: 1. Should I just keep bumping up Warmup and afterstart enrichment, or is there a point where you're just putting in so much fuel that it can ignite? Are my numbers worrisomely high already or should I feel comfortable increasing them? 2. Could this be caused by not having a stepper motor or idle control or would that show up differently? 3. Do you see something in the datalog or MSQ that I could be missing?
Guys, I'm really getting stumped on this one, so my apologies for all the questions, I just REALLY want to get this figured out once and for all.
Car specifics: '73 BMW 2002 (4 cylinder, SOHC, 292 cam, stroked motor). MSII version 2.88. EDIS. Bosch 24lb/hr low impedence injectors.
Thanks so much, in advance.
Upper limit to warm up enrichments?
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Read the manual to see if your question is answered there before posting. Many users will not reply if the answer is already available in the manual.
If your question is about troubleshooting, configuration, or tuning, you MUST include your processor type (MS-I or MS-II) and code version in your post. If your question is about PCB assembly or modifications, you must also include the main board version number (1.01, 2.2 or 3.0). For tuning/troubleshooting questions, please attached a datalog and your MSQ file to your post.
If you have questions about MS1/Extra or MS2/Extra code configuration or tuning, please post them at www.msextra.com Such questions posted here will be moved to: a temporary MSextra sub-forum, where they will be removed after 7 days
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Upper limit to warm up enrichments?
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66fb
Re: Upper limit to warm up enrichments?
In the data log at ~28 sec. all your values freeze for about 3 seconds (the engine seems to be running at this point though). Also, at about 34 sec., you must be cranking the engine because the MAP comes down from its max value to ~64 kPa yet MLV is still showing zero for RPM. What are you using for tach input?
Re: Upper limit to warm up enrichments?
I'm just pulling my tach signal directly from the coil. In terms of the starting and stopping of the engine, from lines 284-295 the engine is cranking, then running with afterstart and warmup enrichment until line 305. Then, when I tip on the throttle to bring the revs up to a sustainable level, the enrichment seems to fall off and from there things fall apart until eventually stalling on line 326. I then start cranking again on line 367-372 and then the engine successfully starts, albeit still with throttle input. I just can't seem to give it enough enrichment with the after start and Warmup Wizard to keep it from stalling on start-up, and I'm worried that I'm throwing in so much fuel that it won't be able to ignite or I'll just flood the engine.
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66fb
Re: Upper limit to warm up enrichments?
Are you viewing your log files in Excel or MegalogViewer? I see the lines you are talking about, the engine bit values show the transition between states.
In MegalogViewer the graphic display is a bit easier to relate one parameter to another. You show a very strange (to me anyway) jump from zero rpm to running with about 360 rpm -no cranking phase indicated in MLV. As I said, at time of (no line number) ~34 seconds, the log shows a decreasing (numeric value) MAP but at the same time flatline ZERO rpm. The engine is obviously cranking but without the tach pulse Megasquirt doesn't know that. The loss of rpm information to Megasquirt while cranking or running will turn the fuel pump off if it goes beyond 2 seconds. This could be the root cause of the hard starting.
After the engine is running your AFR reading goes from "rail to rail", from 10 to a solid 19AFR. Is the right type controller selected and sensor calibrated? Just curious, no impact on starting.
Intermittent problems are among the hardest to fine...
In MegalogViewer the graphic display is a bit easier to relate one parameter to another. You show a very strange (to me anyway) jump from zero rpm to running with about 360 rpm -no cranking phase indicated in MLV. As I said, at time of (no line number) ~34 seconds, the log shows a decreasing (numeric value) MAP but at the same time flatline ZERO rpm. The engine is obviously cranking but without the tach pulse Megasquirt doesn't know that. The loss of rpm information to Megasquirt while cranking or running will turn the fuel pump off if it goes beyond 2 seconds. This could be the root cause of the hard starting.
After the engine is running your AFR reading goes from "rail to rail", from 10 to a solid 19AFR. Is the right type controller selected and sensor calibrated? Just curious, no impact on starting.
Intermittent problems are among the hardest to fine...
Re: Upper limit to warm up enrichments?
Thanks for the input. I've been looking at this information in Excel, for some reason I find MLV to be harder to read on a granular level. That said, I'll give it a try and see how it looks. In terms of when it hits 0rpm, I can definitely feel this as the engine sort of just pauses momentarily, but certainly nowhere near 2 or 3 seconds, it's more like a fraction of a second. At this point I usually try to give it a little throttle but am only able to save it half the time or so.
In terms of the AFR going to 19.9, this is something which just started happening in the last week or so and I haven't figured out why. It gets back to a "normal" reading after 2 or 3 minutes, but still much longer than the normal start up duration for the sensor. I'll try recalibrating it and see if that fixes it.
In terms of the AFR going to 19.9, this is something which just started happening in the last week or so and I haven't figured out why. It gets back to a "normal" reading after 2 or 3 minutes, but still much longer than the normal start up duration for the sensor. I'll try recalibrating it and see if that fixes it.