mspnp cranking enrichments
 

a cold front came through last night dropping the temperature from 75 to 52 degrees. This morning, my CLT temp is 41F.

I have tan-tops, and am running the mspnp 9093 basemap. This combo worked great last night and for weeks prior.

I can't get the car to start. I tried to crank it for a few seconds and got nothing. it sputtered a bit but never caught. a few seconds later, i tried again. this time it caught, but ran terribly for about 5 seconds and quit.

I haven't been able to get anything but an occasional backfire out of it since.

I pulled the plugs. The were drenched, so i cleaned them off and replaced them. The cranking pulsewidth in the basemap for the 9093 looks odd. at 60F, the pulsewidth is 7.5. At 40F (where I'm at), it jumps up to 8.2, then goes back down to 7.3 at 20F. Is there any reason for this?

I set the pulsewidth to 7.3 and started working up. No matter what I do, all I get is backfires.

Any suggestions?

you went the wrong way. Make the PWs lowers.

The reason it jumps around is because they were only able to tune to the lowest temperature that they saw in Atlanta.

Always start low. The car should crank and crank and BARELY catch if you're getting near. Then increase slowly until the car starts reliably every time. If you start too high, you'll just flood it, and then it will crank and crank forever.

My after start enrichments were all way to lean to make the car start reliably in cold weather. I made them richer and set the fixed map period to 15 seconds. It starts reliably to the coldest it's been here, about 35-40F or so.

I recall Jerry saying in another post to start low and work up, so i'm basing my method on that advice. However, it may have been prudent to start a little lower than 7.5.

At any rate, my 550's came in, so i'm just going to install those and use mach's cranking settings as a starting point. then i'll start over. :p Makes more sense to do that than to spend all this effort on injectors i'm not even keeping.

i also killed my battery trying all this, so it's on the charger.

I've never been able to make the fixed map bit work for me? the revs just bounce around during that period and then settle out.

without it I don't get the revs going awol, but it really chuggs for a sew seconds and then flares back into life.

there are two keys to the fixed map, the timer and the map value you lock to. mine is set at 89kpa. meaning, that for the first 15 seconds the motor is running, fueling is based off a steady map value of 89kpa. the map value you selected might have been a bit lean.

okay, swapped in the 550's. copied the cranking enrichments, accel enrichments, and req_fuel settings from mach929's msq file and manually input them into my base map.

Happily, the car fired right up, ran like crap for about 10 seconds (lot of fuel still in the system from before), then ran smooth as it began its warmup idle at 1600 rpm.

However, about 1 minute after that, the car started missing pretty badly. i loaded megatune, and everything looks good, but the narrowband O2 gauge starts fluctuating all the way full lean every time the car misses. Obviously, that doesn't tell me much.

That long into the startup, i should be out of the afterstart enrichments, eh? that should be in the warmup period? i wonder what would cause it to miss.

It's probably not much use to you, but I have a nearly stock 1.8 NA with stock injectors and a MSPNP and at coolant temps of around 40 degrees the car takes a couple turns of the key before it turns over and idles at 1400-1600 rpm without dying first. I'm going to work through the cranking PWs over the next few days. My base map has the same cranking PWs as you listed, but the injector opening time is different than the base 9093 map and I have the 1.8.

The good news for me is that I'll be putting in the 550cc RX7 injectors soon so let me know how that goes. :)

WUE isn't over until your car reaches 160*. If it's missing you either have bad spark or you're going lean. If you're too lean, add some fuel in the VE table once the car has passed 160*. That should correct your bad idle.

reason number 2,327 i need to get off my lazy ass and install my AEM UEGO. For what it's worth, i believe it started running poorly after the coolant temp surpassed 160*. I will experiment with that later. it's too cold to be screwing with that after dark. hehe.

Install your AEM. Quit messing around and do it right.

the only, and i do mean ONLY reason i haven't installed it yet is because my exhaust doesn't include a catalytic converter. It was like that when i bought the car. therefore, i haven't found a shop yet that will touch it to weld on the bung.

stupid laws and stuff. :p

we don't even test for emissions out here.

find a friend with a welder trent. come join the wonderfull world of the wideband 02 sensor

hrm good point, I'll give it another try.

Actually that telly you a lot. when a car missfires it's either too lean or too rich, a quick glance at the VE table will give a good indication of which way too far you are.