Could they be off just while it's cold and still in open loop, but fine otherwise?
Could they be off just while it's cold and still in open loop, but fine otherwise?
Mine does a similar thing. I have stock cal, fuel system and everything.....When it's cold, if I give very light throttle, it will almost bog...you can actually hear the engine bog down a bit. If I open 'er up a bit, the car runs fine....then the problem disappears completely when the car warms up.
I think it's an over fueling problem, as the A/F guage reads almost full rich during this ....maybe a combo of cold temps and 180 degree t-stat.
That sounds like my problem exactly. Wonder why the would have worked too much fuel in from the factory?
ssheen,
any luck figuring out your battery and cts codes?
I thought it was an over fueling issue as well.
Well, I picked up a new sensor. It tested out close to the old one. At room temp ~21C the new one tested at 9.8 and the old at 10.5. In a cup of boiling water the new one was 2.8 and the old was 3.2. I threw the new one in the car. I test drove it this morning, and the problem was there a little, but only when cold like 'normal'. I do run a cal, though I have not changed it since the summer. I put the stock SMEC back in and so far the problem has not reappeared. Still need to test further.
I will test drive the stock SMEC again later tonight when the car is cold. If all is good, I will put the socketed SMEC back in and see what happens. If the problem comes back, I will try a stock cal and see what happens.
Cool man! Sounds like good progress. From that point it would just be a matter of figuring out what (accel pump values like t3rse mentioned?) in the cal causes it and what changes are necessary to correct it.
there is a different term for these computers, which I have no idea about, but you might be able to find out what it is from the d-cal page on yahoo groups...but anyways, my SDS has what is call "accel pump", which is meant to duplicate what carbs do, it just changes the pulse width under quick tps value changes, enrichening the fuel as needed to help with throttle response...i have found that leaner is better, as you are pulling from vac to boost and keeping the a/f around 13.1 until boost seems to make a big difference with off boost power...
Sounds reasonable. I just wonder how that's connected to engine temp. Surely the cal is programed to give a larger accelerator pump effect when the engine is cold and evidently it's a little bit overkill in some situations. That would explain the bog. So in theory, you'd want to lean the accelerator pump effect out a little when cold, but leave the stock values for when it's warm.
Make sense?
Tony,
The daytona did it when it was cold too. Could it be those before mentioned accelerator pump values. I mean we are running auto computers in 5sp cars. I wonder if the auto computer is a little richer when cold to compensate for the added load of a torque converter.
That's a real good question John. Wish I had a 5 spd 2.5 computer to test.
It could be that the added flywheel effect from the torque converter smooths the bog out so that you don't really notice it in an automatic.
It does bring up the question for those of you having this problem, what trans are you running, and what computer? I'm running a 5 spd. (520) with an auto computer.
I am running a 555 with a manual cal.
I dont think there is any difference for transient enrichment between the auto and manual cals. at least I cant see anything different.
here are the curves for both throttle enrich and map enrich. if there is a sudden change in pressure or tps volts the enrichment kicks in. these are just to show you what the curves look like.... not to use in a cal as these are my specific ones for a 2.5L.
Brian
Originally Posted by turbovanman
Well, mine is an automatic car with an automatic cal...plenty noticeable.
Wish I knew enough to play around with the cal. I'd try making some small changes and see if they had any effect.
Well, that shoots that theory.
its not that hard. there are some threads in the efi section where I wrote up some simple basics. http://www.turbododge.info/ has the process on how to socket the smec.
if you want to try, feel free to contact me and ill give you the info that i know.
Brian
Thanks Brian. I've got a smec laying around that I pulled apart and started removing the potting on. It's been buried since the move. I need to dig it out finish with the potting, desolder the chip and solder in a socket.
I get all that handled, dig up a burner, eraser, and some chips, and I'll probably take you up on that offer. The hardware I can handle, but programming is definately not one of my strong points.
Tony, my issue seems to have resolved itself when I swapped coils.
That's interesting! Did you replace it with another stocker or aftermarket?
I think I've got a spare stock coil laying around here somewhere...
I had an aftermarket on the car. I replaced it with the 19 year old stocker for now. My problem became really bad. I was lucky I got the car home today. Which did make it easier for me to find the cause.
What kind of aftermarket coil was it? I'll be upgrading the coil once I get some of the other stuff taken care of and get ready to crank up the boost. Sounds like I want to stay away from the one you were running.
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