Can I get some eyes

[EagleMark]

Yes there are GM large cap HEI distributors made for EFI. I beleive 1990 Corvette would be a lookup... Yup found it on RockAuto.
http://www.rockauto.com/catalog/moreinfo.php?pk=1393025

I wonder if ACCEL would give you Spark Latency Corrections numbers for their module? Probably not in the book the tech support person reads...

[srobertsfsj]

Do you think this one will work as well as the AC Delco? http://napaonline.com/Catalog/Catalo...7SB_0305897904

[CDeeZ]

I would think so.

I used to try to have only ACDelco or Delphi parts for things of this nature for a long time, but anymore alot of the Delco stuff is made overseas and is probably no better than anything else.

[EagleMark]

They will all work! Problem is GM is the only one we know what Spark Latency Correction is for. So it's the only one we can get timing close for. Even it is not perfect but never been an issue. Aftermarket ones have been tested and dialed in with hours of work to show huge differences in timing that can vary with RPM to who knows what where? So yes they can be done without real testing if your knock sensor is working. Does not mean your timing table will be actual timing, it's just a can of worms.

This is probably the most important part of an ignition system. Get a GM/AC Delco, it will last longer then your rig for $50.

Till then back off your timing and check timing at 1000 rpm to data, 1500 RPM to data, 2000 rpm to data etc to as far as you feel comfortable revving the engine with your face in belts and fan (wear safety glasses please)... and see where your timing really is? You'll need a timing tape or a dial back timing light too...

You have way to many variables right now to be running that much timing without knock retard! Actually if you knew everything was perfect and timing table was accurate I still think your way to much for that motor, let alone in a heavy truck. Pull ten degrees from the entire table, that's pretty drastic for me to say that, use the latency table I gave you and do a log run, we can see real quick if all those knock counts are false. Looking at your timing table I believe them to be true. This would not be good with knock retard being disabled...

I looked at your log a little more and BLMs are all real close. I did notice no readings above 80 MAP? Are you at a really high elevation? Did you really never go near WOT? Or have a restrictive air intake? Or do you have a MAP sensor issue? Pull the air cleaner and do a WOT run, MAP should go higher then 80 kpa?

You may have a MAP sensor issue? Your idling at 50 kpa MAP = 13 inches vacuum? That's a big cam or high elevation or an issue? With 35 degrees advance? Lets see where that ends up with less timing?

[srobertsfsj]

I didn't realize the aftermarket units had that issue. I dont mind swapping to a GM unit if it performs better, its just a pain to re-wire. I live at 5300ft and yes my test drive this morning took me up a few hundred more feet. Vacuum is usually around 13 to 15 for this engine and elevation. Leaving work in a few will report my run when I get home. Thanks for the help!

[EagleMark]

I thought you had a 7 pin? Gm has a 7 pin... do you have a 4 pin? You can actually get rid of it altogether and wire in a newer small cap 7 pin.

Anyway all moot points if you have a stock engine and only rev to what your log showed, any EST/ICM can be tuned, just by brail as you don't know what actual/acurate timing is unless you check by timing light. Bin will not be accurate. Data is also off. Yours has spots over 50 degrees advance...

[srobertsfsj]

I had a 4pin HEI before I started the TBI upgrade. I installed a 7pin with the TBI. I have an adjustable timing light with built in tach, just hard to adjust throttle and keep light on the mark.

I couldn't do a long drive home today because I had to get to my son but it was running really lean due to the timing changes. I would almost stall if I gave gas too fast. I made some VE adjustments and will do another long run in the morning.

[EagleMark]

it was running really lean due to the timing changes.

You took out 10 degrees timing and it went lean? I'm not sure what to make of that... and it was running good on that first log? I'm confused... have you ever watched timing at balencer on this engine? Is it 35ish at idle and drop when accelerated?

Stick differant thickness of feeler gauges in throttle stop screw to keep engine reved and check timing. Start with idle...

[srobertsfsj]

Attached is the short log I got on the way home. I only changed the timing (minus 10deg in all cells) and the latency changes that you sent me.

Also, I dont know if you remember from awhile back but the other issue is that my idle in park/neutral is at 1250rpm and I cannot for the life of my figure out why, I dont even have the PK/N wire hooked up....

Must have something to do with KPA, IAC or temp but I cannot find any parameters that change the RPM to 1250, its been very frustrating. When I put the Jeep it drive it drops right down to my idle rpm. I am assuming that if I ever figure why this is happing it might be contributing to some of my performance issues.

[EagleMark]

Didn't Dave say the Park/Neutral wire needs to be grounded? Yes they will idle higher if Open Loop..., that's why I always run CL Idle on these 1227747 ECM.

[srobertsfsj]

So I did another long run this morning with the timing changes and I did see an improvement with mid and top end power BUT now the Jeep almost stalls on take off and it runs warmer at idle. Also, there is a steep grade as part of my route and I noticed less power and a temp increase. I attached the log from the run.

You asked about my timing table and if you look at the docs below this is why its so high. Keep in mind they also recommend at high altitude to go 1 deg advanced for every 1000ft about sea level. My question is since this is all based on vacuum and mechanical advance, do I just throw this out the window since I have TBI? I think my performance issues are definitely timing related but I just don't know where to start. I do like your suggestion of verifying the timing, I will give that a try this weekend. Do you have any tips or a quick procedure for this?

[srobertsfsj]

I also noticed a definite decrease in knock count and using the dash my BLM numbers look spot on.

[EagleMark]

Even with that you've got to much mid range and not enough top end now? Slope is just off. Plus I'm n ot used to using a BB bin without the warm spark Bias, I even change BB to what I'm used to using.

Using factory timing tables in EFI conversion is a good start for idle and acceleration, but not optimal for other areas like deceleration. Yes you can get way more performance from spark timing with EFI, getting fuel right is easy.

Your run away knock counts are because you have the TPS% hack enabled. If you turn that off you should try the knock sensor. It's really only meant for true TPS at idle to watch for some paremeter transitions, not to be left on. I have it better commented in next version.

Your timing is all over the place, some cells 8 when should be 20, others OK and some 88 and 98 numbers which I know is wrong? Changes of timing fo 15 degrees from one cell to next? Difference between low and high of 20 degrees?

Been looking at this and posting for hours now inbetween other stuff, go back to PC and find this!

Had some time so I compared this to others because of what's noted above, the more I looked at your data, the more I compared to a known good running data, the more I think you have an ignition issue, not just timing... I checked 3 known good logs and none have the dramatic differnces yours does not including the 88 and 98 degree spike. I compared your bin to others looking for something corrupt and nothing? If I had this in my hands I would be checking all wiring related to ignition, connections, grounds, verifying where timing really is, started with another bin which I'll give you if you want to try, already would have had the Accel module replaced and checked the pickup coil in distributor.

Your lucky day, my job for this morning cancelled...

Here's a bin I know runs well in a 304 AMC with large cap HEI, I changed it to your 360. It has all fuel in VE1, all spark in main advance table so no PE or RPM adders, HyWay lean is installed but turned off for now, your TCC won't lock up anymore..., I think I fixed your idle issue but will still rev higher when cold until CL, raised your idle by 50 RPM because of your altitude and low vacuum, EGR off, Air off. Not sure if I got everything the way you had it but this should run well as is to start. Please keep it to yourself. I'll attatch the newest versions of $42 defs I've been working on which you can share.

Try it if you care to as is and do a log, lets see if there was an issue in your bin we could not find. If the spark advance data is the same, which I think will be the case we have something wrong with ignition?

Oh! Timing is set to 0, there is really no reason for this engine to need 10 degrees, this may also be the ignition issue. If you do need more base timing because of it being a conversion and more likely your elevation then you should add it to timing table. Unless you have a big cam you haven't mentioned?

[srobertsfsj]

First off, thank you very very much for taking so much time on these issues I am having. I know it takes a lot of your time and your knowledge is very much appreciated. Conceptually, everything you have said makes perfect sense but for me, it sometimes take a bit to put all the pieces in order before I understand it fully. That is where I am at now. I would much rather learn how things work so I can fix it myself then someone just give me the answers, hopefully I haven't come across that way. But having someone your experience helps speed up the learning process. I have spent alot of time data logging and making tweaks and changing parameters to see what they do, unfortunately there is just so many variables its hard to keep track sometimes. I will get it tho! And when I do I will share the knowledge for sure :)


That being said I wanted to respond to some of your questions and ask some about the bin you sent:

First off I like the pretty colors in the VE and SA tables, I will have to see how you did that. In the def file I assume?

To address the base timing, I tried like heck when I was first setting this up to set the base timing to 0 but the jeep would not idle at all and IIRC it wouldn't even start. Not sure if that is just the way these engine are. Does the system retard the timing on startup? I know the Chevy's work well at 0 base timing but I just had issues trying to use 0 for some reason and I have heard others with AMC engines say the same. Maybe I will try to set it back to 0 but I should probably wait until I do before I try running the bin you sent.

The cam in this engine is an aftermarket cam but from what I understand its a "mild" one.

Looking at the bin you sent, I did have EGR turned on, really just because it was my understanding that it reduces combustion temps and can bring engine temp down. Overheating on the trails is one of my biggest pet peeves. But I understand for tuning purposes it should be turned off? Does it make that much of a difference?

I didnt even noticed that the TPS hack was on, that is my fault, I didnt notice it was on and to be honest I don't remember what it was for. I remember reading about it before I did all the work on the jeep but that was a few months ago and I haven't touched the TBI since.

You said you think you fixed the idle issue, what specifically do you think is causing it, its been driving me nuts for sure.

[EagleMark]

You've been trying hard and helping others so I'm glad to help. I also learn the more I help, I never stop learning and can always be proven wrong or shown another way. I wish I could type and explain as good as i can tune and diagnose hands on or understand how these things really work inside like RBob or read dissesemblys like Robert Saar or, or, or... I'm blessed to have them as freinds which helps me. Please don't give me all credit, I'm just part of it all. But I'm more a GearHead then a technical nerd. I have a routine and just whip through it, know what should be and what shouldn't be and know how to fix it. Quick funny story... I turned and changed direction last week and dam near knocked an old guy down whos truck I was working on... he laughed and said "I should keep a little distance eh?" We laughed, I do warn people I charge double if they help! Because it takes me 4 times longer... Anyway I really enjoy it so it's not like real work...

I'll try an answer some things if I miss something let me know.

Colors in tables work by setting alarms in the parameter.

EGR does not hurt, I thought yours was gone, there are a lot of ways to turn it off so you may have done it differently. It does reduce combustion chamber temps, but I can't see it helping cooling temps. EGR will not ever come on on the trail.

Mild cam is still a little less vacuum, but combined with your elevation it's worse, unless you did not degree the cam when installing it and it's off and that would explain the low vacuum and idle timing issues. Big cams are like EGR at idle, so more timing, like when EGR is active.

You are more active with the AMC crowd so maybe there is a need for more timing at idle, but I've been getting by with 0 and adding in the spark table. Just a routine to set timing at 0, unless it's a cammed monster then 5... not that I am right, just what I do and has worked.

1227747 has idle issues, no real adjustments if not in Closed Loop, I saw tell tale signs of your bin being one that stays OL or, goes closed loop harder and one setting that has an open loop high temp setting. If you compare you'll find a few differences, I'll point them out later, I have one bin I built based off ASDU I always start with for $42 for all engines with other changes of course and it has served me well. Now you have one and I hope it helps you get back to tuning. It just takes out uncertainties.

I still think you have an ignition issue though. But if that bin is OK then I'd like to see data to disprove your bin had an issue causing the spark advance weirdness?