EBL has been working fine for a couple years now. New EFI compatible cam and it has low vacuum at idle, approx 60kpa. Doing learns closed loop and it keeps taking away fuel each learn until it hits zero in the corrected low speed VE cell. I don't understand how it can be that rich and even then it can't seem to be corrected.
To make things more difficult it doesn't seem to want to idle at the commanded idle RPM (this is before letting it hit zero). I start at 675 RPM and it wants to hold about 800 so I change the commanded idle to 800 and it wants to hold at 900. Chased this all the way up to 1100 and it still wont idle at the commanded 1100. Seems to want to surge too most of the time. Can't find any vacuum leaks.
What else could cause all this craziness?

 

What are the specs on cam? My engine is 350cid and my cam is 224/230 .05 and I idle 36-38 MAP zero steps IAC. I have it commanded at 650 and I idle 750 rpm(manual trans) in OL at 14.0/1 A/F idle RPM set with TSS.

Your idle rpm would tend to suggest vacuum leak. As you are aware. Or your steps on IAC for coolant temp(160-200F) could be very high. IAC is a controlled vac leak. How many steps do you see for IAC? I recall 5-20 is about right. I forget the name of the table. Is your IAC functional? Can you do a visual to confirm?

Cells in VE go to zero. That is differrent. My car once had a leak at collector to ext pipe. It drove VE #'s high to 100. What does the log of NB02 activity look like at idle?
What does the NB02 logs look like during a cruise?

 

Thanks Ronny. The cam specs are here.
http://www.compcams.com/Cam_Specs/Ca...csid=1110&sb=0
The IAC seems to be working right. If I open the throttle plate too far at idle the counts go to zero and if I close the plate the counts go up. I also tried setting the IAC to zero via the ALDL and then adjust the idle and it still didn't work right. I even tried plugging the map hose at the TB and use a vacuum pump to give a steady signal to the ECM to try and smoothe it out which didn't help. I'll attach a snap shot of the WUD while running for what it's worth. Keep in mind the actual playback is all over the place and it's hard to keep the engine running without giving at about half throttle.
I understand what you're saying about the exhaust leak. It's actually doing just the opposite though and the NB is switching.
I also have a WB but don't trust it in the tail pipe but it was indicating like 12.5 AFR fluctuating while running, also covered in black soot when I took it out. I have a weld in bung for it but couldn't get the plug out yesterday. Soaking in WD 40 now so maybe I can get the WB working right too.
This is a off highway vehicle so a cruize didn't happen yesterday and the way it runs wouldn't work so well anyways.

 

You are using xdf supplied with EBL? What is your BPC?

WB in tailpipe is most likely accurrate. Maybe less accurrate at idle.

Any malf codes in WU logs?

 

Yes, EBL_V23XDF and BPCvs Vac of 124 and a 350 CI displacement scalar.
I've had issues with the WB in the tail pipe being REAL jumpy for this vehicle that's why I installed the bung back when....
High Map malf code initially but I changed the code parameters so it doesn't come back below IIRC 85 map.
It's funny you should mention the XDF as when I initially fired it up the XDF seemed wrong and I did some checking to find the EBL bin file to be ~4000kb which was supposed to be 16kb. **** canned that bin and restarted the XDF and it SEEMS to be right now.
Keep in mind I messed with this all day yesterday and tried everything including the kitchen sink but don't have all day today to write it down. Off the top of my head I tried N alpha mode with no help. Whenever I updated the low speed VE I made all of the cells the same around idle to avoid jumping RPM between cells. Changed the stall saver RPM range with each commanded idle change to keep the stall saver from making it crazy..... Changed something (don't remember exactly what right now) because launch mode was on at idle..... Changed idle SA to 30 predicting it may need to change with this cam..... Tried closed loop idle. There's no EGR or CCP on this one...
I'm sure there's more......

 

Oh yeah 85 lb injectors at 15PSI fuel. I expect this engine to make close to 400HP so I may need to up the FP but first I need to get a handle on things.
Can I attach a bin file and data log here?

 

Made great progress tonight. It seems as though the problem was a computer glitch. I got to thinking about the whole 4000kb bin file and how in the heck did that happen anyways???? Went to reinstall the EBL XDF file and realized I had a updated XDF that RBob sent me last week. Installed the new XDF and loaded a bin that I had saved from about a year ago and ran until a couple weeks ago. Started right up and ran fairly good too!
Still need to do some tuning on it but at least now I have a realistic starting point.
Thanks for the help!

 

Hey guys I got to do some driving/ tuning yesterday. VE tables look prety good though I haven't tuned for PE yet. Bigger concern right now is idle. At idle I have the Idle state SA bit checked and all SA cells around idle match the commanded 25 value.- I don't think spark is the problem....What it wants to do is drive the IAC open as the MAP increases. It's a quick cycle that goes up until the IAC is max open, MAP is at like 90 and the engine dies. Before this cycle starts it wants to idle about 60MAP or so. I tried changing the stall saver RPMs every which way but it didn't help...I had to take advantage of my driving time so I didn't screw with it too long. I drove the IAC closed with the ALDL and unplugged it. I read this morning that I should have also zeroed the AE-IAC opening fuel to make this work right. I don't like the way it's set now as any time there is a engine load at idle it drops RPM too much. Electric fan wants to kill it.
I would really like to get the IAC working correctly but not sure where to start with it?

 

Does it throw a MAP code prior to stalling??? Mine would when I was running it on my 224/224 cammed 305 when I was beta testing the EBL. At idle/in gear the map would rise above the threshold, the EBL would enter limp-mode and it would stall.

 

No it didn't yesterday. I raised the MAP hi BARO limit to 80. Seems like it should have though being the map goes well above 80 before stalling....Now that I've though about it a little I wonder if it would be as easy as lowering the VE in the high map/ low RPM cells?
I'll give it a try and see.

 

Well I did this and it helped tremendousely but it's still kinda doing the same thing. What I did was flatten the VE table in all the cells from 400-700 RPM ranges from 55 map on up. What it seems to be doing is when I shift it into gear the converter puts a load on the engine and it drops RPMs thus loosing vacuum from about 60 map up to about 70 map. The IAC opens up to get the RPMs back to the commanded 725 idle but when the IAC opens it looses even more vacuum. It kinda chases it's tail for a second and now it levels out at about 75 map and 75 IAC where before it would just keep going up and die. It's good that now it doesn't die but the idle quality in gear is very bad........
Is it possible that the IAC needs to add more fuel per step to make up for the added air? How would I change that?

 

Also my BPC calculation is off as I raised the fuel pressure and didn't change the BPC (cuz I'm a dumb azz). From what I understand this is like a BPW setting of a factory bin? I really don't want to change it now because I would have to startover with the VE tables. Am I OK to leave it as is?

 

I better jump in & say change your BPC before you work on the VE values.

 

I have no experience tuning an auto trans. Fast 355 is your man on this one.

Dont know if you want to try this but I will throw it out there. Seems your idle is being controlled by IAC and or IAC/stall saver. You could try to control the idle by throttle stop screw rather than IAC steps. Set IAC steps to zero at idle. You may want to reduce the max steps as well so IAC never opens that much. Not sure if this is related but I idle OL. My stall saver still works for AC and it wakes up when I do a fast stop from speed.

Still, I dont undunderstand why you idle at such a high kpa/MAP? Can Fast elaborate on that?

 

Thanks for the input! Basically I had the idle set with the stop screw Sat when I was tuning. What I don't like about it is whenever there's a load the engine didn't seem to be able to mantain RPM. This is in open loop idle or closed. To make things worse I think there's no shift indicator so only the idle RPM in gear table is used. Right now it idles fairly well in neutral but goes to crap when in gear.
I'll try to limit the IAC max steps and see how it works. I'm not sure what that would effect with throttle follower and such but I never did really understand the purpose of the TF.

 

That is a fair amount of cam. Most likely will need to idle at 800 to 850 in gear. Has the converter been changed for one with a higher stall speed? It may be that it is too tight at the higher idle RPM and is lugging the engine.

The other thing is that at lower speeds more spark advance is likely required. This is due to the self EGR affect with the increased overlap.

RBob.

 

Suposedly this cam is made to work with a stock torque converter. If it needs to idle a bit higher that's fine but right now raising the idle speed doesn't seem to help. I'll definately try it again though along with lowered IAC max opening.
So for more spark advance should I let it be variable at idle as opposed to locked in at 25 degrees as I have it now?
It seems so close but not quite there yet.

 

The other side of this is the mechanical set up. Intake manifold leak, cam degree setting, valve lash, spring bind, retainer to seal clearance, base distributor timing. Lot's of areas that will also affect the tune.

RBob.

 

Thanks, all points well taken. I've though about most of these too.
Intake manifold leak- This intake has been used with these heads for about a year and seemed to seal well before. I did use a new product-gaska cinch (sp). I've never used it before so I hope it isn't screwing me. There doesn't seem to be a leak.
Cam degree setting- I didn't degree in the cam as it's a retro roller so the lifters are expensive and I don't have a solid lifter to use for this. It is a custom grind, not from Comp cams just ground to their specs. The machinist said every cam he has gotten from this grinder has been spot on when checked.....I hope.
Valve lash-Valve lash was set cold with engine off. It's been in the back of my mind that I would like to do a running adjustment but it would be a real bear with this engine configuration so I've procrastinated.
Spring bind, retainer to seal clearance- Should all be good as the heads were machined to accept this cam along with matching valve springs.
Base distributor timing- I assume you mean verify timing with a light? Done. I should double check that the timing is steady as I've had issues with this before.
All great ideas!

 

This came to mind. Do you think you are getting MAP-AE in excess? Maybe you could look at a log of event in that regard. Overfueled and engine drowned in AE excess fuel? I wonder if reducing the AE-MAP values by 50% would help. I once read something that RBob posted regarding MAP AE over fueling.

 

Just looked at a log and AE doesn't come on at all when it does this..
I think I'm going to readjust the valves with the engine running just to make sure it's good.
I'll report back, could be tomorrow before I get to it.

 

Well I did the running valve adjustment last night and there is no change. I do have the piece of mind knowing that this isn't the issue.........I didn't have much time to mess with it otherwise but I hooked a timing light up for a minute and the timing is jumpy. I've had this same thing happen before and replacing the distributor pickup coil was the fix. Whether or not the jumpy timing is the problem it still needs to be fixed. Once I get that done I'll continue with the tuning.

 

...............

 

Well I've been busy with this and I now have it running prety good so thought I would post up for anyone interested......
First for the jumpy idle timing I replaced the dist pickup coil and all of the secondary ignition from rotor to plugs. Idle timing still jumps around a little so I'm thinking it's just due to the endplay of the new roller cam. After this it didn't run any better so onward to more tuning in my next post.

 

The predicament I was in with thew tuning was as R Bob said the new cam made the engine want to idle higher (like 800+ RPM) but this would load the torque converter too much. A lower idle didn't pull much vacuum and it ran poorly. So I did what many back yard doesn't know what the heck I'm doing tuner would do, I started pushing all of the buttons to see what they all did. Kind of like at the eye doctor being fitted for glasses, "better or worse". Most of the changes made were based on othewr EBL bins I had to compare to. Here are the changes I ended up with, I don't know how many of them will make sence.
1)Option word 2 bit 1-unchecked to let the timing be variable at idle.

2)Bumped the idle SA up from 25 to 27 in all of the 400-600-800 RPM cells of the main SA table.

3)SA Idle high compensation table-Was all zeroes but now
200-8.09
150-4.92
100-3.87
50-2.11

4)SA Idle high map multiplier raised all of the values.
20-45 kpa is 100
50-78.4355
60-49.80
65-60
70-80

5)SA idle low compensation was all zeroes and now-
200-3.87
150-3.87
100-3.87
50-2.81

6)SA Idle low map multiplier-
70-60 kpa is 100
55-49.80
50-47.06
45-31.37
40-20 kpa is zero

7)Stall saver RPMs
exit 675
enter 600

8)IAC idle high step delays-
large 400
small 200

9)IAC idle low step delays-
large 400
small 800

10)IAC idle gain breakpoints-
low 50.00
high 62.50

11)IAC steps decay filter-
Normal was 12.48 now 24.96

12)Idle speed drive lowered from 700 down to 675

It's set for open loop always. Along with all of this the IAC goes to zero at idle. For some reason if I change the IAC to have counts at idle then idle RPM is not as steady.....I drove the p*ss out of it yesterday and everything seems to work well except there is a slight bog when you snap the throttle open at higher RPMs. I'll have to hook up the WB and see what I can do about that later.