This is my first time tuning and am way over my head at this point. I'm currently just trying to get this thing to run on it's own.

Here are the engine specs.
1968 327+.030"
KB Hypereutectic pistons
Comp Cams XE268H - C.C Hydraulic flat tappet lifters Dur. 268-280 Dur.@.050 224-230 110*LSA
Vortec heads - 1.6 roller rockers
Stock length C.C. pushrods
Milled for 62cc chambers
Screw-in studs
C.C. springs
Edelbrock RPM Air-Gap Vortec intake
TBI bored for 52mm throttle blades, 65lb. injectors, adaptor plate to intake(forward .5" from stock)

So far I've used the Vortec spark tables and removed 2* from all cells as a starting point. I have also reduced the IAC vs. Coolant temp cells by roughly 10 counts.

I can get the engine to start if I use the pedal and can keep it running that way, but I have not got it to run long enough to really get much data to find out if I am way to rich, or to lean. I have some info from when I forced it to run for a minute ro two. I'll need to get it cleaned up a bit and will post it as soon as I can.

I'm wondering if I am letting to much air through the IAC and not enough past the throttle blades causing all the fuel to pool. I have tried this same chip with 65lb injectors and it ran about the same, but I'm willing to give it another try tomorrow.

 

I might have posted to quickly out of desire to get the car back on the road after 2 years. After doing a bit of rereading, I think I do need to bring the IAC down in the Park Position to get the fuel distributed better. Are the BLM readings from the data table trustworthy? If so, I do have quite a bit of fuel to take out in open loop.

But any other suggestions would be great.

 

TZF

Which ECM are you running with your setup 8746???

IMHO to keep your 327 properly idling you must set base timing first - you'll have to experiment. Vortec heads do not too much timing so I would venture to say 0 deg (4 to 6 deg maybe perfectly acceptable) with EST disconnected and about 18 to 20 deg at 650 RPM idling with EST reconnected (make sure to clear codes after reconnecting EST). Naturally, you'll have to update EPROM for base SA value. Idle speed is subject to further experimentation and may require setting minim idle speed (idle set screw) and repeating min IAC procedure.

The 268H cam may not be producing enough vacuum - resulting in higher MAP voltage.
Post complete specs on 268H cam. Try to get your engine idling at about 650 RPM with maxim vacuum level (measure it).

//RF

 

RF

Yes, 8746 ECM.
Therein lies my problem also. I have not been able to get the car to even start with the ETS wire disconnected so I could set the timing. So I have the wire connected and set timing by ear since I knew the engine would be adding timing anyway. I am mainly just trying to get the thing to run with the ETS wire connected so that it will at least start with the wire disconnected.

The whole reason it will not idle could be the fact that the timing is so far off, but there is no way to set timing unless the engine will run.

This would explain the only Code I throw being MAP High. Could that be causing the ECM to throw the timing way off in order to get the MAP levels back into order? I'm slowly making my way through the bible stickies, but it's slow reading and hard to pick out posts with questions and those with actual information.

Thank you for pointing out the low vacuum from the cam. I'll have read up on that in relation to timing.

 

Double checked to make sure I have dist. in correctly. Lost count how many times I have done that. Still could not get it to start with EST wire disconnected. I did get it to idle by itself with the wire connected, so obviously it is able to adjust timing enough by that means to be able to run. I had an insane spark count that made my stomach uneasy. I'll probably frag the engine before I even get the car to move. It wasn't audible but as loud as the car is it would be to late if you could hear it.
I was able to get a few cells filled in as far as BLM and INT goes. I'm going to adjust to lean it out just a hair. The large knock count would have to indicate that I am to far advanced?

I know I'm talking to myself here, sometimes it works though.

 

The large knock count could have been from cranking the engine. It could also have been from some other noise that is being picked up. To know for sure that it was from or not from detonation you need to look at the spark plugs.

You have an uphill battle getting that set up tuned. An airgap intake will be adding very little heat, the fuel is going to puddle and stream down the runners. It will want gobs of AE.

With the amount of cam you are going to need to pull fuel from the lower end of the VE table. Will also need a fair amount of SA to compensate for the self-EGR. The 65#/hr injectors at 30 psi of fuel pressure should be able to fuel that engine.

But I wouldn't bump the pressure up until you have a better handle on the VE and SA requirements.

To get the base timing set, start the engine and warm it up some. Then with a timing light set the SA to the 26 - 28* BTDC area. Opent eh BYPASS connector (for the EST) and at the same time keep the engine running. Even if you have to grab the throttle linkage and hold the RPM higher.

Then let the RPM down to less then 1200 and set the timing to 6* BTDC.

Now tighten the distributor hold down and double check the timing. Shut off engine, and reconnect the BYPASS. Go into the calibration and set the initial SA to the same (6* or wherever it ended up after tightening the distributor).

Install updated calibration and restart engine. Start a data log, see if you can drive it around some. Adjust calibration from there, rinse and repeat the data logging/driving cycles.

If you continue to get high MAP DTC's (33) then increase the MAP threshold for that DTC. If the SES turns on with this DTC you can't use that data log for adjusting the VE table. For that matter, because of the cam I would bump the DTC 33 MAP threshold by 10 KPa. It's going to need it, so best to just do it and get it over with.

RBob.

 

TZFbird

Knock count at idle may indicate couple of things.
Did you calculate static compression for your engine combination??? I just did a quick check on KB website and they list bunch of hyper pistons for 327 (KB154-158) and with 64cc head you have compression around 10:1 depending on a piston type:
KB154 9.7:1
KB155 10.8:1
KB156 9.7:1
KB157 11.5:1
KB158 9.0:1

General observations:
Going lean is not a good idea at this time. When getting a new engine up it is better to go slightly rich.
Did you get basic timing set with a timing light???
Due to cam duration your NBO is seeing extra oxygen from intake mixture during overlap (both intake and exhaust are partially open allowing intake mixture to flow into exhaust) . It is a common issue with longer duration cams and narrow LSA. Oxygen detected by NBO causes ECM to lean mixture - opposite of what you need making for lousy idle (and possibly pinging).
You have a difficult position at this time. You need to burn a chip to disable CL at idle while dialing in base line PW.
Your total timing at 650 RPM should be around 15 deg BTDC. EST module ads another 10 degrees, built in, above 400RPM.

//RF

 

I gave it a few jabs when I was trying to get it started/stay running, so I'm sure quite a bit of the knock came from that.
As of right now I am running the 40lb 305 injectors because the 55s would just about teargas me out of the garage even with the door open. Could literally see the haze rolling out. I'm going to go through and pull some fuel tonight with the little bit I got from the BLMs. I have a set of NIB 80lb injectors that I picked up for this.
As soon as I get a chip tuned that will make the car mobile, I'll tune with the 55lb injectors up to midrange rpm, then drop in the 80s and do a complete tune.
I know I had to go with a really thin HG and ended up real close to 9.5:1.

I guess I had no idea the EST wire could be disconnected while running and that the engine would drop off and the base timing could be set.

I'll give all this a try in the next few days and hopefully it will turn out.

 

The 305 injectors are 55#/hr (not 40).

If the 55's you mention are from a 350 then they are one of these three sizes: 61#/hr, 65#/hr or 68#/hr.

Make sure that you get the BPC set up correctly for the injectors. If you used 40#/hr when the 55's were in there the BPC is too high and will cause the engine to run rich.

Don't forget to disable the EGR in the calibration. Otherwise more problems will ensue.

RBob.

 

So I was correct the first time in saying 65lb. Ok, I was going off diy-efi that listed the cop injectors as 65, 350 as 55, and 305 as 40.

I tried calculating the BPC but came up with a rediculous number(196) that would have added lots more fuel, so I left it alone(134) until I find the correct calculation.

Never heard of DTCs. MAP DTCs?

I pulled anywhere from 3-5% depending on KPa and RPM from VE table 1 in the low RPM, low MAP range. I was down around 108 for what few BLM cells filled in.
I have 2 different tunes to try so far, I'm also going to try one with the MAP threshold adjusted as you stated before.
Luckly I have a 20-30 minute drive each way to work for tuning as well as 20-30 minutes to get to the PROM burning equipment. So I have plenty of opportunity to get this thing tuned quickly once it's reliably mobile under it's own power.

As far as EGR goes, I increased the MPH for EGR enable to 255. I should probably adjust the TPS for EGR enable as well.

 

DTC is a diagnostic trouble code. Same as a malfunction code.

The formula for the BPC on TBI's is:

BPC = 1461.5 * (Volume / Injector Flow Rate)

The Injector Flow Rate in grams per second
The Volume of one cylinder in liters

gms/sec = (lbs/hr / 3600) * 453.6

For a 305 with 55#/hr injectors the BPC is: 132
For a 305 with 65#/hr injectors the BPC is: 112

This is with the fuel pressure set to 13 psi.

Also, note that the BPC is more of a centering device for the VE table. If the VE tops out at 100% the BPC can be increased. Same for the other direction.

However, this is only true as long as the injector duty cycle is within 85%. Once the DC goes above 85 then more injector/fuel is required.

RBob.

 

I just realized there are 9 pages in the "Come in for a FREE Tune" I always wondered what made it so special. BMMonte pretty much serves it on a silver platter in that thread.

No trouble codes when I got it to idle by itself for a minute at least. Now I realize was all screwed up because I was using total engine volume in cubic inches instead of an individual cylinder in liters.

Sp this puts me at:
5.4/8=0.675L
(55/3600)*453.6=6.93gm/sec
1461.5*(0.675/6.93)=142BPC

If I am 10 off(low) for my BPC, I'm running so rich because of horrible timing. I guess this tells me not to pull any fuel and instead should get my timing set so I am able to increase to the required BPC as well as VE%. Vicious cycle!

Thanks for not telling me to search for that. I feel like an idiot now. I'm going to try and pick up the pace here real soon.

 

RBob

1. Added some timing tape to the balancer.
2. Needed to add about 6* timing and double checked with EST wire disconnected. Didn't really try to die at all when I disconnected the wire. Reconnected, double checked timing and it was still on. Aside from a few plug wires wiggling loose and #1 happened to be one of them(wondered why it would run rough, smooth out, then rough again, timing light also going out).
3. Adjusted throttle stop to get in the 800-1000rpm idle as well as IAC counts 0-13 or so. I need to work on hunting idle, but that should come with getting the fuel straightened out.

So after I get a new chip with the BPW set to 142, and CL disabled so I can take care of BLMs around idle
I'm also hopefull to try and throw it into gear and it wont die like before, or if it will move.
So aside from being stupid and needing to get the timing set, I'm now on track as far as my expectations for starting out.

I've also started taking all the text out of the 'Come in for a FREE tune' post and I'm going to try and summarize it. Not sure if it will turn out, but hopefully it will turn out like a Cliff's Notes for tuning. Of course it can't replace asking questions and researching, but at least point out all the required areas, and enough information for a decent tune.

 

Sorry to keep bringing this to the top, but I just want to clarify everything I've learned so far. All these questions are in reference to an 8746 ECM with $61 mask. I am running TunerCat and TunerPro at the same time so I make sure I get the correct tables looked up.

1. After setting BPW/BPC, can jump into adjusting VE#1 to get out of 108 or 150 BLMs; enough to drive around and start logging?

2. Check off idle throttle responce and use:
wall wetting vs. MAP = AE vs. Diff. MAP(TunerCat)
pump shot vs. TPS = AE vs. Diff TPS(TunerCat)

Adjust these to get rid of any sluggish or lean-pop in low RPM, low-mid MAP depending on cam

3. Setting idle would require the use of IAC counts, RPM, and TPS% and adjust the throttle stop to balance them out. Would it be wise to idle a bit higher for a cammed engine, or the lowest that will idle well but not stall out when under load, such as starting out going uphill?

4. Adjust VE tables #1 and #2 to get BLM withing 1-2 of 128?

5. Adjust SA up until knock is detected, then back off 1-2*?

6. The final issue is tuning for open loop. I understand how everything else is relating together, but open loop is a bit of a mystery. So far I've figured that:
A: 'O.L. AFR vs. CTS' and 'O.L. AFR Correction vs. MAP' are added together to get the base AFR for O.L.?
B: Crank AFR vs. CTS is then subtracted from the O.L. AFR to make the cranking AFR which needs to be much higher than while running in O.L.?
C: Likewise, AFR @ startup vs. CTS aka (choke) is then subtracted from the O.L. AFR for running ater the engine is started?

7. Where I get lost again is the Choke AFR Multiplier vs. CTS? I cannot figure out where or how this can be used. I've printed off and been through the FREE tune post done by BMmonte and never really saw anything mentioned about this. Not saying that some more searching will not yield some information, but I'm trying to get this all ironed out in hopes of getting this engine tuned very quickly since the daily driver is in need of some major TLC.

Please correct me on any of these thoughts that I have wrong.

 

See post #8 below

https://www.thirdgen.org/forums/diy-...cold-idle.html

 

'multiplier'.... they are a percentage, which eplains why the values are up in the 90's. Multiplying the O.L. AFR by a number in the 90's will make it a bit more rich, which explains it being for the choke.

I suppose as long as I got that figured out I'm well on my way to starting.

 

Also jerk out the stock pushrods and get one's that are hardenend! I run a 30 over 350 with the 268h cam and vortec heads as well, and I twisted two of them into what resembeld a pretzel at about 5 grand. I am assuming you have at least beehive springs with screw in studs. Good luck!

 

I updated the engine info. I knew that was going to come up. Everything in the valvetrain is Comp Cams that they recommended to use with that cam.

 

Thanks again RBob

I pulled the 10K resistor from my ALDL cable. Car wouldn't start again. I thought that was odd. I also found it off that Bruce Plecan's cam was incredibly close to the one I am running. Then it hit me when I got to his spark table. I hadn't adjusted the spark table to account for the fact that my cam idles around 65Kpa instead of the 35Kpa stock. I've been trying to run this engine on about 10* of timing.

Had I not pulled that resistor, I would be adding and removing fuel trying to get this thing to run good enough to drive and start data-logging.

It's always the simple things that make a problem harder.

 

Well, attempted to move the car today. Put in gear and idle dropped low, but did not stall. Started missing. I had to pull all plugs and clean since the were fouled the other day, so I'll bet they are due again. I'm still getting black exhaust, so I'm thinking it's just running so rich I'm fouling plugs and not keeping power when put in gear. I've gone through almost a 1/4 tank idling for about 15 min. Some VE adjustments are definately required.
Burned a new PROM with 10% removed from VE below 1200 and in the 50-70Kpa range. I'm also going through the Common idle issues posts. It appears the next PROM will need some work done with the O2, but I'm sure I'm going to need to get some logging done to get the VE% somewhere close to 120. I know there are quite a few 108s around idle.

It also appears that larger duration cams can be run much leaner than ones with less duration. Not sure why this would be but I have no problem leaning out idle just so long as the internals stay in shape.
**EDIT**
I pulled about 25% from the VE around idle and I no longer have black exhaust at idle. Sounds much better. I still need to pull plugs since I'm sure they're about fouled again. After cleaning plugs it's 2nd attempt at getting the car to move.

An admin... could you please read through this an add it to the Tuning Guide Book
under 8063/7747/8746 ($4D/$42/$61):

https://www.thirdgen.org/forums/diy-...idle-gear.html

 

Still pulling from the VE table. Every time I start it up and log at idle I'm pulling more fuel. O2 reads increasingly richer as I enter closed loop. So I can only take this as needing to pull more fuel as temps increase at idle. On a side note, engine will idle in gear, but I am loosing a lot of vacuum since I'm fighting the stock converter. My next step will be to increase timing around idle in attept to lower the idle RPM so I can burn that extra fuel instead of slowly drowning in fuel. As of now I'm idling around 900, but that is still to high for the converter. I can definately tell the difference between the new engine and the LO3 just at idle.

I need to get this thing going soon or I'll be making a few trips to the station with my little 2 gallon can.

 

Looks like I'm talking myself through this, but that's how we learn.
Well, as I entered closed loop and watched the BLMs drop vacuum went up slightly. Until I got down low enough and then got into the O2 swing, so I must be close as far as fuel goes.
I did lower the idle setpoint down to 700, so that needs to come back up again. Probably try 800... fight the converter again.

It's to bad funds are a little low, but after reading the writeup about converters, it looks like I should save up for a decent one. Would probably make tuning at idle a bit easier.

 

* Set idle target back down to 825rpm.
* Pulled tons of fuel from VE table around idle... I'm idling steady at 128 somehow for at least 30 counts. This is out of gear though. I was able to pick up some extra vacuum so now I idle around 60Kpa instead of 70.
* Put in gear and my Kpa shoots up to 80. I have yet to lower VE around idle at 80Kpa so that could be part of the stumble before it dies. So by theory I should just use the same numbers and give a few extra points for fuel. I'm assuming it's a fuel issue since I can idle at 5 IAC counts and it jump to 40, run a bit better, jump to 65, but is stumbling by that point.

Next trial will be pulling fuel in my 'in gear' range and adding a couple degrees of timing all around idle to see if that helps at all with the vacuum issue.

**EDIT**
I'm still wondering about this whole concept between larger cam/duration and the need to remove so much fuel at idle. I know my BPC is close to that of stock. This is only raising the question of all that extra fuel just sitting around on a stock tune. Before I go accusing a stock tune of having extra fuel sitting around I'm going to double-check my BPC and the amount of VE I've pulled since starting.