Sniper on Mopar 440, starting issue.

[Pool Fixer]

Hi all. I'm new here. I just completed my installation. Sniper 550-511 with HyperSpark distributor, coil, and CDI box.
cam is:
MP purpleshaft
4452993
Cam Style:
Hydraulic flat tappet
Basic Operating RPM Range:
2,000-6,000
Intake Duration at 050 inch Lift:
238°
Exhaust Duration at 050 inch Lift:
238°
Duration at 050 inch Lift:
238° int./238 exh.
Advertised Intake Duration:
280°
Advertised Exhaust Duration:
280°
Advertised Duration:
280° int./280 exh.
Intake Valve Lift with Factory Rocker Arm Ratio:
0.474" in.
Exhaust Valve Lift with Factory Rocker Arm Ratio:
0.474" in.
Valve Lift with Factory Rocker Arm Ratio:
0.474" int./0.474 exh.
Lobe Separation (degrees):
110°

I'm getting it dialed in and it drives pretty well. midrange is great, WOT is OK with a bit of a bog, but I just got it running yesterday so I feel I need to drive it around more for it to Learn. My pressing issue is hot or cold start. If I don't press the gas pedal just a little, it either won't start or will start and barely stay running untill the system seems to right itself. If I give it just a touch of pedal during crank or when it's sputtering, it immediately settles into a solid idle.

I have crank timing set to 18°, idle timing to 20°. I've tried changing the Startup Enrichment. i've gone down to 50% and as high as 300% and it seems to make no difference. I was hoping for reach through the window and twist the key capability.

IAC Position % is also baffling me. I temporarily disabled the Idle Spark control compensation while idle to set the IAC. I get it down to 6-8% but it's jumpy. Then if I turn the car off and back on, it's back up to around 30% and doesnt come back down. It doesn't seem to make a difference whether or not I reanable the Idle Spark control compensation while idling feature.

It seems to run good except for the starting issue, but I like my world to make sense so that IAC Position % is bothering me.

Also, I did spray carb cleaner all around the intake and I can't detect any vacuum leaks. I have the PCV port on the Sniper plugged and not connected to the PCV valve until I figure it all out. This car has vacuum headlights and there's a plug in the intake for that, but I put a sealed threaded plug there too.

I'm chasing down exhaust leaks. runnning factory manifolds and I had to disconnect them at the pipes to drop it all down to install WBO2 sensor. I put new gaskets in while I was in there and it worked because now they leak. thought it was the driver side at first and my WBO2 is on passenger side, but now I think it's both. That's where I'm at now. I ordered some better/thicker gaskets and I'll resolve that before I go any further.

However, I don't think that's causing my cold start issue because I don't believe the system is even utilizing the WBO2 sensor until it warms up. Again, just a touch of gas pedal and it settles into an acceptable idle. I hate when I increase the fuel Startup Enrichment and I can see the gas shooting up out of the throttle body. That seems sketchy to me.

[AndyF]

Holding the throttle open gives the engine more air. So look into giving the engine more air at idle, or perhaps less fuel. First thing I'd do is check the IAC Parked Position position. For a big engine the IAC should be at 80% for a cold start and 60% for a warm start. If the IAC Parked Position is too low it won't start without opening the throttle.

If that doesn't solve it then you have a fuel problem. You'll have to look at your datalogs to see if it's too rich or too lean, but it's most likely too rich. If that's the case then you just need to lean out either the prime or the Startup Enrichment. Cranking Fuel for your engine should be roughly equal it what it needs at idle. Probably something in the 7 lb/hr range when warm.

[Pool Fixer]

Thanks Andy, I appreciate the help!

[GPatrick]

Please download the Config File from the Sniper using the Save As function so we can see the tune that's stored in the ECU. Next, when the engine is fully cold turn on the ignition and start a datalog before starting the engine. This way we can see exactly what the system is doing and make recommendations for improvement.

Then record a datalog of a full warm start. Just the start and about 15 seconds of steady idle is all that is needed. Zip the Config File and the two datalogs and post them here.

The idle area must be well tuned before making any changes to startup or Temperature Enrichment. Changing these parameters without having the idle sorted out often has the opposite of the desired affect. It's not unusual for the IAC to change from when the engine is warm on the driveway to when when the engine is heat soaked. However, having the IAC go to 30% when restarting is not normal and often indicates a potential issue with the TPS. If the TPS is over 2% the system will go into the IAC Hold Position. At startup it will go to the Parked Position, but this only is used for a few seconds. After a warm start the IAC should drop to 2 to 5%. Check your throttle linkage and ensure that it's not preventing the throttle shafts to return to zero. Also check the front and rear shafts to ensure they are freely closing/opening. In some cases and inadequate throttle linkage spring or a weak rear throttle shaft coil spring will allow the blades to open from airflow and force the IAC to go to the Hold Position. Concentrate on this first as the idle cannot be set up properly if the IAC and TPS values are not consistent.

For cold and hot starts there may be an issue with your CTS. The coolant temperature sensor from Holley often reads warmer that actual temperature when cold (10° more more higher than the MAT). This messes up your cold start enrichment. On the opposite end, some of the Holley sensors will read low at high temperatures (mine was off both cold and hot). This can cause excessive enrichment during a hot start and as AndyF mentioned, having to give the system more air usually means that the mixture is too rich.

To test the CTS turn on the ignition after the engine has sat overnight. Navigate to the monitor displays and check the MAT and CTS. If the CTS reads 10? or more higher it must be replaced. You should avoid trying any tuning changes if the CTS is not correct.

[Danny Cabral]

https://forums.holley.com/showthread...898#post227898 (Holley Sniper EFI Replacement CTS)

[Pool Fixer]

Sorry for the delay, had to sort a few issues. I had exhaust leaks at the collectors or whatever you call it when you run manifolds. basically where head pipes connect to manifolds.

- I installed new gaskets and no more leaks.
- Installed new NGK spark plugs gapped to .045"
-I see how to datalog and I'll get a couple of those going. Still watching a lot of YouTube videos on how to actually use the Sniper EFI software. I'm plodding through that slowly.

Tried to start a datalog on a cold start a little while ago, but I either didn’t hit start or something. Will do it later when engine cools down.

I did see that MAT reads 58°F and CTS reads 73°F. I’ll head out now and get a new one.

[Pool Fixer]

OK, so I just got back with my new 213-928 GM CTS sensor and it looks identical to the one that came with the Sniper. So if Holley is using a generic GM CTS sensor, why do I read so much about failing sensors? Are the people who's cars this sensor is really for also having these problems? Is Holley running them over with a truck before boxing them up? I'm biased I guess, I see ACDelco temperature sensor and what comes to mind is reliability. Anyway, I'm $28.00 further from retirement thanks to them. I'll keep this thread updated with my progress.

[Danny Cabral]

https://forums.holley.com/showthread...898#post227898 (Holley Sniper EFI Replacement CTS)

[Pool Fixer]

This is a cold start. I think, LOL!
sniper_0009.V3.dl - Shortcut.zip
I'll do better next time. Still working through how to get the Config File to make a file for that.

[Danny Cabral]

Originally Posted by Danny Cabral For further assistance, post your Config File and a short datalog of this occurrence for us to analyze. Also, review the datalog and inform us of exactly where in the datalog (time/seconds) the problem occurs. Datalog & Global Files can be linked to a document hosting website. I use Dropbox.com. Files can also be "zipped" (compressed zipped folder) & attached directly to a forum post ("Upload Attachments"). Your Config File is in the "Documents", "Holley" folder, "Sniper" folder, "Config Files" folder (.hefi file). Your Datalogs are in the "Documents", "Holley" folder, "Sniper" folder, "Data Logs" folder (.dl file). Someone will analyze/troubleshoot the problem & offer advice. https://www.youtube.com/watch?v=iqHOtDNiTNA (How To Record & Email A Datalog) https://forums.holley.com/showthread.php?21942 (Holley Sniper EFI Save GCF On SD Card & Laptop/PC Usage, LINK - Page 73)

[GPatrick]

That was a zipped shortcut, not the datalog. To ensure that we'll be able to open it, zip and upload the datalog file with the .DLZ extension. Zip it up with the Config File that you download from the Sniper. Use the Save As function on the handheld and rename the Config File so it isn't confused with the Wizard tune that's also on the SD card. Only the Sniper ECU has the latest Config File, the Sniper does not automatically update the SD card.

[Pool Fixer]

Hot idle:
hot idle 03-18-23.zip

Cold Start:
4150_4 CONFIG zip 3_18_23 (2).zip

This should be the Config File:
cold start zip 3-18-23.zip

[AndyF]

I gave you some advice on the IAC Parked Position in the second post, but you didn't follow it.

[Danny Cabral]

Originally Posted by Danny Cabral • The Cranking Fuel (lb/hr) & IAC Parked Position % are the "cranking air/fuel ratio". Tune these tables. Adjust the idle speed screw on throttle body, to achieve an IAC Position of about 5% at hot idle. Some engines start better with more timing while cranking (Cranking Timing in Ignition Parameters). Ensure the ignition timing is synchronized: http://forums.holley.com/showthread....ing-Holley-EFI Sequentially injected engines will always crank slightly longer for the ECU to receive the cam sync signal. The new Quick Start "Fuel Prime Percent" feature works very well, but be careful; too much % will start fine cold, but not hot. • You can only tune the Startup Enrichment parameters after the Learning has self-tuned the Base Fuel Table and if the Coolant Temperature Enrichment & A/F Ratio Offset tables are acceptable. This is because the aforementioned parameters & tables are modifiers of the Base Fuel Table. Exception: Cranking Fuel (lb/hr), Cranking Timing & IAC Parked Position %, because they function independently under 400 RPM (or whatever your "Crank To Run RPM" is). FYI: The "Crank To Run RPM" parameter (in Ignition Parameters) is not your actual cranking RPM when starting the engine.

[Pool Fixer]

I gave you some advice on the IAC Parked Position in the second post, but you didn't follow it.

I thought I moved the points on the graph for IAC Parked Position to 100% up till about 140°F engine temperature. This was through the handheld. Maybe this is beyond my ability that’s what I’m trying to figure out. I appreciate the help and I’ll do my best to follow any suggestions I’m given. In this case, I did follow your advice, at least I tried too.