HI all, Could a lean fuel condition cause a Ping? I installed a ZZ4 motor in my 87 with a 58mm TB and 24lb injectors. At Idle the lean flag is rich and from about half throttle to WOT it is lean. I have the hard timing set at 6 deg. The only way I can get rid of the ping is to add 4 gallons of 100 octane gas to a full tank. Any thoughts?

Thanks

 

Yes

I went through a similar problem with my motor running lean. Retard your timing to 2* btdc that will help...at least for me it did.

I just put 30# injectors in mine and reset the timing to 6* btdc. All seems well now.

 

Actual scan data would help. Rich/Lean Flags don't really tell you very much and at WOT, they're meaningless. Need to see BLM's at idle and then in a couple of Cells - say at 1800 to 2000 rpms. What are the knock counts? How much timing is being taken out? What did you do to adapt the ZZ4 to the TPI; ie, what cam is in it?

 

BLM's? Don't know what that is. I had Alvin at PCM4LESS program up a chip to get it to idle. He did a great job concidering all he had was a description of what I put in the car. Do I need to do some data logging? If so, what program would you use? What cable? I don't have a local dyno with an AFR set up. If you know of one Close to carson city, NV(or Sacramento, CA) let me know. Thanks for putting up with an injection Newbie. I guess I could save some time and put on a 650 Holley but I like the injection.

 

HO 350 ZZ4 ENGINE DESCRIPTION
355 H.O.
5.7-LITER
“ZZ4” H.O.
CHEVROLET
V8
P/N 24502609
5.7L (350ci) High Output Chevrolet V8
Several significant improvements have been made to the 350-cubic-inch High Output Chevrolet small-block V8. This updated engine assembly is available as part number 24502609 (ZZ4 manufacturing code).
The 350ci High Output Chevrolet is the perfect power plant for many high-performance off-highway applications. The H.O. engine offers outstanding performance at an affordable price. It is a bolt-in replacement for all 265-400ci small-block Chevrolet V8s.
High Output 5.7-liter engines are assembled using brand new, premium quality components. This assembly combines proven small-block components with the latest advances in engine technology, including lightweight aluminum cylinder heads, low-friction hydraulic roller tappets, and hypereutectic (high-silicon) pistons. All H.O. small-blocks are fire-tested and final balanced at the factory to ensure their quality and performance.
Imagine an aluminum head small block that makes 355 horsepower. What if it had a steel roller camshaft, four-bolt main block, undercut rolled fillet crankshaft, high silicon pistons and strong PM connecting rods? GM imagined it, and then engineered, developed, tested and built it. The ZZ4 is the evolution of our popular ZZ series of small blocks that power thousands of street rods, hot street cars, circle track racers and drag racers. With over 400 ft.lbs. of torque, the ZZ4 is the best way to put an aluminum head, roller cam, high performance small block between your favorite fenders. The aluminum angle plug cylinder heads have screw in rocker studs, 1.94” intake and 1.50” exhaust valves and 58cc combustion chambers that yield a crisp and responsive 10 to 1 compression ratio. Also included are our lightweight valve spring retainers that weigh half as much as our previous design. The valve seats are radiused and we've included valve stem seals to help keep the oil where it belongs. To compliment the cylinder head design, GM incorporated a steel roller tappet camshaft with .474” intake and .510” exhaust valve lift. The combination makes 355 horsepower at 5250 rpm and has that great sounding muscle car idle, with just enough lope to let people know that this is no station wagon engine. Also included with the ZZ4 is an HEI distributor with an ignition timing advance curve developed for performance, a dual plane aluminum intake manifold that accepts your spread bore or square bore carburetor, an 8” high-RPM torsional damper, 12.75” auto trans flex plate and cast iron water pump. The ZZ4 is currently our most popular crate engine, and you can see why. With a long history of successes in circle track and drag racing as well as street rods and other performance applications, the ZZ4 may just be the bullet for your next project.
The ZZ4 is not intended for marine use, and should only be used in 1976 and earlier pre-emissions street vehicles or any year off road vehicles.
A prototype H.O. 350 engine with a Quadrajet carburetor, 1 3/4” headers, and low-restriction mufflers produced 355 horsepower (at 5250 rpm) and 405 lb.-ft. torque (at 3500 rpm).


Part Number: 24502609 (ZZ4)
Displacement: 5.7-liter (350 c.i.d.)
Bore/Stroke: 4.00”x3.48”
Engine Block: 10105123 Four Bolt Main, Cast Iron
Compression Ratio: 10:1
Pistons: High silicon aluminum piston with offset pins, 10159436.
Crankshaft: 12556307 Forged Steel
Connecting Rods: 10108688 PM rods
Camshaft: Hydraulic roller tappet (#10185071)
Valve Lift (Intake/Exhaust): .474”/.510”
Duration (Intake/Exhaust): 208°/221° @ .050” tappet lift
Valve Lash (Intake/Exhaust): Zero/Zero
Cylinder Heads: Aluminum, 58cc chambers, 12556463.
Valve Diameter (Intake/Exhaust): 1.94”/1.50”
Valve Springs: LT4 chrome silicon, 12551483.
Rocker Arms: 12495490 - Kit, 1.5:1 ratio, self-aligning, stamped steel, 10089648 single replacement rocker arm.
Distributor: HEI with centrifugal and vacuum advance, 93440806. Use connector P/N 12167658 to attach tachometer and 12-volt power supply wire to distributor.
Spark Plugs: MR43LTS Gap .045, AC FR5LS Gap .035, Rapid Fire #5 Gap .045.
Fuel Requirement: Unleaded Premium 92 Octane
¹Ignition Timing: 12° BTDC @ 800 RPM, 36° total @ 3,000 RPM with vacuum advance line disconnected and plugged. This setting will produce 36° of total advance at wide open throttle (WOT).
Max. Rec. RPM: 5800 rpm
Flexplate: 14088765 - For automatic transmissions, 153 tooth. Requires a starter with a straight bolt pattern or dual bolt pattern usable with a 153 tooth flywheel/flexplate.

 

Recommend you pickup Ben Watson's Chevy Fuel Injection so you can learn how it works (usually at Borders). That will explain Block Learn (BLM which is simply a numerical expression of Rich/Lean) and a bunch of other stuff that will get you pointed in the right direction. Data Logging is useful, but you could probably accomplish a basic tune with a scanner.

Assuming all you did was swap out the intake and carb for the TPI you need to do some work as the cam is designed for the carb. Do get your timing back to stock which 6 BDC and if you didn't install the knock sensor, install it now.

 

The only way to really fix it is to do a scan and start editing the chip to eliminate all ping, get your fuel trims (BL) in line and then use a wide band to set your WOT AFR's. With the right tools, it would take a couple of hours and make a HUGE difference in how your car runs. There is no magic, just give the engine what it wants. If you hear pinging that's really bad, the ecm will pull out a lot of timing, 10+ degrees to keep it from pinging, so if you still hear it, it's either that your knock sensor isn't working or it's pinging so bad 10deg isn't enough. Lean will make pinging worse, but TPI engines don't need a lot of timing. Call MSI and set up a tune. I know someone who can help!
Roseville CA 916-784-2323
Mark

 

Well, it scans 36 degrees at idle and about 45 to 50 at 2000 RPM's (WOW)What would cause that? I will give you a call after X-MAS to set up an apointment. I miss carbs, it was a lot easier.

 

Base timing is off - knock sensor and esc isn't hooked up - a couple of other things. You need to learn how it works - it's not that complicated. Electronic fuel injection controls fuel delivery, timing and has the ability to allow in some air for idle control and it works far better than any carb or mechanical/vacuum distributor which aren't coming back anytime soon. So if want to learn how to work on your Vette or that Toyota that's in your future, pick up the book I mentioned earlier (and along the way, the Field Service Manual for your Year).