730 startup problems

So my friend has a 350, with a Comp 270 cam (224deg at .050) and a TPI with hi flow runners. He's running a custom bought harness, with a 730ECM, and has an autoprom with AUJP loaded. He has 30lb injectors that are new. This engine has zero miles.

Problem is- it wont start... It'll try, a little.

Running $8D mask, TunerProRT

Disabled VATS.

Set injector size to 30. Actually reads 29.xx something

Tried setting the mask to AA to disable checksum, then just let the checksum update at every load to make sure that wasnt the problem.

After a few tries if you pull the plugs theyre pretty wet with fuel.

Not every cylinder generates heat (IR temp gun on header tubes), but every plug is firing when checked.

Plugs are new and gapped at .040. All ignition is new- dist, coil, wires, etc

IAC cycles at key start, as does the fuel pump. Fuel pressure was 45 key on, I believe.


I was looking at the crank fuel setting in the mask as a possibility, not sure if these scale when you change injector sizes or not.

Im looking for opinions and things to check or change, please

Diagnose rich condition by disabling all fuel delivery and cranking with throttle open. If car eventually fires then dies look at excess fuel as an issue.

Cranking fuel tables rarely scale with injector flow changes. Scale cranking fuel tables by amount equal to difference between old and new injector flow as a beginning. Fuel injector correction values can also be very important. If car was converted to 7730 from older 165, ensure cold start injector is disabled (if equipped). Ensure spark at plug can jump 1/8" gap or greater.

Have you made sure that the distributer is stabbed correctly? It sounds like it might be installed in the wrong position.

Quote:

---

Originally Posted by 1project2many

Diagnose rich condition by disabling all fuel delivery and cranking with throttle open. If car eventually fires then dies look at excess fuel as an issue.

Cranking fuel tables rarely scale with injector flow changes. Scale cranking fuel tables by amount equal to difference between old and new injector flow as a beginning. Fuel injector correction values can also be very important. If car was converted to 7730 from older 165, ensure cold start injector is disabled (if equipped). Ensure spark at plug can jump 1/8" gap or greater.

---

Stock cam will likely idle around 30-40 kpa but the installed cam will idle more likely in the 60-70 kpa range so you need to reduce the idle fuel as well.

I would also double check that the valve lash is not too tight if you are getting cold exhaust temps.

So after many many hours of trying to get this engine to start we figured it out the other night. Although we had checked that #1 on the cap was indeed #1 TDC, we decided to try it 180 degrees from where we were. Rather than pull the distributor we decided to just re-orient the plug wires on the cap. So as my friend is reinstalling the wires I noticed that he was putting them on 1-8-4-3-6-5-7-2, but he started at #1 and went counter clockwise! Since we were both very fluent with chevy firing orders and neither of us were noobs with engines I never doubted what he was doing. Somehow he just went backwards, and as soon as I questioned the way he was installing them he immediately realized the mistake. Consistently, every time he reinstalled the wires, they were in the wrong direction! After correcting the firing order, it started up instantly.

Quote:

---

Originally Posted by sbnova

So after many many hours of trying to get this engine to start we figured it out the other night. Although we had checked that #1 on the cap was indeed #1 TDC, we decided to try it 180 degrees from where we were. Rather than pull the distributor we decided to just re-orient the plug wires on the cap. So as my friend is reinstalling the wires I noticed that he was putting them on 1-8-4-3-6-5-7-2, but he started at #1 and went counter clockwise! Since we were both very fluent with chevy firing orders and neither of us were noobs with engines I never doubted what he was doing. Somehow he just went backwards, and as soon as I questioned the way he was installing them he immediately realized the mistake. Consistently, every time he reinstalled the wires, they were in the wrong direction! After correcting the firing order, it started up instantly.

---

More often than not, when a seemingly simple problem is complicated to solve, it is almost inevitably a simple solution. This would happen to me.

Bet you were glad to finally hear it fire off!