IROCThe5.7L

Hey guys, I could use some help. I'm confused.

Car was originally a 350 TPI car. Car still has original wiring, sensors, ECM...etc Ran flawlessly since the new motor was built 5 years ago.

Now it will not start on the first cold start of the day. The pump primes with the key forward and I have adequate fuel pressure at the rails. After a lot of cranking I pulled some plugs and they weren't wet with fuel.

I sprayed some starting fluid in the intake, and it fired up and kept running. I immediately turned the car off. And it re started no problem. Then when the engine was warm, hot, sat 4 hours...etc It fired no problem.


Can anyone think of a reason why the injectors won't fire for the first cold start but once it does start, it will start all day no issues?

Tuned Performance

iTrader: (92)

Have you used a noid light to confirm that there is no injector pulse cold ?
Sounds like your saying it was flooded then popped off with starting fluid.

mmadden55

broken wire thermal issue. Had it happen to me , basically a wire somewhere is broken inside the insulation and doesn't make contact when it is cold but expands enough when warm that the ends make contact. Need somebody who knows his way around a multimeter chase down the short when it is cold.

IROCThe5.7L

I did not. I just assumed since the plugs weren't wet, and it started with starting fluid, that it wasn't getting fuel when cranking. You can rent a noid light from autozone right?


When the car does start cold, I can immediately turn it off. I'm talking it was running for 2 seconds. Nothing is hot or warm. And it will restart every time after that. It's just the first start of the day,

Tuned Performance

iTrader: (92)

https://m.autozone.com/test-scan-and...ter/948078_0_0
To get injector pulse the ecm needs to see 400 rpm or more on the purple/white wire of the icm to pin b5 of your 1227165 ecm . Unfortunately this is a square wave signal so you would need a scope to see it while cranking. When you start the engine with starter fluid all is well I’m wondering if there is a solder joint in the ecm that’s bad.
Can you try to blink codes engine cold. Sometimes when a ecm fails it won’t blink codes.
They usually fail when hot which is weird. You might want to check the wiring for heat damage near the distributor especially on the purple/white wire.
Moving around the harness while the engine is running you might find the culprit.

IROCThe5.7L

Thanks for taking the time to help. I am a moron when it comes to wiring. I did ohm the injectors and they're fine. I grounded the A+B terminals. The fan came on, and the SES light blinked a code 12.

Weird thing is I had this no start issue weeks ago. I bypassed my MSD box, and the car would start. When I hooked up my MSD ignition box, it wouldn't start. I did this like 10 times. So I sent the box out for repair as it would start every time with it disconnected. Now there's no ignition box in the car, and I'm having the same issue. I think the noid light is a good idea. Maybe the injectors are firing and I have an ignition component failing like a coil or ICM? It seems when I searched here, when people spray starting fluid in the intake, it will fire and then die when it's burned off. Mine fired and kept running.

I will definitely check that wiring tomorrow. And also hook up my laptop to make sure none of my sensors are giving crazy readings. Again, I really appreciate the help.

mmadden55

Yep exactly that can even be that little bit of vibration does it.

bjankuski

My assumption is your cold start injector is not working and the starting fluid is providing the fuel necessary to start the car. After the first start there is enough fuel in the intake and heads to start the car until it cools off again. Your injectors are probably working just not supplying enough fuel. Verify injector pulsing, and then look at the cold start injector system and see if it is working. Either fix the cold start injector or have a new chip made to eliminate the cold start injector and add in the extra starting fuel with the main injectors.

This also assumes you still have the cold start injector, if not maybe the temperature sensor for the EFI failed and is providing a temperature that is too warm so you do not get enough fuel to start the car cold.

IROCThe5.7L

IROCThe5.7L

Well, here's an update just in case this comes up in someones search. My buddy Chris (IROCZTWENTYGR8) thought the coil was on it's way out. I figure there was a chance it was taking a dump when the MSD box was connected to it. But ok when it wasn't. And now it's just crapping out all together.

Well the coil was an old MSD blaster. So I ordered a new one. Even if it wasn't the problem. It was old, so I had no problem replacing it. Well the coil came yesterday. Figured I'd throw it in real quick before I go and get a noid light to make sure my injectors were pulsing. And problem solved. It was the coil. Fired up no problem twice cold so far. The plug not being wet after a lot of cranking threw me off big time. But apparently my injectors were firing when I was cranking.

I absolutely appreciate you guys taking the time to post and trying to help me.

Tuned Performance

iTrader: (92)

Glad you got it solved. That’s a good find