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Car just cranking and not starting after Engine install.

Bluemagic

Bluemagic

New member
Ok little bro just installed an engine with 50k in his comp g after the last one was killed lol. Ok now it's just cranking so now we are trying to figure out why. We have fuel (checked it at the fuel Schrader valve) so what can we check now? New didn't have a starter so we swapped the one from the old engine. Any thoughts?
 


Hmmmm. How do I check for spark? And the case relearn, do you think the engine would need it? We are using the original pcm and the original wiring harness
 
Possibly does...if you used the cps sensor from new engine might not be recognized by old pcm..sometimes it.works, sometimes it doesnt.
 
Did you put the ICM harness from the old engine onto the new one? Had an issue where my '97 wouldn't start after swapping the motor, took the ICM harness off that came with it, put the original on, and fired up on the first crank.
 


Case learn wont ever cause a no start.... Considering the engine has to be running to do a case learn. Step 1 is to find out what you are missing. Engine needs fuel, spark, and air. Sounds like you have fuel pressure. Next check to see if you have spark. If you have spark it means your crankshaft position sensor and the wiring leading to the ICM and coil packs is ok. Next you check for injection pulse with a test light or see if you have a tach signal with a obd scantool. I have seen numerious 3800s with no starts from icm / crank / harness issues due to the interesting way our ignition / tach system works.
 
Pull a plug wire, insert screwdriver, lay screwdriver plug wire combo near a exposed grounded bolt with about a 1/4 to 1/2 inch gap. Crank car and watch for the spark to jump.... Or if your a man just shove a pinky into the plug wire and grab the car with your other hand while cranking it over.... You will know if you have spark. Trust me.
 
There's a few things that could be happening here.

Step 1: Check that you wired the battery cables, grounds etc correctly


If that's all good... then let's hit Step 2: did you soak the plugs? Pull a couple of the front ones. If it hasn't started, they should be wet. If you have fuel and no spark, they should be wet. PS.. got fuel right? Cause some guy once had me swap an engine, I fired it up.. and it wanted to die. Guess what.. bingo..there was that little gas in the tank. This situation really pisses a guy off.

Step 3: check the connection at the ICM if that baby is loose, you ain't going no damn place.

Step 4: Got oil? Make sure you have oil and the oil level light isn't on.

Step 5: Unplug the maf sensor and give it a try.

Those are the few things that'll keep you from starting up. Normally.. I don't get past step 1 before a car will fire up.
 
Ok so here's what we have, we have power and no wet plugs. So we are going to go down the list and start with the grounds
 


Ok more updates

This is what we pulled with a live scanner.

C0896, u1016, c0898

Now we can hunt down the issues
 
Spark, fuel and compression are what make an engine run. Since you said the car has fuel, we can check that off the list. Are you getting spark? Check to see if you are. If you do have spark, hook up a compression gauge and check the compression. Start with the simple stuff first, and then go onto the more in depth stuff.
 
if the engine has been sitting uninstalled pull the icm connection and clean the terminals on the harness and icm.
i even took off the coils and cleaned those connections. They were very dirty. also check the connections for your injectors.
while you are checking the connections clean them with some contact cleaner and apply a bit of dielectric grease.
 


Ok.. so now you have spark which the ICM will provide automatically to start you up. Puts you at 10* of timing until the handoff to the pcm. You say you have fuel.. bet you actually only have it to the fuel rail though.

Next two tests..
Test 1: Take a 194 bulb out of your corner blinker, bend the tabs straight out from the bulb. Unhook an injector and stuff the two tabs into the connector. Have someone else turn the key. I bet you don't see a blink. At the same moment the fuel pump primes, the pcm spits a quick second of fuel into the engine. If you have no blinking.. your pcm connection is holding you up from getting fuel.

Test 2: This will confirm that you aren't having vision issues. Have a friend crank the car over, meanwhile I want you to spray some carb cleaner, brake cleaner..anything basically that is flammable into the intake right in front of the throttle body. A couple quick sprays should get the engine to fire for a moment. If that happens. The problem is the pcm connection keeping you from getting fuel through the injectors.

Make sure your pcm connections are snugged down with the 7mm bolt in the center of them. And that blue goes to the blue side and clear goes to the clear side on the pcm. The pcm is labeled and the connectors..are blue and clear.

I think you'll have this figure out very soon.
 
Ok. So pcm was never removed during the swap, we are using the original pcm with the new engine. Could this cause issues?
 
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