New engine installed...started right up. Then would not start...need troubleshooting

[87LtdT]

Installed new long block...with new crank sensor, and a very slightly used cam sensor with Casper's cap. Original wire harness

Engine fired up immediately...no issues. Over the next few days finished a few details and then took it for it's first drive today. Again fired right up...drove it about 1 mile...no hot rodding, 40MPH max, then let it idle for about 10 minutes. Then shut it off.

15-20 minutes later attempted to start if to pull into garage and it cranked over fine but not a hint of firing. Hit the key 5-6 times....each time cranked fine but no fire...not even a weak cough.

Pushed it into the garage...thought and researched it for 2 hours.

Removed #1 plug, attached the plug wire to the plug, and laid it on the valve cover. Cranked it over watching the plug for spark and it started immediately. Shut it off...reinstalled the plug and wire and cranked it again.

Started, then it would not start, started, started, started, started, did not start, and started again on my final attempt. All of these starts or attempts were done in a total of 30 seconds or so. Had good fuel pressure whether it started or not.

Ideas??

Thanks, Bob

 

[GSTOY]

Are all your connectors plugged in completely? Since this seems intermittant, and you had the engine in/out, I would double check your connections on the crank, cam and ignition module to make sure they are fully seated. Are the grounds on the back of the heads tight?

Steve

 

[turbojd]

When I had that problem with the car cranking and not starting after putting it back together , it was my ignition module harness, it was in place but I forgot to tighten it!

 

[87LtdT]

Thanks guys...by ignition module you are referring to the connector below the coil pack right?? The one with a "locking key" ??

Thanks for the advice.

Bob

 

[Nasty Wendy]

See if you can spin your cam sensor by hand.

 

[whitehot1]

If you have rechecked all your connections as reccommended, you could check to see if your chip is seated properly and that will also reset your ecm since you have to disconnect the orange power supply wire to it before removing the chip to verify it is seated.

If you want to follow a troubleshooting guide / tree you can go to this website there is a lot of good info to read.

Vortex Turbo Buick Performance

 

[87LtdT]

Thanks for all the advice...results:

Crank sensor was fully plugged in. I unplugged it...checked for bent pins etc...all looked OK. I added a tiny amount of dielectric grease to each pin and reconnected the connectors. The sensor itself is solidly held in place by the bracket

Cam sensor...is securely fastened in place..cannot rotate it. The connector was fully plugged in. Noticed the back side of the connector joint was a small bit wider than the front..ie the two connectors were bent a tiny bit at the joint... Unplugged and again checked for bent connectors etc...added dielectric grease and reconnected the connectors. The "bend" is still in place regardless of how much I push...doesn't look like a problem...more of an observation.

Did not attempt to inspect the ignition module connector...I can see that the connectors are fully seated and the locking tab is in place.

Did not look at ECM nor it's chip...the ECM has not been touched in 2 years.

After these checks I started and shut off the car successfully 10 straight times...

Will take it on the road again tomorrow and let it get hot again...and check then.

Will advise....thanks again.

Bob

 

[Chuck Leeper]

"Did not attempt to inspect the ignition module connector...I can see that the connectors are fully seated and the locking tab is in place"
I think the reference to the coilpak being tite referred to the mounting nuts, under the plate.
If they are loose, and/or, if the mounts to the engine are loose, the pak will lose ground.

 

[87LtdT]

Oh...thanks I didn't realize the intent. I never removed the coilpack from it's bracket and am 99% sure the bracket is tight but will check both.

Thanks again.

I did just notice that the capscrew for the ground at the block-to-turbo mounting bracket wasn't tight. It was 1/2 a turn from being fully tight but not quite snug.

Bob

 

[turbojd]

Yeah, I forgot to mention the block to turbo mounting bracket, make sure that is tight!

 

[87LtdT]

It's tight now!! Bob

 

[87LtdT]

Took car for a 5 mile ride today...again no hotrodding but it did pull strong at 5psi. Started fine a few times in the garage and then off I went.

Got back and shut the car off in the driveway...would not restart. Hit the key 2-3 times and no start. Left it for about 20 minutes...then 2 no starts and then it did start....pulled it into the garage and shut if off.

So I've not fixed the problem...here is a list of sensors that I purchased as I rebuilt this engine. All others are OEM that came off my car.

Crank sensor-new
Cam sensor-slightly used, Casper's cap-new I think
Oil pressure sensor-used
Knock sensor-new
also a Mini Starter-new

My guess is one of them is intermittent...gonna get me a noid light and do some checking.

Bob

 

[G NASTY]

collant temp sender? mine was doing that, car got hot and would stall and not restart until 20/30 mins

 

[turbojd]

I had a similar situation with my GN a couple weeks ago, went out to start it , cranked fine, no start, I let it sit for an hour try to restart it it fires up this time. Fine for a couple days then go to start it in the morning, wouldn't start but cranked fine. Problem was it turned out to be a going bad now bad 30 amp relay in my hot-wire kit.It ran fine when I connected the factory fuel pump wiring, I called John at Caspers and ordered a new relay and all is good now. Just throwing this out there.

 

[G-Force]

I Had this problem with my 87GN. Turned out to be the cam sensor cap was getting heat soaked. Next time it happens spray some water directly on the cap and see it fires up. Good Luck