Bp1987

Ideas to what the hell is going on? Car ran perfect before I painted some engine pieces and did a thorough HAND cleaning on parts. Never sprayed anything on the motor only on a rag. I did reroute the fuel lines but I wouldn’t think that would drop the pressure that much. I realize I’m gonna have to run a lot of tests but figured I would see if these symptoms scream out to anyone on where to start. Thank you guys!!

bammax

What did you unplug when you did the engine work?

Does it act the same when warm?

It's probably a vacuum hose that you forgot to reconnect or a sensor not fully plugged in.

Bp1987

Unplugged nearly everything. I placed tape on each connector and plug and labeled them. The problem was the car did run fine when I bought it but it was jerry rigged all to hell. The fans were on a toggle and the wires hanging. The temp gauge was unplugged. The MSD was zip tied under the car etc. I was thinking vacuum line as well but I have looked over diagrams from the FSM multiple times and everything is where it should be.
While everything was off I polished the TB and added the NOS plate. I have taken off the MSD optispark to ensure it was on the right way. All plugs and wires are clean and are in order.
I will be getting a fuel pressure gauge and testing the fuel pressure because in order to start it I have to give it gas or it will turn and act like it hits something. You can kind of see that in the video where I start it. The battery and starter were purchased last week also.

and yes when it’s warm it doesn’t change

bammax

There are 2 temp sensors on the LT1. The sensor in the head is just for the gauge. The sensor in the water pump is for the pcm. If that sensor goes bad the fans won't work right and the engine will surge then stumble. If you have issues with surging and fan control you should double check the connector for the front temp switch to make sure it's fully seated and the wires aren't backing out. It may be worth spending a few bucks and swapping out the sensor too just to rule it out.

Bp1987

I assumed they hard wired the fans because of the sensor so I changed the one in the head as well as the water pump as a precaution. The car will warm up to about 210 but hasn’t gone above that and I haven’t noticed the fans kicking on. I’ll double check the wires and make sure they are good. I appreciate the info, that’s news to me

Alex41

iTrader: (14)

Check EVERY ground

Bp1987

So all grounds appear to be good. I do however have the MSD optispark. I removed it to wipe everything down and reinstalled it (properly). I’m wondering if I didn’t bump the timing screw on it. Would this cause the motor to surge, idle around 1200, and shutter when holding the rpm around 2k?

Bp1987

So I did a smoke test on the vacuum lines using a fog machine lol. I had a leak around one of the injectors as well as the tube connector at the ram air box that goes to the air system (which is removed). Car is now producing white smoke from tail pipe. I let it run for awhile thinking it was the excess fog but it didn’t change. I wouldn’t think the O ring in the injector pulling air would make this much of a difference but I may be wrong.

Bp1987

Now that spring is here time to pull the car out of the shop and work on it again. Problems have not changed other than a new problem is the starter isn’t catching the flywheel. It’s happened multiple times now but thought I would reopen the thread. Any thoughts on the above?