97rebuiltZ28

First off, hello, I'm Evan and I'm new to this forum. I bought my 97 Camaro with a blown engine 6 months ago.(it blew while driving the guy said, so everything was in working order.) I spent 6 months slowly buying parts and building the new engine. I built it back all stock using the intake from the blown engine and using all the same wiring so I wouldn't run into problems. We put the engine in and it fired up first try! I drove it home (30 miles) after we made sure of no leaks and that everything was in order. Now on to the problems.

Problem 1: First off, the car starts decently when cold, but doesn't want to start when hot. It also stutters a little and sometimes tries to die when idling. It drives fine when past 30 mph but seems to struggle with heavier throttle at lower speeds(It does have a few gallons of old fuel but topped off with 10 gallons of 93 fuel and some stabilizer and sea foam.) I replaced the ICM as that seemed like a likely problem but it still does the same thing(Coil was replaced too, along with Opti) The only code I get are P0336(crank position sensor) which that lines up with the misfires occasionally. Also pending codes P0171 and P0174 both sides lean. So I'm thinking it is the Fuel Pump or maybe could it be clogged Cats? I had the P0171 and 174 on my old truck and it was a bad cat but it never had performance issues. So Fuel Pump or Cats or anything else?

Problem 2: This is the main one I want to know. It's temp gauge on the dash doesn't work and I want to know how to know if the engine is overheating without the gauge. The intake manifold is hot to the touch after driving. So when replacing this sensor in the side of head 1 the autozone guy gave me a 2 pronged plug and the one in it was 1 wire. So a mechanic rigged it up to hopefully work but I don't know if the gauge was broke when I bought it so that's where I'm at. The engine hasn't smoked once but just for peace of mind what are signs of it overheating?

Chimera96

get the correct sensor for the temp on the PS head.

A IR temp gun will give you a "idea" of what engine temp is by shooting it on the upper radiator hose once the engine comes up to operating temp

get a fuel pressure gauge and confirm FP is good at idle AND under driving conditions. One with a hose on it so you can tape it to windshield

if the new Opti was a "store brand" one...very likely the issue with the CPS code

97rebuiltZ28

Thanks for the reply. I'll definitely try that stuff. I won't be able to work on it any until Wednesday or Thursday but I'll comment again with what I find.

Do you know if a aftermarket temp gauge mounted on the dash would cause any SES lights since the original sensor would be unplugged?

Injuneer

The coolant temp sensor for the gauge only connects to the gauge, not to the PCM. No codes in the PCM for a missing gauge or sensor. But why not verify the system by getting the correct single pin temp sensor? Shoebox has the part #'s for many LT1 parts.

4th Gen LT1 F-Body Tech Aids

When you open his parts reference guide, you can do a control + f to "search" the page.

The crank position sensor is only there to DETECT misfires. It can't CAUSE them. The PCM only uses the cam position data from the Optispark distributor to run the engine (injector and ignition timing). If both cats were bad, you would have codes for inefficient cats.

97rebuiltZ28

Thank y'all for the replies! Me and a buddy put in a new fuel filter, fuel pump, and drained all the gas. We let it prime for a second and fired up easier than ever! Mine already had a cutout for the fuel pump which made it easier. Now it's way way faster and performing good.

Now just to fix the temp gauge.

97rebuiltZ28

Just a quick update. Ive been using an OBDII display to read the pcm temperature for the last several months and I just got around to replacing the cylinder head temperature sensor. To my surprise my engine runs really cool. The needle sits between the 160 and 185 marks on the gauge. The PCM temp shows 190 consistently. It will get pretty warm when idle my though.