raycer

86 IROC 305 TPI Auto

Car won't run. It cranks and starts fro a sec, then cuts out. I can hear the pump prime and it is only a month old. Also replaced withing the past 2 months have been IGN module, pickup coil, Fuel pump and relay plugs, wires, rotor, Alt, ESC, IAC, TPS, added 2 more grouns from the block to the frame, (had a ground issue before). checked codes that were stored, (light did not stay on when it did run), and got

22. Low voltage at throttle positon sensor OR Fuel cutoff relay circuit open or shorted to ground
34. Low voltage (high vacuum) at mass air flow sensor (or MAP sensor)
42. Fault at electronic spark timing circuit OR Fault at direct ignition system OR Fault at fuel cutoff relay circuit

Thanks for any help

raycer

I believe the 22 is from before I replaced the TPS

raycer

I checked the cpnnection to the MAF and noticed the harness connector looks a bit melted on one side.

raycer

OK cleared codes and went to restar it and still won't stay on. Check codes and I'm now only getting
34. Low voltage (high vacuum) at mass air flow sensor (or MAP sensor)
42. Fault at electronic spark timing circuit OR Fault at direct ignition system OR Fault at fuel cutoff relay circuit

Please help me if yoy can. I can't afford to just toss a MAF or any other parts at it unless it is the problem.

raycer

also niticed that the oil pressure switch isn't working the gauge again.

raycer

replaced Oil pressure switch with one that actually looks like the original (the NAPA one it had was larger), gauge works again and after fighting with car to idle, had it idle enough to check timing(EST unplugged) which is fine, and car kept bit of idle. Drove it around the block and car ran but had stubble at idle and lacked power. I came back home and noticed if MAF is moved, car starts running bad and shuts off. BTW I unplugged the battery for 5 mins and replugged the EST before taking it out.

Rod Behring

Maybe try running it with the MAF sensor unplugged. The computer will go into limp mode and if it actually runs better that would be a good indicator that the MAF is bad.

cIaRmOaCrZo

check and make sure your knock sensor down on the side of the block is plugged in. that would cause an open in the est circuit, which will throw a code 42. and it will run like crap when engine is hot because timing isnt being pulled out due to hotter combustion chamber temperatures.

raycer

car won't run with the maf unplugged. It'll just fire up, stumble and die.

As for the knock sensor, gotta check that

ASE doc

Knock sensor will not cause code 42. It will cause code 43. Knock sensor unplugged will retard timing 18 degrees. That may explain your idle problem. The engine should run, if not stellar, with the MAF unplugged. I am concerned that you either have an in range sensor failure, possibly CTS, or you have a severe lean condition.

clutchkicker123

Hi, I don't mean to bump a topic from 4 years ago, but my car is doing the same thing... I have a 1986 camaro sport coupe with a 305 (carb), I believe it's an H vin... Anyway, It ran mint yesterday... This morning i went out to start it, and she'll crank for days, but only kinda sputters a little... I cranked it for about 20 seconds, and it acts like it's not getting fuel... I pulsed my foot on the gas a little, and she acts like she's trying to pick up, but it just won't... I noticed that I have a small fuel leak on the bottom of my fuel pump yesterday, but i doubt that's the problem... I FINALLY got it to start, and she'll idle, and if you finesse the gas a little, she'll rev up, where as before you could stomp on it and she'd jump right to the redline... When I got it to run, my check engine light was on... So i shut it down, read the code, and the only code i'm getting is 12 and 42... I know 12 comes on every time, but i can't make sense of 42... Why would it just stop running like that? Any help would be greatly appreciated... I'm not gonna lie, I'm a 16 year old kid, I have ONLY cursory knowledge under the hood, but if you could break it down for me as best as you can, that'd be great! Thanks!