crookedbowtie

Just installed LTs, full exhaust, and put my car back on the road for the 1st time in over a year after paint. When I get into the throttle hard all of the guages flash, the speedo and tach bottom out, the traction control resets itself, the stereo blips, car loses power but doesn't shut down. Security light also comes on for a few seconds after. After this happens all is fine gauges go back to normal car drives fine, until I get into it hard again or put it under just the right throttle load.

My service engine light is on, but no codes show on the handheld scanner.

Is this related to the new exhaust and knock sensors, no tune, or something simple? I hope it is an easy fix...anxious to drive the car again and be able to throttle it!

crookedbowtie

Mods, if there is a better section for this post please feel free to move it.

I checked my battery connections, all is good. I am going to go have it load tested in a few and drive it a while to see if it will store some codes.

crookedbowtie

SES light is on, I am assuming because the cats are gone, but no codes. Had battery load tested, load tested bad. Replaced battery. The problem is better, but still there. The car doesn't loose power, just kind of a little laggy for a split second. The gauges have flashed a time or two with the new battery but under a different load...roll on in second gear, but the power loss is nothing like before, just a blip now. I am going to check all the chassis grounds tomorrow. Any other ideas??

The O2s, AIR, and other sensors read INC on the handheld. Miss-fires read OK. Maybe it is just in safe mode and never switching out?

SMOKINV8

iTrader: (6)

If your car was just painted, check and double check the grounds. I suspect they didn't tighten up one of your main grounds when they reassembled your car.

Brad Campbell

iTrader: (19)

Good suggestion... can you log voltage at all while you are doing a pull?

t/a98

iTrader: (6)

Oh oh oh pick me pick me!!! (raises hand) you got a short their mister! I dropped a spark plug socket changing passenger side plugs. Couldn't find so I decided it would fall out of the car and be fine. Wrong. Fell between starter and block and would cause a massive short that would kill everything for split seconds then act like nothing ever happened..

crookedbowtie

I painted and reassembled the car...I didn't remove any main grounds other than the battery. It is new clean and tight. Anyone know the ground location related to the gauges/radio?

I don't have a way to log the voltage and I am pretty sure that all the gauges bottom out, but I did have the alternator and charging system checked at the time of battery install. All was good.

Light acceleration, small skip on the radio occasionally usually before a shift. Hard acceleration the car scares the crap out of itself cuts power and resets the gauges. Usually happens between 3 and 4500 rpm in first gear.

For the most part it will cruise around town just fine,

Finally stored an 1153 code (oxygen sensor low switching). Could this be the cause? Doesn't seem related to the gauge problem.

SMOKINV8

iTrader: (6)

The engine would shut down if you popped in the clutch for that brief instant when the power cuts out. Run your hand around the perimeter of ALL the parts recently removed/installed and make sure you didn't pinch a wire. I would check the main grounds under the hood first.

One of my buddy's had a similar problem on an LS1 S10, and his issue related to a wire on the back of the motor getting pinched against the firewall and shorting out.

crookedbowtie

I scotchbrited all the grounds I could reach up top. 2 on the core support, 2 on the inner fenders, the battery neg...again, 1 other that I can't remember were it was at the moment, pulled the battery tender fuse, popped open the under-hood electrical centers and made sure everything was firmly pressed down.

It seemed like a big 50amp blade fuse settled in when I pressed down on it.

It is in electrical center 2, my label is missing and I can't isolate it in my manuals wiring diagram. Any body still have the fuse location label intact on electrical center 2 and can identify this fuse?

Went out and flogged her pretty good. I can't seem to duplicate the malfunction at all and she pulls hard into redline in at least the first three gears.

I am hesitant to claim "fixed", we all know what happens after that, but I am crossing my fingers.

Thanks for all the help guys!!!!

t/a98

iTrader: (6)

Still sounds like a short. I would carry some cable cutters and a fire extinguisher for when your car catches on fire like mine. Luckily I was in front of a fire station when it happened. Idk guess you don't have to listen to us. Just trying to help. Since I've been there and had the same issue and all.

t/a98

iTrader: (6)

Also the reason it's only doing it is because the short is only making contact during the acceleration. Kinda like how you get pushed back in the seat. Well the foreign conductor is doing the same. Maybe the socket or whatever fell out. Maybe it didn't.

crookedbowtie

t/a 98- I am listening to you guys, very interested in responses. Not sure why you keep relating to a spark plug socket causing a short on the stsrter. Did I mention I lost a socket before and it is coming back to haunt me or is this something that actually happened to you?

I have done a pretty thorough visual inspection for pinched wires, melted or frayed wires, loose connections, blown fuses, etc. All my tools have been accounted for. If it is a short it is going to be a long process of checking resistance on wires.

I did loose a 10mm deep socket in the K frame, but it came out on the first test drive and was recovered...after I bought a replacement of course...! am pretty sure that the dash problem is gone, but the car did pop 7 codes after a hard drive home through the country. I expected most of them due to no tune and no cats, but the P0101 (MAF range/performance problem) is something I didn't expect as well as the two repeat codes...may just be my scanner. I will do a check for vacuum leaks or, something stuck to the MAF heat wires, or a cracked MAF to TB bellow, I read that may cause the MAF code....

2-P1153....why two I don't know
2-P0141....why two I don't know
1-P0101
1-P0151
1-PO131

jimmyblue

iTrader: (11)

Battery hold-down, if not doing the job, will let the
battery roll back and short post to the fenderwell
or TCS gizmo bracket.

I've had the A/C pulley chafe through the starter hot
lead insulation and make a similar-acting short under
hard accel / right cornering.

crookedbowtie

Thanks Jimmyblue I will check that out tonight. I already checked the battery hold down, so I will definitely check the hot lead under the ac pulley.

My service engine light (Not the SES light) stays on even after I clear codes. The SES light goes out, but not the other one. I am describing the one on the lower left of the gauge panel in relation to the SES light. Secret to re-setting it? Doesn't even mention it in my POS Chilton manual.

How do you guys quote posts in your replies? I see the little box, but it won't let me check it.

jimmyblue

iTrader: (11)

Check Engine means a fault that the PCM thinks it
can't even limp along with. Codes may indicate what
it's about and ought to come back right quick if it's
that kind of trouble.

Like if a sensor is being called out, run the harness
from there and maybe find your IGN short fault too.

crookedbowtie

Yeah the P0141 and P1153 come back up quick after a clear and the secondary check engine light never goes away. The car really seems for the most part to cruise around good. Will that light be on until I can tune out the rear o2s or because of the lack of cats. Looks like some Corvette longer o2's (1311s I think, I'll do a search for the number)may be in order, supposedly they have a better heater as well.

crookedbowtie

It is the "service vehicle" light that won't turn off is that the one you are thinking of jimmyblue?

jims z

My buddy had the same issues under hard accelerations. The battery would rock back and hit some part of an a/c line.

t/a98

iTrader: (6)

I lost a socket, Yea, but I meant hard acceleration was causing the conductive whatever it ends up being to make contact. Could be a loose wire, the battery or whatever. Sockets are bad because you can drive for a year untill it positions itself just right to cause problems.

Look into your battery hold down like others have said, my bolt is pretty hard to get started so that is likely too.

crookedbowtie

Battery hold down is rock solid. I have already checked for possible pinched wire points. All tools including sockets are acounted for.

The service vehicle light ended up being the Airbag fuse that I pulled when the flashing gauges started, because I was afraid something might trigger them to blow with all the gremlins at work. I didn't think it was related because it has its own separate light. It also triggers the service vehicle light. Nice and simple when at least.

I pulled the MAF sensor and cleaned it with MAF cleaner ( it was pretty dirty), I also blew out the MAF screen ( had some debris on it), and replaced the bellow with a smooth one I had sitting around and made sure it was nice and tight while I had it all apart. I had recharged the K&N earlier, may be related to oil on the MAF if some made it up there. Scanner shows the front o2s functional now, as well as the heaters. The car has only threw the rear o2 codes so far ( to be expected with no cats) and it feels alot smoother, responsive, and quicker. It is cutting loose under throttle easier and pulling harder. Hopefully that simple, but some more driving will reveal the truth.

Thanks for all th input so far! I will post up the outcome.