mattp427

Okay so ive got a 99 TA, its had Truck 243 heads put on it, a comp cam, comp gold roller rockers, chromolly pushrods, and headers and exhaust. About a month ago i was driving the car and it acts as if i shut the car off, i turn the key back and turn it forward and it starts right back up and keeps driving, over time the problem has gotten worse and sometimes it wont crank back up until i let it sit for a while, the only codes it has thrown is a cam position sensor, a crank position sensor, and its had this code in it but it does not turn the MIL light on, its the generator terminal l circuit, ive checked all my grounds and checked the connection at the pcm and made sure it was all good. im just hoping that someone has some insight or can maybe help diagnose this very frustrating problem.

99SSJarhead

iTrader: (2)

Is it just the engine cutting out or is it a total electrical shut down where all power from the car is gone (engine, lights, etc etc)?

mattp427

Just the engine shuts off, its like its cutting spark or fuel for some reason.

Darth_V8r

iTrader: (4)

Check that little red wire going into the top connector on the alternator. Mine would do something similar to yours, though less severe. That red wire had broken. I soldered in an extra couple feet of wire and stuffed it into the loom so it had some give. Never done it since.

mattp427

ill check that as soon as i get home, but when i was looking at the plug into the alternator the other day it looks like i may need to take it off to inspect it, did you have to do that?

wssix99

iTrader: (5)

You need little squirrel hands to do this. Usually, I can't do this easily unless I take the alternator out. (Disconnecting this wire is the last thing, from underneath the car.) I have been able to do it from the top in the past with a custom-fashioned hook. (It takes some time and isn't easy.)


You need to tackle this stuff first. ^ Unless you do, you'll just be chasing ghosts. In all likelihood, one of them is giving you a clue as to what is going on. Given that the last one deals with the system that gives you electricity, it would be a real good idea to look up the specific code and learn more about it.

The normal situation for the car is to have no codes at all. If you have any, something is wrong and is related to a big problem you are currently having or a big problem you are about to have. The MIL is is just for the more urgent scenarios.

Theblacknightls1

iTrader: (1)

Mine did something similar a while back. It ended up being my MAF sensor was arching and shutting off the car. Always happend on hard/half throttle acceleration. I guess it wasn't on right and was touching another object making it cut off.

mattp427

@wssix99 the weird thing is that one minute it'll have the codes and when I go to start it again it has no codes, I know the cmp code was a p0341 which is a sensor performance code so I swapped it with a new one yesterday and it didn't help anything. The ckp code was a p0335 code and the other is p1637

Darth_V8r

iTrader: (4)

Actually the easy thing to do is pull the power steering pump. Just so it leans forwards. Don't have to disconnect the lines. You can look right down at the red wire.

That wire is called the exciter. It's how the PCM increases the charging voltage from the alternator. If the exciter is not connected, it will still charge, but you won't get the higher charging voltage. Computer knows it commanded the higher voltage. Voilà. 1637 code.

I'd check that before replacing sensors.

mattp427

So I got home and just pulled the alternator off, the red wire was attached and I checked the resistance from the connector to the pcm and it had no resistance, so I'm gonna go get the alternator tested

mattp427

Alternator tested fine so I got back put it back on started it up to take it on a test drive didn't get 2 miles without it starting to act up so I pulled off the side of the road and checked codes and it threw the ckp code again and then it crunk back up cleared the code itself and then I went to autozone to check to see how much a sensor would be and of course they didn't have one but I didn't get out of the parking lot and it started to act up again, I got it home and it had both the camshaft and crankshaft codes, I'm really just confused now

wssix99

iTrader: (5)

Do these last. They could be caused by electrical issues. If you read the fine print of the codes, causes, and resolutions, those will give you clues. ie: if the codes are for undervolt conditions or low/high values, they could be caused by electrical dips/spikes.

I'd get to the bottom of the generator fault code first and work back from there.

mattp427

mattp427

So I have been tinkering around with my car and now it seems that it can sit and idle all day but if I try to move it it won't go but about 5 feet before shutting off, could this be a ckp problem?

mattp427

So there seems to be one correlating factor no matter what happens, the only time it wants to act up is when the car is moving, so do the wheel speed sensors have anything to do with shutting the vehicle off, I mean I've been testing several things and sometimes when it shuts off the tach needle goes to like 7 grand and then back down.

Darth_V8r

iTrader: (4)

The tach signal is actually sent via a serial port. Getting a random 7k signal like that indicates a grounding issue of the harness and possibly the ECU/PCM itself. In other words, the only reason you get that is specifically if the PCM sends that signal.

Most common loose grounds are behind the cylinder heads.

Now, another thought. If the crank or cam sensor signal is being interpreted as 7k it could be triggering the rev limiter logic.

mattp427

I checked all the wires on the driver side, and they were all tight, are there any on the passenger side, or are there supposed to be? And you meant the pcm thinks the engine is going 7k and shutting it off?

A little update too I put a fuel gauge on the rail after it shut off and no rail pressure static or dynamic so it's cutting fuel, not sure about spark but I can turn the key to the off position and start it right back up

Darth_V8r

iTrader: (4)

Yeah there are two really important grounds on the back of the passenger side head

Second, yes I'm saying that for some reason the computer is sending a 7k rpm signal to the tach. Possibly this is triggering the rev limiter but that last part is a bit of a guess. The rev limiter is a fuel cutoff. I don't think it cuts the pump though, just the injector pulses.

If the entire car is going dead that really does point to a short or bad ground.

Need4Camaro

iTrader: (1)

As stated earlier, the abnormally jumping like that is key that 90% likely this is an electrical issue. Thats the same kind of symptoms I get when my battery cables are loose on my battery. (You may want to check this btw, just get an 8mm socket and confirm they're really on there tight, even if there's alittle play that could be enough to shut you down while you're in motion)

Basically its a loose connection, its not happening until you move because it takes the vibration of the vehicle to disposition the cable just enough to cause a gap in the circuit killing your vehicle. Does anything happen to the tripometer? clock? reset? (even if it doesn't, it doesn't rule this issue out)

Under the passenger side, there are two battery cables, one goes to the starter and one goes to the engine ground. I was actually quite surprised how loose my engine ground was. I was able to HAND REMOVE IT when I just recently completed the Big 3 Upgrade.

If you get back to the starter, feel your way up the starter cable until you come near the exhaust header and you'll feel the engine ground cable (black) join it. where it joins, follow that cable toward you again and it will go under the header and to the engine block, it will be right under the head and behind the starter, it's alittle hard to see with the starter still in place. I believe its a 15 MM but a spark plug socket with a 3/4" drive extension on a 3/4" ratchet works better and gives you just enough room to tighten / loosen it with the starter still in place. I'm suspecting that cable has come loose or may be corroded.

mattp427

Okay so quick update over the past few weeks I pulled the harness out to check all the grounds and found that all 3 of them were corroded so I replaced them up to good wire and checked continuity and had 0 ohms of resistance, problem was still there so I got fed up with it and took it to a tuner because it had never been tuned anyway so, he found a bad wire to the maf and replaced the pcm because it had a corrupt file in it and tuned it and I got get it and he couldn't get the tune just right because of the fuel trims were all funky because of a bad 02 but that was fixed the next day, anyways I drove it home from the shop which was about 50 miles and it drove fine until about a mile from my house and started with its **** again and shut off, so I get it home and it threw a ckp code again and just that code so I put a ac Delco ckp in it and still have the problem pulled the wiring to the sensor and fine the another wire had already been sliced into it so I replace that wire and solder it in and still have the same problem just not throwing any codes now, so last night I was messing with the vats delete and just re soldered the releys in and it drove fine for about 3 miles to a gas station and then once I filled up I didn't get 50 feet on smoothe concrete, and no codes only thing it's doing is when it shuts off the gauges start going crazy and then I turn the key off and back on and it starts back up, swapped in a known good battery and that didn't change anything so now I'm out of ideas