sabastian458

I just bought a Vette a week ago and am having intermittant issues with a no start condition. Saturday nite I went out to the car and it wouldnt start, all gauges would cycle, relays and throttle body and fuel pump cycled, but starter would not engauge. At the time I did not have a scanner, nor did I know the exact steps on the DIC retrieval.

After 30 mins the car started up fine, and I cut it off and started it another 5 times that nite (happened at 11pm sat) with out any issues. Drove all day sunday (75 miles) and monday (10 miles) to work and it started every time. On Monday when trying to go home, car would not start and I had my Laptop with HPtuners with me.

Found-
P1516- TAC module actuator position performance
P1517- electronic throttle module
P1518- electronic throttle to pcm communication
Codes would not clear, car would not engauge starter.

(along with an ABS code and some AC actuator codes from before hand- history codes)
U1040 loss of abs/tcs communications
B0361 motor 1 feedback short
B0441 LH mix motor out of range
C1232 Left front wheel speed sensor circuit open or shorted
P1571 Traction control torque request circuit
P1689 Traction control delivered torque output circuit.


Started checking connectors and wires, found that the car had a n2o system previously at sometime. (had a few spliced into wires, had a WOT switch, and could see that a bottle had been mounted in the hatch area.) After 45 mins of messing and checking it, the car randomly started up. I took it home and parked it in the garage and starting repairing the wires.

I removed all the extra wires and splices, being sure to isolate and seal each splic correctly. I used liquid electrical tape on the bare wires, allowed that to dry, then used regular electrical tape to cover the liquid electrical tape and about 1/2 inch on either side. Once that was covered, I then taped that wire to 1 or 2 wires to secure it from moving. I ended up doing that to 5 wires. 2 under the dash, above the fuse box in the passenger floor board. 2 on the harness for the PCM, the connector that is on the outside of the vehicle. And 1 wire on the TPS.

After doing all of that, and looking over all the other visable wires for any signs of damage, or areas that do not appear stock, the car still will not start. I am hoping for some more insight as to what my next step should be in tracking this down.

Mod's:
Long tubes, unknown brand or size
off road mid pipes
factory Ti mufflers
G5x2 cam and springs
MSD wires
Cone style airfilter
tune.

sabastian458

Just got home from work a min ago, and went out to see if the car would start. It did, first attempt.

Last nite all I did was remove and seal the slices, nothing else. The car would not start last nite or this morning at all, but tonite it did. Any ideas?

sabastian458

bump for a lil help

sabastian458

wow, no body has any insight as to what I should check next?

sabastian458

Ok, looking up the codes on my own I am seeing that both the p1516 and the p1517 only set when p1518 does not set. SO that leads me to belive that the originating issue is the p1518, correct?

sabastian458

bump for some help

sabastian458

No one has any suggestions?

sabastian458

Drove it yesterday to work with out issues. Went to get in it this morning and it wont start again. I really would like some insight if at all possible.

SMaster

Without reading all of your messages again and this isnt' really any help, but, if this were a common problem others would have chimed in to help. I have no idea what's causing it because I've never had those problems or those codes, etc.

I would Google those codes, search here extensively, and keep trying to ask for help here in the forum. You may have already done that but I can see you're reaching for help and not getting any.

Sorry I can't be more help,

sabastian458

Yeah I have googled, searched here and ls1tech, and I have read and read, even had acess to alldata information on this. So far nothing has paned out. I did get to borrow a midtronics battery tester and had my battery tested today. It show 12.97 volts with 493 cold cranking amps (out of 650) it said replace the battery, so I went and purchased a Optima red top.

Now it is a waiting game for it to act up again, as it has acted fine all day today.

sabastian458

Quick update for anyone paying attention.

Yesterday morning, when attempting to start for the morning, it would not. I cycled the key several times and then just held it over in the start position for about 20+ seconds. Surprisingly it started up. Drove it to work (15mins or so) and started it several times in sucession without issue. No issues for the rest of the day.

THis morning same thing, no start first time in the morning. Cycled key a few times, then held in the start position for about 15+ sec and it fired up. Then when I left for lunch no start, cycled key 3 times and held in start position for about 10-15 sec and fired up.

When it startes and runs, no codes and no check engine light, drives fine.

Went to leave tonite for work, no start again, only cycled key 2 times and then held for about 10 secs and fired up. moved car from parking area at work to the front of the store and parked it. waited 1 hour on a customer, then started it up to leave for home, fired right up that time.

I am starting to think it maybe in the ignition switch? or in the actual throttle body. All the wires and pins are checking out good. At least now it is being consistant and eventually starting.

sabastian458

FInally, some new information.

went to run an errand at work just a few mins ago. Car would not start, cycled key aprox 15 times, randomly holding in the start position for 10-15 secs. no start. Held over in start pos for aprox 25-30 and it fired up. The DIC said "pull key, wait 10 seconds" but did not display service column lock.

Looked in the stickies and found this thread;
http://forums.corvetteforum.com/c5-t...ky-please.html

and it says this

So what should I do now? Get a new key? or delete VATS from the ECU?

SMaster

Sure you should try a new key. You can order them from ebay. Just look for the tips on how to measure the resistance so you know which one to order. The dealer, or even Lowes can cut it for you. It doesn't need programmed like the newer PK3 stuff.

BUT... how's it doing on all those OTHER codes you mentioned at the beginning of the thread?

STeve

sabastian458

The other codes (except P1516, P1517, P1518) turned out to be history codes, none that are current. So I have not looked farther into them.

The P1516, P1517, & P1518 only come on when the car does not start, once it starts or is running, the codes are no longer there.

sabastian458

Update:

I did the ignition switch repair I found on here, cleaning the contact points in the electrical side of the switch. 2 of the contacts had basically turned all blackened, and 2 others had slight black marks. Cleaned all of them, and bent the tabs for more contact pressure. I also installed the CLB kit too.

It didnt fix it, but it seemed to help a little. My next step is finish cleaning all the ground points and then running dedicated ground wires from the negitive battery terminal to all the factory ground points.

Oh, no codes present when it is running. When it doesnt start, the only codes are the P1516, P1517, P1518. Once it starts, those codes go away.

sabastian458

Update.

For awhile after the last update, the car seemed to have been doing better. Maybe once a week it wouldnt start right up, but by holding the key inthe run position for 12sec or so it would start.

Now for the last week or so it is acting up more often again, 2 or so days a week and about 2-3 times each of those days. It has become really annoying and embarassing.

Yesterday it finally did something different. I went to start it just after lunch time. It would not start, cycling the key and holding the key over would not help. After about 10 cycles, the car started dinging when the key was on, with the "Reduced Engine Power" displayed on the DIC, with the engine not running. I continued cycling the key and eventually it started. But now the "Check Enging Light" stayed on, which is a first. I pulled the codes and it was the 3 amigos again P1516, P1517, & P1518.

When I got home last nite, I rechecked the wire connectors for the Throttle body and the pins all looked good, checked the grounds too. I pulled the throttle body to check for any phyical issues. I find that it is a ported throttle body, looks kinda Chitty too. It is all smoothed out, which is good, but the vacuum port on the inside looks to have a brass piece in it and what looks like JB weld holding it in (its been smoothed down too). I checked the movement of the blade and it moves freely (with the exception of the actuator motor resistance) but I can close it another 1/2 in or so. The blade rests in a partially open position.

Would a crappy ported throttle body causing these codes?

FRCTony

Don't have a clue on your issue, but I would reccomend you move this to C5 tech to get more views.

I would verify that the connections at the starter are OK. This seems to be a common issue people are discovering relating to no start/intermittent start. You don't want to be holding the key in start position, especially if you have loose melted wiring at the starter.

sabastian458

it is def an issue with the tac, not the starter. (I have varified good connections and no melted wires 2-3 times since this has started)

I have a lead on some checks to do, a guy at work gave me a few things to check out and voltage tests to try. At least now I am getting something different and solid (actual set codes in ECU)

Tonite it did it again, but this time the engine was running unusual, like it had 2 or so dead cylinders. The reduced engine power was displayed. I turned the car off, started it back up, still ran badly, then turned off and restarted and it ran fine. Oh the Joys of intermittant electrical issues.