adillhoff

I recently put in some 5.3L heads and a TSP224R cam with 110 LSA.

I got on it after the break-in period and noticed when I hit about 5.5k rpms that the SES flashed once and then the car would not hold idle. I had to keep it running by giving it gas. I would park it, wait 5 minutes, and start it up and it would idle fine.

I got it dyno tuned and it still does the same thing. Any clue?

Michael02hawk

iTrader: (26)

Did you perform a crank re-learn?

adillhoff

I did not perform one myself, no. I do not know if they did either. I did replace the CKP.

TOS98SS

iTrader: (2)

What kind of valve springs did you use . It almost sounds like a pistion hit the valve and bent it . Strange with the small cam but if the valves floated they could hit the pistons .

The symptoms you discribed are symptoms of a valve not sealing and being you reved it high maybe higher than you thought . I hope it is something stupid but you could tell if it was the valves buy doing a compresion test

adillhoff

It is 100% electronic. I would know if the valve was hitting and I ordered a cam that was sure not to hit. The springs are Comp .918. If it were mechanical it would constantly have a problem until fixed. I was driving today and went WOT at 2k rpms and it did it then.

So now I think it is throttle related or MAF, possibly.

I guess I should also state that it doesn't always do this. It picks its moments. The clutch also sinks in around 5.5k-6k rpms.

orangeapeel

iTrader: (18)

Misfire most likey. That is what an SES light *Flash* is. You might want to check for fouled plugs or bad wires/coil packs.

Grimes

iTrader: (3)

another vote for wires or sparkplugs. you really have to make sure the wires are on there, on the plug side and the coil pack side.

bandit1

iTrader: (12)

I would say have the MAF checked to make sure your not maxin it out if your at over 400 at the wheels and the stock MAF is good too 500 crank you may be on the ragged edge try a simple trick like removing the MAF screen and then reset the computer. Mine did this when I started making over 400 at the wheels and we had to turn off the MAF and go SD and now no probs. Can't hurt and its a quick fix if it does plus you'll get more airflow and thats always a plus!!!!

adillhoff

Yeah I was thinking the MAF as well. I do not see any logical possibility of it being the spark plugs and wires. When the motor does not idle, it still runs. I just have to keep it running by giving it throttle. The plugs and wires have no effect on the idle. They either work or they do not.

Thank you everyone for the input. If anyone has anymore ideas, please share.

camarojunky74

iTrader: (14)

the best way to approach this is to get a sutiable obd2 scanner and get a freeze frame picture when it does its thing whether at idle or close to redline, that will give you a clear picture of what sensors are saying what at that moment, but off the top of my head it kinda sounds like an ignition prob to me like the ckp or the cmp aint right.

'Trust'

iTrader: (24)

Another vote for fouled plugs/coils/plugwires. Flashing SES light shows a misfire.

adillhoff

But if it were to misfire you would be able to hear it. The engine still revs smoothly as the SES light flashes and will continue to run smoothly, but it simply will not idle. I have had misfires before and it is nothing like this. When it misfired before it would not flash an SES light. The SES light would come on and stay on.

The bad thing is that is flashes so quick there is almost no possible way I could read it.

adillhoff

bump... Maybe something to do with the TB?

orangeapeel

iTrader: (18)

Still think it is a misfire. You need to get a GM Tech II to hook up to it and find out what is up.

TOS98SS

iTrader: (2)

The way it sounded in the first post was that the light was on all the time after you reved it . I misunderstood

adillhoff

Sorry for the confusion. It was on a GM Tech II a week earlier and they couldn't find anything.

It did it again this morning on my way to school so I decided to disconnect the TPS. I tried starting it and it idled. So I guess it is narrowed down then.