derekstl

iTrader: (2)

I appreciate all of your guys input and suggestions! This is by far the biggest project that I have done and I was a little hesitant to do it myself but it has been an amazing learning experience for me and despite it taking way to long and still having problems, I have really enjoyed it. I will keep chipping away and see if I cant figure this thing out.

BALLSS

well the 503 cam is a 224/230 cam. Others replying say they have run one without any need for TB adjustment.

Your tuner pcm4less.....may be the reason. IDK...have read several negative posts about them. YMMV

Assuming you don't have any "mechanical" issues causing this idle issue, it is typical of high IAC counts.

If you could go to a good mechanic who has a Tec 2 or other scan tool that reads IAC counts that may be the fastest and cheapest way of determining if in fact they are pegged at 160.

a valve lash that is off, I would think, would just cause the motor to run rough vs not idle at all.

You mention you need to check wiring on your "aftermarket fuel pump"...have you measured what your fuel pressure is at the Schrader valve on fuel rail??

ACE1252

At this point I certainly don't think he needs to drill the throttle body.

He needs to get the cranking problem nailed first. Really should have been done before modding the car as it is compounding the troubleshooting process.

As myltwon mentioned, the CC503 will idle just fine on the stock tune. I've done it myself. Had no trouble firing and idling at all. Even ran it around town for a couple of days(but I did correct it for my larger injectors..no other change to the program).

I'm just not sure what difficulty the automatic brings to the table. However, I don't think there should be any issue idling in park.

As far as crank voltage, this video is what you need to target....voltage should hold around 10.5V when cranking and you can hear that the starter is not laboring to turn over the engine. My starter is stock....20+ years old.

I agree with ****** that checking the fuel pressure would be a good idea as well.

derekstl

iTrader: (2)

So I finally had time to work on my car again. I moved it a little to get the drivers door open and pulled the PCM fuse. This is still with the throttle body stop adjusted, I did not touch the gas pedal the whole time and it died on its own. The car holds 14v when running so I guess I wasnt as concerned about it and more focused on why it wouldnt idle correctly. Weird thing is that it is hard to get started when it has been sitting for a while. Once it does start and run for a bit, starting it after is much easier and I dont have to crank multiple times. I am also going to take a video with it cranking without the fuel pump wiring connected to see the difference.

What is the expectation of pulling the PCM fuse??

derekstl

iTrader: (2)

I did check the fuel pressure it was completely fine.

derekstl

iTrader: (2)

Ok so I adjusted the TB back to normal and dialed the TPS back to .67v then recorded this video. Still have the PCM Fuse pulled, you can see the cranking is the same (slightly lower voltage since the battery is getting lower) but a few times it will start and then shut off. This is why I tried to adjust the TB. At least it would start and run for a while, now it just shuts off.


Then lastly here is a video with the in-line fuse for the fuel pump pulled. (I have a wahlboro pump with the Racetronix wiring kit here.) As you can see, the strain seems to be gone and the motor cranks much easier, obviously the voltage is still a little lower than it should but I am charging it back up now. Why do you think this is?? I traced the whole power wire from the battery back to where it plugs in the fuel pump and everything looks perfect.

drptop70ss

iTrader: (21)

Starting and then immediately shutting off is a symptom of a bad MAF sensor, any idea if anything happened to it? FWIW I have a 383 LT1 with the 503 cam and my MAF failed in some way, engine would run but idle would hunt and had a horrible off line stumble. My PCM was tuned but I couldnt read it with my software (LS1 PCM) and I dont think the SD tables were tuned because if I disconnected the MAF the engine would not run at all. If your SD tables are tuned you can try disconnecting the MAF and see if it runs better, otherwise swap it with a known good one.
I went through all of the same stuff you are doing, TPS, considering the drill mod, trying to read IAC counts, etc.

craby

best to set your lifters while the engine is running. if you have stock lifters i would recommend 1/2 turn (1/4 turn at a time) although book calls for 1 turn. would not surprise me if it was the lifters off a tad.

derekstl

iTrader: (2)

I can definitely try running it without the MAF plugged in, that is something easy to test. I know I did it before and it didnt seem to make a difference. I dont have an extra to swap out, and I dont know anything that would have caused a problem, but it is worth a shot.

You think the lifters would really cause this much of a problem? I think they may be a little off either way, because the motor has a little bit of a shake to it. I had read that it was best to set them with the motor running, but I did it while the motor was out. I honestly dont remember exactly how much of a turn I did, I think it was 3/4 turn.

craby

just listening it does sound like a timing issue. almost like a crossed plug wire.

BALLSS

Nothing wrong with adjusting lifter lash with motor not running. That is how it is done when GM makes them. 3/4 turn is fine. Factory spec is 1/2 to 1 1/2 turns

what is your fuel pressure reading, especially when the motor stalls?

derekstl

iTrader: (2)

Ok guys I am back at it this weekend. I have dedicated all 3 days to getting this damn thing running and finishing the project so I can have fun driving and get my garage back! If any of you are able to lend a (virtual) hand I would appreciate it.

I ran it without the MAF connected as suggested but it seemed to have the same exact symptoms. After running it for a while I also checked around the fuse box with a infrared digital thermometer as suggested but did not find anything that was heating up.

I am going to rent a fuel psi guage from advanced again. I have checked fuel pressure before and it was fine, but I will watch it while cranking as ****** suggested.

BALLSS

the FP wants to be 38-42 psi (43.5 PSI with vacuum hose pulled and plugged)....you want to watch it especially when engine dies to see if it drops

while my cam does have a exhaust note...the motor does not have a corresponding "shake" to it

derekstl

iTrader: (2)

Ok just checked it and it stays at 42 PSI even when the engine dies. I am assuming that is what it should do. Any ideas of what to try next?

craby

fuel pressure should drop at idle, should not be a constant 42.

BALLSS

....Op's fuel pressure is fine. He can rule out that as a potential cause of his problem

FP does rise a few lbs when you mash the gas..."generally" drops to 37 with vac line connected . can increase to 40 ish under acceleration

43.5 without vac line connected is considered "spec" but 42 under that condition would be fine

The main concern is FP does not drop when reving the motor or sustained WOT...

derekstl

iTrader: (2)

Well my car doesn't really idle, that is the problem. It was at 1500 - 2000 RPM to keep it running while I measured it.

derekstl

iTrader: (2)

So I took the valve covers off and inspected the rockers/pushrods and I actually found a few that were loose. I think when I set the valves I did it incorrectly thinking that when cylinders 1 & 6 are at TDC that I could adjust both valves for both cylinders, I didnt realize at the time that the cylinder needed to be on the compression stroke. I went back through and readjusted all of them per instructions on shbox website. I was so confident that was the problem but when I started my car again . . . no luck. It is still doing the same thing.

Not sure if that wasnt an issue or if there is still a remaining issue overriding that.

Kevin97ss

Agreed, this is an ignition issue.

What you are experiencing during cranking is a cylinder starting the burn process in the earliest stage of the compression stroke. The result is massive resistance to the starter motor as the crank is being forced backwards.

I would start by double checking ignition cable routing at the cap. http://shbox.com/1/opti.jpg

Kevin97ss

Pulling the PCM fuse will stop the injectors and ignition system from working, the engine will not start. The point is to allow an extended cranking session to check voltage(in the case of that video).

In your case pulling the PCM fuse should allow the engine to crank at normal speed.