87 rag

I know how to set the timing but when I disconnect the ESC wire my car stalls.
I am curious if there is any way I can set the timing with the wire connected. Is it possible to check timing with the wire disconected if someone is in the car giving it a little gas to keep it running?
I am also trying to find out why the car stalls. Could be IAC or vacuum leak I figure. Fuel pressure is fine and holds. Car will run so I don't suspect spark. I replaced all my vacuum lines but suspect one connection is not sealing properly on the way to the ball/cannister thing by the drivers side headlight.
Idle is also erratic (goes up and down) when the wire is connected. It stalls a couple of times when I first start it cold then it runs but almost stalls when the idle drops to 400-450 rpms.
No codes. Checked and double checked all electrical connections.
I have a FSM and have been looking through it but it's hard to figure out where to start. I figured I would start with what other people have found that worked with similar problems.

Any tips or things to check will be appreciated.
Thanks.
Jeff

CFI-EFI

The idle should never drop to 400-450 rpms with the ESC connected. The second thing *I* would do is pull the IAC and check the IAC passages for carbon, gunk, sludge, etc. Make sure both the valve and passages are clean. Particularly after everything is clean, make sure you have a fast, cold, idle that returns to normal (600-700) with a warm engine. This confirms that the ECM and the IAC are performing. If it still won't idle with the ESC disconnected, as you suggested, have a friend maintain an idle while you check the timing. Let them slowly reduce the idle speed until it barely ticks over or stalls. Note what the timing was at that point. Was it at least 6°? The reluctance to idle may be caused by not enough advance. BTW, The first thing to do is to check and cure that suspected, possible vacuum leak.

RACE ON!!!

87 rag

Thanks.
I will attack it in this order:
#1 Possible vacuum leak fix.
#2 IAC cleaning.
#3 Set timing. Hopefully without someones foot on the gas.

I was also thinking that I need a fresh tank of gas. I'm still running last years but I doubt this is causing my full problem.

87 rag

I have one other quick question.
Could this be related to the Oxygen sensor? I am assuming that the oxygen sensor would only effect things after the car goes into closed loop and therefor is not related if the poor idle is present during closed and open loop.
Am I on the right page here?
Thanks

RRT vette

How does it idle when the engine is warm or in closed loop?

87 rag

I haven't gotten it to closed loop since yesterday.
The idle will go up and down. When it goes down it will almost stall or stall. When it goes up it goes to 900-1000 rpms, when it goes down it will go to 400.
Even at 600 rpms it would sound like it was fighting to keep running.

Tonight I corrected the one vacuum line that I thought may be leaking, I cleaned the IAC and throttle body, I set the timing with my GF touching the gas to keep the car running and I put 7 of last years plugs back in because they were working fine when I took them out but I broke one that's why only 7.

I checked all electrical connections again and checked all vacuum lines agian.

Nothing changed. The car still will not idle. I think it may even be getting worse. I get code 12 and code 42 now but I haven't reset the codes after setting the timing.

The part I didn't mention earlier is that this winter I changed my valve seals, rockers and springs. I was praying that I wouldn't need to take the valve covers off again but it looks like that's all I haven't done.

I will check each plug wire for spark next. A couple of the plugs were wet when I took them out but not soaked, just wet.

I'm almost ready to get it to a mechanic but I don't want to pay the shop to go through everything I have already checked.
I'm getting real frustrated now.

88BlackZ-51

Jeff, I will see you tomorrow if you want to come early. Not sure if your still online. Hope you can get the car all figured out. Call me in the morning around 10.

mseven

Is the 900-1000 rpm in open loop? and when it goes down to 400 after it is warmed up(closed loop)? How smooth is the idle at the higher rpm?

If you are certain no vac leaks, and timing is atleast at 6*
With the timing set and then the idle drops down in rpm, sounds like the IAC (min.air) needs adjusting. If it is dropping that far down after it's warmed up, that sounds like it is out of range for the ecm to compensate. Other thing I would consider is how the v.lash was set.

comp

87 rag

I will get it to go into closed loop this morning and report back exactly what happens.
I hooked the car up to my laptop and scanned it running before I cleaned the IAC. I have the IAC position reading and it seems very high in open loop then it goes up and down once in closed loop.
I actually put a different IAC in because I have two and the other was cleaner.
I'm going to check my FSM for the proper procedure to set the IAC.
Then I'm going to see if I can get it to a gas station for somme fresh gas.

87 rag

I see in the FSM that the correct way to set the IAC is to start the car momentarily and turn the ignition off.
I'm sure I set it correctly but I'll do it agian.

Looks like I need to check my valve lash.

Keep the thoughts coming.
Thanks.

rick lambert

Resetting the IAC is fairly simple-it's in the FSM, but-Grasshopper, when things start happening after we've worked on it-the first place to look is the last place we worked-valve lash!!!! you may also want to
add some HEAT, fuel additive, letting gas sit for a year is not good. Didn't post fast enough-NOW, I think you're on the right path.

87 rag

Thanks Rick.
I wanted so badly for it not to be the lash that I was willing to check everything else first.
The car was running after the work but only in the garage. It seemed to idle fine. It is only after a couple of times out on the road that this problem has appeared.
I also had the plennum, runners, TB, and vacuum lines off the car so I was hoping it would turn out to be something external.

I know what I need to do.

rick lambert

You're absolutely sure that you have no vac leaks-those old plastic suckers get brittle, and you were in that area, I was visually looking at mine-looked good, but found one that looked good but was just sitting there-found it before I even checked for leaks.

87 rag

Absolutely sure is a tough one.
I did replace all of the brittle plastic vacuum lines with new non hard plastic ones.
All my connections are tight...real tight.
The only one I couldn't replace is the one that goes down behind the distributor to the heat/ac control. I have that one capped off with a screw.
I would say I'm 95% sure.

rick lambert

Sounds good to me. Have you tried advancing the timing at all? I really feel you're on the right track though.

87 rag

I think I have the timing at 6*.
It's hard to be sure when the car wont run. With the ESC wire disconnected it stalls immediately.
Set it yesterday best I could with the girlfriends foot on the gas pedal.

I'm trying to find valve lash in the FSM.
I don't see it but I do see the part on installing the rocker arms.
I have heard 1/2 turn, 3/4 turn and 1 turn. FSM calls for 1 turn?
I have read engine on, engine off. FSM doesn't mention so I assume off.
Finally engine warm or cold. I have read warm but the FSM doesn't specify.
I know what I did last time but it doesn't seem to work perfectly.
What do you reccommend?

Thanks.

mseven

Looser would be better 1/2-3/4 turn, however do the giggle method with the pushrod not just the spin method. Unless you have experience here I would go w/3/4 turn max. (the helms does state 1 turn). A little less will help assure not bottoming out the lifter. It should state engine off, bringing it up to TDC then doing 8 (don't remeber order) rotating crank 180* degrees than doing other 8. Because I use an aftermarket cam, I use a different method, to determine base circle of the cam (EX., opens set int., INT. before closes adjust ex.).

This is why I asked about v. lash in my earlier post. Checking/setting the IAC would be my first move. Follow the directions as per the helms (warm it up first) to set, after on off 5 sec., etc. to insure proper setting.

As to timing, a roll back (dial, back) timing light will tell you what's going on w/out removing the est.

87 rag

Thanks for the answers.
I followed the helms last time and thought I had it.
what I didn't do was warm the car up first. I had the intake off so I couldn't start the car and I did 1 turn not 3/4.
I'll warm the car first this time and go with 3/4 turn.
Today is the day, I can feel it.

Thanks agian.

mseven

Actually I do mine cold, but really the thing here is more of where you start 0 lash. It is very easy by spinning to already be preloading the lifter. Unless you can actually see the plunger going down, you are basing it on feel, why I suggest the jiggle method. Other things are the helms order will have you going from bank to bank when at TDC. It is easy to loose track with this method of which ones you have done. Make sure you it is on #1 cylinder for tdc not #6.

I would still look at the IAC first. MO