Car idles fine until..... see pics inside...help

[Methodical]

I recently changed from head bolts to heads studs, removed the EGR valve and did a smog pump delete. When I got everything back together and started the car, initially there were no problems (1st day) then the next day the car had problems idling. Here's what I've notice:

When I disconnect the fuel pressure vacuum hose and remove the cap from the EGR vacuum port (where the red line was connected), the car idles fine but at about 925 rpms (have rpm set at 850). When I reconnect the fuel pressure vacuum hose and cap the EGR vacuum port, while the car is running, the car dies. With the FP hose connected and the EGR vacuum port capped, the car will start but then die. (SEE PICs below)

I drove the car with the FP vacuum hose disconnected and the EGR vacuum uncapped. The car runs very strong, it just wants to die when it comes down to idle.

Diagnostics performed:

Performed vacuum test with both the FP vacuum and EGR cap removed (only way to get the car to idle) and it held steady at 15-15.5 hg.

Sprayed around the intake, TB etc with the vacuum gauge connected to see if there was a vacuum leak - No vacuum change in vacuum, no vacuum leaks.

What could be the problem? This is a mystery to me.

Thanks for any help

 

[95BlueStallion]

Oh buddy, if you get a solid answer to this one Ill be greatful as well. Im having the exact same issue, but my EGR is still functional for time being... Someone please help us!

 

[Methodical]

Oh buddy, if you get a solid answer to this one Ill be greatful as well. Im having the exact same issue, but my EGR is still functional for time being... Someone please help us!

I will reinstall the EGR valve to see what affect it has. However, from my readings, probably nothing since it's not suppose to be on at idle. If I figure it out I will definitely post my results. And if you figure it out let me know as well.

By the way what are you symptoms/problems.

 

[HISSIN50]

Al, is that vacuum signal what you'd expect with your combo? It's about 5" lower than stock.

Since creating a vacuum leak allows it to idle:
Have you verified that the IAC didnt get broken/disabled? When parts get moved around during a swap, sometimes a piece of coke will free-up and it eventually causes the pintle to bind.

If you run the idle bleed-screw out (the one under the rubber grommet), does that help enough that you can plug up your vac lines?

 

[Methodical]

Al, is that vacuum signal what you'd expect with your combo? It's about 5" lower than stock.

From what I understand a stock motor is 17-22 but also, I've seen that it would be a bit lower with a cam, which I have, but nothing to aggressive though(500in/510ex, LS = 114)

Since creating a vacuum leak allows it to idle:
Have you verified that the IAC didnt get broken/disabled? When parts get moved around during a swap, sometimes a piece of coke will free-up and it eventually causes the pintle to bind.

Even though creating a vacuum leak allowed it to idle, when I took the car out for test drives, it would continue die when it comes down to idle.

To eliminate things, I cleaned the IAC but to no avail.

If you run the idle bleed-screw out (the one under the rubber grommet), does that help enough that you can plug up your vac lines?

I ran it out but not all the way. One thing I noticed is if I open the throttle blade one full turn it idles ok, but higher.

Next, I plan to look into the adj fuel pressure regulator. What do you think?

Thanks

 

[fastgtfairlane]

possibility to be a bad regulator. but cleaning a broken iac is not gonna make it work. sounds like it is broken. can you verify a working iac with the tweecer?

 

[HISSIN50]

I kinda agree with the IAC sentiments. They very often dont like to be cleaned (I do it if willing to buy a new one anyhow). If a buddy has a spare one around........... (if I had a spare, I'd mail it to you to try out).

Good luck.

 

[Methodical]

I turned the TwEECer off and just ran it on the stock ECU settings and the car start right up and held an idle at the stock 672rpms. I compared the Stock MAF settings to my tune MAF figures and noticed the stock is leaner by about 14% in the idle area. So I plan to do some idle datalogs to try and correct things. I'm going to do an idle reset and go from there.

It's a mystery that it would be so rich because it ran fine prior to me making those changes. Only change I made was the head gasket size - went to .027 (MLS) from .039 (felpro), which changed the compression ratio a little -from 10:1 to about 10:30 or so.

Could this have caused such a dramatic change?

 

[Adam95GT]

Well any change in compression ratio would show a change... but thats decent in size man... good luck

 

[95BlueStallion]

By the way what are you symptoms/problems.

Sorry, I havent been on here for a few days... My parents came down to visit for the weekend. Anyway, I just have a problem with idle in general, and it all started after my intake swap. I removed the intake and reinstalled it to ensure a good seal, plus I have retorqued it after a couple heat cycles, so Im thinking it has to be vacuum related. Everything else is hooked up just like it was in stock form. I cleaned my MAF for giggles, but have not done anything with the IAC. Im a novice, and dont know how to measure vacuum pressure, but the check engine light has come on and off with the change in vacuum lines when I move the order of them off the EGR. Even when they are hooked up in stock form, my idle is still choppy and it's died at a few lights recently, but the check engine light hasnt come on for a few days... The idle improves when I disconnect the EGR vacuum lines, and thats what made me think my problem was similar to yours.

 

[Methodical]

I'm working on it. Will post results.

Thanks

 

[WHITE94COBRA]

Have you tried disconnecting the battery for 30 min, try resetting the computer before worrying too much.

 

[Guero]

I kinda agree with the IAC sentiments. They very often dont like to be cleaned (I do it if willing to buy a new one anyhow). If a buddy has a spare one around........... (if I had a spare, I'd mail it to you to try out).

Good luck.

You do have a spare its at my house lol!!! I still have all the stuff here for you....I just gotta make time to go over

 

[Methodical]

I think it's a fuel issue (fuel pump). When I drove the car it would feel as if someone was holding me back and then letting me go, holding me then letting me go (best description I can give).

Played around with it yesterday and now the car doesn't want to start without me pressing and holding the gas pedal. When I let off of the gas it dies.

When I did get it to idle and then datalogged the idle, I noticed the Kamrfs were showing a lean condition (1.15 to 1.25) as if it's not getting enough fuel. This is the same MAF curve I've been using for over a year with no starting, idling or driving issues.

Also, I noticed that with KOEO, the fuel pump primes but the pressure doesn't climb to 40psi like it used to. It goes to about 28-30psi.

Next steps:

Change Fuel filter

Test to ensure I have voltage at the injectors.

 

[WHITE94COBRA]

Try this real quick, pull the vaccuume line off the pressure regulator, you should notice a difference in driveability, and idle. If it runs better you need to disconnect the battery and put the vaccuume line back on the regulator, make sure you have no open vaccuume lines, leave the battery disconnected for a while then re connect it, start the car and just let it idle for about 10 minutes, shut the car off, let it sit, for a few moments, then restart and let it idle again. When the vaccuume line is disconnected the fuel pressure should stay at a constant 39 psi, when resetting the computer the pressure will be recognized and re learned.

How fast does your fuel pressure bleed off after you shut the car down? Hopefully it stands steady for a while.

 

[R.J.]

Try resetting your idle with the following procedure. If your idle problem is NOT being caused by a bad part then I have never seen this not fix the problem!

Begin with a cold vehicle. The idea here is to get the car to a firm cold idle with enough air bleed capacity left in the idle circuit for IAC adjustment.

The idle stop should be set first. Back out the idle stop screw, away from the bell crank arm, until about 1/2 turn past the point where it no longer makes contact (blade fully closed). Using a 0.010" feeler gauge, tighten until gauge just drags between screw and bell crank arm. Remove feeler gauge. Tighten screw exactly 1 1/2 turns. If the screw is very loose, put a drop of loc-tite or silicone on it, so it doesn't work out of adjustment.

Now remove the connector to the Idle Air Controller (IAC) just on the other side of the throttle body. Start the car and allow vehicle to warm for 2 minutes. Give a small "blip" to let it settle. If it is having a hard time staying running you may have to get an assistant until you can get to the front of the car. Now open or close the air bleed screw (CCW opens) next to the IAC until the car idles at 575 to 600 rpm. For guys with aftermarket cams and an EEC tuner, you might want to idle a bit more briskly, say 650 to 675.

Obviously, this rpm range is by what the car and driver wants...IE, no set idle speed, whatever works for YOU.

Turn off the car. Now count the number of turns clockwise to close on the idle air bleed screw. If it falls between 1/2 and 2, it's okay, now reverse it out the same number of turns. Log the number somewhere in case you need it for the future. Reconnect the IAC. You are done.

If the air bleed screw is above 2 turns, it's a good idea to tighten the idle stop screw another 1/2 turn, and then repeat the idle setting. If it is below 1/2 turn, then loosen the idle stop screw by 1/4 to 1/2 a turn, and repeat the idle setting. Be sure to put another drop of silicone RTV on the stop screw if it was disturbed. Reconnect the IAC.

Now remember we adjusted the set screw on the throttle body. That means that the voltage reading from the TPS sensor has changed. It should read between .96 and .99 volts. Anything outside of that range will cause all sorts of issues including misfires and rough idle.

you will have to back probe the TPS connector. With the connector attached to the TPS stick a paper clip into the rubber boot on the connector where the top and middle wires go into the connector. The rubber is very flexible the paper clip will slide in between the rubber and the wire.

Set your multimeter to volts. Turn ignition to ON. Then place your multimeter leads on the metal pins. If it comes up as a negative that is okay as long as you are -.96 to -.99. If you get this reading then great you are done and hopefully your issues are gone. If not proceed to step 9

This is where and extra pair of hands come in handy. Using a large screw driver you will need to loosen the bolts that hold the TPS. DO NOT USE A SCREWDRIVER THAT IS TOO SMALL BECAUSE YOU WILL STRIP THE BOLTS. They probably will be really tight so you have to really lean on the screwdriver and use some finesse.

Once the bolts are loose you will need to move the TPS up or down and continue to read the voltage. Once you get it to the desired setting you can retighten the bolts. What I do is I find .97 and then as carefully as possible I tighten the TPS down. what will happen is the voltage will change usually to .96 or .98 but that it okay. Once you are done with this manually open the throttle body a few times and close it then reread the voltage and make sure it is still within our desired range.

Depending upon how loose your set screw was you might want to cover it in RTV to hold your setting. At this point you have CORRECTLY reset you idle.

 

[Methodical]

Update: I did an ignition system test. See below

Testing of the MSD: Checked for spark

Removed the MSD white ignition trigger wire, removed the ignition coil wire and set it about 1/2" from a ground and with the KOEO I tapped the white wire to ground and there was spark at the ignition wire. So the MSD box and coil (old coil, new one coil is bad - sheesh) is ok.

Testing of the Distributor Ignition Module:

First I check to see if there was power to the ignition module. With the KOEO, I test for power at terminal 4 (red/light green wire) and there was power at the module. Checked Ok

Second, I tested the PIP signal from the stator. Got the wifee to help here. While cranking, I probed the ignition module's solid green wire (terminal 1) with a test light. The test light did not flash while the car was being cranked, which means the PIP is not getting a signal from the stator.

Lastly, I tested for power to the Stator with the KOEO. There is power to the Stator.

So according to the diagnostics testing, I have a bad stator.

Note: Don't know if it made any difference but I performed the above tests with and without the MSD connected.

Now, whether or not I continue to use MSD products will depend on how they handle this. I purchased the distributor on 1/29/07 and the new coil (purchased on 2/23/07) but went bad on me in the summer.

Now I will call MSD to see what's the next step.

So I will work this issue out before I address the fuel pump issue. I will update this post.

Thanks for all the help and suggestions

 

[95BlueStallion]

Thanks for the follow up! Im still having my issues, but I have a random on/off CEL and I just ordered a code reader, so Im check that first. I never would have thought thatd be the culprit.

 

[Methodical]

update:

Ok. I purchased a reman distributor from Napa ($105 with core) and the car fires right up and idles smoothly - both with and without the MSD 6AL box

. The Fuel Pump is ok

So I would like to thank everyone for their input.

 

[Methodical]

Oh, the stator, PIP, Pickup - what you want to call it - died. The distributor began it's troubles after only 15 months. No more MSD distributors for me.