Trouble with idle speed in park

[srobertsfsj]

This could point to a malfunctioning EST/7pin module... but even when malfunctioning it can be seen jumping around when watching timing with timing light.

Well you could be right, I was just out running the jeep in the driveway and it all of a sudden died while I was waiting for it to warm up and wont restart. I am getting fuel but no spark, it's either a HEI coil or the 7 pin module....sigh

[EagleMark]

Hard to tune out bad mechanical parts... if your getting fuel EST has to be working somewhat or injectors would not fire, so likely coil. But did the malfuntioning EST casue coil failure?

The EST is one part of these systems known to still work and be faulty, both large and small cap. All other parts are fairly relibale and either work or don't!

[srobertsfsj]

I replaced the cap and rotor yesterday, they were both a few years old but no change, still no spark. I am going to pick up an ignition module in a bit. Before I lost spark I did notice that I was not in ALDL mode and still getting the higher RPM in park so it looks like I am still chasing a gremlin. Maybe a new EST will fix that but I am not hopeful. When I originally instaledl the TBI I did have the polarity switched on the pick up coil, could that have done some damage? I did try swapping ECM's but that didn't help and the wiring looks good. If the ign module doesn't fix it then what should I look for next?

[FSJ Guy]

If you go with the 8 pin module, IIRC, the PURPLE wire from the distributor goes to the P side of the P/N terminals. I can check mine and let you know...

[EagleMark]

I think he has 7 pin module designed for EFI in HEI large cap. So plug should just plug on. Sounds like FSJ has Duraspark and external 8 pin EST?

I have never experianced EST damage from crossed pickup coil wires on duraspark or small cap GM. Usually it just reverses timing and sometimes needed in reverse rotation distributor from GM origanal design. But back in post 12 area of this thread 1project2many said it will change timing by 45 degrees or with large cap HEI? So maybe refer back there and get this straight with working parts!

[FSJ Guy]

I think he has 7 pin module designed for EFI in HEI large cap. So plug should just plug on. Sounds like FSJ has Duraspark and external 8 pin EST?

I have never experianced EST damage from crossed pickup coil wires on duraspark or small cap GM. Usually it just reverses timing and sometimes needed in reverse rotation distributor from GM origanal design. But back in post 12 area of this thread 1project2many said it will change timing by 45 degrees or with large cap HEI? So maybe refer back there and get this straight with working parts!

Correct. He is currently running a 7 pin module as part of an HEI. He is thinking of changing out to an 8 pin module and running a stock AMC 360/401 distributor with the vac advance and mechanical timing locked out.

[srobertsfsj]

Ok we are back up and running, the issue was the 7-pin ign module. Here is another thought on my idle issue. I was messing around while emulating and noticed that my issue really seems to be with the timing table, I think I am just trying to run too much advance at idle which is bringing the rpms up. The problem is my engine likes more advance of the line, has more get up and go. I guess I need to find the in between. Seems that the C/L Desired idle speed only controls the RPM's in Drive and not Park. Can anyone confirm this? The only other thing I can think of is if there is a parameter that advances spark when in Drive vs park

[srobertsfsj]

I also had a question about the ESC. Would the ESC from a 5.0L be the same for a 5.7L? I noticed that the part numbers are different when I am looking it up online.

[FSJ Guy]

Remember, you will likely be in a different MAP (engine load) area on the table when idling in DRIVE versus idling in PARK. Thus, you can adjust the timing for idling in PARK and have it different than the timing when you're idling in gear.

[EagleMark]

Ok we are back up and running, the issue was the 7-pin ign module. Here is another thought on my idle issue. I was messing around while emulating and noticed that my issue really seems to be with the timing table, I think I am just trying to run too much advance at idle which is bringing the rpms up. The problem is my engine likes more advance of the line, has more get up and go. I guess I need to find the in between. Seems that the C/L Desired idle speed only controls the RPM's in Drive and not Park. Can anyone confirm this? The only other thing I can think of is if there is a parameter that advances spark when in Drive vs park

Well this could be true but I would expect the IAC count to drop? Yours is 50, if it were 0 then yes! Is the IAC counts moving at all when driven? If you'd like I could look over your bin later tonight and see if I can find anything obvious that may be causing the issue? If you post it?

I also had a question about the ESC. Would the ESC from a 5.0L be the same for a 5.7L? I noticed that the part numbers are different when I am looking it up online.

The knock sensors are differant as to frequency of cylinder displacement, and the ESC has to match.

[gregs78cam]

Well this could be true but I would expect the IAC count to drop? Yours is 50, if it were 0 then yes! Is the IAC counts moving at all when driven?

This is what I have been thinking all along, 50 counts for idle is pretty high, that's why I asked for a log, and .bin.

[srobertsfsj]

I will post up my bin shortly. I am pretty sure that my ESC is from a 5.0L, I am going to run over to the JY tomorrow and grab one from a 5.7L. I also need to get another TPS as mine is starting to fluctuate a bit even when its tightened down. I had to oval out the holes a bit to get to the .54 range so that may be why. Is it ok to just bend the tab instead of ovaling out the holes?

[EagleMark]

5.0L ESC and knock sensor matched set. 5.7L knock sensor and ESC matched set. Whatever is closer to your engine. But I don't think this is your idle issue.

You can bend tab a bit but wait till you get good TPS as you might not need to. Ovaling holes is better. You can test with Digatal volt meter from 0 to 5 volts or close at each end. Smooth transition from closed to open with no jumps or glitches. Check wires into TPS plug for issues... this could be your idle issue.

Your bin and log will help us find an issue.

[srobertsfsj]

Here is my in progress bin. Which log files?

april17VEsmooth(C).zip

[gregs78cam]

Which log files?

Just a datalog of a few minutes worth of high idle, maybe even a few minutes of the 'set timing' plug disconnected.