Help tuning with MS4 Cam! I'm stuck

[Kevin Doe]

Hello all, I've got EFI Live, and I'm trying to tune my car. My modifications are as follows.

MS4 cam, 1 7/8" long tube headers with 3" collectors, 3" true dual exhaust through an X pipe then into two straight through mufflers, dual 3.5" intake to a single 4" right at the throttle body, no MAF, LS6 intake manifold. The engine is from a 2004 GTO.

With EFI Live, I made it run in open loop speed density. I was going to do the auto VE tuning. I also had to have it in speed density mode since no MAF. I have the stock configurations, other than these changes. I have tried several VE maps, stock, stock with mulitpliers, and one from a car with a similar cam.

Here is what I'm experiencing. Cold startup, starts ok, usually requires two cranks. Idles decent. Almost exactly 14.6 AFR. Timing jumps around, between 8 degrees or so, and 25 degrees or so. It seems to be every 0.1 seconds it switches. The car will idle up to operating temperature and run ok. If I shut the car off, it will not idle at all w/o my foot on the gas. I have to wait for it to get totally cold before I can start it again. I have done some idle modifications to the desired airflow at idle table. I added 1.0 to almost every temp during the warm up phase. I did this because I logged a touch over 2.0 during the RAFIG process with EFI Live. I have since logged the RAFIG again, and it still says a touch over 2.0. The IAC steps are ~135 warm. When I try to restart the car warm/hot, I hear a lot of noise from the intake area, the rpms drop to about 400, and see the IAC steps go up to about 250, then it stalls out.

The car will not accept any throttle. Any amount of throttle will stall it out. I understand hot to preform the auto VE tuning using the BEN factor, however the car in its current state is not drivable. I see approximatly 71 kPa MAP at idle.

Can anyone point me in the right direction as far as how to get it drivable so I can at least begin to do some VE mapping.

This is the car its in. Its my build thread from a V8 RX7 forum. Its very long, and have hundreds upon hundreds of pics of my extensive build.
http://www.v8rx7forum.com/v8-rx7-technical/40258-ls1-fd-progress-not-using-kit-56k-no.html

Thanks in advance,
Kevin

[ScarabEpic22]

Sorry man, Im no help but Ive read the whole thread of your build and man is it sweet. Im an American muscle/truck guy, but man such a light car and a huge engine is sweet now matter how you cut it. Good job man!.

Ohh, btw your link doesnt work. Copy the link and then click the globe button at the top of the reply page and copy it.

[Kevin Doe]

Fixed the link.

[joecar]

Kevin,

Some comments:
- during warmup, the AFR should be richer than 14.6 (more like 12.8-13.8 getting leaner towards 14.6 as it warms up;
- 71kPa sounds like an air leak (unless you are certain that your cam is doing that);

Need some more comments from others versed in getting a cam to run.

[Kevin Doe]

I forgot to add AFR to my log when I was doing the RAFIG process. The 14.6 AFR was once it was warm. I'll have to check on the vaccum these cams usually run at.

[Doc]

Hi Kevin,
I take it that since the motor came out of a 04 GTO, it has a cable driven throttle body. What are your IAC counts when the motor is fully warmed up? I've seen it vary from setup to setup but most vehicles are happy ~40 to 60 IAC counts.

Brief caveman explanation of the IAC or Idle Air Control valve,

The purpose of the IAC is to control engine idle speed. It does this by extending and retracting a pintle in the throttle body. When the IAC counts (steps) is at 0 the pintle is fully closed; and 500 when fully open.

You are going to have to get the relationship btw the TB blade set screw adjuster and the IAC valve down pat. You wil have to perform a TPS reset every time you move the TB set screw.

Just remember that the IAC position is run by the RAFIG / PN tables.

The other side of the idle coin is the spark. Both stock settings for the air and spark tables are very aggressive when it comes to trying to control the idle. This is not a good thing for a MS4 type cam.

Jeff, screen name SSpdemon has a really nice sticky on idle tuning. Sorry to be so brief but I have to get to bed.

[Doc]

I just started to look at your project. Very nice.

Here is the link to Sspdmn's (Jeff)'s sticky on idle tuning.

http://forum.efilive.com/showthread.php?t=4661n

[SSbaby]

I agree with joecar. Cold start should be around 11-12 AFR at least before leaning off gradually. 14.63 (or leaner) should be the target figure once operating temps have normalised.

It sounds like you're running a relatively rich idle and your idle timing may not be advanced enough. Your engine shouldn't take two attempts to fire up it should fire up immediately... hence why I suspect you're running too rich.

What are your afterstart enrichment factor values {B3662}? I've got mine set to 0.75 for the first 8 mins. This implies that the mixture is leaned off by 25% once the engine is restarted within 8 mins of cold startup.

[Kevin Doe]

I've read through those threads, but I still have a few questions in my mind.

Is is normal for timing to jump around like I described? Also, why won't idle when you start it when its warm/hot. Even if I ease it down to 6% down to 0% throttle over like 5 minutes, and it dies out as soon as I get completely off the throttle.

[Doc]

http://carprogrammer.com/Z28/PCM/LS1/Holden_LS1.pdf

Page 100 , lots of good stuff in this