RonRed89

All,

Well, after a new top end on the L98, we're at the tuning stages and having some problems.

Namely, the idle out of gear is about 1000RPM. This appears to be fine. When shifting into gear (D or R), the car stalls unless you feather the accelerator pedal (as in give it a little bit of throttle and then move the shifter into gear). Once in gear, the car does not stall and operates at either 700 or 800 RPMs at idle. 800 is a little better in terms of smoothness, but in either case the car does not stall at the light and has no hesitation when throttle is applied.

The work that was done (from the Heads/Cam perspective)

1) Comp Cams Part # 08-422-8 (218i/224e/110LSA)
2) Matching valvetrain components as spec'd by CompCams (springs, pushrods, 1.52 rockers)
3) Ported / Polished L98 D-Port heads (stock valve sizes) gasket matched to Felpro gasket.
4) Gasket Matched SuperRam base
5) Accel 1000 cfm Throttle body
6) Cloyes Timing Chain set
7) Accel 24lbs Injectors

The big question... Car is still running with the Hypertech stage II chip as we try to get the custom chip more closely calibrated. The custom chip is being done by ADS. Can this type of problem be corrected by chip tune, or is this really totally torque converter related? Would a multi-spark box like the Accel 300+ improve the situation any? Mine is currently in need of service and is not connected. The Comp Cams website claims that this is the largest cam that can be used on the stock converter.

Most of the easy stuff has been tried such as checking the TPS and IAC, cleaning the MAF, raising and lowering the idle. Looking for some more suggestions to try. Unfortunately, I'm not the one doing the work so hopefully I've given you enough details to point me in some general direction.

One thing to note is that there are NO driveability problems once the car is going. Of course with this type of problem, parking can be a little tricky. :-) The car has full power in all other situations with no hiccups. Just need to get this final tune completed and it'll go back to the track.

I'm hoping that something else can be the cause of the problem besides the TC. I am way over budget and don't want to spend any more money this year. Hoping there can be a less expensive solution.

Thanks for all of your help.

Ron


[Modified by RonRed89, 1:57 AM 10/2/2002]

kaiser

With an SR & a cam the stock chip won't idle worth spit. Needs to be massaged for fuel and spark in the idle region - and probably at upper rpms too, to take advantage of more flow. ADS should be able to figure out something for you, it's hardly an unusual combo.

Ignition box and TC have nothing to do with the idle problems, it's cam/intake reversion.

C4-Wolf

I agree, I don't believe it is so much the cam as it is that the computer just needs some work. If you have an adjustable fuel pressure regulator you might try playing with that a little - for a possible temporary fix. Be careful though about leaning it out too much as it could cause problems at higher rpms.


[Modified by C4-Wolf, 2:28 PM 10/1/2002]

RonRed89

Well having said that, I stopped by the shop today to get that ADS chip. It's installed, and the problem still exists. The car is a little bit smoother all around, but the idle problems when switching into gear are still there.

I guess I'll give Ed Wright a call, and see what he has to say. I hate to make any more gambles. If the chip will fix it, I have no problem buying it. However, I don't want to mess around now, and then only find it to be something else. Damn cars! <grin>

Does anybody have any real problem with this particular cam? It seems to be spec'd fairly close to the 219. Wondering how far off my calibration would be to someone running the SR and 219 cam.

Ron


[Modified by RonRed89, 1:47 AM 10/2/2002]

RonRed89

I'll have to play with that. I think it's running a little rich at idle. I only say that because I can smell gas fumes when it's at idle. No smoke or anything though. I'll have to get the FP guage and see what they had set the pressure to.

Ron

h rocks

RonRed, have you checked how much vacuum you have at idle?
The BIG difference in your cam and the 219 is the LSA. I'm no expert in that area, I just know that most computer cars like no less than 112. Many cam guys will tell you as much as a 114 LSA. I think that the 110 may be problem. I would take your question to the Engine Tuning and the Prom and Programming forum.

RonRed89

I have access to the necessary testing equipment, and won't claim my sense of smell was is that accurate to begin with. :-) I'm really trying to find any possible things that could be causing this particular problem and what can be done to correct them. I'll likely start taking a look at other shops around the area that could help out.

You did bring up one interesting point about the newer ECM. What is involved in changing ECM models anyway? Will the same PROM function in the same way with a different model ECM?

Ron

RonRed89

It would definitely SUCK to pull that Cam and replace it should that prove to be the problem. I'll cross post this thread to the other boards to get a better perspective.

Thanks,

Ron

snydcat

Yep, I have been told never to go any lower than 112 LSA on a computer controlled car because of vacum problems.

Rich

vader86

I agree it might be the LSA, but i think with proper tuning you could overcome some of the bad idle and the rich running, but with the LSA i dont think youll ever have a really smooth idle.

C4-Wolf

I think if you are smelling raw fuel then there is a problem that needs to be addressed. My guess is that fuel pressure was turned up in order to compensate for more power at higher rpms, but it is hard to say. If this is actually the case then you might be running quite rich at idle and this might be the problem. This may lead to fouled plugs etc... which will cause the problem to get worse over time. I don't think that a 110 lsa would be that problomatic, but I'm no cam expert. Anyway, try turning down the fuel pressure a little, and check out the low rpm response. If it gets better then it was probably running too rich at low rpms ( don't run at high rpms with the fuel pressure turned down as it may run dangerously lean) . If it doesn't then you will have to address different issues, but if it does then you can have the chip easily programmed to compensate for this. If you have access to scanning equiptment this will help a lot as you can check your blm's at idle to see if you are running rich or lean. Good luck, and keep us posted.

C4-Wolf

Again, I don't think tha the cam is too big or the lsa is too close together, but that is just my opinion. Many people here on the forum are running much more duration which I would think would cause more overlap on even a 112 or 114 lsa then what you are experiencing with your cam. If you still have power brakes than I don't think you have a vacuum problem.
There are a several people on the forum with a very vast knowledge of camshafts and their effects I suggest you get a hold of one or more of them. I will IM you with a little info here.

RonRed89

I can hook the scanner up and monitor the BLMs at idle to check this. Next time I start working on it again, I'll get the scanner and see what it says about the BLMs.

RonRed89

Brakes are working just fine whether at idle or while driving. They could use an upgrade due to the new power, but they are not any worse off now than they were before.

I did start looking around at the LSA based on your guys feeedback. The TPIS L98 Super Profile cam has an LSA of 108.

The funny thing about this whole situation is that I actually LIKE the idle it has. I just don't want to have to hit the accelerator pedal to get into gear. :-)

Ron

Goody

If you are still running around the stock displacement, then I think you might want to try stepping down to the 52mm TB. 58mm seems way to big (1000cfm) for any smallblock combo unless into the upper RPM's. Hence the idle problems. You are confusing the computer by allowing too much air in so it over compensates with too much fuel (the nose thing).

Also, the Accel injectors have not had great reviews from most whom I have read on here that tried them. Please don't take that as a slam or criticism. I am surprised you aren't running the 28# or 30# FMS units.

Good luck.... :seeya

RonRed89

While I've read the 58mm vs 52mm TB reviews on the forum, I don't know that the extra 250cfm of the 58mm TB comes into play at such a low RPM. The shop claimed that after adding the TB, it woke things up a lot. The original TB was still on the car when we first began experiencing this problem. The difference in price between the 52mm and 58mm TBs is not that great, so I doubt it was an attempt to make more money on their part. Again, the interesting thing about the car is that it runs perfectly in all other aspects but the idling problem being discussed in this thread.

As for injectors, it's probably a matter of personal opinion more than anything. I personally like the Accel product line, and have had very little issue with their products, hence the choice of Accel. The 24lbs injectors seem about right from what I've read. The shop also suggested the 24lbs size. I would think that if the injectors had issue that I could feel this problem across the powerband which I don't.

Thanks,

Ron

89gta383

I think you have a vacuum leak or some other mechanical problem. I ran the superram and a 214-220 crane cam in a 383 with AFR 190 heads with the stock chip with no problems. I have a 230-236 cam now and it idles fine with my chip. Idle is smooth as silk at 800, but gets lumpy and cammy sounding below that.

AquaMetallic94LT1

Your probably going to need some additional spark timing at idle in drive to get a better idle. Check for vacuum leaks as well.

You can test to see if more advance at idle will help by advancing the distributor when the car is at idle with the est connector still connected to the distributor. Temporarily tighten the distributor down when idle seems acceptable. Then disconnect the est connector and note what the timing reads. Subtract that from the normal stock setting of 6 degrees to get the actual number of degrees you would add to the programmed ecm value. Reset the distributor back to the stock timing position.

RayJay

Ron,

In no way do I consider myself an expert in this area but I thought that I might mention that I have just gone thru most of the things you are experiencing. I added an LT4 HotCam to my '96 LT1 coupe (A4). I added a 52mm TB and already had an AFPR and an SLP "Claw" when the mod was added. It would idle at ~ 900 rpm and lurch quite a bit at stop lights. In higher rpms, there was no problem and the power was great. We tried several custom tuning profiles but none really gave me the drivability I was looking for. In short, the factory TC just would not uncouple (slip?) enough to make me happy. I've heard that the factory unit has anywhere from a 1400 stall speed to an 1800 stall speed. Whatever it really was just would not make me happy. I've just recently added a Yank TC with a 3000 stall speed and that finally made me happy.

I went thru the custom tuning thing, added a new IAC valve, vacuum leak checks, the whole nine yards. The new TC was the fix. The 6-spds seem to handle bigger cams than the A4s. Personally, I wouldn't recommend adding a bigger cam without a TC upgrade.

For what its worth... :seeya

ANTI VENOM

I would look at your IAC counts. I keep mine around 25 at idle in park with the engine warm.