SW Chip Question

Inniswhe · 08-07-2010, 12:12 PM

I know you are supposed to have your car working 100% before you install a performance chip but I am wondering if it matters that the idle when cold is not like a new car . My 84 carrera is pretty lumpy when I first start it up cold. It works fine after it runs for a minute or a few revs of the throttle. It works fine through the entire rev range when driving but the idle is not perfect like a new car.

I am just wondering what these cars idle like when they are in top form ? I have never felt like I needed to investigate further as it starts right up and does work well but I am wondering if I should be doing some investigation before installing the SW chip ?

I have also read reports that indicated the chip improves idle so maybe it was just like that from the factory ?

Thanks for any insight

steely · 08-07-2010, 12:30 PM

I would suggest you try to improve the idle, because mine had an idle issue when I first bought it, and I was able to improve it. Symptom was hard starting - had to keep my foot on the gas until it warmed up. I was never sure what the exact issue was, because I tackled a couple of items like replaced some of the smaller vac lines, cleaning and setting the idle switch, cleaning the throttle body, new intake gaskets/isolators, and re-attaching the O2 sensor (oddly, against the advice of the PO's wrench - I never understood why).

On edit - yes the idle is much improved, cars starts easily, and it purrs at the same rpm ~8-900(?) consistently w/ no hunting in cold or warm weather.

I say this also because she had a SW chip when I bought it, so your problem may not go away with the chip. I can't say for sure, but maybe this history may help.

grailtown · grailtown's Garage

I recently installed the SW 911 CHIP in my 1989 C4. Idle was not smooth prior ( meaning with my OEM chip installed , idled better all around with the new 911 CHIP from S Wong ) , it surged and was erratic but typically did not stall ..... It is notably better if not completely smooth since the CHIP change ( if I'm picky I can detect less than perfectly smooth idle..) . Nothing else done prior to CHIP change as nothing really wrong with way car ran any way , idle exception as noted obviously. I suggest you send SW your question, he was very good about answering questions I had prior to my purchase of his chip. His911 CHIP 'tweaks' the fuel and ignition delivery, does not make extremely radical changes that would necessitate unusual concerns prior to an install ( imho ).. best you just ask SW ( Steve Wong ) . I like my CHIP btw, car pulls smoother and stronger ( basic stock set up no primary muffler, at 5000 ft elevation in Colorado.. 91 octane / premium fuel ). Enjoy the ride.

ALXinNZ · ALXinNZ's Garage

Yep same issue with mine. I even replaced the original chip to make sure it was the chip change. Original chip idle perfect from cold, new chip had the cold surge until everything warms up then its mint. The instructions that come with the chip ( yes instructions ) describe the adjustments needed to fix this minor issue. I personally have it on the things to do list! Hasn't stopped me having a blast!

Iowa911 · 08-08-2010, 05:08 PM

My '84 had a stock chip when I bought it. Spent quite a bit of time trying to get it to idle properly. It idled a bit low and had a little hesitation of the line. Never got it right, but I bought Steve's chip anyway. In addition to other improvements, the idle improved and the hesitation disappeared. Yours may do the same.

Inniswhe · 08-09-2010, 06:38 AM

Based on Iowa911's comment I might as well just install it and see if it works any differently. Like I said after 30seconds or a minute post cold start it works fine, just a little rough initial idle when cold. Its not rough enough to stall buy it feels rough so I give it a few blips of the throttle to help it along and after the idle smoothes out I pull away . If I pull away from cold without giving it the time to smooth out there will be hesitation.

Maybe that first generation carrera chip programming had this issue. THe power was increased by OEM chip tuning in the later Carrera's so maybe the idle tuning was also improved.

Thanks everyone.

Ross

JJ 911SC · JJ 911SC's Garage

Inniswhe

Why don't you ask Steve??? info@911chips.com

Great guy, great costumer service.

J.J.

djcdmv · djcdmv's Garage

Quote:

Originally Posted by JJ 911SC

Inniswhe

Why don't you ask Steve??? info@911chips.com

Great guy, great costumer service.

J.J.

I agree. I called him and he talked to me for about 25 minutes.

Inniswhe · 06:00 PM

Before I got the chip installed my clutch's life came to an end. I pulled my engine last weekend and before pulling the clutch apart I had a look at the vacuum lines at the rear of the engine as my rpm's were not dropping much on removal of oil tank cap.

As I suspected there were some cracked lines
- the small U bend line that runs from the intake to the thermo valve
- The rubber section at the end of the copper pipe that runs from the intake to a Y fitting by the break booster vacuum line. I am not sure what this line does ? It is called a fuel line.See pics below.

Next I will repair lines and decide what other things I will do when the engine is out. I will start a new thread to address that topic.

JJ 911SC · JJ 911SC's Garage

Quote:

Originally Posted by Inniswhe

... and decide what other things I will do when the engine is out.

... The famous, "while I'm in there"

Standby for lots of sujestions!

Here is mine; major cleanup using this http://forums.pelicanparts.com/cleaning-detailing-polishing/550748-best-cleaner-bar-none.html

steely · 09-03-2010, 08:41 AM

The pic of the cracked rubber hose is certainly in the vac line and a/the contributor to your lumpy idle. I repaired mine with new vac line.

steely · 09-03-2010, 08:57 AM

Save $150.00

Inniswhe · 09-03-2010, 09:20 AM

Steely,

I think I will save the $150 as you say and just repair the rubber part with a new short piece as per your pic.

Does anyone know the purpose of this vacuum line exactly ?

Ross

Techne · Techne's Garage

Car and Driver's 1984 road test did complain about unsteady idle when cold in the new Carrera.....I think a combo of a SW chip and fixing other items mentioned may be the final answer......

steely · 09-03-2010, 12:58 PM

Ross,

Honestly don't know - have seen this little reducer mentioned here with the same problem - and I thought I read it was related to the brake boost vac line. As to why it goes to the thermo valve (or above the TB in my case) - I wish I knew.

I have also read of repairs like duct tape &/or silicon, but I took a tip here and stuffed short a pc. of vac rated line inside another to make my own reducer.

The orig item is called a pipeline I in my 87 and is oriented 180 degrees from yours - don't know if this was to make allowances for something else, or a change in function - but I think the repair methods are still ok.

Inniswhe · 09-03-2010, 03:28 PM

Another easy fix might be to clean the cracked hose up and slip some large diameter heat shrink tube over the damaged section and heat to fit/seal the cracked section. It may not be thick enough to make a good long term fix but would be relatively easy to do.

I can't figure out the purpose of t his line .

It appears to permit metered intake air ( connection is downstream of airflow sensor to be drawn into the intake manifold on the engine side of the venturi tube serving the break booster system.

I wonder if it is there to prevent pressure fluctuation on the brake booster circuit as the line should dampen any effect of the throttle valve moving ?? Just a wild ass guess