Saturn bellypan

[theycallmeebryan]

My 99 Saturn SL1 does the same RPM hike when clutch is pressed in or shifting to neutral. I've found that it's ECU and IAC related. Disconnecting the battery overnight has fixed that problem, but it seems to be coming back after about a week. Since i do a lot of pulsing between 1800-2300rpm and EOC gliding, i think the ECU is thinking that i don't know how to drive and is trying to hike the rpms to compensate for early shifting?

I suppose, like others have said, putting the IAC on a switch could solve the problem. Or, just disconnecting the IAC all together and manually adjusting the idle speed. I'm going to look in to it further as I,too, feel like it is hindering my fuel economy.

I really like the mods you did to your front end. It looks very clean. All i have right now is clear window seal tape blocking the radiator . I've been hitting between 43-46mpg this winter, and hope to break 50mpg once the temp warms up here.

[arcosine]

My sc1 does the same thing it you coast with the ignition on and the engine off, so I just don't coast anymore and the idle is just fine.

[orbywan]

Having built a vapor type carburetor back in the 80's I learned first hand how much gas even a four cylinder consumes when it idles. It's surprising to watch.

Does anyone have an electrical diagram of how the IAC controls the idle speed. I think it uses a prindle covering a bleed hole. If I know the current vs opening settings I can build a 'cheater' to adjust the reaction. I don't know if the ECM will try to undo the 'adjusted' values but I'd sure like to try.

[orbywan]

Originally Posted by cfg83

orbywan -

What dennyt said. When the car is warmed up you can disconnect the IAC and it will stay in the same position. What might be better is a switch that would disconnect the IAC at your will. The IAC could rev high when the engine is cold. When the engine warms up, flip the switch so that the IAC will be stuck in the same RPM position.

I really like the headlight covers. Can you post close-up pictures of the connections? What kind of plastic and thickness did you use? Do you think they will have a negative effect on headlight refraction/visibility? I don't think they will, but I always ask this stuff. The execution reminds me of mcrews' rear wheel-skirt pictures.

CarloSW2

Hi Carlos, aren't you the guy that did the Saturn gear swap? I'm still trying to get the hang of navigating this web site. Anyway, I'd like to try that swap on my SC2 but after a nationwide check on the computer, the GM dealer tells me there are driven gears still in inventory but no drive gears. Any idea where to find one, or a set? I contacted a place called Vintage Parts, or something like that, they used to supply Saturn with some unusual parts I'm told, but they have zero stock for either.

I'm working today but this evening I'll take some better close ups of the headlight covers and brackets and post them. The slightly tricky part was bending the angle just right on the brackets and especially spacing the bracket just far enough back from the edge of the opening so the cover is just flush with the body.

I'll go through that process for you this evening if you want. You use two scrap pieces of lexan to both determine the angle of the bracket, and to get the right front to rear spacing in the opening.

[orbywan]

Carlos I forgot to answer your question about the covers. I thought they were lexan, but the plastics company just told me they're clear acrylic. It's 3/16th's thickness, which is perfect for this application. The good part is this stuff has a very hard surface to it. Unlike uncoated lexan, if you brush dirt or whatever off, it doesn't leave 10,000 tiny little scratches on the surface.

I made a cardboard template for it, marked it, and cut it out on a band saw. I just realized my digital camera is in the shop so I can't send photos until I get that back, they said it would be a week or so till the parts get here, sorry.

[cfg83]

orbywan -

Ok, the description is what I need. I will start making cardboard cutouts. I have a feeling that the "deep/sharp" shape of your SC2's headlight is better than my SW2's "sedanish" headlight design.

In terms of the gears I had the luxury of a Saturn parts department. I would guess that any 1998+ MP2 S?1 tranny would work. You could probably salvage the 5th gear set from any MP2 tranny with a blown diff-pin (S-Series are infamous for that).

CarloSW2