TheFormula350

Just got off the phone w/ the shop that installed my new SR, AFR 190s, LPE 219 cam and they said it's running good except that it dies while in gear when stopped (ie left in D at a stop light or R). They think the only solution to this would be to get a bigger stall converter (stock right now). Is this really the only solution, or could something else be causing the problem? Thanks for any help...

Matt
87 Firebird Formula 350

irocz

Offhand I'd say get your car and run away from that shop. I've got an SR & a bigger cam, although with stock heads, and my car idles fine even with a stock chip.

What kind of chip are you running? Do you still have the maf? I had major driveability problems when I first cranked mineuntil I turned the tps voltage down to .35v. I had to grind open the slots a little, but the payoff was huge. Of course, it's just a crutch until I learn how to burn my own, but if you are in the same boat it will at least let you start driving it.



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87 IROC-Z, 5.7, auto, 3.27, leather, !cat, Holley fpr, K&N'S, SLP 1-3/4" Jet-Hot coated headers, SLP .218/.224 .495/.502 cam, Comp 1.5 roller tip rockers, $uperPITAram, Edelbrock lower intake, Holley 52mm tb, Dynomax\Flowmaster catback. Coming Soon(?)- Fasttrack/Accell DFI

1989 Pontiac 20th Anniversary Turbo Trans Am - 161,000 miles, !cat, 9" K&N

TheFormula350

I have the stock EPROM w/ MAF. The shop set the TPS at .74 to get the idle at ~800 instead of the stock ~550. I had heard about setting the TPS at .35 to fix some of the drivability problems of the SR, but the shop said they first tried setting the TPS lower and it just made things worse I plan on burning my own chips too but don't have the $$$ for the equipment right now, but I at least need the car to be drivable until i can afford a converter/chip.

IROCKZ4me

A higher stall won't help you here. There is something else wrong.
The 219 cam isn't that much of a cam. The converter isn't your problem

I'd be looking for a vacuum leak. That would be my first guess.
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Tracy /AKA IROCKZ4me
'86 IROC-Z Camaro
"Cogito ergo zoom"

• 355 cid
• AFR heads
• Arizona Speed & Marine hydraulic roller cam w/ AFR hydra-rev kit
• modified SLP runners
• TRW forged pistons/ceramic coated
• fully balanced
• Edelbrock headers/ceramic coated
• SLP cat-back
• Paxton supercharger
• Nitrous Express nitrous oxide

My IROC-Z
EFI Performance Club on Yahoo
Club IROC-Z


[This message has been edited by IROCKZ4me (edited March 06, 2001).]

TRAXION

If the shop isn't familiar with extensive EFI modification then they are just being stupid. Here is my bet....

They didn't open the throttle stop screw. With a bigger cam the throttle blades need to be opened more at idle because there is less vacuum to pull air in. Do you have the stock throttle body? If so, they will need to remove the plug that blocks access to the throttle stop screw. Set the TPS back to normal. Adjust the throttle stop to achieve 800 rpms.

However - this won't solve all your problems. You definitely need a custom chip that raises the idle AND ALSO resets the MAF error table. Most likely you will get codes that correspond to a MAF problem. Playing with the TPS can give a quick fix ... but, all of this should be done in the PROM.

Tim

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TRAXION's 1990 IROC-Z
Best Time = 12.244 @ 112.51mph (1.778 60' / 7.819@88.32mph in the 1/8)
All Natural. No Force. No Drugs. Stock Bottom End. Stock Body Panels.
Gunning for NA 11's with bigger cam, bigger stall, and bigger exhaust.
-=ICON Motorsports=-
Moderator: PROM board at thirdgen.org

Guido

Thanks Tim. I felt like calling the shop who has this guy's car and telling them how stupid they are.
Torque converter?



Good luck!

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-86 IROC
Vortech Supercharged 406
-=ICON Motorsports=-
"Well, you're equipped to be a prostitute, but you're not one, are you?"

Hank Brote

Tim's right...... You need to have the chip done and you need an idle of at least 750 RPM. I have the same set up as you and once the idle speed is corrected, along with the MAF you should be all set.

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Hank
87'IROC Z28
Hanks 87 IROC

TheFormula350

Thanks for all the help guys. I'm gonna have the shop set the TPS to .54 or .35 and use the throttle stop screw to raise the idle. LPE figured the .74 setting might be causing a rich condition. I really hope it's not a vacuum leak, i've already had to take it back to the shop once for that I'll definitely be taking my vacuum gauge to check that out. Hope the TPS/throttle stop screw adjustment solves it though, searching for vacuum leaks is NO fun. Thanks.

Matt
87 Firebird Formula 350