I have a 86 trans am with a gutted cat. Can someone tell me why when u stand behind the car the smell causes your eyes to burn. Its so bad that u couldn't stand back there for long without passing the freak out! The cam is stock & everything internal has never been touched. the car runs very smooth with a slight bit of hesitation right after idle. The tpi seems to be okay, no check eng light codes. I also had a 83 Z28 with a holley carb setup & the car produced that same Very rich smell out the exhaust.I had to get rid of that car because it wouldn't pass emissions in NJ. U can check my sig. for the mods that are on the car, but I dont think that any of them would cause the car to run rich.
thanx in advance
njdaewoo

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86 Tramaro 90% Trans Am/ 10% IROC/Z (nose, hood,& fenders)
Trans Am Mods as of 1/10/01
3inch
T.E.S/Flowmaster setup,gutted cat,gutted maf,relocated mat,373 gears,upgraded factory chip,255 liter h/press. walpro f/pump & throttle body coolant bypass
njdaewoo@excite.com

 

relocated mat and tb coolant bypass.

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91 Formula
305 TPI 5speed
1LE/G92/WS6

Paxton SN92 polished kit, SLP airfoil, ported/polished plenum, March alt. pulley, Crane AFPR(43psi),Crane Gold 1.6rrs,MSD coil,MSD6AL (5400rpm limit),Holley 9mm wires,Ac delco R43ts plugs,stock chip,Ford SVO 24# injectors,Bosch O2sensor,SLP 1 5/8" headers,SLP catback,shortened shifter,3:73s w/Auburn posi,180* t-stat,JET 195* fan switch, Macewen white face gauges, Autometer gauges, Zoom hi-performance clutch.

 

Relocated MAT might one of the reasons, but I bet the biggest reason is the gutted cat. My car has stunk the same way and also burns your eyes since I gutted the cat, even when it was bone stock.
Rick

 

yeah the gutted cat would do it.

plus what is an upgraded chip? if it's aftermarket then it's probably way too rich considering the stock chip is way too rich to begin with.

 

The chip is just the revised edition (recalled on some 86 models) factory chip with the newer part # If the factory setup runs rich wouldnt it ruin the Cat?
Now I have a new problem!!!! my car dies when I let it idle. If I rev the motor too 3000rpm it slowly drops off rpm until it gets to about 900 rpm & then it sputters, races back up to about 2500 rpm, runs really rough, pops in the intake if i give it more throttle, then dies again!!! do any one have any Idea of what might cause this? Also, if the car is idling & snap the throttle open I can hear the valves rattle & then pick up speed and thats with no load on the motor in neutral!!!!!! the car has 12600 miles on the dash. do U think its the timing chain. the car is also all stock internally

 

It would be very hard to figure out without getting some scanner readings on the computer to see what exactly is going on.
One quick thing you might want to do is check the TPS sensor adjustment, and clean your IAC motor, removing the carbon from it.
Do you see black smoke when flooring it. This would be a sure sign of a rich condition.

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http://members.home.net/regulators/kevg.html
-=ICON Motorsports=-

 

From experience, it sounds like a dead O2 sensor. Replace it and see what happens.

 

Check your fuel pressure for the cause of your new problem. Speed run up then down and back up sounds pressure related. Possible pump or return line clogged.

 

The fuel pressure at idle is 36psi, when u hit the gas it jumps to 45psi, Ive notice that when the car sits overnight the fuel pressure remains at 41 psi the next morning! is this normal?

 

fuel pressure seems good. the o2 doesn't do jack under open loop control (first few minutes) maybe bad maf/cts/iat sensor(s)

Borrow a scan tool to see whats going on and change the o2 if you hadn't in the last 50k mi.

Hope it helps.... You can check these sensors with a digital vom but a scan tool is much easier..

 

How much do a scan tool cost? Whats a good brand to buy?

 

Gutting the cat will cause the exhaust to not get up to a hot enough temperature for the O2 sensor to begin operating, keeping it in open loop. Using a heated O2 sensor will speed it up into closed loop. The throttle body bypass will also throw readings off along with the MAT relocator. Al of these things will cause the car to run rich, especially in NJ. I had the same problem. Installed the heated O2 sensor, went back to coolant running through the TB and everything went fine. The past winter it ran like **** here in Roselle Park, very close to Newark. My car did the same, it would start up then die out. Start it up again and idle would be really rough, causing backfire when the throttle was depressed. After a while of warming up the car ran fine. I noticed that immediately when the car ran good it went into closed loop (via Auto X-ray). If you want to keep the gutted cat, MAT relocation and TB bypass, stock O2 sensor, I suggest you have the PROM reburned by Fast Chips and talk to Ed Wright. Let me know what happens. you could email me at JosephAndres@aol.com. I went throught the SAME EXACT THING YOU ARE GOING THROUGH!!

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1988 GTA 5.7L TPI Auto
355 ci. block,TPIS ZZ-9 Camshaft, SLP Headers, Borla Cat Back, B&M Holeshot 2400 Stall Converter, 3.73 Richmond Gears

"Why ride a stang when birds can fly?"

http://www.geocities.com/thegta

[This message has been edited by Joseph Andres (edited March 22, 2001).]

 

BTW I was running a cat before I put in the heated O2 sensor and it still ran rough. I believe that the cat does not make a significant difference. Now with the new heated sensor I can run a cat or not via exhaust cut out before the cat and it still runs fine.

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1988 GTA 5.7L TPI Auto
355 ci. block,TPIS ZZ-9 Camshaft, SLP Headers, Borla Cat Back, B&M Holeshot 2400 Stall Converter, 3.73 Richmond Gears

"Why ride a stang when birds can fly?"

http://www.geocities.com/thegta

 

How much are the autoxray scanners?