Okay, for those who remember I posted a while back about a chugging problem I was having on my 87 IROC. Well, I just got done with my LT4 HOT Cam swap and its still chugging. I replaced the O2 sensor, plugs, cap, rotor, timing chain and my base timing is set at 6*. What the car will do is sorts of chug and hop through the RPM range. Its not as bad at the higher RPMs than it is the lower ones. It also seems to run worse going up hills. Another problem that goes along with it is that under WOT there is a popping sound comming from the engine bay. A few people told me to check my wires for any burns and their are a few, but I wrapped them with electrical tape, could that be it? Or I was also told maybe a clogged catalytic converter? Or could it be somthing else? Thanks for the help!

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1987 Chevy Camaro IROC-Z
L98 TPI 350 (5.7L)
TH 700R-4 Transmission
Borg Warner 7.75" 9 Bolt Rear End

Current Mods: LT4 Hot Cam, Comp Cams 1.52:1 Roller Rocker Arms, Edelbrock TES 1 5/8" Headers, Hooker 3" Aerochamber Cat-Back System, Performance Resource Chip, Accel Ignition Coil, Cap, Rotor, 8.8mm Wires, K&N Filters, JET TPI Air Foil, All Free Mods, Falken ZIEX Z-Rated Tires.

Best ET (w/o LT4 cam): 14.32 @ 97.7mph
(corrected for elevation)

7.5" 10 Bolt with 3.42s soon to come!

 

By the way, the problem started before the cam swap.

 

Check your MAF sensor. If you have a Scan Tool you can diagnose the problem more easily.


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Gunmetal 89GTA T-Tops L98
700R4 with 3.27 gears, street tires
Best 60 ft: 1.996
Best 1/8th mile: 9.02 @ 76.5mph with 60' time of 2.14
Mods: air filter, hypertech chip, 3" exhaust (no cat.)
Current Mods: 8.8wires, cap, rotor, +4 plugs, MAF screens, Servo, custom Ram Air, TPIS air foil, and some tuning

Going to the track this weekend...hopeful for improvements.

 

If the wires were burned get new plug wires. Eletrical tape provides little insulation and even less protection against heat which could cause it to ground somewhere else on the engine (if this was causing the problem, you'd see melted/burned pieces of tape. I would replace them anyhow because they sound rather old). Could be a clogged cat and if I were you I'd research the high load popping (is it pinging?) Did you unplug the brown? wire on the distrib to time it correctly?

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1984 WS6 Trans Am Hartop
Former L69 Car under restoration
1984 Trans Am T-tops
4-bolt main 350, performer intake, headers, Holley 650, T-5, hayes clutch, dual elec. fans and 3.23's.
Daily driver and restoration
13.98 @ 101

 

The MAF sensor is new, so is the ECM, started, alternator, battery, fuel pump, head gaskets. There are no codes what so ever either.

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1987 Chevy Camaro IROC-Z
L98 TPI 350 (5.7L)
TH 700R-4 Transmission
Borg Warner 7.75" 9 Bolt Rear End

Current Mods: LT4 Hot Cam, Comp Cams 1.52:1 Roller Rocker Arms, Edelbrock TES 1 5/8" Headers, Hooker 3" Aerochamber Cat-Back System, Performance Resource Chip, Accel Ignition Coil, Cap, Rotor, 8.8mm Wires, K&N Filters, JET TPI Air Foil, All Free Mods, Falken ZIEX Z-Rated Tires.

Best ET (w/o LT4 cam): 14.32 @ 97.7mph
(corrected for elevation)

7.5" 10 Bolt with 3.42s soon to come!

 

Sorry to hear about the problem and not having any help for the problem since i am having the same problems myself. Or so it seems anyways.
It will chug and jerk around 2500 or so sometimes but not all of the time. But once you hit like 3000+ it is definatly flying by then. It doesn't do it all of the time either.
Very odd. Hope you figure this out. I'm looking for ideas also.

Brendan

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1987 IROC-Z L98,SuperRam,EB 6085's,LPE 219/219 Roller, Crane 1.6RR, EB TPI Base, 58mm TB, ADS 24#, AFPR, K&N, EB TES, Catco Cat, 3" Borla Cat-Back, Accel cap,rotor,distro/other crap, MSD 6AL, MSD Blaster 3, Aluminum DS, 94 Disk Rear, Adjustable Valve, Precision 3.73 Gears, Sub-Frame Connectors, Hotchkis Lower Control Arms, KYB Shocks/Struts, Suspension Techniques Lowering Springs, Polyurethan Bushings all over the place, Moog Upper/Lower Ball joints and Tie Rods ends/Idler Arm,

To see the ROC, Check out the webpage Here

 

btt

 

I'm thinking maybe EGR problems?

 

How hard/expensive would that be to fix?

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1987 Chevy Camaro IROC-Z
L98 TPI 350 (5.7L)
TH 700R-4 Transmission
Borg Warner 7.75" 9 Bolt Rear End

Current Mods: LT4 Hot Cam, Comp Cams 1.52:1 Roller Rocker Arms, Edelbrock TES 1 5/8" Headers, Hooker 3" Aerochamber Cat-Back System, Performance Resource Chip, Accel Ignition Coil, Cap, Rotor, 8.8mm Wires, K&N Filters, JET TPI Air Foil, All Free Mods, Falken ZIEX Z-Rated Tires.

Best ET (w/o LT4 cam): 14.32 @ 97.7mph
(corrected for elevation)

7.5" 10 Bolt with 3.42s soon to come!

 

It sounds to me like the EGR or EGR Vacuum Soleniod. I've been having the same problems with my car. When it's cool outside it's really bad. First start it doesn't idle like normal. It acts like a vaccum leak. I took mine to my mechanic and he said it was the EGR vacuum solenoid and EGR valve. I replaced the EGR solenoid myself, was very easy and cost about $55.00 at AutoZone. Replacing the EGR solenoid didn't fix the problem so next going for the EGR. I haven't had time to replace mine yet but I picked up the part at Autozone for $50.00. Replacing the EGR valve on a TPI requires removing your intake so it may take some time. There was a link I had found to check your EGR valve and Solenoid. I'll see if I can find it and post it.

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'87 Trans Am
305 TPI:
160 Degree Theremostat
Accel 300+ 8.8 Racing Wires
Accel Super Coil
Bosch Spark Plugs
Custom Ram Air with K&N

 

Here's the link https://www.thirdgen.org/newdesign/t...diagnose.shtml

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'87 Trans Am
305 TPI:
160 Degree Theremostat
Accel 300+ 8.8 Racing Wires
Accel Super Coil
Bosch Spark Plugs
Custom Ram Air with K&N

 

my car does the same thing as Ierich(sorry if I spelled it wrong). But my car put out a code 33.

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88 iroc
LB9 305 tpi
k&n, flowmaster, ADS chip
160* thermostat
home made ram air
removed smog pump
TB bypass
ASCD big block hood

 

Two words....FUEL PUMP!

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1986 Trans Am
305 TPI
"If it's not one thing, it's another!"
http://www2.hanover.edu/hierlmeier

 

It seems that I am in the same boat as a bunch of other people. I took my car out for a nice long drive yesterday and when I am cruising at any RPM's between 1500-2500, the engine loses power. No codes, nothing.
I ran it with a Snap On 2500 in road test mode for about 50 miles and that didn't pull any codes either.

I have a new FPR diaphram, new MAF, new engine, TPS, and lots of other new stuff.
It's not the EGR cause I have a ZZ4 engine with aluminum heads - no EGR ports. I also have the EGR disabled in the EPROM, running a modified ARAP bin.

So why would this be a fuel pump? The first indication that the fp is crapping out is a loss of power at WOT, right?

my fp gauge says 45 PSI when I turn the key on, and it takes about a 1/2 hour to bleed down.

It's starting to **** me off. Maybe I should put in a new fuel pump just to eliminate the chance that it is the problem...

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89 Firebird Formula
WS6 package,ZZ4 Crate engine
SLP 58MM TB, Edelbrock TES Headers
Random Tech 3" cat, SLP 3" stainless exhaust
9 bolt rear, Hotchiss swing arms, Lakewood panhard rod
Corvette 2/4 servo, kevlar band, full poly rear.
Centerline 16x8 rims, B.F Goodrich drag radials