problem really bothering me
Thread Starter
Burning Brakes
Joined: Nov 2004
Posts: 1,107
Likes: 0
From: RI
problem really bothering me
93 LT1
Here's the situation....
The car takes a few seconds to start. It turns over fine. Second, when at operating tempor just about (189), theres a small stumble upon acceleration around 1800-2000 rpms. Third, the car sometimes stalls when stoppingor with the clutch pushed in. Its happened only when warm. Rev it up a bit and its fine.
Here's what the car has...
new filter, cleaned injectors, normal psi at the fuel rail (39 in ign.), SW headers, Bullet cats, 3" B&B exhaust with resonator, MSD ignition, MSD wires, MSD coil, new plugs, PCM chip.
Possible causes?
bad fuel pump, bad regulator, needs heated O2 sensors, bad IAC
I'm getting it scanned for codes tomorrow.
Here's the situation....
The car takes a few seconds to start. It turns over fine. Second, when at operating tempor just about (189), theres a small stumble upon acceleration around 1800-2000 rpms. Third, the car sometimes stalls when stoppingor with the clutch pushed in. Its happened only when warm. Rev it up a bit and its fine.
Here's what the car has...
new filter, cleaned injectors, normal psi at the fuel rail (39 in ign.), SW headers, Bullet cats, 3" B&B exhaust with resonator, MSD ignition, MSD wires, MSD coil, new plugs, PCM chip.
Possible causes?
bad fuel pump, bad regulator, needs heated O2 sensors, bad IAC
I'm getting it scanned for codes tomorrow.
Burning Brakes
Joined: Aug 2004
Posts: 1,174
Likes: 125
From: Dunstable MA
St. Jude Donor '05
I just got my 87 back from the mechanic. It was sometimes hunting for idle, sometimes having power surges under throttle, and sometimes throwing code 33 (MAF circuit). I first started having problems with it last year when it would sometimes stall if I lifted off the throttle. I replaced the MAF relays, and the problem took a vacation and then came back ... sometimes. I ran with the MAF disconnected for a few weeks this year and decided to let a trusted pro work on it. He saw that the O2 sensor and coolant temp sensor were both reporting slightly out of range, and replaced them. I saw nothing in the Helms to send me in that direction, but that is what did the trick. There is so much stuff in these cars, it really takes a trained person with the right diagnostic tools ... er ... sometimes.
It sounds like you are on the right track: Fuel Management. Good luck with it.
BTW, I notice you are in N. Smithfield. I work in Cumberland, and the guy who solves my mysteries is Ken at Smithfield Imports Auto Service in Greenville (401/949-3910). He has worked on my baby (successfully) for the last six years.
It sounds like you are on the right track: Fuel Management. Good luck with it.
BTW, I notice you are in N. Smithfield. I work in Cumberland, and the guy who solves my mysteries is Ken at Smithfield Imports Auto Service in Greenville (401/949-3910). He has worked on my baby (successfully) for the last six years.
Last edited by Rich Silvestris; Apr 27, 2006 at 08:56 AM.
Thread Starter
Burning Brakes
Joined: Nov 2004
Posts: 1,107
Likes: 0
From: RI
I do alot of construction work in cumberland and lincoln. If my mechanic can'tfind anything, I'll be sure to give him a call.
thanks.
btw... I have replaced the O2 and waterpump temperature sensors
thanks.
btw... I have replaced the O2 and waterpump temperature sensors
Team Owner
Joined: Aug 2000
Posts: 40,156
Likes: 45
From: San Pedro CA
The stalling makes me think IAC.
The 1800 RPM stumble makes me think Opti.
His is a Speed Density (MAP) car, so that doesn't count...
Any codes? Have you hooked a scanner up to see what all is happening.
Are the wires all firmly installed? A slightly weak connection can lead to a load biased miss.
The 1800 RPM stumble makes me think Opti.
His is a Speed Density (MAP) car, so that doesn't count...
Any codes? Have you hooked a scanner up to see what all is happening.
Are the wires all firmly installed? A slightly weak connection can lead to a load biased miss.
Burning Brakes
Joined: Jun 2005
Posts: 861
Likes: 1
From: Hyde Park NY
St. Jude Donor '05
Thread Starter
Burning Brakes
Joined: Nov 2004
Posts: 1,107
Likes: 0
From: RI
brand new EGR valve. I brought it to my mechanic today. He hooked it up to the scanner and we went for a ride. No codes and everything looked good. O2 sensors were reading good and he said the stumble felt like it was a misfiring cylinder. I assured him that I firmly put the plugs boots on. But I will check once again. Is there a way to detect a cylinder misfire? The scanner didn't have the option. The opti is brand new so I sure as hell hope its not that. Could the MSD ignition throw something off? Only other thing I can think of is a bad ECM.
