1999 LS1, low on power, rich on fuel, poor idle
05-12-2011, 07:37 PM
#1
Teching In
Thread Starter
Join Date: Apr 2011
Location: MA
Posts: 12
Likes: 0
Received 0 Likes
on
0 Posts
1999 LS1, low on power, rich on fuel, poor idle I picked up a previously swapped LS1 RX7 over the winter. when i test drove it, it drove great and ran smooth. It sat in the garage (stabil in the gas tank) for several months. Upon taking it out of storage, it ran fine for a day and the second day it felt sluggish, the throttle response was muted, it surged at idle, the idle was very rough and had an occasional knocking/tapping sound, and threw a few codes. P0327, P0140, P0500, P0650- I pulled the knock sensors and replaced them both and RTV'd the caps to keep water out. This has improved the idle but it still surges hard/almost dies after driving it and feels sluggish. The gas has been switched out for fresh 93, the air filter was cleaned/lightly oiled, the plugs were pulled and replaced with new plugs (most looked great, but rear passenger side was slightly oily/gassy), and of course the oil and filter were changed. the old oil came out reeking of gas and was very thin from the gas. The freeze frame from the current CEL's (P0140, P0500, P0650)are showing short term fuel trim 3 at -96.7% (long term 8.5%) and short term fuel trim 4 at -89.7% (long term 1.5%). All other fuel trims are 0.8% or less. The issue seems to be nonexistent when car is cold/first driven, but once driven/warmed up it gets worse and worse until it doesnt want to start.
I'm confused with the VSS error since both the tach and speedo work just fine and are being driven by the output of the PCM. The car was tuned via HP tuners and the P0140 should not be showing up since the rear o2 are turned off. The P0650 is being tripped because the MIL is disconnected at the moment while i switch from a column mounted light to using the RX dash MIL.
what fuel trims to 3 and 4 refer to since there are only 2 o2 sensors that determine fuel? car is definitely running super rich at idle/cruise, but seems to be more ok under throttle. do not have ability to log at the moment.
the motor is a 1999 Camaro LS1 with:
LS6 intake manifold
SLP adjustable timing chain
32lb injectors
lightened crank pulley
comp custom cut 228 234 cam 112+4
comp spring, pushrods and retainers
ported ls6 oil pump
port and polished TB
Stock exhaust manifolds
160 t-stat
any thoughts or suggestions on what to check would be highly appreciated.
car in question
I'm confused with the VSS error since both the tach and speedo work just fine and are being driven by the output of the PCM. The car was tuned via HP tuners and the P0140 should not be showing up since the rear o2 are turned off. The P0650 is being tripped because the MIL is disconnected at the moment while i switch from a column mounted light to using the RX dash MIL.
what fuel trims to 3 and 4 refer to since there are only 2 o2 sensors that determine fuel? car is definitely running super rich at idle/cruise, but seems to be more ok under throttle. do not have ability to log at the moment.
the motor is a 1999 Camaro LS1 with:
LS6 intake manifold
SLP adjustable timing chain
32lb injectors
lightened crank pulley
comp custom cut 228 234 cam 112+4
comp spring, pushrods and retainers
ported ls6 oil pump
port and polished TB
Stock exhaust manifolds
160 t-stat
any thoughts or suggestions on what to check would be highly appreciated.
car in question
05-12-2011, 09:13 PM
#4
Teching In
Thread Starter
Join Date: Apr 2011
Location: MA
Posts: 12
Likes: 0
Received 0 Likes
on
0 Posts
Have any recommendations on cleaner? I've heard very mixed reviews on cleaners. Some folks swear by them and others claim there is no benefit. I've had good luck in the past removing and cleaning injectors out of the car.
05-12-2011, 10:36 PM
#5
Staging Lane
iTrader: (3)
Join Date: Jan 2006
Location: Houston, TX
Posts: 73
Likes: 0
Received 0 Likes
on
0 Posts
I would see if your temperature sensor is reading right, My friends firehawk was having smiler issues. Was running super rich smelling of gas, few of the same codes, would just die if driven to long. After months of like WTF we found out it was reading -100 or something and it was fixed in 10min with a new sensor. Computer was just dumping more and more gas in it to try and warm it up when it didn't need it.
Last edited by NightKid#2; 05-12-2011 at 10:42 PM.
05-12-2011, 10:49 PM
#6
Teching In
Thread Starter
Join Date: Apr 2011
Location: MA
Posts: 12
Likes: 0
Received 0 Likes
on
0 Posts
Try the cleaner you've got nothing to lose by try it except $5.
I would see if your temperature sensor is reading right, My friends firehawk was having smiler issues. Was running super rich smelling of gas, few of the same codes, would just die if driven to long. After months of like WTF we found out it was reading -100 or something and it was fixed in 10min with a new sensor. Computer was just dumping more and more gas in it to try and warm it up when it didn't need it.
I would see if your temperature sensor is reading right, My friends firehawk was having smiler issues. Was running super rich smelling of gas, few of the same codes, would just die if driven to long. After months of like WTF we found out it was reading -100 or something and it was fixed in 10min with a new sensor. Computer was just dumping more and more gas in it to try and warm it up when it didn't need it.
05-12-2011, 11:05 PM
#7
Staging Lane
iTrader: (3)
Join Date: Jan 2006
Location: Houston, TX
Posts: 73
Likes: 0
Received 0 Likes
on
0 Posts
I'm talking about the coolent temperature sensor. 60f is way to low of a reading for coolent after it's been running. If that's the coolent temp, the coolent temp sensor is exactly what you need to replace.
Trending Topics
05-12-2011, 11:13 PM
#9
Staging Lane
iTrader: (3)
Join Date: Jan 2006
Location: Houston, TX
Posts: 73
Likes: 0
Received 0 Likes
on
0 Posts
Also all mention that the coolent temp sensor should be on the drivers side head towards the front. If the person that did the swap didn't know better and put it on the passenger side head, that will cause issues. It needs to be on the drivers side period.
05-15-2011, 08:05 PM
#10
Teching In
Thread Starter
Join Date: Apr 2011
Location: MA
Posts: 12
Likes: 0
Received 0 Likes
on
0 Posts
Swapped coolant sensor and ran cleaner. ran through about 1/2 the cleaner. still does not run right. tried pressure testing injectors and two seemed to seep a very small amount. however one injector launched with the clip still attached. going to send the lot to witchhunter and have them clean and test them.
05-15-2011, 08:27 PM
#11
Staging Lane
iTrader: (3)
Join Date: Jan 2006
Location: Houston, TX
Posts: 73
Likes: 0
Received 0 Likes
on
0 Posts
Did you get another computer read on the temp? Might be the sensor wire grounding out somewhere and not the sensor.
When you say it still doesn't run right does that mean something change but it still runs bad or it still runs the same?
If it got better but still not full right, I might say you destroyed your O2's with all that unburned gas.
How does the car run in open-loop with the MAF disconnected?
I'm not saying it's not the injectors but if it's running that rich and that temp reading was right I would still be looking at that.
When you say it still doesn't run right does that mean something change but it still runs bad or it still runs the same?
If it got better but still not full right, I might say you destroyed your O2's with all that unburned gas.
How does the car run in open-loop with the MAF disconnected?
I'm not saying it's not the injectors but if it's running that rich and that temp reading was right I would still be looking at that.
05-15-2011, 10:36 PM
#12
Teching In
Thread Starter
Join Date: Apr 2011
Location: MA
Posts: 12
Likes: 0
Received 0 Likes
on
0 Posts
Did you get another computer read on the temp? Might be the sensor wire grounding out somewhere and not the sensor.
When you say it still doesn't run right does that mean something change but it still runs bad or it still runs the same?
If it got better but still not full right, I might say you destroyed your O2's with all that unburned gas.
How does the car run in open-loop with the MAF disconnected?
I'm not saying it's not the injectors but if it's running that rich and that temp reading was right I would still be looking at that.
When you say it still doesn't run right does that mean something change but it still runs bad or it still runs the same?
If it got better but still not full right, I might say you destroyed your O2's with all that unburned gas.
How does the car run in open-loop with the MAF disconnected?
I'm not saying it's not the injectors but if it's running that rich and that temp reading was right I would still be looking at that.
Per the symptoms of a leaking injector on witchhunter it does sound like it:
Leaky injectors can cause:
- Hard starting, especially when hot
- Poor idle
- Emission problems
- Increased fuel consumption
- Exhaust odor
I have all those symptoms and the hard start especially when warm really struck a chord with me.
06-03-2011, 06:25 PM
#15
Teching In
Thread Starter
Join Date: Apr 2011
Location: MA
Posts: 12
Likes: 0
Received 0 Likes
on
0 Posts
Coolant temp sensor was replaced to no avail. Sent injectors to witchhunter and they found a leaky one. After cleaning it passed their testing. Put them back in and it drove great. Second drive and it was back to the same old issues. Pulling my hair out on this one. Beginning to wonder if their is something in the gas tank that is clogging the injectors.
06-03-2011, 08:51 PM
#17
Teching In
Thread Starter
Join Date: Apr 2011
Location: MA
Posts: 12
Likes: 0
Received 0 Likes
on
0 Posts
06-08-2011, 08:09 PM
#19
Teching In
Thread Starter
Join Date: Apr 2011
Location: MA
Posts: 12
Likes: 0
Received 0 Likes
on
0 Posts
M I. was more thinking small particles that could clog an injector that would make It past the filter.
What's the chance that this could be plug wires? It was 90+ out and the car had not been run yet still idled like crap. Was thinking that any heat may be causing me issues but no clue what it could be.
What's the chance that this could be plug wires? It was 90+ out and the car had not been run yet still idled like crap. Was thinking that any heat may be causing me issues but no clue what it could be.