Running rich, rough idle. Help!!
Thread Starter
On The Tree
Joined: Dec 2009
Posts: 123
Likes: 6
From: Taipalsaari, Finland, Europe
Running rich, rough idle. Help!! Help would be much appriciated.
I have -01 LS1 on my -68 camaro. Just recently completed my swap. There are still lot to do, but engine swap part of the project is basically done.
Everything worked great from first start to about 200 miles. Then out of nowhere she started to stumble and it gets worst all the time. Now she is not driveable at all.
She is running rough. Rich, way too rich. Stumbles and dies easily. Difficult to get idle. Feels and acts like when having manual choke on with a warm carburated engine.
Checked on HP Tuners and showed +40% too rich. From idle on. Scan shows like o-sensors could not "follow".
Engine is stock 2001 LS1. "New" ported Jantzen TB on. That is OEM TB which has been cleaned, ported and polished. MAF is original. O-sensors are new Bosch ones. Plug wires are MSD ones. Exhaust is headers, no cats.
Fuel pump is new Walbro 255 inline and vette regulator is used.
I have done the following:
- tried another maf (original)
- tried another o-sensors (AC delco)
- checked vacuum leaks
- tried another plug wires (original)
- checked TB and IAC
Nothing helps and every checked/replaced part looks okay. I even had battery cables off for 3 days and tried again. Same symptoms.
I am lost, donīt know what to do.
Any ideas?
I have -01 LS1 on my -68 camaro. Just recently completed my swap. There are still lot to do, but engine swap part of the project is basically done.
Everything worked great from first start to about 200 miles. Then out of nowhere she started to stumble and it gets worst all the time. Now she is not driveable at all.
She is running rough. Rich, way too rich. Stumbles and dies easily. Difficult to get idle. Feels and acts like when having manual choke on with a warm carburated engine.
Checked on HP Tuners and showed +40% too rich. From idle on. Scan shows like o-sensors could not "follow".
Engine is stock 2001 LS1. "New" ported Jantzen TB on. That is OEM TB which has been cleaned, ported and polished. MAF is original. O-sensors are new Bosch ones. Plug wires are MSD ones. Exhaust is headers, no cats.
Fuel pump is new Walbro 255 inline and vette regulator is used.
I have done the following:
- tried another maf (original)
- tried another o-sensors (AC delco)
- checked vacuum leaks
- tried another plug wires (original)
- checked TB and IAC
Nothing helps and every checked/replaced part looks okay. I even had battery cables off for 3 days and tried again. Same symptoms.
I am lost, donīt know what to do.
Any ideas?
Is the PCM the 1 that was originally w/ the engine?
Any codes set?
Since you have HPT, if you can get it running, why not do a data log, and post it??
Are the IAT and coolant temps reading correctly? [Check cold and hot]
What does the MAP sensor read, key on/engine off?
Have you verified all grounds?
Have you checked fuel psi?
Exh leaks?
O2's "could not follow"???
O2 volts engine off, key on?
Any codes set?
Since you have HPT, if you can get it running, why not do a data log, and post it??
Are the IAT and coolant temps reading correctly? [Check cold and hot]
What does the MAP sensor read, key on/engine off?
Have you verified all grounds?
Have you checked fuel psi?
Exh leaks?
O2's "could not follow"???
O2 volts engine off, key on?
Check the IAT during a run scan. I remember the STFTs going mid 40's with the IAT unhooked
Next, check for a leaky injector(s)
If those are ok, have you done a crank relearn since installing the engine. It wont always throw the relearn code when it needs one and can seriously muck up how the car runs. You can do a search on my name for a detailed list of symptoms "Drivability issues"
Next, check for a leaky injector(s)
If those are ok, have you done a crank relearn since installing the engine. It wont always throw the relearn code when it needs one and can seriously muck up how the car runs. You can do a search on my name for a detailed list of symptoms "Drivability issues"
Thread Starter
On The Tree
Joined: Dec 2009
Posts: 123
Likes: 6
From: Taipalsaari, Finland, Europe
Thanks for all tips.
PCM is engine original and running ok. Fuel trim readings are odd. High peaks every now and then.
Just got a Snap On fuel pressure gauge from a shop, I will have to return it tomorrow morning. Reading at rail shows around 10 psi?! Isnīt that very low. I thought it should be around 50 psi. Am I right?
Maybe my vette filter/regu is blocked up or something. It was brand new WIX unit. I will have new AC Delco unit by tomorrow or so.
I was thinking to replace the filter/regulator and I have another set of OEM injectors which I will try on after replacing the FPR.
Will the vette regu/filter handle the pressure that Walbro 255 pump can produce?
Any ideas? What the reading at rail should be?
PCM is engine original and running ok. Fuel trim readings are odd. High peaks every now and then.
Just got a Snap On fuel pressure gauge from a shop, I will have to return it tomorrow morning. Reading at rail shows around 10 psi?! Isnīt that very low. I thought it should be around 50 psi. Am I right?
Maybe my vette filter/regu is blocked up or something. It was brand new WIX unit. I will have new AC Delco unit by tomorrow or so.
I was thinking to replace the filter/regulator and I have another set of OEM injectors which I will try on after replacing the FPR.
Will the vette regu/filter handle the pressure that Walbro 255 pump can produce?
Any ideas? What the reading at rail should be?
But at the same time you are running rich. Stuck injector?
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Thread Starter
On The Tree
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From: Taipalsaari, Finland, Europe
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Launching!
Joined: Sep 2008
Posts: 234
Likes: 0
From: Ashland,VA
well if the FTs are reading +40 then the PCM is adding fuel because it thinks its lean not rich. Is it actually rich ( smoking) or just running like crap from poss a lean condition? If the fuel press is at 10 PSI that would most deff explain why your FTs are at +40. If it were rich the PCM would be pulling fuel (-40) if the O2s are reading correctly.
Thread Starter
On The Tree
Joined: Dec 2009
Posts: 123
Likes: 6
From: Taipalsaari, Finland, Europe
well if the FTs are reading +40 then the PCM is adding fuel because it thinks its lean not rich. Is it actually rich ( smoking) or just running like crap from poss a lean condition? If the fuel press is at 10 PSI that would most deff explain why your FTs are at +40. If it were rich the PCM would be pulling fuel (-40) if the O2s are reading correctly.
It is not really smoking, just smelling heavily and running like crap.
Thread Starter
On The Tree
Joined: Dec 2009
Posts: 123
Likes: 6
From: Taipalsaari, Finland, Europe
Thread Starter
On The Tree
Joined: Dec 2009
Posts: 123
Likes: 6
From: Taipalsaari, Finland, Europe
10 psi is both on prime and when running. (If one can call it running)
Thread Starter
On The Tree
Joined: Dec 2009
Posts: 123
Likes: 6
From: Taipalsaari, Finland, Europe
Launching!
Joined: Sep 2008
Posts: 234
Likes: 0
From: Ashland,VA
Cool glad you got it straight. I had one in the shop the other day with a filter/reg that had almost 90 PSI at the fuel rail. that was a 4 cyl s10 haha. bad regulator was the cause for that as well. now you can enjoy it again. good luck.
