Jump to content
HybridZ

LS1 Misfire & flat spots.. Lean running?


Recommended Posts

Question for you guys running LS1s, did your computer require re-programming beyond the base changes to allow it to run in the swapped car?

My setup is a stock 2000 Camaro LS1, emissions deleted in the computer, intake and airfilter setup like the LS1 page on JTR, MAF has been de-screened and ends polished up a bit, sanderson headers into 2.5 in. then a Y to 3 in. pipe to a Flowmaster 40 delta.

The problem I have is under maybe half to full throttle I get lean pops (that's what they sound like) out the exhaust, flat spots and some studdering in the powerband from about 2k to maybe 3.5k rpm.

It's obviously not pulling like it should be in that range.

I don't have tuning software yet, I was going to be ordering HPtuners but wanted to wait a bit, thought I'd be able to drive it as is without additional tuning.

Has anyone else run into this with a stock motor swap with these minor mods?

Should this run well as is (assuming there are problems with any parts)?

I thought the computer could accommodate for these minimal mods.

Any input would be appreciated.

Link to comment
Share on other sites

Question for you guys running LS1s' date=' did your computer require re-programming beyond the base changes to allow it to run in the swapped car?

My setup is a stock 2000 Camaro LS1, emissions deleted in the computer, intake and airfilter setup like the LS1 page on JTR, MAF has been de-screened and ends polished up a bit, sanderson headers into 2.5 in. then a Y to 3 in. pipe to a Flowmaster 40 delta.

The problem I have is under maybe half to full throttle I get lean pops (that's what they sound like) out the exhaust, flat spots and some studdering in the powerband from about 2k to maybe 3.5k rpm.

It's obviously not pulling like it should be in that range.

I don't have tuning software yet, I was going to be ordering HPtuners but wanted to wait a bit, thought I'd be able to drive it as is without additional tuning.

Has anyone else run into this with a stock motor swap with these minor mods?

Should this run well as is (assuming there are problems with any parts)?

I thought the computer could accommodate for these minimal mods.

Any input would be appreciated.[/quote']

 

 

My setup is just like yours. I had similar problems with mine, popping and studdering. I had some minor exhaust leaks that were causing the problem. Once we replaced the collector gaskets with copper ones the problem was fixed.

 

I hope yours is that easly to fix too.

Link to comment
Share on other sites

Thanks for that, hopefully that's it.

Oddly enough yesterday it blew out one of the collector gaskets .

The car has only been driven maybe 40 miles total but hopefully that was the cause the whole time.

It doesn't do it when sitting still and revving up but it's had the problem the whole time it's been driven.

That was about the only part I didn't actually bolt on myself, the muffler shop did it and probably didn't use the best quality ones.

Link to comment
Share on other sites

Because the collector flange on the Sanderson headers is loose it makes it hard to get it to seal up. I have gone to the soft aluminum gaskets on mine. They will stay tight for about 500 miles now instead of 50. Maybe this next tighten up session (this weekend) will secure them on finally.

Link to comment
Share on other sites

Yup... What I do is start it cold, and use my hand around the joints and connections to "feel" leaks. However, with the situation described above, the leak is only under load... That won't work with my way of checking.

 

Other things to check: MAPP sensor is notorious for getting hit and damaged when motors are pulled. check it with an Autotap for codes.

 

Descreening the MASS... Everyone I know who has done that has had to retune with LS1edit

 

Plug wires can also cause this. A faulty plug wire will start to suffer spark loss under load at full operating temps.

 

Good luck.

Mike

Link to comment
Share on other sites

Pulled the plugs last night as I've read on LS1Tech that a cracked plug could cause something like this but no luck, they were all good.

Pulled what was left of the collector gaskets last night one blew out completely, the other was in 3 pieces.

Start with the gaskets and wanted to do larger plug wires anyway.

Might have to buy myslef HPtuners for christmas...

Link to comment
Share on other sites

Just replaced the collector gaskets and took a spin but it's still running off a bit.

I've read on LS1tech that it can go either way with the MAF, so tuning software it is.

That's fine, I planned on getting it at some point, this just accelerates the timeline a bit.

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
  • Create New...