LS2 404 only trapping 92-93mph, with p0108& O2's not reading correctly...
05-31-2009, 04:27 PM
#1
LS2 404 only trapping 92-93mph, with p0108& O2's not reading correctly... Ok I guess I should start with a little background info first...Last year I installed a 403 LS2 I bought used. It had a custom 248/253 .615/.612 110 camshaft. Patriot stage III heads, Fast 90/90, pacesetter headers with TSP true dual kit. It dynoed 505 to the wheels, and would run 7.40's consitent with 1.70 60's. at 98mph. Well I dropped a lifter, and it ate the cam up, and messed the lifter bore up. So I had the motor freshened up with new pistons, and bearings.
Fast foward, and I have the car running again. But with the addition of a slightly larger Patrick G grind camshaft, FAST 92/92, and Kooks 1 7/8"-2" headers, to a kooks 3" y-pipe to a 4" mufflex. I haventt had it on the dyno yet, but the track times are pitiful. The best I have managed is a 7.77@93mph... The car is'nt leaving hard like it use to, and just feels sluggish. I had my tuner data log one of my passes last night, and it shwoing that my o2's are only working half the time, and its throwing a p0108 map high voltage code.
My question is this, would these codes make the car run this horrible at WOT? I thought the 02's didnt even read at wide open any ways...I'm just trying to figure out why the car is such a pig now.
Fast foward, and I have the car running again. But with the addition of a slightly larger Patrick G grind camshaft, FAST 92/92, and Kooks 1 7/8"-2" headers, to a kooks 3" y-pipe to a 4" mufflex. I haventt had it on the dyno yet, but the track times are pitiful. The best I have managed is a 7.77@93mph... The car is'nt leaving hard like it use to, and just feels sluggish. I had my tuner data log one of my passes last night, and it shwoing that my o2's are only working half the time, and its throwing a p0108 map high voltage code.
My question is this, would these codes make the car run this horrible at WOT? I thought the 02's didnt even read at wide open any ways...I'm just trying to figure out why the car is such a pig now.
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06-01-2009, 09:55 PM
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Did you look up the code and diagnose the problem with the MAP?
It screams vacuum leak, go to http://gearchatter.com and diagnose the problem.
It screams vacuum leak, go to http://gearchatter.com and diagnose the problem.
06-02-2009, 05:43 AM
#10
FIX THE CODE ISSUE, eliminate known problem first.
The MAP sensor is referenced by tons of tables in the PCM, if it is flaking out it will cause problems. Your tuner should have told you to fix it before it was ever tuned. Did your tuner log the data and review it to see what the MAP readings are or is he just a tuner who doesn't know how to diagnose problems?
No offense but these kind of questions drive me nuts because you know there is a problem, don't look into fixing it but still complain about the car running like crap. If you read these forums long enough you will see it too, people on here will take their car to a dyno and get a bad number and say "well I know the plugs, clutch and air filter are bad but I shoulda put down 500 rwhp like my buddy"
The MAP sensor is referenced by tons of tables in the PCM, if it is flaking out it will cause problems. Your tuner should have told you to fix it before it was ever tuned. Did your tuner log the data and review it to see what the MAP readings are or is he just a tuner who doesn't know how to diagnose problems?
No offense but these kind of questions drive me nuts because you know there is a problem, don't look into fixing it but still complain about the car running like crap. If you read these forums long enough you will see it too, people on here will take their car to a dyno and get a bad number and say "well I know the plugs, clutch and air filter are bad but I shoulda put down 500 rwhp like my buddy"
06-23-2009, 08:22 PM
#12
just because you cleared the code doesnt mean it still isnt a problem it takes a while sometimes to pop back up again, drive it hard several times like the night at the track and do it a couple days in a row and wait to see if it throws another code which it surely will if something is acting up. Sometimes it wont throw the actual ses light for a little while, its gay like that. good luck
06-24-2009, 11:19 AM
#13
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I would expect that big of a cam to maybe punk
it down low, but without a believable MAP input
the PCM has no chance of fueling properly. What
do your MAP readings look like at idle and WOT,
codes aside? And "not working" O2 sensors, what
does that mean anyway? Just you don't believe
the readings, or you know the readings to be wrong?
it down low, but without a believable MAP input
the PCM has no chance of fueling properly. What
do your MAP readings look like at idle and WOT,
codes aside? And "not working" O2 sensors, what
does that mean anyway? Just you don't believe
the readings, or you know the readings to be wrong?
07-03-2009, 10:36 PM
#14
I would expect that big of a cam to maybe punk
it down low, but without a believable MAP input
the PCM has no chance of fueling properly. What
do your MAP readings look like at idle and WOT,
codes aside? And "not working" O2 sensors, what
does that mean anyway? Just you don't believe
the readings, or you know the readings to be wrong?
it down low, but without a believable MAP input
the PCM has no chance of fueling properly. What
do your MAP readings look like at idle and WOT,
codes aside? And "not working" O2 sensors, what
does that mean anyway? Just you don't believe
the readings, or you know the readings to be wrong?
07-03-2009, 11:56 PM
#16
Well I never degree'd the cam. Just lined it up dot to dot. I'll try and get a graph up tomorrow. My tuner thinks that the cam has to much overlap and is causing a "reverberation effect", and screwing with the MAF. The MAF line he showed me was very jagged and not smooth like it's supposed to be. So maybe going to speed density will help?
07-04-2009, 02:11 AM
#17
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He's referring to reversion which is more a symptom seen at idle from big cams with a large amount of overlap. That can skewer MAF (and wideband 02) readings at low rpms. What are the specs on the new cam? Your previous cam had 30 degrees of overlap which is a lot. The WOT MAP reading is low for your setup. I don't see that exhaust as too restrictive, what was your previous setup?
07-04-2009, 03:46 AM
#18
I don't have the cam card in front of me so these numbers may be a little off, but very close. 254/257 .623/.623 111+2.
Old exhaust was pacesetter headers to the TSP true dual x-pipe/dynomax bulllets. I saws thread a while back where a guy gained 37hp through a cutout over the spintech muffler. So I installed a cutout, just to rule that out.
Old exhaust was pacesetter headers to the TSP true dual x-pipe/dynomax bulllets. I saws thread a while back where a guy gained 37hp through a cutout over the spintech muffler. So I installed a cutout, just to rule that out.
07-04-2009, 11:07 AM
#19
Also since you mentioned skewing wideband readings. I was also having a issue of my AF changing each pull. It would read 12.8-13.0 one pull, let it cool off for 5-10 minutes and make another pull it would read 14.0-14.2??? Any reason for that?
07-04-2009, 11:18 AM
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I don't have the cam card in front of me so these numbers may be a little off, but very close. 254/257 .623/.623 111+2.
Old exhaust was pacesetter headers to the TSP true dual x-pipe/dynomax bulllets. I saws thread a while back where a guy gained 37hp through a cutout over the spintech muffler. So I installed a cutout, just to rule that out.
Old exhaust was pacesetter headers to the TSP true dual x-pipe/dynomax bulllets. I saws thread a while back where a guy gained 37hp through a cutout over the spintech muffler. So I installed a cutout, just to rule that out.
Have you tried running the car with the cutout open? I'm not familiar with the Spintech muffler, so I can't say how good or bad it is. I run QTP 1-7/8" headers, 3" Y/Flowmaster merge to a Hooker catback and saw very little gains at the track with the exhaust uncorked at the Y.
BTW - What is the MAP reading at idle?