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Old 01-22-2009, 12:14 PM   #26
doubledribble
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You might have me there, this is the first time i've checked the service manual...

8/10 meaning .0079/.0098in

From the discussions I've had with Ken, I was told that factory specs were .010/.015in.

I'm now confused myself.

Quote:
Originally Posted by fastenova View Post
I'm truly lost. I'm looking at the FHI factory service manual and it clearly says that valve lash for the 2.5L DOHC motor should be:

Intake: 0.20 0.02 mm (0.0079 0.0008 in)
Exhaust 0.25 0.02 mm (0.0098 0.0008 in)

I don't know what you mean by 10/15 or 8/10. When I called Jon and specifically asked what I should set valve lash at, he told me factory spec. I verified that he meant .20 and .25 mm for intake & exhaust respectively and he said that was correct.

EDIT: I checked the MY2000 FSM (SOHC 2.5L) as well, and the lash specs are the same as they are for DOHC - .20 and .25 mm.

Aaron
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Old 01-22-2009, 12:41 PM   #27
fastenova
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I got a check engine light again, Cyl 1 misfire, and so I hooked up my OBD2 scanner and watched the live values. I noticed that when it was hunting for idle, as it hit the bottom of the rev band the front o2 sensor was dropping to zero, which I believe indicates a lean mixture. I grabbed my S-AFC Neo and modified the air map to +2% MAF signal at 700RPM and <20% throttle, and it seemed to smooth out the idle. It was previously set to 0.

While I don't have any way to change my idle, I may get my good friend to watch the front o2 readings while I'm driving around and see if I can play with the map a bit to get things right in the middle. I am also thinking a LOT more about getting a wideband o2 sensor for the front because that will really enable me to tune the fuel/air maps better.

I can't verify that this is a permanent fix for my problems yet as I haven't had enough time in the car, but I think it may be a step in the right direction. I had kind of forgotten about the ability to modify the MAF signal...

I'll update as I get more miles on the car.
Aaron
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Old 01-22-2009, 03:41 PM   #28
GrimmSpeed
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Well atleast its a step in the right direction!

Mike
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Old 01-22-2009, 03:45 PM   #29
fastenova
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By the way, Mike, I have your 8mm intake spacers installed, and the old OE gaskets were baked on pretty good. I used a gasket scraper and they cleaned right up. The finish on them is great, and I haven't had any problems getting them to seal up right on any of the three motors that have been in the car! Thanks to you and Justin, and everyone else there at GrimmSpeed, for a durable and well-engineered product!
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Old 01-22-2009, 04:33 PM   #30
GrimmSpeed
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Haha glad you like them! Its good to know they're standing the test against time/abuse.

I can't believe i dont have them on my personal car yet haha.. some day.

Mike

Quote:
Originally Posted by fastenova View Post
By the way, Mike, I have your 8mm intake spacers installed, and the old OE gaskets were baked on pretty good. I used a gasket scraper and they cleaned right up. The finish on them is great, and I haven't had any problems getting them to seal up right on any of the three motors that have been in the car! Thanks to you and Justin, and everyone else there at GrimmSpeed, for a durable and well-engineered product!
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Old 01-26-2009, 10:45 AM   #31
fastenova
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So I just wanted to update - I've got 500 miles on the motor now, thanks to a trip to the coast this weekend... Drive was nice, a fair amount more power, torque was great going up hills in 5th gear. Motor has definitely smoothed out a lot. I got 25 mpg and drove it pretty fast - 70-75 on the interstate and mostly 60-65 on the highway. I wasn't too light with the throttle but I also wasn't on it all the time. Overall, the fuel economy hasn't really changed.

Cold starts are still pretty rough, but I don't think that will change. Once the motor is warmed up, it idles decent, but still revs up and down a little. After talking a bit with Jay Storm, I may work on bumping up my idle a little bit to help cold starts and general idle quality. I may also just pull out my "Check Engine" light because I'm getting tired of it starting at me! It usually comes on 100 or so miles after I clear it (always misfire codes). Since it's currently showing a false positive I don't see any issue with pulling the bulb and just checking the codes every couple weeks.

I just switched out 5w30 dino for 5w30 full synthetic. First filter change (at 20 miles) yielded a high amount of metallic content; second filter change with fresh oil yielded almost none, so I think break-in went well. Feels like the rings are fully seated.

As an aside, synthetic oil has gotten very expensive! I run Castrol most of the time and it was $8.00 a quart! It seems like a couple of years ago it was $5-6 a quart. =\ Oh, the things we do for the cars we love...

Aaron
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Old 01-27-2009, 11:29 AM   #32
calgearhead
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Good to hear it's workin for ya. I think I will DEFINITELY be cammin' my 98 when I blow the motor and very glad to hear the fuel economy is the same as I have currently.
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Old 01-27-2009, 12:55 PM   #33
fastenova
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So I've had a CEL on for ~150 miles or so. I noticed some 'surging' going up hills in fifth at about 2700 RPM / 65 MPH. Not sure if this is fuel related or not, if I downshift into fourth gear, putting me at 3500 RPM, it goes away completely. Also does it at slower speeds too. I will reset the CEL today and see if that makes the surging go away. I'm wondering if the ECU is 'learning' to be bad?

I am also wanting to look at getting a wideband o2 sensor so I can see what my AFR is looking like. While the only means of 'tuning' I have right now is my AFC, I can definitely make adjustments for open loop.

Can anybody tell me more about how modifying the MAF signal in closed loop would affect the rest of the fuel map? This is a 1997 ECU. I've read that MAP-based ECUs can learn around piggyback controllers after a short period, but that MAF-based ECUs aren't as prone to this problem. I'm wondering if the idle adjustments I made are affecting the rest of the factory fuel maps...

Aaron
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Old 01-27-2009, 03:40 PM   #34
doubledribble
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fastenova-

just got my car back with the mild grinds (1000)...no cel so far, slightly lumpy idle at times not much worse than before. haven't really laid into it yet, but it seems to have smoothed out the powerband some. i was hoping to eliminate some of the bucking i get from letting off the throttle, but that is still there...had GroupN engine mounts installed at the same time. no substantial increase with NVH.
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Old 02-05-2009, 04:24 PM   #35
Ninja007
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Quote:
Originally Posted by doubledribble View Post
i was hoping to eliminate some of the bucking i get from letting off the throttle, but that is still there...had GroupN engine mounts installed at the same time. no substantial increase with NVH.
Thats good to hear about the GroupN mounts - I have a set waiting to go on. About the bucking from throttle let off.... that is your drivetrain moving back and forth... get some poly bushings for your diff and a group N tranny mount and that should decrease substantially.
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