Another "won't rev past xxxx" thread. Ive tried everything...

[RVaillant]

remove the o2 sensor and see if it still does it. that will rule out your plugged cat/exhaust.

the coil resistance is interesting. dont have any extras? did you only measure one side? there's a primary and secondary side of a coil.

good thinking. An improvement on that would be to disconnect the exhaust after your downpipe, before the cat and rest of the exhaust, while keeping your o2 installed, preventing a code from open-airing your o2. this would also keep the proper cross sectional surface area of the "hole" in your exhaust, and would really show if your exhaust was restricting.

Let us know how it goes, this sounds like its going to be interesting.

[eazyduzit509]

Ive tried unplugging the 02 sensor, not only did it not throw a code but it still ran the same. i do get horrible gas millage but i think its cuz its not tuned yet. as for the rocker assembly, the the first time i put my cam in, it took me 10 hrs, this last time it didnt even take me 1.5 hours. the first time i did have a hell of a tining the ro assembly, the dizzy diznt want to go in. this time everything lined up beautifuly with no problems, but i will check it. i just bought a new coilso i will trim posting on my phone so for some reason the spelling is kina fucked up. i'll let yall know! thanks.

[fatboy1185]

How's your battery? A weak battery can cause issues like this, and you turning on your AC and experiencing even more issues means it could be a weak battery.

[eazyduzit509]

How's your battery? A weak battery can cause issues like this, and you turning on your AC and experiencing even more issues means it could be a weak battery.

Battery is less than 6 months old. Its an interstate, and has a 10 year warrenty so it better be good. Car sits at about 13 volts after its turned off, and is at 14.2 (give or take) when idleing. So the alty and battery are good.

Update Just put new coil in, did NOTHING... Unplugged 02 sensor for 15 minutes (10 miles) did nothing, didnt even throw a code. All i know is im getting horrible gas millage (like 15-20 im gonna guess) had full tank with 23 miles on tank, within 410 miles of that tank, ive ADDED $31 of premium fuel ( $3.40 a gallon, 9 gallons) and ive only gone 400 miles on 1.5-2 tanks of gas. Before my bigger mods, i use to be able to go further than that on 1 tank! ughhh, i know i need the tune but it needs to be fixed first.

Im runnin outa ideas guys, Im pretty sure i did the timing check right, i mean basically if #1 cyl is at TDC, cam pulling is pointing up and spark plug rotor is at #1 then its gotta be perfect right??? I put my dipstick in the #1 cyl to double check it with the flywheel mark (which dosnt say TDC i just assume it is cuz it lined up with everything else). Someone tell me im doin something wrong here. Other than crank and tdc sensor (whole dizzy) ive basically tried everything... Unless my injectors are magically F'd up for some reason, or theres some fuel leak somewhere. I could check my cat tomorrow, but im not sure why i'd be that clogged if it was at all, i'll just unbolt it and rev it to 6k and see what it does. Ive never had a problem go unsolved for this long.

Hang in there everyone, shoot me ideas...

[RVaillant]

Battery is less than 6 months old. Its an interstate, and has a 10 year warrenty so it better be good. Car sits at about 13 volts after its turned off, and is at 14.2 (give or take) when idleing. So the alty and battery are good.

Update Just put new coil in, did NOTHING... Unplugged 02 sensor for 15 minutes (10 miles) did nothing, didnt even throw a code. All i know is im getting horrible gas millage (like 15-20 im gonna guess) had full tank with 23 miles on tank, within 410 miles of that tank, ive ADDED $31 of premium fuel ( $3.40 a gallon, 9 gallons) and ive only gone 400 miles on 1.5-2 tanks of gas. Before my bigger mods, i use to be able to go further than that on 1 tank! ughhh, i know i need the tune but it needs to be fixed first.

Im runnin outa ideas guys, Im pretty sure i did the timing check right, i mean basically if #1 cyl is at TDC, cam pulling is pointing up and spark plug rotor is at #1 then its gotta be perfect right??? I put my dipstick in the #1 cyl to double check it with the flywheel mark (which dosnt say TDC i just assume it is cuz it lined up with everything else). Someone tell me im doin something wrong here. Other than crank and tdc sensor (whole dizzy) ive basically tried everything... Unless my injectors are magically F'd up for some reason, or theres some fuel leak somewhere. I could check my cat tomorrow, but im not sure why i'd be that clogged if it was at all, i'll just unbolt it and rev it to 6k and see what it does. Ive never had a problem go unsolved for this long.

Hang in there everyone, shoot me ideas...

on a stock ecu, unplugging the O2 would for sure bring up an error code when the coolant temp sensor kicks it into closed loop (for sure after 10 mins of driving). maybe THAT has to do with your modified ecu. But I don't think thats where your "limiting" problem is.

With the car in neutral, does it only still rev to 6000rpm?

I really believe you have a restriction to airflow somewhere in the system.

Something in the intake, exhaust or a valvetrain issue.

Unbolting the exhaust before your cat and revving the engine won't take you long, and if anything it will tell you your problem isn't there.

Goodluck!

[eazyduzit509]

on a stock ecu, unplugging the O2 would for sure bring up an error code when the coolant temp sensor kicks it into closed loop (for sure after 10 mins of driving). maybe THAT has to do with your modified ecu. But I don't think thats where your "limiting" problem is.

With the car in neutral, does it only still rev to 6000rpm?

I really believe you have a restriction to airflow somewhere in the system.

Something in the intake, exhaust or a valvetrain issue.

Unbolting the exhaust before your cat and revving the engine won't take you long, and if anything it will tell you your problem isn't there.

Goodluck!

Not sure why it didnt throw a code, but when its out of gear, yes it revs to 6k and stops... This engine has never seen more than 6k at any point, no matter what. It does sound like a restriction almost, cuz as i said, it pulls to 55 or so, then gets kina slugish almost like it cant breath and stops at 6k HARD. The car sat for a month, but i had paper towels in the header to make sure no debre fell in (yes i took the towels out).

We need more people on this case! Wheres deev hiding?

[eazyduzit509]

Update

Unbloted cat, did nothing... Checked rocker assembly for alignment, looks great. Re-checked timing, and have a few pictures of the TDC points alighning... 02 sensor is disabled threw chipped ecu.

Heres a few pics of my timing, i alighned the mark on the flywheel and this is what i got. The ingraved mark on the flywheel is the only one like it. There was no 15* timing mark like on the stock flywheel so i lined them up before putting it in and marked the 3 points with a paint pen. I might add that when i check the timing with a light, the 15* mark is about 15* away from the block marker (few inches above marker) and when i put a vaccum gauge on my intake manifold to test engine vacuum at idle i only got about 15-17 psi, with my last engine i checked it and got about 23-25. So to me it reeeealy sounds like my timing is off mabey a tooth or two, but for some reason its tricky for me to diagnose this for sure. And basically if i hold the rpms steady at 2,000, 2,500, 3,000 and so forth i can hear the engine missing.



















BELLOW is what happens when i line up my 15* mark with the block pointer...



(the screw drive is showing where the sapposade TDC mark is, in coralation with the 15* marks in yellow just bellow.)

[nine_deuce]

Could a damaged map sensor cause this? I remember when we pulled the motor, the box that the map sensor is in got broke, not sure if it affected anything inside the box, any plugs or any hoses.

[eazyduzit509]

Anyone? should i try moving the belt a tooth and see if thats it? But which way...

[wed3k]

i personally wouldnt touch the physical timing. id recheck your chipping. im not sure why o2 is disabled unless it runs off one preset map.

[eazyduzit509]

Ive been talking to my ecu/chipping sapply'er, he said when his tuner dynoed a 272 it ran better withought the 02 sensor, and the 02 made little difference in the overall operation and didnt adjust the MAP barely at all. And as i said, ive put the stock ecu in several times and the same problems persist...

When the cars cold, it kicks and misses pretty bad, it dosnt sound very healthy, still pulls decent but not at all like its capable of... Other thoughts still on mind are TDC sensor, crank sensor and possibly MAP, we cracked the black casing around the MAP but everything inside looks normal and intaked so i wasnt really worried about it.

[eazyduzit509]

Anyone notice anything weird in the 5th picture?

[CB7LX93]

You mentioned that you had the rocker arm assy. off a couple of times...
Did you re-adjust your valve lash after reinstalling the rocker arm assy.?
Mis-adjusted intake and/or exhaust valves can definitely make the engine feel as though it can't breath... especially at higher RPMs. I would go ahead and double check yopur valve lash. They're pretty picky, and will also affect the fuel mileage problem you said you were having...
Good luck, let us know.

[eazyduzit509]

FOUND IT!

Cam was retarded 1 tooth. Threw the ignition timing off 15*. She runs beautifull now... Pulled the rocker assembly off, turned the cam 1 tooth and slid the belt back on. Took me about 2.5 hours from pull in to pull out. Thanks guys! Gotta watch that damn timing!!!

[dano28]

I was going to ask if the little scribe marks on the outer edge of the cam sprocket were level with the top of the head casting. I could see the marks but the photo angle was bad. You really can't go by the "UP"arrow.