That's got to be annoying! Mine is smooooooth... I can feel and AC kick on and off is about it...
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That's got to be annoying! Mine is smooooooth... I can feel and AC kick on and off is about it...
It is really irritating. it runs pretty smooth in OL.
The engine started life as a Goodwrench replacement for 86 trucks, which was a one piece main, 2 bolt block, with the parimeter valve cover bolt heads. Ran rough then too, but I thought the E4ME and C3 ecm was the problem.
Installed the TPI one year later...power was awsome, choppy idle
Installed TBI heads, and the new cam in Feb. 09...same Idle
TBI fuel system installed last october...same crap.
In researching the problem, I read in a few places where a few guys got some bad GM "Hecho en Mexico" Crate engines....citing mis matched pistons, sub par machining...the list goes on. That just gave me mor grey hair.
Old lady around the corner has an 87 Caprice, police package, E4ME 5.7...SmoothER than a new LS engine, as smooth as a Northstar...enough to consider suicide.
And a mechanical vacuum gauge is smooth?
Have you done a compression test?
You probably wouldn't want to drive this then...Quote:
enough to consider suicide.
http://www.gearhead-efi.com/Fuel-Inj...id-Life-Crisis
Too late brother...I had one. Black, T tops, bought it brand new in 01. Compression test says 180+ in each cylinder after 7 seconds of cranking.
With the vacuum and compression that good, and after all you've been through, I'd still put a small cap distributor in it before I shot it... is it the same distributor as the TPI?
Yep, I used the Big cap on the tpi too. I thought it was ok, because it was the same distributor used on the 85 L98 TPI.
Dont have money right now for it, and not alot of wrecking yards out here have that kind of inventory anymore.
Yeah it works, but it's one of the few parts that were on both systems with idle issues. With good compression test and solid engine vacuum a questionable engine build still does not make sense? Even if cam timing was off, tests still show good to go.
I'm all for diagnosing parts before replacing but sometimes you can't find the issue. Look at some GM test procedures and pretty simple, then replace part... only way to test ignition beyond basics is an Osiliscope, it'll show all 8 sparks and point out an issue real quick. Watching ignition on an Osiliscope was fairly common practice for tune ups in old days...
The only data from your truck that is off from mine is coolant temp gets to 202F at end of log when you do the idle logging. But that is only 10-15 degrees hotter?
I think the only reason the temp got that high, is because i buzzed it up over 5k.
I did have a small cap dist here a few months ago. I did notice that there is no up and down play in it, compaired to my large cap. I had the coil, and the harness to run it too...Dang it!
I ended up Donating my entire TPI setup, along with the small dizzy to a Buddy on the GMSB forum, who is also a Friend of Robert Issar's down in Austin. Everything ended up getting stolen from his garage when his step son left the door open.
Here is a log with Bin 6.
Surging is barely noticeable...almost completely gone.
Took the plugs out and cleaned them before start up, didnt look too bad.
Idle counts at 0, probably because I gave it a turn before starting.
Idle still a bit choppy.
But, is the blm supposed to go below 119 at all?
May just send in the injectors next week.
GETTING BETTER!
And here is the result of re setting the Min Idle Air again.
I do notice much more power, under less throttle.
Did you try 7?
Not yet....the idle is just a little higher, and less 2 degrees right?
I have it loaded onto another chip, will go back out after my daughter wakes up.
Is there a possiblity that the lower idle could be used, once all this other stuff is ironed out?
Have you watched for a drippy injector? That whole log was dam near perfect, I think I'd add a little more fuel, it did go lean as I expected but just to about perfect.
Except at idle! BLM will be exactly as expected from rest of log then bottom out at 108, then back to where should be. Have you watched for a drippy injector?
Not a single knock count.
Ok...i was adding to my last post when you answered.