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Old 01-23-2009, 05:14 PM   #1
aclver1
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Default delta cams and mis fires.

I had some delta cams 1000 grind installed a few weeks ago and I started getting misfires on random cylinders. I have a lw flywheel and lw crank pulley so it may be that but I got the 1000 grids so i would have less chances of having issues. It had a mis fire CEL right after we got it put back together and I reset the code and didn't have one for about 350 miles so I wasn't worried. I readjusted the valve lash because it was ticking like crazy and about 3 days later I got a p0301,p0303 and a p0304 code. Is there a chance that if I have the valve clearance set to tight, that it would cause a misfire? I just want to make sure it's not really a misfire, if it is just because of the flywheel or pulley it's fine, i just don't want there to be an issue.
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Old 01-23-2009, 05:25 PM   #2
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hmmmmmm... I don't know if those are the codes that lightweight flywheels and pulleys throw. You sure it's not a misfire? when was the last time you did plugs and wires?
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Old 01-23-2009, 05:31 PM   #3
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my deltacams have been throwing misfire codes since day one. i just keep a scanguage in the car to clear the codes that show up at least once a week...
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Old 01-23-2009, 05:51 PM   #4
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I have a code scanner and i can reset them I just wanted to make sure it wasn't really a misfire. Is there any way to tell?
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Old 01-23-2009, 05:56 PM   #5
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The computer reads it as a misfire. It isn't but the ecu is kind of picky sometimes. We are finding that most who have lwfw and pulleys are getting codes almost automatically. Just one or the other is about 50-50. What did you set your lash to?
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Old 01-23-2009, 05:56 PM   #6
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Quote:
Originally Posted by aclver1 View Post
I have a code scanner and i can reset them I just wanted to make sure it wasn't really a misfire. Is there any way to tell?
Yeah, I'm beginning to think that they just do that. How does the car run?
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Old 01-23-2009, 05:57 PM   #7
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is the tapping still there? does it run smooth? if it's not riding abnormally it's probably just the ECU.

simple, but have you checked your plugs?
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Old 01-23-2009, 06:10 PM   #8
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It has a lumpy idle but anything over 1000rps is seems to be fine, i figured the idle is just the cams. The tapping is gone and it sounds good, I had the lash set to .006 for the intake and .008 of the exhaust but my feelers are tapered on the ends so I thin they are .002 smaller on the tip so if I didn't have them in all the way they could be off. I wouldn't imagine that .002 would make that much of a difference. I haven't checked the plugs so maybe that will be my next step.
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Old 01-23-2009, 06:11 PM   #9
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Quote:
Originally Posted by aclver1 View Post
...I had the lash set to .006 for the intake and .008 of the exhaust
Isn't that too tight?
Quote:
Originally Posted by fastenova View Post
I'm looking at the FHI factory service manual and it says that valve lash for the 2.5L DOHC/SOHC 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)

Last edited by fastenova; 01-23-2009 at 06:13 PM. Reason: neenjah
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Old 01-23-2009, 07:23 PM   #10
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I read that is was .011 and .015 but for a regrind on cams it was .006 to .008 for intake and .008 to .0010 for exhaust depending on the grind. The first time i adjusted them I did .008 and .0010 and that is when it was ticking like crazy so I went to .006 and .008 and the is no ticking at all. If it is set too low would that cause a misfire? should I set it to .007 and .009?
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Old 01-24-2009, 03:29 PM   #11
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a misfire is an ignition problem. its timed with your crank and piston position.

if your getting a misfire, its either , the plugs the wires the coil pack the ecu .

or you could have a compression issue , cracks , leaks , ?

or lastly and most likely is your afr is out of wack because of the cams install.

what are you using for engine management?
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Old 01-24-2009, 04:13 PM   #12
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I get misfire codes with my 2000 grind Delta Cams and a 14lb ACT Flywheel (and many other mods). I was working on a recent theory that it was my AFPR, but that has not panned out. It has helped the idle situation with a correctly set FPR though . Prior to installing my 14lb FW, I never used to get misfire codes with the delta cams ( and a 900 rpm idle) I repeat.. NEVER!!!. But, since the LWFW went in, I cant' seem to quite stop them. It might take a week for it to happen, but the 0301-0304 codes usually come back. And it always happens while sitting at a red-light. Oh yeah, and I currently have my lash set at 0.08 and 0.10.
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Old 01-24-2009, 09:35 PM   #13
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if your geting misfire at idle its most likely because your not giving it enough fuel. richen the mix see if it helps
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Old 01-24-2009, 09:43 PM   #14
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isn't the combination of a lightweight flywheel and lightweight pulling combined notorious for causing misfire codes anyway?

I recall reading something about the accel. and decel. on the crank being too fast, causing the ECU to throw a misfire.


EDIT: nevermind, reread your post - you addressed that. This convo is over my head.
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Old 01-24-2009, 09:55 PM   #15
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yea i hear the lightweight flywheel / pulley combo is no good. i run a light weight pulley , if i had the combo i would shoot myself in any traffic.

you probably need a stand alone ecu if you wanna run a race set up. there is only so far modifying the stock goodies will get you.
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Old 01-25-2009, 12:12 AM   #16
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I ran a lightweight flywheel and pulley with my delta cams on my 03 TS and had to remove the pulley so that the car would idle normally at 700rpm and removing the pulley greatly improved the smoothness of the engine. No idea about misfire CELs since I had a persistant catalytic converter CEL.
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Old 01-25-2009, 02:49 AM   #17
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Quote:
Originally Posted by watchunglava View Post
if your geting misfire at idle its most likely because your not giving it enough fuel. richen the mix see if it helps
What? richen the mix? uh.. yeah.. I'll get right out there with my screw driver, set of idle jets and try that? How exactly do you propose we richen the mix? The fact is, the ECU is pulling fuel at idle mostly due to the lack of vacuum caused by a lumpy cam. Closed loop STFT and LTFT are in the negative. So, if anything.. it's too rich.
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Old 01-25-2009, 04:03 AM   #18
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Dude u tell me then? Lol.

My motors not misfiring.

U even said it that your pulling fuel at idle. So I was correct then in telling you your mix is too lean.

If you have a lack of vaccum then that's an issue. Do you have lower vaccum under load as well . Or just at idle?
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Old 01-25-2009, 11:31 AM   #19
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Quote:
U even said it that your pulling fuel at idle. So I was correct then in telling you your mix is too lean.
Actually, no.. that's backwards.. if the ECU is pulling -20% LTFT in closed loop, then it's an indication of the AF being too rich.

I'm not pulling fuel, the ECU is pulling fuel due to the O2 sensor in closed loop detecting a rich condition. That's what STFT and LTFT is all about. The only thing I can do is change the fuel pressure to find the setting the ECU likes the best. (currently 39psi static). The ECU is in 100% full control of AF targets. The only way to change the AF targets in closed loop is to modify the ECU directly (open tune, access port, i-speed). And the only one that works on my car is the i-speed flash.

As for a lack of idle vaccum, it idles and sits nicely at 18-19Hg waiting at a stop light. In fact, it's not even rough given the modified cams. When you change the way a cam is to perform, it's offen a sacrifice of something. In this case, it's a rougher idle.

Here is the kicker.. I don't have a misfire either!! But, due to the things that I've done to my car, my idle is no longer stock smooth. The ECU is way too picky about idle smoothness, and throws misfire codes when a mouse farts next door! It's almost a 50:50 change, that if you put cams in your car, you might throw a code, and you might not. I did not throw any codes (with 950 idle) until adding the LWFT.

Last edited by Skidd; 01-25-2009 at 12:00 PM.
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Old 01-25-2009, 01:49 PM   #20
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well its not too rich when the ecu is pulling fuel lol!!!!!

open source doesnt work for your car? thats way too bad .

i was going to suggest the fuel pressure next , but you seem to have it all figured out.

irridium plugs are supposed to ignite the mixture better and more complete maybe give them a try.

or swap out your ecu for a more modern one that open sorce works with . same motor should be pretty easy neigh?
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Old 01-25-2009, 02:04 PM   #21
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Correct.. if the ECU is pulling fuel to match it's target AF, then it "should" not be the fuel mixture. Unless the ECU can't pull or add enough fuel. But, I watch my STFT and LTFT every time I get into my car (see pic below), and the LTFT never goes below 22-23% while the STFT sits around +-5%. But, sometimes it takes the ECU a few moments to detect the rich condition and pull enough fuel, then for the LTFT to learn that condition. But, once the LTFT is set, it runs like a champ... but.. with the odd misfire code! D'Oh!

OpenSource doesn't work on any of the JECS ECUs (99-01). Only the Denso ECUs. I believe that means the OS tune is only good for 02+ (or was it 03+? can't remember).

Plus, I'm way to cheap to drop for Irridium plugs!! Besides, the good ol NGK coppers have just always worked great in my car. I might try the irridiums.. but.. we'll see. Remember.. that I'm 99% sure it's not a true misfire, but rather the ECU "thinking" it's a misfire. So.. plugs should not be an issue.

ECU Swap is not a trivial thing at all. My car is a MAP car, and most of the NA ECUs that are OS tunable are MAF cars. So right away the wiring is going to be way different. Then there is the whole SOHC vs DOHC issue. The cam sensor position is different on each, so I'd need a custom cam sprocket. Blech! Basically, I'm stuck with what I have until I make a decision for piggy-back ecu.

How I watch my fuel trims
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Old 01-25-2009, 02:21 PM   #22
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true that i thought 98-07 was pretty much the same deal. guess not
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Old 01-30-2009, 01:06 AM   #23
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I've had cobbs spicy cams (~ delta 200's) in since early 05 (almost at a 4yr anniversary!) lwfw the whole time, stock crank pulley. ganzflo intake, brullen EL headers, highflow cat, stromung resonated exhaust. over the course of those fours years, i've replaced plugs, wires, coils, 1 set of headgaskets (popped the radiator, overheated bad), and gotten an ispeed reflash almost2 yrs ago.

I have Always gotten misfire codes with regularity. after four years of driving it, i'm pretty sure it's not actually misfiring.
unfortunately i can't change my idle (2002) to see if that takes care of it.
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Old 01-30-2009, 01:20 AM   #24
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In all honesty I am sure the cams have some to do with it, but mixing it with lw crank pulley and lw flywheel. You motor is pissed try removing the lw crank pulley and I gets better and doesn't throw as many codes.
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Old 01-30-2009, 12:36 PM   #25
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i and my tuner have not figured out how to correct the misfire&cam issue. he says that he does not have access to the closed loop idle solenoid map (iirc) which is what he needs to get to in order to fix this. I have a 2005 drive by wire btw. the car is tuned, runs great above 2000 rmps, but the idle is all F'd up. the idle target is 1400 but it settles between 800 and 1200. i get misfires when it is below 1000, moreso towards 800. I was thinking it needs fuel at idle, but there's no way to get it there with the maps we have access to...
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