copmagnet

OK here's the situation. Blew a heater hose on the interstate, which overheated the car and blew the head gasket. I pulled the head, put in a set of ARP studs, Cosworth HG, and some 264 cams while I was in there. Also got the ECU retuned by Enthalpy. So, ever since then I have had major trouble with the car. It won't even idle at 15*. I have to advance the timing I'd say a good 20* past that to get it to run. I've pulled the valve cover a dozen times at least checking and rechecking the cam timing. 9 links in between the dots, exhaust cam at 12:00 intake at 10:00 etc etc.

As to what it's doing, misses at idle and low load revving. When driving, pulls smooth at heavy throttle, but under low load (interstate cruise etc) it kicks, bucks, misses, and basically just runs like complete ass.

Just for reference, here's what I've checked and replaced recently.
02 sensor is new
swapped MAF's, no change
CTS is new
swapped CAS from a friend's running engine, checked the wiring, plug was jacked a bit, spliced in a new one. No change.

So, what else can it be? Knock sensor? That thing is a bitch to get to, is there a good way to test it to see if its the problem? I've searched like crazy and I've found so many conflicting stories about it I really don't know what to do with that other than replace it. But I've dumped a ton of money in this thing lately and don't want to buy one just hoping its the issue.

waxball88

Check TPS for tip in throttle bucking.
Seeing as you had the chain off while doing cams, make sure that is correct and the dizzy is stabbed correctly. I had to stab mine a few times before i got it correct.
Here is my chain on the engine, make sure yours isn't drastically different.


Wait is this on an SR or KA

copmagnet

lol forgot a pretty major part there didn't I

SR redtop. GT2871R turbo. 740 Injectors. Z32 MAF. Enthalpy tune.

I have checked double checked and triple checked cam timing and CAS. It can't get any more right. TDC, valve cover off, exhaust cam key is at 12:00 dead on. The intake is at 10:00. 9 links (20 rollers) in between the 2 dots. Installed CAS at the right dot, so it rolls in to the left one. I can set the timing on 15, it just won't RUN there. I have to advance an additional 20 or so to get it to idle. Drives fine under load, just at cruise it kicks.

copmagnet

OK just to try one more thing, I have been reading everything I can about the knock sensor.
The sensor itself reads 556M ohms, or something close to that. The ecu is seeing ~2v at idle at pin 27. So, I tried the resistor trick. 1 Mohm resistor grounded and hooked to pin 27. .9v at idle. So, key on, engine off, knock sensor wire cut, I see 3.3v at the ecu. WTF. From what I've read, it should be 5v, and see 2.5 at idle. Seems like that's the issue, but it worked perfectly before I sent it to have it reflashed. I drove the car home, even with the blown head gasket, it still ran. Am I doing something wrong? Is my ecu fried? Kind of hard to test with it being modified, I don't have the parts to revert to stock and try a stock ecu. Any info out there? Anyone else see this issue? Any ideas? I'm 1/2 tempted to part the entire drivetrain out and drop an LS1 in the damn thing. Which would get me killed by the wife. So, before I go and get myself murdered, help a brother out!

Kingtal0n

When you swapped the CAS, You did this with the valve cover off?
does the CAS seem to be about center adjustment with the timing set to 15*?

What sort of timing light are you using, and how are you using it to check the timing?

My initial suggestion is, perhaps you are not reading the right timing. The CAS should be just about center when the engine is around 15* BTDC cylinder #1. That means the spaces between the two bolts holding the CAS in place are about equal.

To ensure proper timing light reading, you may want to clip a light directly on to coilpack #1, and try using the clamp in both directions, it may give two different timing numbers. The one that sets the CAS about center around 16* is the right one, usually.

The only thing that doesnt make sense is this:
If you set the timing too far retarded, it would make sense for the engine to run right during cruise, but not during heavy load. Your scenario is the exact opposite- which makes me think its too far advanced, but even then, it would take a LOT of timing to over-advance a cruise situation or idle to the point of misfiring. So perhaps the issue is not timing related at all.
Has it ever run correctly on the new ECU tune? Has it ever run correctly after the cam install? any way you could try an OEM ecu and OEM injectors to verify the cam install?

copmagnet

I have been having trouble since the ecu/cam install. I had the stock cams back in for a while, same issue. Worse now with the 264's. The timing light is the same one I always use, I checked the timing before with no issues. I installed the CAS with the valve cover off, to verify the dots lining up. If I set the timing to 15*, it's right in the center of the range where it should be but runs rough as hell and dies quickly. I reversed the clamp, same exact readings. My next question, is why would it die out at 15* but idle and drive when advanced an additional 20*? It runs and pulls hard at WOT but misses like crazy under light load.

I would swap in a spare ecu a friend has, but I would need to source a set of 370's, and an SR MAF. Mine are long gone, used to help friends with stock SR's who were having trouble last year.

rcdad123

sounds like the tune is way off. too lean at low load.

Kingtal0n

Invest in a wideband, useful for safety, and you can simulate narrowband output to increase fuel economy, and determine if your problem(and future problems) is related to air/fuel ratio, which makes some sense.

copmagnet

I have a wideband. But, when I blew the headgasket, upon disassembly found a huge crack in my downpipe. The new one I ordered didn't have a bung for the O2 sensor for the wideband, didn't find that out til I was installing everything. I bought a new bung, and I'll be climbing under the car to weld it in when I get back in town next weekend. If it IS too lean, I'm confused as to what would cause it. Enthalpy usually tunes a touch rich, to be safe, from what I hear. I sent a detailed list when I had it tuned, should be spot on.

Working 300 miles from home sucks. Couldn't drive the 240, had to take my truck. 10mpg sucks ass. Need to figure this out quick lol.

Walperstyle

If you are curious on how to set to factory timing, go to youtube, type in 'upper timing explained' You will find my youtube channel.
edit: here it is http://www.youtube.com/user/walperstyle/videos

BUT do not go by my vids on degreeing cams, they are incorrect. Actually I'm going to remove them.
edit: I deleted a couple of my "degreeing" vids. I will make new ones.

If you go to my build thread on ka-t.org, the most current page I have quoted the 'how to' on using JWT cam gears.

You should also look into tripple checking how your dizzy is 'stabbed' into the timing cover. It may be off too. All too often I read about someone that stabbed it wrong.

but also listen to above posts. You really should have a wideband.


Worst case, you will just have to set everything to factory timing again, just be careful you don't turn the engine over when the valves are in the wrong position.

__________________
KA-T ORG-Function over Flush

copmagnet

The timing has been checked over a dozen times. I've read every article I can find about it, checked, checked again, and checked a third time. The only thing I haven't done is pull the front cover and check it again that way. BUT...engine at TDC, 2nd mark from left. Exhaust cam KEY, not the dot, at 12:00 on the button. Intake cam KEY, at 10:00. there are 9 full links between the dots, the dots are centered in links themselves, not between them. Stabbed the CAS in on the right dot, moves to the left one when the gears mesh. Left dot lines up to the mark in the CAS housing. Did it with the VC off. I CAN set the timing at 15*, it just won't stay running there.

Very frustrating. It acts like timing, everything makes me think its timing, but it sure as hell doesn't seem to be timing. Unless its in the ecu, not base timing.

Wideband will be reinstalled Saturday when I get back in town and dig out my welder. Then, if I don't figure it out, I'll update with pics and video.

Walperstyle

well if you are sure you are on the proper compression stroke and not 180' off, then I would start over

What I would do. Would only take an hour or two of your time but its the best way to be absolute. Remove upper timing cover, remove valve cover, remove cams. Manually find TDC with a wrench. (but turn the engine over a few times (may take several) so you get the idler mark pointing at 5 o'clock, and on the yellow mark. If you can, use a dial indicator or something down the spark plug hole of no1 to make sure its TDC.

Then re-assemble the cams to factory settings. But before doing anything, if you wish to mess with the timing so its not factory, use your cam gears and make adjustments at this point.

Things to keep in mind: I have dual valve springs, and when I degreed my intake cam to 124' CL last night, I was running into a VERY annoying issue. I would get everything perfect on the one cam, but when I took the chain off to adjust the exhaust cam, the intake would move on its own from the extra pressure of the springs... thus throwing the whole thing off again.

Just letting you know what I'm doing and going through. If you can, get a friend to help you with making any adjustments on your cams. But go over my vid's a few times because the ones I uploaded so far seem to be descent.

ps. if you are using JWT cam gears keep in mind you don't just adjust the cam to match a new hole, you have to match the letters and the hole to the marked chain mark. This is best achieved at TDC.

this description helped me with JWT cam gears.
www.ka-t.org :: View topic - really stupid cam question

__________________
KA-T ORG-Function over Flush

Walperstyle

...wait, you said you might drop a LS1. lol, after spending thousands on my KA, I fully support going LS1.

__________________
KA-T ORG-Function over Flush

ForceFed

I thought the cam marks were supposed to be at 10 and 1?

Luvs2slide

If you're still having issues, your timing is still off. SR is very very tricky, and you have to finess it just right. Take a picture of the front top of your head with the valve cover off and I'll tell you if it is. Here's a drawing I made to refer to each time I have to deal with timing. Hope it helps.

__________________

copmagnet

Thanks for the pic. I'm pretty sure that's exactly what I have, checked it tons of times. I'll check again in a day or two and take some pics. It's still f-ed, I just haven't had a chance to mess with it.

Luvs2slide

Biggest thing is the chain links b/w the timing dots and the head's surface and the 20 dots from gear to gear. TOMEI has a picture floating around that I think they supplied with their cams to help out also (explains the 1.5 links and 3.5 links)

I had to re-do my timing about 8 times and now I feel like im a pro at that shit. Basically your cams have to go in almost exactly pointing away from each other. Once you put the exhaust side in, tighten the slack up on that side so you have slack to do the intake side. Once you have the intake side in, tighten up the slack from cam gear to cam gear...the only slack you should have left is where the tensioner will go in.

I also stab the CAS with the valve cover off to make sure everything is aligned correctly as well.

Good Luck.

__________________

copmagnet

Ok. Coil on the #1 cylinder was cracked all to hell. Finally got a new one, put it on, huge difference. Got the timing backed down, fiddled with the IACV to get the idle right. Here's something odd...the car won't run with the fuel pressure set to stock. 3 bar with the vacuum line unhooked and blocked off. Absolutely will not run. I have to run it up close to 4 bar. Before the cams/retune/head gasket it always ran perfect, dead on factory setting. I only have the adjustable regulator because my stock one went bad and I had this one lying around from another project. Used it for 2 years with no issues. Any ideas?