Mudflap

I pulled my head to get +1mm valves, new guides, double springs and have re-installed and it won't start!


I already know what you are going to say, timing. But I have thoroughly explored that rabbit hole and can't figure this out.


I only pulled the head and did not touch the crank/pulley. I've checked the spark and it is sparking away. I can smell the gas being pulsed in (E85) and can hear the pump going when I let Tunerstudio turn it on (and when initial priming). It is VVT so the intake cam is fixed and the CAS is fixed. The exhaust cam was checked and double checked for position on both the pin position ("E" towards pin) and then for the alignment to the backplate. The crank notch is aligned to the arrow and I've got the obligatory 19 teeth between the intake and exhaust cam.


I had old gas and a nearly empty tank so I put in fresh E85. I put in new plugs and have a fresh battery. I've taken the valve cover and timing belt off to re-install to make sure I didn't have it off a tooth.


I'm running a Megasquirt with tons of sensors so I'm wondering if someone can help me explore what info can be gained by looking at cam angle sensor, crank angle sensor, etc.


One odd thing is that I tried to see if I could use a timing light to see if I was in the right neighborhood while cranking, but the marker is so far off that I couldn't see it (36-2 tooth on an ATI superdamper). QUESTION: is that even relevant? Can you check your timing with a timing light while cranking without a start?


I tried starter fluid to see if that helped and the only thing I got was a great big belch of flames out of the intake manifold.


Of course it turns over, but no signs of starting up. If I open the throttle wide open it eventually farts out a loud backfire or two. But that's it!


Help please!


Mud

Ted75zcar

iTrader: (2)

Sounds like you might be 180 out with sequential. I suggest switching to waste spark, and batch fire to see if it will run.

codrus

I suspect the most likely cause is a wiring problem during reinstallation. Forgot to plug something in or damaged wires or something. Have you done a composite log with the mega squirt to check that it's seeing both signals?

--Ian

Joe Perez

iTrader: (8)

Not only is it relevant, you have ID'd the problem.

When starting up a new engine for the first time, I like to turn it on the starter, with no plugs or fuel, to get the cranking timing into the correct neighborhood. If you have it set for 5° for instance, then you should see it at about 5° under the timing light when cranking.

So, yeah, it does sound like maybe you got the two coil banks mixed up? Try clipping the timing light to the #2 coil and see if your timing mark magically appears somewhere in the vicinity of where it should be.

sonofthehill

iTrader: (1)

Hmmm, maybe I recall incorrectly but I think the "I" on the exhaust cam is supposed to line up with the backing plate. At least that's how I think it is on a non-VVT motor, maybe I am just sleepy still.

Mudflap

Ted I am on wasted spark. should I try the alternative?

Joe I presume that this is telling me the problem too. Only thing is, my coil wires are exact length, so it is impossible to screw up the connections. I'll try triggering the light off of the 2nd wire to see if I see the TDC line.

Codrus I want to try this next.

Son, yes, the "I" faces the backing plate line. I meant when initially mounting the cam, there is a pin you align the cam to. You could mount it one of three different ways.

Thanks folks!

Ted75zcar

iTrader: (2)

Hmmm, already running waste spark, interesting. The suggestion to hook the timing light to another plug wire is spot on.

Composite logger helps here to verify inputs, only crank is needed for waste spark (you need cam for your VVT)

You can get most of the behavior you described with fuel lines hooked up backwards (return style), but starting fluid should have worked in that case.

Use a jumper cable to ground the head to chassis

Edit: I may be able to swing by at some point to help, lmk

codrus

While you don't need the cam signal for waste spark in principle, the megasquirt probably won't sync without it.

--Ian

Ted75zcar

iTrader: (2)

agree, but a VVT car running on MS3 (probably MS2) will start and run with the Cam sensor disconnected. It will issue a cam fault.

Mudflap

Ted it seems like you are slightly concerned about a fire. Couldn't I just do the same thing given the fire department is pretty close to my house? Oh, wait, I live in Louisville CO, people don't like fire around here!

I'd love to get your help if you have time. I have no idea how to read the composite logger, seems pretty cryptic.

Mud

pdexta

iTrader: (17)

Looks like you may already be onto a timing issue, but...

I did something very similar years ago, dropped my NB1 head at the machine shop, got it back, threw it on, and the car wouldn't start. Fought with it for a few days before realizing the valve job had left zero clearance and, despite the incredible air flow, for some reason the car didn't want to run with all the valves open. Re-shimmed the head to adjust the valves and what do you know, it ran great.

Mudflap

!!!!
Woo hoo
!!!

Joe had it. Each pair of spark wires, very close in length, were swapped.

Now on to the next problem. It sounds rough. Like down a cylinder sounding. So I've got +1mm intake/exhaust valves now with heavy double springs. So a little more air can come in, do I need more fuel? I'm sitting on (adjusted) 14.7:1 at idle.

I'm going to check on the idle timing, but I don't know what to check next. Anyone have advice about how to hunt down which cylinder is down?

Joe Perez

iTrader: (8)

Disconnect one injector at a time.

Or measure the temperature of each individual exhaust tube after the engine has run for about 30 seconds.

Ted75zcar

iTrader: (2)

I just pull spark plug boots 1 at a time and listen for a change (or lack there of)

Mudflap

found it. I used the timing light to check each wire. 3rd one back is not working. new d585 on its way!

Mud