[hegg]

Just finished a full engine rebuild (pistons, rings, head, oil pan, etc.) plus installed the VF stage II kit (injectors, fuel pump). Just got it all back together and it won't start. Cranks over just dandy, fuel pump is going, and I can smell fuel at the exhaust after cranking. Cleared the CEL (it was there before rebuild) and no other codes are showing up.

I've done plenty of older engines, but this is (by far) the newest rebuild I've done. I don't even really know where to start troubleshooting cuz it's all computer controlled and there ain't no points or coil to easily check spark or whatever.

Sorry for being a retard, but where should I start?

 

[cokey]

cams gears line up correctly?

 

[hegg]

My apologies - I posted last night in frustration and wasn't all that clear on my situation.

I guess I'm trying to get the correct understanding of how these fancy new engines work. Here's what I'm thinking:

First, the car figures out the position of the crank based on the crank position sensor plate down by the oil pump. It also figures out where cam #1 is from the cam angle sensor on the intake. Then when it "knows" that #1 is on its way to TDC it fires the #1 fuel injector and then fires the #1 coil pack on the spark plug. Then there are a bunch of sensors like the MAF and knock sensor and whatever that start to adjust things like a/f ratio and retard the timing and all that stuff.

But it seems like the basics of how it runs are all determined by those crank and cam angle sensors, is that right? And I would assume that it fires only one injector and one plug at a time when needed.

Initially my answer to the previous post was 'yes' since I lined up the dots on the crank and cams and put the fancy colored links on the new timing chain on the sprocket as specified in the manual. However, now that I've talked it through, it seems like - if my understand above is correct - the only thing that *could* be wrong is the physical timing of the cams because the car figures out the rest? (well, obviously other things could be wrong, but assuming the injectors and plugs are working anyway...)

I'm just so used to twisting the distributor or squirting a little fuel in the carbs or taking plug wires off to see if they're sparking or fiddling with the choke or...

Thanks in advance for everyone that endures my rambling.

 

[Bender Rodríguez]

Did u try a compression test? Also if you take the coil out attach a plug and ground it to anything while someone else cranks it over you should see it spark. Not a proper method but it gives you real verification that there is spark. If it's no spark the systems pretty simple the ecu is directly linked to the coils.

 

[hegg]

I was thinking of trying that method to check for spark since I couldn't come up with anything else other than maybe trying to rig up my old timing light somehow.

I'm feeling sorta worried I got the cams hooked up wrong. I hand-cranked the engine through a few times and it seemed like it went normally, so I hope there at least hasn't been piston-to-valve contact. Maybe I got a cam off by one tooth?

 

[Bender Rodríguez]

I was thinking of trying that method to check for spark since I couldn't come up with anything else other than maybe trying to rig up my old timing light somehow.

I'm feeling sorta worried I got the cams hooked up wrong. I hand-cranked the engine through a few times and it seemed like it went normally, so I hope there at least hasn't been piston-to-valve contact. Maybe I got a cam off by one tooth?

It odd, I don't know exactly how ecu logic is but if it's sending fuel usually spark goes w/ it. And if you hand cranked the engine if it's going to hit a valve you will defiantly know. Plus the compression test will fail badly.

 

[hegg]

I'll definitely try compression and spark when I get home. I may crack the valve cover and just double double check the cam timing.

Thank you for the suggestions and sanity checks.

 

[hegg]

Oh, and one other thing I failed to mention earlier. The first time I tried starting it, the first cylinder definitely fired. I heard the pop, but then it just kept turning over with no firing. After I let it sit (for a day) and tried again, the same thing - the very first cylinder that hit fired, but then nothing.

That seems to confirm that spark is at least in there somewhere.

 

[Bender Rodríguez]

I'll definitely try compression and spark when I get home. I may crack the valve cover and just double double check the cam timing.

Thank you for the suggestions and sanity checks.

No problem anytime I can help. I know exactly how you feel. After my rebuild mine wouldn't start and it was hard to keep my mind from racing. Also do note that it takes quite a few revolutions for all the timing marks to come back to their original alignment mark with respect to the chain. Rather than opening up a gasket I would just do the compression check if your off even a little you'll see a difference from one cylinder to another.

 

[Jean]

Hegg,
I loved these old twin-cams too...
I'm sure you checked it but...your cam timing is on the compression stroke ?

 

[hegg]

Hegg,
I loved these old twin-cams too...
I'm sure you checked it but...your cam timing is on the compression stroke ?

That was my first thought, but then I couldn't figure out how to "rotate the dizzy" to get it on the opposite stroke in case I had it on the exhaust stroke. That's when I did my deep thinking and realized that the cam and crank angle sensors have to basically provide the right signal for the ECU to figure out which stroke it's on. It seems to me that - in theory - if you put the crank at TDC but hooked up the cams at exactly opposite what they should be (i.e., lined up the timing marks with the exhaust instead of compression stroke), that the engine would still run. Just in theory anyway.

 

[hegg]

Haven't done the compression or spark tests yet (crazy 2-year-old on my hands), but got the plugs pulled and they're soaking in gasoline. Even after sitting 24 hours.

Injectors and intake valves definitely must be working...

 

[SirLotus]

Did you check the engine bay fuses, especially R4, 6 & 7?
Michael

 

[hegg]

Just checked all 8 engine bay fuses and all have continuity.

 

[hegg]

Compression roughly 160-165 in all cylinders. New rings, plus I'm at 4,500 feet. Seems about right?

One odd thing though... I removed the fuse for fuel injectors so I wasn't spraying fuel with all 4 plugs out, but the car completely freaks out when that fuse is removed. As soon as I turn the key I can hear spastic clicking noises - looks like it's the throttle copening and closing rapidly. Also another occasional (every few seconds) click from the alternatorish area. Car also refused to turn over or connect to my ODB tool. Replace the fuse and back to normal. Should that happen?

 

[hegg]

Independently verified each plug and lead - bright, blue, huge, beautiful sparks. Feeling like next step is to verify timing by pulling the valve cover.

 

[hegg]

Alright, I'm feeling like I might have found it. Intake cam looks to be off by one tooth. Now too see if I can get 'er rotated...

Thanks for hanging in there with me.

 

[hegg]

Alright, cam rotated and now looks exactly like the shop manual diagram instead of just pretty close. Got it all back together and tried starting. A few pops from the engine, but still not starting. However, it's smelling pretty rich in there. I'll give it a day to air out - maybe it's just flooded now.

 

[JLSELISE]

That might be an issue, but certainly would not cause the no-start, or wet plug symptoms--it would just lead to poor running. Maybe ignition timing is not where it should be.

 

[hegg]

Tried again this morning and no luck, although it did pop a few more times than it has before.

How can I check / adjust ignition timing as previously mentioned, other than ensuring the cams and crank are all aligned?

Could my new injectors be leaking / faulty? Could the VFII ECU flash be malfunctioning?