CA18DET problems starting after new head gasket

[aintnobiscuit]

Hi guys.

I have the following mods on my CA18DET.

resurfaced block
block was bored to 83.5mm and honed
8.5:1 83.5mm CP pistons
Pauter connecting rods
Resurfaced oem crank shaft
ACL race bearings (properly sized based on crankshaft)
Supertech dual valve springs
Supertech intake/exhaust valves
Tomei 260/8.8mm cams (same for intake and exhaust)
haltech platinum sport 1000
t3 .50 trim .48 a/r

I had recently finished my build of the engine with a resurfaced block/head and cometic head gasket with arp head studs. The rings are installed correctly, seated and engine is broken in. The engine showed 150psi +/- 0.5 psi across all 4 cylinders. It started and ran absolutely perfect. I broke the engine in as per the instructions here (http://www.mototuneusa.com/break_in_secrets.htm) at the recommendation of float_6969 in a different post.

I have not boosted much. The first time i got into boost (roughly 1 bar... slightly less) the engine started acting funny so i immediately drove it home (a couple blocks) at which point it died. I did notice if I made left hand turns it would run on 2/3 cylinders. I assume it's something electrical since oil and fuel pressure are both good. Temperatures were 170-180 fahrenheit while driving and boosting.

I popped the hood and could see oil coming from the Cometic head gasket all around.Ran a compression test which was showing 140psi across all 4 cylinders after this. I swapped the Cometic head gasket for an OEM nissan head gasket I had lying around. Compression test still shows 140psi across all 4 cylinders. I started it up to see if it would run and I got the following result.

[youtube]http://www.youtube.com/watch?v=ypfgiq0Y1UM[/youtube]

So I'm curious if anyone can provide feedback as to what could cause the compression #s to go from 150 to 140. There does not appear to be any blow-by. The head gasket is not leaking either. I think the reason it's running off only cylinders 2 and 3 is because of the coil packs. I saw that they are arcing at the base of the plug on more than one cylinder. I'm going to see if I can find another harness in my spare parts to re-test. Cylinders 1 and 4 are wet with fuel after cranking, 2 and 3 look normal.

I tried re-starting it now and it just cranks. It won't even start like in the video above. I re-checked the numbers and i'm still getting 140psi across all 4.... so it seems like it may not even be related to the compression numbers but I would like people's opinions on what could cause the numbers to change that much anyway.

I provided back story for all of this and the coil pack info to be thorough. It's not my daily driver but I do have a dyno session scheduled for Saturday and i would REALLY like to fix her prior to that so I don't waste that appointment.

Thoughts?

For comparison, here is a video of how it was running before the engine work. Also, it does stumble a little bit but thats because i'm running a rough tune on a haltech and theres a spot that's too rich.

[youtube]http://www.youtube.com/watch?v=AF06tRXsTpY[/youtube]

[float_6969]

cam timing?

[aintnobiscuit]

hmmm... not a bad idea. I sort of doubt it because I was pretty diligent about keeping tension so it didn't slip teeth when installing the timing belt again, but that doesn't mean it didn't happen. I'll pull the timing cover off and check it again when i get home from work.

Any other thoughts?

[aintnobiscuit]

Is it possible to install the CAS 180* the wrong way?

[aintnobiscuit]

Thought about what i said above on the way home... that doesn't make sense.

Checking cam timing right now and will update when i check the teeth. I repaired the coil wire too.

EDIT: I re-set the cam timing via the belt. I started with the intake mark on the cam as 0. The 39th tooth is the mark on the exhaust cam. Is this correct or is the mark on the intake cam 1? Reinstalled everything and tried to fire it up. Same symptoms but I noticed more arcing. I repaired the coil wiring and found even MORE arcing. f***.

I looked through all my spare parts and found another coil pack harness. It's not reliably running on 3 cylinders. It will stay running if I give it some gas but dies at idle. I swapped it with another CAS and have the same issue.

Intake cam


Exhaust cam


Crank

[float_6969]

CAS cannot be installed incorrectly unless the splines inside the exhaust cam have broken off. Cam timing looks good from the pics, although it's a bit hard to tell because of the picture quality.

From the issues you were having with the coil's, I would verify all 4 coils and plugs are good and have spark.

[aintnobiscuit]

Is there another way to verify coils/spark are good other than the spark tester below?



I stuffed a rag between each side of the belt when i removed the upper timing cover to make sure it didn't fall down or get slack.

Symptoms have improved from swapping coil pack harnesses. I also found that the timing belt tensioner was loose and tightened that. It jumped a tooth on the exhaust side, which i fixed. It now runs on 3 cylinders.

(Float, sometimes I need someone to bounce ideas off of and verify my work. I appreciate the help)

Heres my list of things to check when i get home. I'm worried because i only have from 7pm-10pm to work on my car each night and Saturday is fast approaching.

• Double-check the crank timing mark is lined up 100% perfect
• Compare lines on cam timing to make sure they still line up with step above
• Count cogs (39/48)... I NEED TO KNOW IF THE FIRST MARK IS 0 OR 1!? i/e 39 INCLUDING the timing mark/cog, or STARTING at the next cog
• Pull fuel injector rail/injectors and throw in the 550s
• Test spray pattern of all 4 injectors
• Pull all spark plugs and inspect again (take pictures so I can compare
• Pull one coil at a time to try and identify if it's spark and identify the cylinder
• Pull one injector clip at a time to see if it's fuel and identify the cylinder

Can you guys think of anything else? I think this pretty much covers the 3 essentials. Compression/Spark/Fuel.

[aintnobiscuit]

I literally tried everything on that list and everything is ok.

The only thing i could find was wiring wise. The (ground?) wire on the alternator was not hooked up. It's an 8mm bolt with a black wire and circular connector so I assume it's a ground.

Anyway, just hooked that up and I'm going to put everything back together.

I'm seriously f*** lost. I swapped injectors, everything... does anyone have ideas?

[aintnobiscuit]

To reiterate: Cam timing is dead on as well as the timing belt install. Injectors are spraying/have good fuel pressure. Compression is 140psi across the board. Have spark. Ability to run is not affected by spraying starter fluid. Wideband shows flatline (7.4 afr / 0 volts) while gauge shows proper voltage. Swapping wires yields same result. It seem like only 1 output on the innovative wideband controller works at a time. I tested the voltage with a multimeter straight off the analog 2 and analog 1 outputs. Whichever is hooked to the ecu is always 0v.

Heres a video that shows timing belt markings better
[youtube]http://www.youtube.com/watch?v=9KSy3Y4f55Y[/youtube]

Here's a video of what my 440cc injectors are doing when i turn the CAS manually (yes I know this is dangerous). Fuel pressure is at a base of 36psi w/o vacuum line attached. Almost nothing. The injectors are running in batch mode. I put the 550cc injectors in and have the same problem. I show 12v at the injector plugs and the signal jumps on the other pin when i turn it. Anything else I can check here guys? I recall when I did this test a couple months ago, the spray was MUCH more.
[youtube]http://www.youtube.com/watch?v=JgmpUdJkd3U[/youtube]

And here's the result.
[youtube]http://www.youtube.com/watch?v=cb-6s1JJCOo[/youtube]

Are these forums dead?

[float_6969]

Ok, your cam timing is definitely dead on.

I know you tested to injectors, but just to make sure, you tested all 4? And you know all 4 are cycling? How did you test that the ECU is actually switching them? Did you use a noid light?

Have you put a multimeter on the dropping resistor to make sure it's OK? It should fail in a way that leaves an injector with out a 12V+, but if it got wet somehow, maybe it's got an internal short. This would test out OK, but would have probably damaged the ECU.

I'm still leaning towards a spark issue. Have you confirmed you have good spark on all 4 cylinders? I use the same tester you posted a picture of.

You might also test the ignition amplifier. Sometimes they get weak, but don't totally fail. The coils will seem to have a good spark until they actually need to fire inside the combustion chamber. Then the inductive load is too much and they stop firing. VERY frustrating to diagnose.

Lastly, if at all possible, I want you to hit it with a timing light. I have heard about, ONE TIME (in almost 10 years) of the splines inside the cam turning. This set the ignition timing way off.

[aintnobiscuit]

Son of a b****. I thought i filled up my fuel cell when i parked it for the rebuild, I guess i forgot. I haven't installed the fuel tank sender unit yet so gas gauge is no go. It was empty.....

Have a good laugh at my expense, but here's a vid of the finished product... thanks Float, appreciate the help... LOL... you have no idea the lengths i went before realizing there was no gas. I pulled the whole harness apart and tested continuity on all the wires...

[youtube]http://www.youtube.com/watch?v=nhua6WGvAJs[/youtube]

[TheMAN]

ok, but there still is a question about the head gasket issue... did you use NEW head bolts and torque them to spec per the FSM?

[float_6969]

Son of a b****. I thought i filled up my fuel cell when i parked it for the rebuild, I guess i forgot. I haven't installed the fuel tank sender unit yet so gas gauge is no go. It was empty.....

Have a good laugh at my expense, but here's a vid of the finished product... thanks Float, appreciate the help... LOL... you have no idea the lengths i went before realizing there was no gas. I pulled the whole harness apart and tested continuity on all the wires...

I'm having a REALLY good laugh right now

Glad you got it sorted out though!

[aintnobiscuit]

Lulz!

Yeah, no idea why compression #s are at 140. Theres no smoke from the exhaust. Theres no oil in coolant or vice versa. The valve oil seals are brand new. The piston rings were properly gapped, checked, re-checked and checked again before installing. Engine was torqued per the assembly instructions to ARP specs (80ft/lbs). I hand tightened all bolts then did 27, 54, 80 in the proper order per the tightening order (there is a loosening and tightening order which are different).

IDK why the #s are lower. My tuner said that the compression ratio is the same and boring .5mm won't change the compression #s like that. I will admit 10 psi is a pretty big difference...

Not to mention, aren't these bishez supposed to be at 180 when fresh? Before I rebuilt it, the #s were like 170psi on 3 and 160psi on 1 which is what sparked the rebuild.

[float_6969]

Didn't you change cams? In my experience, the compression numbers in the FSM are only accurate with stock cams.

The first time I built this motor, compression was 210psi across the board. (E85 only motor running 10:1 compression, stock cams)

Then the oil filter failed (f*** FRAM FILTERS!) and ruined the head (which had been port matched and polished) and the main and rod bearings.

Rebuilt the motor, exact same pistons, rods and crank. Head was a 4 port instead of an 8 port and I went to HKS 264's IN&EX.

Compression is now 190psi across the board. I personally gapped the rings and installed them, so I KNOW they're in correctly, and the compression numbers are all within 2psi of each other. I asked a few engine builders about it and they both said it was from the longer duration cams. More overlap decreases the static compression ratio.

[aintnobiscuit]

I definitely agree with you on the cams, which is why I wasn't worried when i did the compression test on the fresh motor (with MLS gasket) and saw 150 instead of 180. I suppose when i think about it, the cam timing could have been off a tooth because the tensioner was loose. This could account for dropping from 150 to 140. The timing is dead on and the motor is still tight and seeing 140, so yeah... makes sense.

I am not going to adjust the cams until after i get a really epic base map, but I'm suuuuuper excited to see what this puts down.

I search these forums but never post. You and boost_boy are the only people i really listen to. Do you have a link to your build thread?

[s13drifter88]

Larger cams will cause a drop in static compression but higher dynamic compression. It is from the increase in overlap like you said.

[aintnobiscuit]

Of course, that all makes sense. I was just pointing out that the same cams were in from the time of the rebuild (150psi) to the next head gasket (140psi). So the only explanation for that 10psi drop should be the cam timing (i had not bolted the rear of the upper timing cover down. It has quite a bit of play, so I am assuming it was off a tooth or so)

[cbh148]

gotta love those moments where you feel like an idiot but don't care cause your engine's running.

[aintnobiscuit]

this^

[aintnobiscuit]

Just for s*** and giggles... here's some pics from tonight. Threw on the hood and fenders. I have some crash damage so the driver's side fender doesn't fit well right now. I'll get it pulled out soon.

Tuck!


3/4 view


LOW....


f***... maybe too low?

[cbh148]

so dope. i'd kill for a 510 2 door. true story, my parents drove off in my dad's 510 when they got married in '75.

[float_6969]

Yea dime's are the sechs!

[aintnobiscuit]

this is my third one. I NEVER should have sold the other two. They're the best car(s) i've ever had. I only sold them because i needed the money. So let that be a lesson to you guys (if you're young). Never sell something you love because you need money.