[TunerThings]

Turbo D16Y8 on a P28 with Crome with a freshly replaced head not able to hit the correct timing marks.

I set my crank to the singular mark by itself which I believe is TDC.

Then I set the camshaft sprocket to TDC and matched up the marks with the edge of the block.

Got the belt back on and rotated counter clockwise a bunch of times and it still lined up so I assumed that it was good to go. I warmed up the car until the fan kicks on and jumped the service connector and for some reason my car only hits the white TDC mark and will not go any closer to the 3 marks I'm supposed to be aiming for. I was told that it was a tooth off so I took everything off and repeated the process and it's STILL doing it. The distributor is as far forward (Towards the bumper) as I can get it to hit that TDC mark and when I rotate it back towards the car it goes further away from the target 3 marks and starts hesitating. The car idles well, revs just fine but I don't think this is how it's supposed to be.


Here is what my tune looks like in Crome as far as timing goes

Any suggestions?

 

[drtalon123]

What kind of emulator are you using with crome?

I didn't see it in your post, but I'm sure you have an idea of what your doing, you do have a timing light right?

Also, I know you have timed everything with the balancer, but is it possible the balancer outer ring might have slipped?

 

[TunerThings]

I'm using a moates ostrich - I do have a timing light. Not one that can be adjusted but just an old school one. I'm reading that the OBD1 P28 + the D16Y8 OBD2 dizzy will need some adjusting I just am reading conflicting info on whether I should set the base timing to 21.5 or 12.. maybe it's neither?

 

[drtalon123]

21.5? Holy timing haha... Y8 stock is at the 12 mark, Z6 and others is typically 16 degrees. Being able to reach base timing with the service connector jumped should always be possible, even though you are using an OBD1 ECU on the Y8. When the ECU is jumpered, the ECU gives up its ability to control timing at all, and it then timing setting and position is entirely mechanical in nature, hence setting "base timing", meaning no ECU control.

When you jumper the service connector, is your check engine light on?

Does crome not have provisions for the service check function? Sorry, not much of a crome guy. Neptune and Hondata have a function to enable the service connector setting without physically having to do it. Maybe you might try the software version of the service connector enable if it is supported?

 

[TunerThings]

Yeah the 21.5 was something about the difference in degrees being 9 degrees or something? I didn't really understand it so I didn't want to try something that crazy. The CEL does flash when my jumper is in.
Crome is trash and I don't think it has that option lol

 

[drtalon123]

Ok lol... yea regardless, if your CEL does turn on when jumped, there is no reason you shouldn't be able to reach base timing entirely mechanically (updated my previous post, sorry realized I left out some important bits).

If you can't get anything near the 12 degree mark turning dist manually with the jumper connected, see if it is possible to even remotely get the red marks in the crosshairs. Pull all dist bolts out, and rotate some more just to see if it will move the distance. If it DOES, then something mechanical is off somewhere.

 

[drtalon123]

If it does, I would make sure outer balancer ring didn't slip or something. It is strange, in the fact that cam and crank line up almost perfect, usually if the balancer ring slipped you would know because those marks don't line up properly

 

[drtalon123]

When you say "freshly replaced head" did you do any headwork to it? Cam? No chance of having a Z6 cam in there?

 

[TunerThings]

I replaced the entire head with one I bought online from a remanufacturer - SHOULD be a y8 (advertised as such) but I'm kinda thinking maybe it has a z6 cam. I still have the cam from my original y8 so definitely could put that in. It just was easier for me at the time to source an entire head rather than the rocker arm assembly that I needed.

It has the y8 cam sprocket though - that came from the old head.

 

[drtalon123]

Just something easy to do before you try swapping the cam. Take a long 1/4" extension and put it down in #1 spark plug hole. Turn crank by hand and watch the extension as it approaches TDC. At the TDC tipping point, before the piston begins to fall, see how far off, if any, the crank pulley TDC indicator is to the timing cover indicator.

If the mark is off a decent amount doing it this way, suspect a slipped outer ring on the balancer. If the mark is damn close, keep looking elsewhere, like cam, etc.

 

[TunerThings]

I double checked it was tdc when I had the head off and the crank lined up but there have been so many wild things with this car it certainly wouldn't hurt to check again. Thanks for the help - it's really really appreciated

 

[TunerThings]

Any chance this could be a failing distributor? I didn't exactly buy the most expensive one on the market

 

[drtalon123]

Do you have another one that you might be able to swap in to try and confirm? It's really difficult to tell you if the rotation sensors in the distributor are out of whack in regards to TDC without using an oscilloscope. Easiest way without getting fancy is to try and swap in another distributor and see if you can reach your timing marks.

Also, I forgot to mention this earlier, what does your car idle at when you attempt to set base timing, and what kind of MAP sensor are you running? Is it's offset and scalar properly determined, setup and programmed into the map?

Having a high idle can affect your results, even when jumpered. same with an incorrectly programmed MAP sensor.

If you idle normal/in spec, and your MAP sensor is configured properly, I won't go into more detail about this.

 

[TunerThings]

I use a Motorola 2.5 bar MAP that up until today was verified as functioning correctly but I could recheck the wiring where it was spliced in, it could have gotten damaged or come loose - that's a great thought. Crome does have provisions to add this to the map and it was set as such. It idles at around 750 currently but I felt the vacuum at idle was a bit weak at 11psi. Unfortunately I don't have another distributor but I can probably still return this one it's within the warranty - to at least rule it out. I did replace the distributor just before the issue with the head gasket so it has zero miles on it to confirm it ever worked correctly.

 

[drtalon123]

Vacuum is showing 11PSI? Or do you mean 11 in-hg (inches of mercury)?

You can test map sensor by using a handheld vacuum pump with a vacuum gauge as well as adjusting the scalar and offsets for 0in-hg/psi in regards to your local atmospheric air pressure (or sea level, which ever you prefer) with it open to atmosphere.

If it is 11 inches of vacuum, that is pretty low. With every timing mark showing lined up, and your other symptoms, I'd suspect cam honestly if your valvetrain is healthy, valve lash is proper and you have no vacuum leaks.

 

[TunerThings]

You're correct 11in-hg
I just looked and I had my 2.5 bar map sensor plugged in backwards which probably shorted it out... I can't believe I made such a mistake.. all the data sheets say its trash after hooking it up wrong but it must have just been some kinda slip when putting everything back together. Could this be the cause of ALL of this? I dunno how it would run wired backwards with only the 5v power hooked up the whole time but... should be interesting trying it tomorrow morning plugged in correctly.

Regardless of whether this fixes it - thank you for bring this to my attention. Better to figure this out now than later. I feel like an idiot.

I'm going to have someone else double check that the crank pulley is correctly lined up tomorrow. I'm 99% sure that I have it on the dot but my eyes definitely could be messing with me. I'll also take 30 mins and toss in my stock camshaft - just for piece of mind.

Thanks again for taking the time to help me with this man I really do appreciate you.

 

[drtalon123]

If the MAP signal was compromised, it very well could have been forcing the ECU into a timing cell that was out of range or a limp home default while you were attempting to set timing. I'm surprised you didn't have a check engine light on with a fault for the MAP circuit?

Definitely get that sensor fixed and reading right before anything else

You could always try wiring it correctly and seeing what happens, it might not have f***ed it up, worth a try!

 

[TunerThings]

Just fixed it while the kids are sleeping lol first thing in the morning I'm gonna fire it up and give it a shot. But yeah surprisingly no CEL for that just my rear O2 sensor which is nonexistent

 

[TunerThings]

Well I rewired all the MAP wires just to ensure that everything had a good connection.. wouldn't stay on. When I unplugged it, it ran just like it did before. Time for a new MAP sensor it seems

 

[drtalon123]

What does Crome say when map is plugged in? Does it show something irrational?