Head Service - Page 10

SilvrEclipse · #**136** 02-19-2010, 08:21 AM

2 and 3 do not apply to the 420a motor. Hopefully that will help you diagnose it. Did by any chance you order one that can display the ECU real time? I know some of the motor expensive ones you can see what the ECU is doing, that may help you diagnose this problem. You could see if you have rpm,pw, etc.

torlok2002 · #**137** 02-19-2010, 08:43 AM

Yeah this one has a 'Freeze frame' which should do that. Here's the product:

http://www.amazon.com/gp/product/B00...ef=oss_product

SilvrEclipse · #**138** 02-21-2010, 12:00 PM

Freeze frame just shows you the motor conditions when the cel tripped. It doesn't let you view the ECU real time. Mine only has the freeze frame on it also.

torlok2002 · #**139** 03-04-2010, 11:44 AM

Well, hopefully this will help anyways.

It just came in(I chose the free shipping) and I'm going to start scanning as soon as I have a break from school/work.

torlok2002 · #**140** 03-12-2010, 11:55 AM

Well, OBD scanner hooked up with no codes being thrown. Looks like I might be pulling the timing once more.

Very frustrating when I had this running the first time, after I tore the entire engine down instead of just the head.

torlok2002 · #**141** 03-22-2010, 09:12 AM

Engine unmounted and timing cover pulled. Somehow did it in under 2 hours alone, I'm getting pretty good at this process.

I started manually turning the Crank, and believe I found the problem... Timing jumped one tooth while manually turning! In any case, this is not good and would certainly explain the lack of spark.

My next goal will be to pull the valve cover and camshafts, so I can reset the timing w/o risking damage to the valves again. (Unless anyone has a better/easier recommendation).

SilvrEclipse · #**142** 03-22-2010, 11:43 AM

I wouldn't pull the cams out. Remove the VC and make sure everything checks out there. Something is making that belt jump timing, check all your pulleys and water pump to make sure nothing is binding, check the tensioner and make sure its not bad. Your not going to bend a valve turning the motor over by hand so just set the crank to TDC and retime the motor. If you feel resistence then you may be hitting a valve so dont force it if it gets stuck. Remove the plugs when you do this so you wont be hitting that compression stroke.

torlok2002 · #**143** 03-22-2010, 01:13 PM

Thanks, I didn't even think of this, and now its incredibly obvious. This will save a lot of time.

torlok2002 · #**144** 11-09-2010, 07:26 PM

Just an FYI, I spent a bit of time troubleshooting again to no avail. Yes it has been a while, and summer is gone so I plan on spending more time on it in the cool weather. My goal is to get this thing out of my garage.

Timing was quadruple checked this time before putting everything back together. Same result whether the engine was unmounted, or completely mounted. Everything turns over fine, but no spark.

The only other ideas I have are that the ECU might be bad (but this should throw a CEL code, and none are) or I have to mount something else stupid (put belts on, intake hose to air filter, Header heat shroud???).

This is just a bump for right now. Will start on it this weekend hopefully.

david-b · #**145** 11-10-2010, 10:08 AM

A bad ECU will not always throw a CEL. Had a bad ECU on my old Oldsmobile. Never had a CEL or anything. Just wouldn't work right all the times. Replaced lots of sensors, and turned out didn't need to. ECU was just not working right.

For the motor to start, you don't need belts, intake or header heat shroud. Those are all little pieces. All you need is fuel, electrical, sensors and ECU.

SilvrEclipse · #**146** 11-10-2010, 07:03 PM

i would swap the ecu and see if that works. They arent that expensive anymore

torlok2002 · #**147** 04-01-2011, 08:09 AM

Well, after a lot more frustration and toil.... There is spark again!

I knew at a certain point I was not going to get anywhere by myself, so I have been asking around for a good local shop. I found one and they had it licked in about 30 minutes!

Turns out I had switched 2 of the wires somewhere in the wiring harness that are interchangeable.(Cam Sensor & something else?) I'll be picking it up this weekend to investigate. The fix was cheap too!

I just wanted to say a big thanks to everyone on here who helped with advice. I'll be putting it back in the garage and bolting on the rest of the accessories and doing a few other things I had not messed with since I couldn't get it to run.(A/C, hatch lifts, clutch master cylinder leaking, etc)

BTW, there isn't much activity on this forum recently. My thread is still on the front page from November :-)

[EDIT: And no, this is not an April Fools prank...]

david-b · #**148** 04-01-2011, 08:57 AM

Glad you found the problem. Get it all back together and fixed and get it running!

Ya there's not too much going on here anymore. Kind of sad, but it happens.

SilvrEclipse · #**149** 04-03-2011, 06:41 PM

probably cam and vss sensor

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