I have a boosted tC for a customer that we built and tuned with an AEM standalone.

We were cruising in the car last night (2-3 mph) and heard some tap noises, and then the car quit (it wasn't loud)

So I thought the car just died, and tried to start it, well the car cranked like ALL the plugs were removed from the car (no compression) I verified this with a compression test.

I pulled the valve cover, and the timing chain is intact, but clearly the car is out of time, after being perfect!!

COULD the VVTI oil control solenoid have went bad??? or has someone else had this happen?

Just wanted to get some opinions, as I HOPE NO VALVES HIT THE PISTONS!!

Thanks

Justin

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PROBLEM SOLVED, SEE POST BELOW

 

Good luck with that. Sound fishy to me.

 

head gasket? did u use aftermarket head studs?

 

what did you torque the head bolts to?

 

what does the compression test say? cant be 0 across the broad also do a cylinder leak down test. if air comes from exhaust and intake then u have a valve issue. if you feel and hear air comming from your valve cover and oil dip stick you lost ur rings buddy... also check your fuses. also check your timing when set it at 0 on the crank. your timing on the camshaft gears should be 7links.. good luck...

 

Thanks for throwing out a few things guys, but I understand how to check the valves and do a leakdown and such, I have a very nice facility with everything I need, and Im grateful. I do appreciate any help ;) so keep it rockin

BUT the part I was shocked on is, the car CANT be hurt, impossible to say the least. car was just fine at idle, then backfired and shut off. so I try to crank the car again and the car has 0 comp. thats why it was cranking straight just like the plugs were all out. this is on ALL cylinders, I verified this with a compression gauge, (which I didnt have to do), the car just sounds like and engine with no plugs cranking, but as always its good to rule out the problem.

So I figured the timing chain broke or something to do with the hydraulic tensioner, pulled the valve cover, all is good, crank on 0 everything is correct. so at this point I was stumped.

I took off the manifold and everything today, including removing the crower cams, and withough the manifold I can see the valves on the exhuast side .. everything looked great. so now is a good time to see if the car has compression now, or at least do a leakdown, since the cams are out. SURE enough leakdown is less than 4% on a cold motor. so evidently the valves are fine and the motor is able to build compression.

I went to my friends house Jimmy who is a 20 some year tech at toyota, there master that goes to school and such from time to time for the new vehicles and other things Toyota indroduces. I fugured he may have seen the VVT-i pulley break before or the hydraulic tensioner possibly release causing the car to come out of time. He was stumped, basically floored.

So my conclusion is the VVT-i pulley inside lock pin has broken or the OCV (oil control valve that actuates it has messed up making the intake valves be out??????(the leakdown rules out any bent valves.)

It has to be a timing issue.. Unless someone else can think of something.

Ive seen alot of crazy things happen, but this one takes the cake.

I dont want to just throw in a new pulley and re-time the car, and drive it, NOT knowing what the issue was that caused this..

VVT-i pulley anyone? or anything else you can think of with the engine related to the camshafts


Thanks

Jusitn

 

watching, its not a head gasket either ?

 

No Def not a head gasket, it would take a serious blow to kill all 4 cyl's, the leakdown was less than 4% on a cold motor. compression test 2 days prior just for curiosity was 180 all across the board. this car was running fine and at ldle, quit and backfired, just like coming out of time..

I will keep everyone informed with what it is, as this could very well be something others will run into

VERY STRANGE..

hoping someone will swoop up on here with some feedback..

Thanks

Justin

 

take out the intake cam......near the gear there are the oil ports.....block off all the oil ports except the one closest to the cam gear.......apply around 15psi of air to it and see if the cam gear will move counter clockwise(i think is the right direction...if not try it the other way).....if it does then the vvti gear is fine.....maybe the gear was put on wrong on the new cams

 

How can you get good leak down numbers and no compression? If you are doing leak down test correctly every cylinder shoult be at TDC compression at time of test. If you are testing in this manner, If the cam timing were off you would have air leaking past open valves. If cam timing is indeed correct and you have good leak down you ought to have cranking compression.

 

Even if the VVT gear was locked, it could still pull air in (unless the cam wasn't moving at all and the gear was just freespinning).

Are you sure your compression gauge is working correctly? How are your plugs? What if you just take one plug out and put your finger/thumb over the hole. Does it push your thumb off? There are lots of things you could do still. It doesn't sound like a lower end problem at all since you don't have ANY compression, unless you broke the crank somehow or you have a hole in each piston hahahaha.

 

hey dont forget to put the piston rings on....bahahahaha

 

When you have the camshafts out, it rules out TDC actually, since all the valves are in the closed position. I did still set each piston at TDC just since I am used to doing that.

We build alot of high hp toyotas, supras, 5vz, and such, and I have never seen anything like it, but then again if the pulleys internal lock pin broke, it could casue a problem.


I still wonder if the aem could have glitched and sent a signal to the OCV that operates the VVT-i pulley at idle? and caused this? Im trying to think of every possible thing.

 

100% compression gauge is working correctly, It only has 0 compression with the camshafts in (timing issue) the car has 2600 on this new motor, everything was installed correctly, it has nothing to due with that, were suprised..LOL.. this was sitting at idle..lol.. just like the timing chain broke.

I knew right off there was no compression when I tried to restart it, because it free spun the crank, rods and pistons wtihout cylinder pressure. (just like the difference in sound when cranking your car with spark plugs in, and removing all 4 and cranking it, sounds like the starter is just going. YEEEEEEE..LOL)

Im assuming the cam gear went bad, the car was in timing when we pulled the valve cover and checked yesterday, we can turn the crank and both cams move, so the only way we cant have compression or hold compression with the cam shafts, is if there out of correct position, the hydraulic tensioner was in place chain was tight..

Ill def. keep everyone updated on what it is when we find out

 

Why the F are you doing a leak down with the cams removed?

 

Because the car wouldnt hold a leakdown with the cams in. The car was in time per the timing marks, but the vvti pulley is most likely broken.

Doing the leak down with the cams out verifys that the valves are sealed properly, and the rings are in fact good (which we knew it wasnt anything like that). It isnt beneficial for you, but in our situation it is. This way we can conclude our timing error with the vvti pulley.

 

There ya go. There was a lack of info in the previous post. All I was getting was you were assuming it was the VVTi. The only thing I saw was a 4 percent leakdown. I never saw that you had actually done a leakdown with the cams in and showed a problem.

 

Well Props to you for keeping the community in the loop on this. Another good thread about a strange problem.

 

I will have the new cam gear tom. Will keep everyone updated!!

 

FIgured it out, I will start a new thread as maybe it should be a sticky..

The dow pin that holds the VVTi cam gear in place broke. Letting the cam gear spin and come out of time(luckily it was at idle)

Another problem with the BC turbo cams is the dow(s) on the camshaft that the cam sensor uses to process the cam signal, have to be pushed out to get a reading on the aem (luckily the stock ecu can use it without the cam signal, but will give a CEL), or you can grind down the base of the cam sensor instead of messing with the dows (I did this) cheaper to buy a sensor than cams, and ended up working well.


here is the pics



you can clearly see where the dow pin is broke inside the VVTi camgear