Need help from fellow Toyota Gurus! 2002 RAV4 no-start

I know this isn't a Tacoma, but let's face it, the people I respect the most are on this forum, and I know we have a great group of people on here. So here is the lowdown:

2002 Toyota RAV4 with 1VZ engine.
Original problem was a oil leak due to a crappy head gasket.
Replaced head gasket.
Engine when first trying to turn over will cough and catch, but won't fully start. Consecutive cranking results in nothing.
Have verified crank and cams are correctly timed
Have verified proper spark (Still replaced all 4 ignition coils because I wanted to be sure)
Have verified fuel into all 4 cylinders during cranking
No codes
Vehicle does NOT have a theft system, nor does it have factory immobilizer system. Key is standard style key.
MAF sensor is reading data
CPS is reading signal
Am assuming CMP is good since we have fuel injector pulse

This one really has me stumped. I've look at and verified everything, and it really should be starting, but I can't figure out for the life of my why it isn't. I have good compression, good spark, and I have fuel. It SHOULD run! Ideas?

 

Bummer..... So many people have read this thread, but no comments. lol. Guess everyone else is as stumped as I am. My kingdom for an Oscilloscope! Hahaha

 

Yea, sorry, it does appear you've covered everything. Stumped also.

I'm sure everyone here on TW would like to help in some way, especially considering how helpful you are to others.

 

I'm guessing you've already checked all the simple stuff like condition of the battery, air intake/filter for clogs, put fresh fuel into the tank, and tried to start it up when in neutral. I only mention it since there have been times I've wasted countless hours troubleshooting something only to find the solution was one of the basics. Let us know what you find. Good luck.

 

Are you sure about the 1VZ engine? According to WIKI, it should have either a 1ZZ or 1AZ .

Have you checked to be sure all sensors are now plugged in after the HG job?
(MAF, crank, cam, air-temp, coolant-temp, IAC, etc)

 

Thanks for the input. Yeah, all the basics are covered.

My bad. it is the 1AZ. Yes, verified all connections are connected, and verified all signals to ECU. It's really a stumper! I have fuel, I have spark, I have compression. If any of the sensors were bad, or disconnected, then I would lose either spark or fuel. Sadly I don't have a scope to check signal outputs directly, etc. Not exactly in the budget. lol

 

Maybe a large vacuum leak? Can you do a 'smoke test' on the intake?

 

Beyond the basics, such as compression, spark and fuel. Modern EFI can have other issues that can throw the diagnostics for a loop.

The values you are getting need to be looked over. Some things can prevent an engine from ever starting and don't follow the basic diagnostic protocols.

The 5V reference can "crash" and no sensor will operate. This can be due to bad grounds or weak ECU drivers.

The alternator can spike above 16v and shut down all modules.

Fuel pressure can be too low or too high.

TPS, ECT, MAF can all show readings that may be wrong etc... It's a bastard. Much easier when you have another car to compare it with.

That said, the 1AZ in those Rav's aren't very good, huge oil consumption issues, blowby could very well cause the no start as well.

 

Was a consideration, so I removed the intake and inspected for cracks, bad seals, or disconnected hoses.

Yep. I have ran the basic electrical runs on them. Verified proper voltage to each sensor for the reference, ECU is powered up and nothing is shutting down while cranking. Voltage is solid while cranking. Fuel pressure is within spec.

Biggest issue I have worried about, and you mentioned, is the accuracy of the input information from the sensors. I know that all sensors are at least sending data, as I can read it on the scan tool. I wish I had a scope so that I could look better at the signals to see if there are any drops or spikes.