Hey guys, short and sweet version:

- evo 4 engine, but same 4G63 as you 8/9 guys
- engine was removed to change timing belt and accessories
- clutch was changed from a stage 2 racing clutch to an OEM Exedy clutch
- timing was triple checked before putting the engine back in
- changed crank angle sensor and plate
- confirmed there is spark by taking plugs out to check for spark, and confirmed there is fuel by removing the whole rail and injectors to check for spray
- however the spray pattern seems off, as its not 1 3 4 2

The next thing I will check is the timing, but with the timing off will it cause the engine to not start? I noticed that theres a random shudder occasionally when I crank the engine. I thought I triple checked the engine's timing, but then I guess it doesnt mean I did it right the first time....Please help

 

might be the camshaft position sensor, sometimes it gets babged up and damaged and it will cause a no start. not 100%, but a thought

 

If the camshaft sensor was bad then it'd be a no spark issue, same with the crankshaft sensor. But I got spark and fuel. It doesnt even help when i pulse the throttle, so its not the idling servo or throttle body.

 

If you're getting spark and fuel the only other things you would need for proper combustion, assuming you don't have a dead animal in your intake tube, is compression and timing (you've already checked timing). I would do a compression test and look more into the injector spray pattern that seems suspicious.

-pal215

 

I've done the compression test and it checks out at 140 to 150 across all cylinders. I agree with the spray pattern though, I'll have to double check the timing again once I get on it this weekend. Will the timing being off cause the engine not to start? I assume itll start, just run pretty crappy no?

 

Hmm, your compression is just fine and you probably wouldn't get numbers that high if your timing was super off.

Timing could definitely cause the engine not to start. Remember that your mechanical timing has a direct connection to how much air stays in the cylinder during your compression stroke. If your timing is very off, you may have an open valve let all the compression out. Or even worse, valve to piston contact.

My timing was off by 2 teeth at my crank once and that gave miserable starting issues. Luckily I figured it out before it was too late haha.


Are you running high-Z or low Z-injectors? If high -Z , did you install the resistor pack delete plug?

-pal215

 

I am running OEM injectors, didn't even touch the fuel system when I took the engine out. Just straight timing change and clutch change. I didn't mess with the ecu or any electronics as well, just the crank sensor. It's a ******* mystery man

 

Yeah man, if I didn't know any better i'd say your fuel is bad. I think this could be an ECU issue as well. How are all your fuses?

If you find out what it is, keep us posted. This is getting interesting.

You have:
1. Correct Timing
2. Fuel
3. Ignition
4. Compression
5. Working cam and crank sensors
6. Starter works
7. MAF plugged in


-pal215

 

Well I THINK its the correct timing. I'll have to confirm this weekend when I'm home to work on it. I'm away for work at the moment. When you say ecu, what could be wrong with it? I already reset it multiple times

 

There is an immobilizer code that needs to be matched when upgrading to tephra roms that could prevent the car from starting if it's incorrect, but if you didn't flash the ECU between now and the clutch job then that can't be your problem.

There is an ECU fuse that could also keep the car from starting. For evo 8's it's fuse number 8. A 20A fuse.

Just to make sure though, if you have a buddy with a known working ECU that you trust, I might even try swapping that in and see if it makes a difference. ECU controls injector pulse and if your pulse is off on your injectors, then the injector driver circuit in the ECU could be fried.

If that fails then I would definitely recheck timing.

-pal215

 

Hmm interesting.... What are the chances the ECU will fry on its own without being touched. Although the fuse is easy enough to check, and I do have a evo 5 ecu handy to swap over if need be. I was actually waiting for my evo 5 engine to come in to change that ecu in, but if I guess its worth a shot