Hey guys i searched about it and didnt find what i was looking for. My new engine acts weird a little bit. When i start the car, it shakes a lot for 3-4 seconds and after its normal... just on startup.. engine runs smooth , pretty strong engine so far, but i dont know where to check for this little problem.

could it be my Fuel pressure reg (aeromotive)... because its not keeping its pressure when the car is OFF. Fuel pressure is good when the engine runs...


Max

 

Do you feel anything while driving, shifting, etc? Or is it just on startup?

 

sounds like maybe a bit of flooding? maybe a small coolant leak. i had the same thing with my dead coolant seals.

 

+1 on the slight coolent leak. Maybe check your coolent level and have some one smell the exhast for a sweet smell. (hope is not a coolent seal). Oh by the way try clicking the key on and off a few times before starting the car (with 3-5 second in between). This should get the pressure up if pressure is bleeding off.

 

i'll check the coolant for sure. it just makes it when i start the car, otherwise, it runs pretty good, no vibrations.. btw engine is new ... i doubt it could be coolant seals.

Max

 

If the engine is a new reman then it good easily be coolant seals. I've had a new reman with a pinched O ring and some others on the forum have experienced the same thing.

Good luck

 

the engine was built by adam from rx7 specialties, he built it in front of me. I hope its not a coolant seal.

Max

 

ok it doesnt smell coolant at all in the exhaust.... coolant is full in the filler neck. I tried clicking the key on off 3-4 times and there was a little vibration, much better than before... it shaked a little bit, but its nothing to compare when i dont let the on off key thing.

my old engine was doing the same thing... it was shaking, we saw that my aeromotive fpr wasnt keeping the fuel pressure when the car is shut down.

Max

 

Well if the previous motor was doing it, then it's obviously not the motor (lucky you!!).

 

might want to put a fuel gauge in to make sure your fuel pressure is good. Don't want to kill a new motor due to a bad fuel filter or fuel system.

 

i have a digital fuel gauge, pressure is good. really seems to be the defective aeromotive unit.

Max

 

Motor mounts?

 

maybe that could be.... i changed one two months ago, they were looking fine..

Max

 

Maybe the other motor mount is bad? but if it only happens at start up, I doubt it would be...

 

It could be that your IAC is gummed up after being shut down for an extended time, and takes a little bit for it to actuate.

http://www.clubrx.org/default.asp?id...ntent=63&mnu=5 (scroll down)

It could be a lot of things, though. And with such a small window of time where the problem occurs, it makes diagnosing the issue even more difficult. Good luck!

 

I'd still test the coolant for hydrocarbons and/or pressure test it.

 

I'll check everything, thanks guys

 

What is considered GOOD? The manual says 71 - 107 psi. When I measured mine with a jury rigged (possibly not so accurate) gauge, I get 50 - 60 psi. I don't appear to be having fuel starvation, but this pressure seems low. Mine keeps pressure with the key off, no problem.

 

Did you have your injectors checked/cleaned during the rebuild? Maybe one's sticking open. How quick does it lose fuel pressure after shutdown?

Check plugs shortly after shutdown to see if they're wet in one chamber. You should be able to smell if it's coolant or fuel.