Rough engine idle Question

[Roleyz]

Hi, i have a 91 turbo that I have been building since Jan 06, just got the rebuilt engine back from precision engines, replaced all hoses, etc. New plugs, wires, (did not replace rotor cap). I installed all of it, started up fine but was running rough. Reset the timing to 10 degrees BTDC, Note(I dont have the exhaust on it yet so it was running with a straight pipe for about 3 minutes) Anyways to my question: Could the lack of backpressure from not having the exhaust on it cause that rough idle? if not do you all have any suggestions, also when I give it gas it tends to hesitate and sometimes backfire?

Thanks

Roley

[tHa kNiGHt FaLL]

in a turbo... absolutely.

sucking air out faster then its coming in. definately cause misfires... lack of power.i wouldn't run it longer than you have to... prevent damage

[Roleyz]

ok cool, I did get the stock exhaust back on and i still have the same problems, I am thinking now that I need to have it hooked up to a diag machine to see if I have any faulty sensors, etc? I am thinking now it has to be electronics since the block, turbo, etc is all new? maybe even injectors?

[Zz_005_zZ]

I think I have seen this post b4... As far as ideas, I believe that taking it to the dealership, or a very trusted and much cheaper mechanic should be on speed dial... stinks that it's happened man I know the feeling, I just hope for your sake it is a cheap ordeal!!
good luck :Brian

[Roleyz]

Thanks Brian, I did call the dealership and the guy i spoke to asked me when is the last time i put fresh gas in it? DUH! I didnt even think of that, I bought the car in Jan 06 drove it home and tore it apart, I have no idea what is even in the tank. I am going to drain the take and try fresh gas first, then on to the dealership (on a trailer) Jim

[JekylandHyde]

I ran Hyde for a good 2 or 3 years with a straight out exhaust.
Not having exhaust back pressure will not cause a turbo MR2 to idle rough.
The turbobien itself will cause back pressure.