so i have a 98 eclipse gs with a hahn turbo and vortech fmu. i started the car yesterday, started perfect, but a few issues i need help on. the air/fuel gauge continually goes from one extreme to the other when idling, and when given a little gas it goes rich. also, i rebuilt my motor with lower compression pistons and all, so i have to take it easy driving it. so we keep it under 2500 rpms, but the boost gauge reads no boost...is this normal? if so, when should it start boosting,and also, during idle what should my a/f gauge read since there is no boost. i have an exhaust leak that i am getting ready to fix...could this be the cause of these problems? thanks

Originally posted by captainstevo
so i have a 98 eclipse gs with a hahn turbo and vortech fmu. i started the car yesterday, started perfect, but a few issues i need help on. the air/fuel gauge continually goes from one extreme to the other when idling, and when given a little gas it goes rich. also, i rebuilt my motor with lower compression pistons and all, so i have to take it easy driving it. so we keep it under 2500 rpms, but the boost gauge reads no boost...is this normal? if so, when should it start boosting,and also, during idle what should my a/f gauge read since there is no boost. i have an exhaust leak that i am getting ready to fix...could this be the cause of these problems? thanks

Bouncing af gauge... NORMAL

RICH When at wot (wide openi throttle aka mashing gas peddle) NORMAL

Boost gauge reading no boost: NORMAL (if I understand your question correctly) THe hrc kit makes boost after 2500. When you enter boost by stepping on the gas, and it goes over 2500 rpms, the boost gauge should move from vac, into the boosted area of the gauge. If that is your problem, then a whole other trouble shooting should be done.

Exhaust leak: That can also be a problem with not getting boost. But if you are keeping it under 2500 then you won't be making boost.

yeah so i gave it 2600 rpms and still no boost...what should i check...?

Originally posted by captainstevo
yeah so i gave it 2600 rpms and still no boost...what should i check...?

Are you just reving the motor in Neutral? You have to have load on your motor, drive it. But if you just rebuilt I would suggest not boosting. Put a few hundred miles on it and then boost. Also durring the break in get some load on that motor, don't just let in idle and wear in.

yeah we were in neutral....so is it normal not to boost in neutral? the oil light is on so we are checking that out before we go and drive it. we think its just the oil sending unit, hopefully not the oil pump...

Originally posted by captainstevo
yeah we were in neutral....so is it normal not to boost in neutral? the oil light is on so we are checking that out before we go and drive it. we think its just the oil sending unit, hopefully not the oil pump...

yeah dude, it's not going to boost when you're in nuetral.

the guage going back and forth is just showing the fuel and air going back forth keeping it in the right mixture.

and go out and drive it a bit. it'll probably be easier to diagnose the problem as well as breaking it in better. and check the oil pressure.

also mine dosent build boost at partial throttle. you have to be at least at 3/4 throttle before it builds boost, so if you're just babying it up to those rpm's you porbably won't build boost.

yeah so we put an oil pressure gauge in last night and drove it around and the pressure is fine. it must have been a bad oil press sending unit. and yeah, i am babying it so im sure thats why the boost is sitting on zero. its really tempting to boost it, but my motor is new so im not going to. the only problem is an exhaust leak from the manifold to the head, prob because i had my head port and polished and milled so it is really flat and the manifold is not perfectly flat because i bought it used. thanks for everyones help