420a turbo idle very odd and scary

[Brad Bell]

Hey everyone, I bought a 2g eclipse 420a with a stage 2 Hahn racecraft turbo kit, that i will be swapping into my own car. The engine is already built up and everything running 11psi. When you start up the car, after a few minutes the car starts to sound odd like its missing a piston, it goes like "bump bump bump bump" and sounds very odd, the rpm gauge starts to flutter between 0 and 1000rpm and the lights and electronics start to turn on and off, like its about to stall but it never does.
The guy I bought the car off of told me that there is supposivly a second fuel pumps for the turbo and it switches over, I don't know any knowledge on that so if someone does please fill me in. The car drives perfectly but it's idle is just so screwed up. Possible reasons I thought it might be.

Possible reasons (I'm a noob to turbo cars just letting you know)

Car has regular unleaded fuel in tank that is not high enough octane

Blow off valve is not set right, spring too loose or too tight (Greddy Rs bov)

Fuel regulator not set right, I don't know where it is on the car but I'm sure it's somewhere.

Please help me out guys, I'm new to this stuff and I need all the info I can get.

 

[jimsgsx]

How much did you purchase your car for?[DOUBLEPOST=1418087145][/DOUBLEPOST]

How much did you purchase your car for?

Also never go below 92 on gas, the bov shouldnt affect the idle. Are you running a maf? Put a pic up of your engine.

 

[Brad Bell]

I bought it for 4k and there's 11k invested in the car. I'm not sure about a maf, i just picked up the car yesterday. I'll try and get some pics up asap

 

[tec_41]

Before driving that car any further I would figure out exactly what you have for engine management in there. If it's set to 11psi you will want to cross your fingers that it has MegaSquirt, or some kind of actual fuel management. The cheaper/easier method of fuel management on the 420a is an FMU (fuel management unit) and a high pressure fuel pump, but this is only somewhat reliable on low boost levels. Like, 8psi and less.

Improperly set BOV won't cause the issues you're experiencing. Improperly set FPR might...Base fuel pressure for a 420a should be 45-50psi.

If you could get a high res picture of the engine bay that would help. Also, a video clip of the idling issue. That whole dual fuel pump thing sounds overly complicated and like some real shenanigans.

 

[Brad Bell]

Alright i took some pics and quick video on what happens with the idle, now when i got it up and running after about 3 minutes the car started to do that "bump bump bump bump" thing like i was talking about and the rpm gauge was going nuts. I then moved it around my driveway a bit and it went away. I then took this video, where the car suddenly begins to stall out then jolts and recovers it, it's very hard to describe whats going on but just bear with me. It also happens when you throttle the car, i revved it up to about 4,000 and as it started to slow down it almost stalled out and then recovered. The fuel pressure gauge doesn't work so i'm not sure what psi its set to. Finally listed carefully to the car and it sounds like has a hissing noise, so possibly a vacuum leak somewhere. Hope this information helps.

In the video there are 3 gauges, the one in front is the boost gauge and the second is a fuel pressure gauge (which seems to be not working). The third you cant see is a air/fuel mixture ratio gauge which comes on randomly and the line is on the lowest it can go which is in the "lean" section.

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[tec_41]

Video is set to private . Going to check out your pictures and then type some stuff up...sit tight![DOUBLEPOST=1418164865][/DOUBLEPOST]The hissing noise is definitely one you'll want to pinpoint. Vacuum/boost leaks can really cause some odd problems. Quickest way to check is with a can of carb cleaner - With the car running, spray it around any suspect areas like vacuum lines, couplers, or gaskets. Definitely try to check the back of the intake manifold. There is a vacuum source port here with several connections, and it could help you find out if maybe the intake manifold gasket is blown. You'll hear the idle change noticeably if the carb cleaner finds a leak.

If you can get that video set to public it'd be helpful to see what your boost/vac gauge reads (if it shows vac, that is). If you're interested in checking fuel pressure there should be a schroeder valve on the fuel rail, unless it's a 95. I don't believe 95's had this. You can usually rent a fuel pressure testing kit from a local parts store and plug it right into that port to check your idle pressure.

 

[Brad Bell]

Okay, i set the video to public. Its kinda hard to focus on the boost/vac gauge, using a crap camera. But it seems to be sitting between 15-20 at idle[DOUBLEPOST=1418247606][/DOUBLEPOST]

Video is set to private . Going to check out your pictures and then type some stuff up...sit tight![DOUBLEPOST=1418164865][/DOUBLEPOST]The hissing noise is definitely one you'll want to pinpoint. Vacuum/boost leaks can really cause some odd problems. Quickest way to check is with a can of carb cleaner - With the car running, spray it around any suspect areas like vacuum lines, couplers, or gaskets. Definitely try to check the back of the intake manifold. There is a vacuum source port here with several connections, and it could help you find out if maybe the intake manifold gasket is blown. You'll hear the idle change noticeably if the carb cleaner finds a leak.

If you can get that video set to public it'd be helpful to see what your boost/vac gauge reads (if it shows vac, that is). If you're interested in checking fuel pressure there should be a schroeder valve on the fuel rail, unless it's a 95. I don't believe 95's had this. You can usually rent a fuel pressure testing kit from a local parts store and plug it right into that port to check your idle pressure.

Anything yet?

 

[tec_41]

I still can't view it . Says it hasn't been made available.

 

[Brad Bell]

Okay i re uploaded the vid

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I still can't view it . Says it hasn't been made available.

 

[p_o_s_pc]

I am able to see the video. Did the person mention what size injectors or the brand of fuel pump?

 

[Brad Bell]

The guy i bought it off didn't know what it had for injectors. Only because he bought the car off of the guy who actually built the car. This is the turbo kit that is installed in the car.>http://www.turbosystem.com/auto/eclipse/eclipsestage2.htm. I do know that there is an upgraded fuel pump installed