Newbie car is sputtering

[Nando15v89]

Hey guys I'm new to forum and dsm scene. I just recently purchased a 99 eclipse gst but the car doesn't run properly..... The car came with a few mods on it it has a fmic, aem fuel rail, greddy bov, injen intake, and a few other small items. The car had a t28 turbo in it but the guy I purchased it from took it out cause he wanted to keep it so I installed a stock t25 turbo and the car started up.... But once I revved up the motor it sputters around 3000rpm like if its hitting the revv limiter and wants to shut off.... The car has the check engine light on indicating Mass airflow sensor, and fuel pressure solenoid... But the mass air flow is new and we did a bypass on the solenoid and it still the same issue any ideas???

Thanks

 

[fourgsixthree33]

Did you do a boost leak test yet?

There is a reason there is a CEL for the MAF sensor. I would try swapping it out with a known good one and see if there are any changes.

Unplug your MAF while the car is running and see if anything changes (sounds, rpms, throttle response, etc.)

 

[Eagle96TalonTSi]

Sounds like exactly what my car was doing after I forgot to re plug the MAF in. May soudn silly but are you sure the clip is on and ALL the way in?

 

[jasjasbinks]

he could have changed the injector sizes and tuned the ecu to run the t28 properly. since you installed a t25, have you checked the injector size and tune? stock injectors for 2g are 450cc. hope this helps.

 

[gofast63]

he could have changed the injector sizes and tuned the ecu to run the t28 properly. since you installed a t25, have you checked the injector size and tune? stock injectors for 2g are 450cc. hope this helps.

I agree with binks. he probably had a manual boost controllor to work with the possible set of larger injectors. If i was you, i would look over everything to see what has been upgraded. It's really important for you to know, and for us to be able to help you.

 

[Nando15v89]

Yea did the boost test

Yea the Maf is plugged in

He installed the t28 thinking it would solve the problem i don't know why but the injectors were running on the stock t25 before

Here's a video and now that I think of it we did a vacuum test not a boost test I'm still trying to look on here on how to do a boost test I noticed the turbo gauge doesn't work after I warm up the car a bit you can hear the bov after I release the gas

[ame=http://m.youtube.com/watch?v=bKBSFcsTpZ0]99 Mitsubishi eclipse problems - YouTube[/ame]

 

[bewstin]

Sounds to me like it's idling rough. Always fun chasing down problems on a new car that someone else had their hand in...
Step #1 like fourgee said, there's a reason you have a code for you MAS. Check the wires going to it make sure they aren't cut or frayed. Also check the connector plug for the Coilpack and ignition module. The plastic gets old and brittle and I've seen them break many times, and they can wiggle off a little bit during hard driving. If they only wiggle off a tiny ammount the engine can sometimes idle smooth, or slightly rough like yours, but wont rev because the connections are arcing. Also I've had plug wires wiggle off the coilpacks and cause the same symptom.
Step #2 Check the hardpipe coming off your turbo inlet going to your intake. Insure that there are absolutely NO leaks or open nipples between the MAF and the Turbo, as the MAF will not be able to register this air going into you engine.
Step #3 If the connections look good and there are no leaks, I would simply try another MAF. It seems like it's not working properly, as the maf adjusts fuel depending on airflow, and if it's not working properly the car could be dumping way too much fuel or not enough fuel once you rev it up.
Step#4 The exhaust leak can cause a boost issue, should still be able to rev past 3k without sputtering like that, but you never want any exhaust leaks before the turbo or on the 02 housing.
Step#5 Check base timing. Pop off the upper timing cover, and put the engine at top dead center. There's a mark on your crank pulley that will line up on the lower timing cover marks. And the cam gears should have the timing marks exactly facing eachother and parallel with the block/head surphace. Search for pictures, its not hard to find.
Step#6 Honestly, It's most likely MAF related seeing is how you have a CEL code for it. But since you just got the car, i would replace the spark plugs and wires. They need to be done often, and make sure you get copper plugs. I run BPR7ES NGK plugs, non other.
Step #7 Actually can be done whenever, do a boost leak test. Even if you fix the problem, do one. You just got the car, ill put money you find at 4+ boost leaks, they always do, and a big enough one will make your car run like pooooop.

Like I said i cant imagine it's anything other than MAF sensor related. If the engine ever runs that bad it will usually throw misfire codes. The only thing I can think of if it is one of the other spark related problems i stated; is if the previous owner had the code previously, fixed the problem, and got a new problem without ever clearing the old code. Hope this helps, keep us posted. I'll follow this thread, because I HATE running/idling/boosting/vacuum leak issues... HATE HATE HATE because they can be a pita!! And i love to see them resolved.

 

[Nando15v89]

I talked to the previous owner and he said he replaced the mafs twice but cel would still pop up
I disconnected the mafs while the car was running and it would just shut off

Today I replaced the PVC which seemed to be it hasn't been changed in years then I replaced the fuel filter and I've done lots of fuel filter changes but this one seemed to be the worst the fuel was extremely black like if it were disel oil so I decided to open up the throttle body and take a look and There's a semi thick layer of dirt n grim all in there.... The iac was filthy as well I cleaned it off with some mafs cleaner but do you guys recommend I replace it?

Any recommendations on how to clean the whole fuel system n throttle body?

 

[bewstin]

Chemtool b-12 is a good product that goes in your gastank. Cleans your injectors and your entire fuel system. You can get it at autozone, advanced, or a regular parts store.

 

[Ghost_92TSi]

I would check timing.

 

[miguelmcv]

If it is mocking that much, then It is running extremely reach, Can you take some pics of your injectors, I have a feeling that you have bigger injectors and has nothing to tune.

Also, check the wiring from the MAF and see if there is anything wrong.

 

[Nando15v89]

So today I replaced my MAFS to a stock oem sensor..... But didn't solve anything I tried erasing code but my buddy said its a hard code and won't delete where do I go from here as far as checking wires and all that

 

[VTDSM28]

sounds like tuning problem since you switched the turbo set up

 

[Nando15v89]

When the guy replaced the stock t25 to a t28 he never tuned it ... He actually never even ran the car with the t28 ### he couldn't figure out the problem