1G Help! Lack of power at low RPMs

1GTSiAWD · Jun 8, 2014

So....not a newbie, necessarily, but I feel like one! I've been out of "the game" with my DSM for quite a few years due to money and time....

Here's what I'm healing with:
'92 TSi AWD (4/6 combo)
3" thermal research cat back
2.5" downpipe and highflow cat
evo3 O2 housing with dump
evo3 exhaust mani
Tial 38mm wastegate
Evo3 Big 16G (Real MHI!!)
Ghetto opened intake
MBC set at like 15 for now because of issues

I have a video of it here that you can kind of hear the sounds.... If someone has some ideas, I will try to get better ones or more specific...I know it is long, but hopefully you can maybe get an idea what I am dealing with on this one

You must be logged in to view this image or video.

- It idles rough (sounds like upgraded cams, but there are none)
- Under load it spits and sputters and has no power unless you can get the RPMs over about 3500-4000m then it grabs and goes like the car I used to know!
- Ticks REALLY loud...think lifter tick, but louder.

I unplugged the MAF sensor to see what happened, and the idle got worse, so I don't think that is it.... I unplugged each plug wire one at a time, and it got worse each time as well.

Thoughts?

phantom_19 · Jun 9, 2014

The condition of the engine is something you will have to check on that later. Compression and BLT.What I first thought is that you have bad spark plugs or your ignition coils are going out. A bad alternator could also be the cause of the coils not getting enough voltage to produce a powerful spark. You said it goes normally when the car is at high rpm. Could be that the alternator wheel is spinning a little faster and is able to feed the coils for that moment.

I also thought about tuning. Do you have a modded/chipped ecu? Any CEL when it sputters? What does the wide band say? I dont understand what it did when it was shown. What is the condition of your o2 sensor?The car could be performing well in high rpm because it will go in open loop mode and ignore the readings from the o2.

nwBryce89 · Jun 9, 2014

dont forget to check timing, ignition and mechanical. I have had the same issue before but it did not make that much noise, my issue was timing related but it ended up being a set of web cams having the dowel pins drilled in the wrong spot. My brother had a 91 gst that sounded a lot like your car and it would show that he was in boost while at an idle like your car does, I dont think he ever figured it out. I will ask him about it tomorrow.

DSM1G90 · Jun 9, 2014

Pull plugs and see how they look.

Black an sooty is signs of a terribly rich condition, or ECU took a dump.

1GTSiAWD · Jul 7, 2014

The plugs are black and sooty....so it is running rich, but no fuel mods have been done, so why would it be so rich????

No CEL at all....

mitsubishikid · Jul 7, 2014

did you do a balance shaft elimination?

it could be a snapped balance shaft belt pull the timing belt cover off and see if the belt snapped, my dsm made this kinda noise, and I got lucky cause the mini belt did not get tangled into the main belt.

Also if you recently had the timing belt/balance shaft belt done maybe the balance shaft is timed on the wrong phase.
or maybe the timing belt is timed wrong.
could also be a spun balance shaft bearing.

DSM1G90 · Jul 10, 2014

Weak spark can also cause black and sooty plugs in as well making it look like you have a rich condition, but you mention no fuel mods.. So thus, we rule out fuel issues.

Pull them out, lay them on the head and find a way to clamp them down on the head for a good ground and see if you have a strong blue spark, or a weak yellow spark when you have someone crank the thing over ... and pull the MPI fuse so the injectors don't fire.

Could have a funky power transistor module (transistors inside not fully shutting down) not allowing the primary coils to fully collapse to create the necessary secondary voltage to fire the plugs hot, or the coil is on its way out.

Been there and done that with both module and coil this last winter. Replaced both and got back on the road.

Good luck - DSM

Zufelt · Jul 10, 2014

Have you checked your CAS

The Top DSM Community on the Web

1G Help! Lack of power at low RPMs

1GTSiAWD

phantom_19

nwBryce89

DSM1G90

1GTSiAWD

mitsubishikid

DSM1G90

Zufelt

Similar threads

Latest posts

Build Thread Updates

Vendor Updates

Latest Classifieds