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Pablobtown

Proven Member
108
3
Sep 16, 2013
Bloomington, Indiana
So I've had this issue for awhile now. But it was only occasional then went away immediately, even on my t-25. About two months ago I upgraded to a 14b and noticed the issue diminished slightly. However yesterday, till now, the motor will not boost. The turbo spools and the gauge (right off the intake Mani) reads 20psi like normal. The car won't move. What the hell is going on?? I also I did a leak test and found nothing.
 
Ok so the ECU is pulling timing... Ive done some research but I am still baffled. I have no tuning or engine management outside a MBC. I have stock injectors and stock fuel system. So I dont suspect any issues in the fuel system. The only difference is that I tired a new gas station last week... I cant imagine changing gas stations would do any damage like this but I have no clue. Hencing why this is in the newbie section.
 
Ha! How did I skip over that 20psi part ^^^ yeah, take that mbc off, don't be that guy that blows his stuff up then knocks on all the dsm crowd. You have about $1000 in parts to buy to run 20 psi reliably.

Injectors, tuning capability (safc is fine for up to 660's), fuel pump, afpr, wideband...

Your car is running like cral because it is probably registering hundreds of counts of knock at wot. Pulling timing is the ecus last resort to trying to get the engine to not go BOOM.

If you like your car, you'll ditch the mbc.
 
I'm thinking its a leak somewhere in that area. Like I said, I experienced this same issue on my t-25 at stock boost a long time ago, but it just happened so rarely I never thought twice about it. Now I'm scared to drive the car! I hate the thought of blowing the motor because I'm running all air all the time...
 
The engine starts retarding timing to compensate for knock around 2200 RPM, which is what made me think it was knock (or phantom knock). Although if your CEL is working that might not be the case, b/c the CEL flashes on while this is happening. And the knock sensor is near impossible to get to so checking it might be further down on your list than a lot of other easier possible solutions
 
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When my car did this it was the knock sensor, it was not installed correctly by the PO. 12 psi is what the 14b was made to run that's stock boost level.

Easiest way to get to the knock sensor is from below just FYI.
 
check it, if it is goopy or leaking it is bad. Also, if it is too tight it needs to be set to the proper torque and, of course, make sure it is plugged in.
 
Here's a good look at what a good vs. bad knock sensor looks like to help explain thomcasey's recommendation of checking for goop. The resin, or goop in the back will melt and run out when they go bad. ;)

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Just throwing this out there but i had an issue with no boost or poor boost occasionally and when i finally figured it out it was too late but the flap on my wastegate had come loose and was moving in and out of the exhaust housing working sometimes but not othertimes..
 
So in your boost leak test you did, you only tested the piping? You realize that's only like 5 couplers out of about 100 places air can leak out of the motor. Upper/lower injector seals, anywhere on the throttle body, all of your vac lines...

If its a big enough boost leak it will retard the timing as stated above, and make it run rich

Edit, I have also been plagued by a broken knock sensor
 
Alright, so it seems to be driving fine. I did a test with a program called torque pro for android with a elm obd 2 adapter. It has a knock detection built in and it didn't see anything at WOT. But it also didn't retard the timing once on my little test drive and drove fine I thought. I also did the test where you hit the IM with a wrench to try to set off the knock sensor. Nothing changed in the idle or sound of the motor when I did that. Nor did the ecu see knock.

I am T-ing off the bov to the MBC which connects to the wastegate.[DOUBLEPOST=1407449015][/DOUBLEPOST]Also the boost leak test. The first test I did was the whole system. Plugged up my tester to the turbo inlet set the compressor to 20psi, and I couldn't listen because of all the noise the tester was making right before it blew up. So then I only tested the piping with a plug on the braided house that connects to the throttle body. So the piping tests out OK.
 
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