The Top DSM Community on the Web

For 1990-1999 Mitsubishi Eclipse, Eagle Talon, Plymouth Laser, and Galant VR-4 Owners. Log in to remove most ads.

Please Support ExtremePSI
Please Support ExtremePSI

Sudden unexplained massive power loss.

This site may earn a commission from merchant
affiliate links, including eBay, Amazon, and others.

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.

bastarddsm

20+ Year Contributor
5,620
1,457
Aug 26, 2003
Mendota, Illinois
So I'm fighting an issue with my car and I can't figure it out.

Last summer the car was on about 34-35psi ~12:1 AFR gas scale on E85, and basically 19-21* timing. It always trapped 133mph, except for one pass it trapped 137 in the 1/4 and 102-104 in the 1/8. On a dynojet it was making right around 600whp as it's 3200lbs ready to race. It never showed any knock on the logger nor was it detectable on the plugs. I showed some plugs to some top alcohol dragster guys and they said I should probably give it a few more degrees of timing. The timing I was at was found by giving it timing and watching the trap speeds. It quit picking up at 19-21*

Come august, I pull a couple degrees of timing out of it, and I drive it 300mi south to school, and one friday night me and my roomate take it to a local 1/8mi. To be cool I drop the exhuast and cruise around campus a bit, maybe rip a launch in front of the engineering building as the chair of the dept is walking out the door haha. Anyway we get to the track and my buddy wants to ride along, and I didn't take out the subwoofers either. Car runs 105mph in the 1/8 spinning hard and weighing probably 3500lbs. I'm like holy shit it's making power. I make 2 more passes and they both back it up. Unfortunatly my computer sucks and I didn't get any logs of the runs.

fall break in mid october comes, I buy qtp's and take it home and to the track on qtp's. I pull the sub box out and drop the exhuast. Car weighs 3080, runs 10.99@131 33-34psi, and 18-19* timing. In third gear it has like 8 knock counts, and it was bad enough that I heard it in car. I figured it was just a fluke, and I kinda hot lapped it. Next pass break the transfercase and both rear axles, have to get 4 wheel dollied off the track.

I fix it, go back to the track, give it the old agressive timing map from the summer. Car runs 132-133 all day and I get a [email protected] But it still knocks in 3rd gear. Car was pretty cool when staged. I take it home put the street tires on it, take timing out, put the boost back down, and drive it back to school in the snow LOL.

Novemember 2, this local 1/8mi down in padukah has a $1000 to win heads up import race. I show up, but not many cars are there so it becomes a $250 bracket race, with like 4 automatic honda accords. One of them is driven by a division bracket champion. I make it to the finals, and runner up get my picture on the website and all. LOL. Anyway during time trials the car wants to go 93-94mph which I though was slow for the boost I was running(which was probably 25-26psi). Computer was gay so I didn't get logs, but it just didn't seem fast enough. I didnt think much of it because it was november, I was on street tires with an open cd and it was spinning the fronts hard on the launch.

Fast forward to this June, I put a 6 point rollbar in the car. Then I goto the track on the same tune I always run. Boost back up to 34-35psi 17 - 19* timing, car knocks like crazy, and runs 125mph.

I can't find anything wrong. Here's the setup from then:
Built 2.0 JE 8.5:1 pistons with quench pads
DKS 272's
AEM cam gears I-10* E 0*
Kiggly street springs instlaled at 1.475"
SMIM
2 sets of FIC 750's
2 walbro 255 externals
Holset HE351 - non VGT
MAFT
Old FP race intercooler. Same size as the JMF one. Bigger than the ETS race core.
3" exhaust straight trough.
BR8ES plugs gapped at 0.022"
Dynatek ARCII
Pump E85
My own tuning on an Ostrich.

Throughout July I forget about these problems and try to make new power to get ready for the shootout.
I put Kelford 272's in, and a Borg Warner S362. Car moves more air for sure, but is only making 500whp at 30psi at 15* 11.5:1 AFR. Knocks like crazy, and is peppering the plugs. And I'm lost. I've fattened it, riched it, more timing less timing.

Things I've checked:
Valve springs - still at 85lbs seat
Compression - 142 146 142 145
Boost leaks - None.
Cam timing - Cams are straight up.
Exhuast restriction - ran open 02 housing
Fuel - Measures E75, as it always does where I usually get it.
Plug wires - Tried 3 different sets
CAS - Tried new one.
Base timing is at 5*
Injectors - did a hillbilly flow test, they are all within a few percent. Also ran 750's and 450's with same behavior.
Ran without hood to make sure it wasn't sucking hot air or exhaust.

Nothing seems to affect it. I'm living/working 2 hours south of my normal home, when I had it here it seemed to feel better on local E85, than from home. Maybe the fuel is the problem?

I'm trying to get some E98 just to eliminate the fuel.

Anyone have any ideas?
 
Build up somewhere on the intake tract (ic, piping, head, smim) possibly even a valve sealing issue?

You've ruled out a majority of the possible problems everywhere else it seems.
 
I would send out the injectors for cleaning and flow test since the alcohol can and will leave residue of sorts like rust and that will inhibit them from atomizing your fuel correctly.
Other than that you have a solid setup and it seems like you have tried almost everything.
 
I've had my own share of unexplained weird things happen to my car, but this really seems like it might be something with the engine itself.
 
Support Vendors who Support the DSM Community
Boosted Fabrication ECM Tuning ExtremePSI Fuel Injector Clinic Innovation Products Jacks Transmissions JNZ Tuning Kiggly Racing Morrison Fabrications MyMitsubishiStore.com RixRacing RockAuto RTM Racing STM Tuned

Latest posts

Build Thread Updates

Vendor Updates

Latest Classifieds

Back
Top