Studder at 10psi...

Jokerman · Post by **Jokerman** » Tue Sep 21, 2004 6:17 pm

For some reason today my car decided to throw me another trick. For some reason if i get on it abit (1/2 throttle or more) at 10psi (ruffly since it is the stock boost guage) it will studder very quickly and then after maybe .5 seconds or so it will go right on up to 15psi. I am not seeing any vacumlines off and i run 93 octane all the time so i am not thinking that its a knock sensor. Any ideas? It is a 5spd car and has been boosting fine since i bought it.

d3m0n1c50ld13r · Post by **d3m0n1c50ld13r** » Tue Sep 21, 2004 10:30 pm

oddly enough i have the same problem, im thinking either my fuel filter is clogged, or the fuel pump cant keep up, once in a while i also get a bit of ping there

Jokerman · Post by **Jokerman** » Wed Sep 22, 2004 8:22 am

Fuel filter i know should be good since it has maybe 500miles on it and as for the pumps once it does the little blip studder it pulls fine at 15psi. Is this maybe a wastegate issue? I found a vacum issue yesterday (the lines going to the control solonoid that i had bypassed. One had split a bit so i cut it and respliced) but not change. The studder also seems to be somewhat intermittant as it will most of the time hit in 2nd, never in 1st, 50/50 in 3rd, sometimes 4th and occasionally 5th. Granted its a bit harder to test in 4th and 5th due to legal constraints (ie a 70mph limit on the highways).

MerkXRTurbo · Post by **MerkXRTurbo** » Wed Sep 22, 2004 8:28 am

Jokerman wrote:Granted its a bit harder to test in 4th and 5th due to legal constraints (ie a 70mph limit on the highways).

Oh yes. We all pay attention to that, don't we?

Jokerman · Post by **Jokerman** » Wed Sep 22, 2004 8:39 am

1 ticket in the merk is enough. Being under 25 and male means it ain't cheap no matter what and i am planning on buying a sport bike next summer so i must behave.

MerkXRTurbo · Post by **MerkXRTurbo** » Wed Sep 22, 2004 11:39 am

Jokerman wrote:1 ticket in the merk is enough. Being under 25 and male means it ain't cheap no matter what and i am planning on buying a sport bike next summer so i must behave.

I'm only 19, so I know what you're talking about there. I haven't gotten a ticket yet, and I want to keep it that way, so a Valentine 1 radar detector is in my near future.

d3m0n1c50ld13r · Post by **d3m0n1c50ld13r** » Wed Sep 22, 2004 3:27 pm

Jokerman wrote:Fuel filter i know should be good since it has maybe 500miles on it and as for the pumps once it does the little blip studder it pulls fine at 15psi. Is this maybe a wastegate issue? I found a vacum issue yesterday (the lines going to the control solonoid that i had bypassed. One had split a bit so i cut it and respliced) but not change. The studder also seems to be somewhat intermittant as it will most of the time hit in 2nd, never in 1st, 50/50 in 3rd, sometimes 4th and occasionally 5th. Granted its a bit harder to test in 4th and 5th due to legal constraints (ie a 70mph limit on the highways).

Honestly, mine does it worst in 2nd too, i've never had it happen in first...

im kinda stumped, i think my headgasket might have a slight leak,
but i would figure if that showed up as a problem, it'd be consistant, not just at WOT between 3K and 4K rpm... for you the problem may be your TPS?

SleeperX · Post by **SleeperX** » Wed Sep 22, 2004 4:46 pm

Fellows,
I think that you can relax about the turbo â€˜stutterâ€™ you are experiencing... i do not believe that anything is broken. My XR does this as well although i do plan to eliminate it through modifications. I wondered about it when i first bought my car then heard that other stock or mildly modified XRâ€™s experienced the same flutter phenomenon... I spoke with some of my professional turbo tech friends and they think that this is a stall or surge condition that will be normal for the system as it is designed on a stock or nearly stock XR. The compromise to have some boosted HP combined with drivability means that certain conditions (rpm vs. boost vs. load) will result in a momentary stall or surge or flutter at times. The gentleman at www.merkurencyclopedia.com under his â€œTurbochargerâ€

Quasi Mofo · Post by **Quasi Mofo** » Wed Sep 22, 2004 5:36 pm

It is generally noticed if you have eliminated your cat or installed a bigger exhaust also. My xr's didn't do it until I installed the larger exhausts. ironically when I put the 3" CAI on the RWB car it calmed it down quite a bit.

Paschek · Post by **Paschek** » Wed Sep 22, 2004 11:21 pm

Quasi Mofo wrote:It is generally noticed if you have eliminated your cat or installed a bigger exhaust also. My xr's didn't do it until I installed the larger exhausts. ironically when I put the 3" CAI on the RWB car it calmed it down quite a bit.

I agree with this, I have a bit of a studder at 4k, but it got alot better after I cleaned the filter in my CAI set up.

-Stef Paschek

edge · Post by **edge** » Fri Sep 24, 2004 12:36 pm

I have bascially the same problem sort of dies out at a little over 10 psi but let off and then back on it usually gets going. Mine didn't start until after I pulled the cat, but at the same time I added the cone filter large vam and PE eec. I think with mine I also need to change the wires haven't done that yet since it seems to be getting worse right now. Plus the guy I bought it from put wire looms around the wires and one of them is partially melted now hanging down from being melted (part of the loom).

edge · Post by **edge** » Fri Sep 24, 2004 1:05 pm

Also on that above list I replaced the wastegate the old wasn't hooked up and was bad.

edge · Post by **edge** » Fri Sep 24, 2004 1:16 pm

double post

richardcurtis · Post by **richardcurtis** » Fri Sep 24, 2004 2:00 pm

Hmmm. I've owned 4 XRs (3 5-speeds and 1 auto) and never noticed this "flutter" or "turbo stalling." My current one -- fresh motor, 3" downpipe into a high-flow (new) cat and Borla duals, cone filter mounted remotely, etc., etc. -- runs right to redline without any hesitation or flutter (18 lbs of boost, too). You say you changed the EEC... look for a problem there. Or put reinstall the original computer and see if that solves your problem. You also say you haven't changed the plug wires, which should've been the first thing you did, in addition to all fresh ignition components (plugs, dist. cap, rotor, plus resetting the timing). I'd try these simple things first before thinking you've got a more serious problem. Hope this helps.

MerkXRTurbo · Post by **MerkXRTurbo** » Fri Sep 24, 2004 2:17 pm

Are you guys running stock ignitions?