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Post by Stinger on Jan 27, 2009 14:04:16 GMT -5
It's a pulse dampener, not a regulator. I see you tried raising fuel pressure and it didn't help. This may sound weird but have you tried lowering it? It's possible it's actually rich not lean and that's causing the bucking.
I'd also pressure test the system to try and locate any boost leaks.
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Post by 89turbolx on Apr 1, 2009 9:39:39 GMT -5
I'm not sure anyone is still responding to this but, I have done more to try to fix this problem. When I removed the turbo to install a gasket between the turbo and exhaust elbow, I found my exhaust manifold had a crack. Replaced with a header. Still goes lean after 10 pounds of boost. Performed cylinder leak test. Cylinder 2 and 4 where at 85% leak. #2 leaking through intake and #4 leaking through exhaust. Ran fuel injector and intake cleaner through motor. Retest and now at 10%. Car still goes lean after 10 psi will still no spark knock.
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Post by Stinger on Apr 1, 2009 13:04:51 GMT -5
Do you have a fuel pressure gauge you can watch while driving? You may be losing fuel pressure under load.
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Post by 89turbolx on Apr 1, 2009 14:54:18 GMT -5
Yes I did drive it with a fuel pressure gauge. Did not drop when car went lean. I don't know a good of a flow test I did, but with the fuel gauge hooked up, I pushed the button and drained gas into a container while the car was running. Engine did not die or attempt to die. I would assume my flow is good.
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Post by Stinger on Apr 2, 2009 11:16:12 GMT -5
Any smoke when it is missing?
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Post by 89turbolx on Apr 2, 2009 11:31:40 GMT -5
Not that that I can see. Also it doesn't seem to have the same power as it did. I ran compression test. All clyinders are about 175. I also notice it does it more during close loop.
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Post by Stinger on Apr 2, 2009 21:43:06 GMT -5
Where are you located?
Bottom line is, if your fuel pump is producing proper pressure when under load (should be base pressure + boost pressure = fuel pressure at wide open throttle) and it is in fact lean, additional fuel pressure will solve the problem. Since yours is not seeing this result, I'm inclined to say it is rich, not lean. There is nothing you've told me about your setup that should require more than stock fuel pressure. Do you have airflow mods you haven't already shared (header, porting, etc)?
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Post by 89turbolx on Apr 3, 2009 12:12:06 GMT -5
I live just outside of Louisville, KY. I did just installed a header, last week. Found my stock manifold was cracked. I would agree that I think it's running rich too. I can smell the fuel sometimes, but I'm going by what my A/F gauge is reading. The A/F gauge has been a good judge of things since the beginning. I've checked and rechecked for vacuum leaks and have fixed my exhaust leaks near the O2 sensor. I keep fixing little problems, but my main problem is still there. What's gets me, this all started when my brake booster went out. From all the I have fixed, the car should have more power than before, but don't think it does. One question, I'm not using the boost controler(the sensor the has 2 vacuum lines that go to the inlet of the turbo), but I haven't been using it even before this problem. I did plug it in and hooked it back up, didn't help. I have since removed it. How would that effect things?
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Post by Stinger on Apr 3, 2009 23:00:06 GMT -5
What are you using to control the boost level?
That flashing light show gauge is no longer a good judge of things. It's rich, back the fuel down to 35psi with the vacuum line to the regulator unplugged and take it for a spin (after you plug the vacuum line back in of course).
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Post by 89turbolx on Apr 5, 2009 9:09:44 GMT -5
I'm using a manual boost control. It's set to around 15 psi. I did unhookedthe battery on Friday night, drove it. One time in 3rd gear, it didn't go lean and had some spark know( good news I guess). I advanced the timing to 20 deg( looking to see if more spark know would happen) but just the opposite. No spark knock, and ran worse. Backed timing down to 8 or 9 deg, ran better, and had some spark knock back, but guage shoes lean still. Monday I will back fuel pressure back down and drive it.
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Post by Stinger on Apr 5, 2009 13:07:22 GMT -5
Are you sure you are setting the timing at BTDC not ATDC?
Check your ecu and chassis grounds (engine to chassis, harness to chassis, harness to engine, etc.).
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Post by 89turbolx on Apr 6, 2009 20:37:30 GMT -5
So I found out tonight I'm an idiot. I assumed with out verfication. I thought I was reading my timing marks on my cover correct. This is not the case, since half of my timing marks where broke off. I know why I have always had so much spark knock, because what I thought was 10 deg, was 25 degs of timing. I remember I had an extra timing cover, so I looked at it. Ok so, what should my base timing be? I though it was 10 degs, but I set it to 10degs and it has no power. I put it to 20degs, good power, no spark knock, but my gauge still goes lean. Do I ignore the gauge now or what? Also I did adjust my fuel pressure to 35psi, gauge still went lean. Sorry for having a Homer Simpson moment!
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Post by Stinger on Apr 6, 2009 23:23:29 GMT -5
Are you unplugging the spout to set the timing? You need to be. When you do, set it to 10 degrees BTDC and then plug the spout back in. It should advance to 25-30 degrees at idle.
Does your guage flip back and forth rich/lean/rich/lean/rich/lean quickly at idle/light cruise after the engine is warm?
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Post by 89turbolx on Apr 7, 2009 8:29:22 GMT -5
My gauge moves a little but it's usually in the center. I do notice that every so often the engine stumbles for a quick second and the gauge will lean out at idle. Then go back to center. I was wondering if I should try changing the o2 sensor that runs my gauge. I have an extra one I know is good. I just don't have the funds right now to buy a wideband o2.
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Post by Stinger on Apr 7, 2009 11:56:03 GMT -5
When it is running properly, it will sweep back and forth at idle/cruise (meaning it is at the proper a/f ratio of 14.7 during those times). I would try changing the o2 sensor and see if it starts doing so.
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