Question about boost issue:
01-05-2006, 10:20 AM
#1
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Question about boost issue:
Before I took my car into the shop I was having some boost issues. (set up) 180 fwd, with APR running 93 program, with a Forge DV (green spring with washers) also tried yellow as well w/out and w/out washers.
On my way on the highway I am running abour 17/18 lbs on full throttle, then it drops hard to about 12/13 lbs at about 4500 rpm in 1st/2nd etc... In the higher gears goes a little higher, but the 4500 range is still the same. That is for starters, just doesn't feel strong.
Then, about midway through the trip the boost just drops to about 6 lbs on the gauge. no matter the throttle it only goes up that far. (now I know how it feels to drive a civic) so I wait and wait.. i undo the dv, it was sticking so it seemed. So I take out the piston wipe it down, put a little grease on it and put it back. Moves smoothly now... start the car STILL the same thing. I go back and check the vaccum lines to make sure all is good, and that the lines around the fpr were ok. All is good (puzzled) I drive off. Well im driving, still no boost (or lack there of) and I release the throttle to shift, back on throttle and WHAM boost is back. Blah! Wth can it be?! Vag'd it at RafaTTs house turned up nothing. And yes a CEL does come on, but nothing out of the ordinary.
On my way on the highway I am running abour 17/18 lbs on full throttle, then it drops hard to about 12/13 lbs at about 4500 rpm in 1st/2nd etc... In the higher gears goes a little higher, but the 4500 range is still the same. That is for starters, just doesn't feel strong.
Then, about midway through the trip the boost just drops to about 6 lbs on the gauge. no matter the throttle it only goes up that far. (now I know how it feels to drive a civic) so I wait and wait.. i undo the dv, it was sticking so it seemed. So I take out the piston wipe it down, put a little grease on it and put it back. Moves smoothly now... start the car STILL the same thing. I go back and check the vaccum lines to make sure all is good, and that the lines around the fpr were ok. All is good (puzzled) I drive off. Well im driving, still no boost (or lack there of) and I release the throttle to shift, back on throttle and WHAM boost is back. Blah! Wth can it be?! Vag'd it at RafaTTs house turned up nothing. And yes a CEL does come on, but nothing out of the ordinary.
01-05-2006, 10:25 AM
#3
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Hmm. Not something I checked out, as again I am kind of ignorant
as I always state, to car repairs lol. Is the harness easily replaceable? Part number? I never heard of any harness issues in here, so is this common??
01-05-2006, 10:42 AM
#4
The connector is easly removed...>>
<img src="http://images1.fotki.com/v5/photos/5/58883/297210/DSCN0433-vi.jpg">
However these things usually don't go out.
Without the ModShack **** or BM the MAF should be =+160 @ 6000 g/sec (logging block 002) If it is lower the MAF is failing.
When I was testing the **** and the MAF was failing, the g/sec was around 140 @ 6000.
As far as boost, In 3rd-5th, it sould be around 15 - 17lbs until 4500 then taper off.
However these things usually don't go out.
Without the ModShack **** or BM the MAF should be =+160 @ 6000 g/sec (logging block 002) If it is lower the MAF is failing.
When I was testing the **** and the MAF was failing, the g/sec was around 140 @ 6000.
As far as boost, In 3rd-5th, it sould be around 15 - 17lbs until 4500 then taper off.
01-05-2006, 10:42 AM
#5
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Try this to see if it's the harness...
<center><img src="http://images1.fotki.com/v9/photos/7/7305/149094/DSCF0071-vi.jpg"></center><p>remove the connector from the N75 (pic borrowed from the schwingster). If memory serves, the engine should not boost pass 5-6psi. Take the car for a drive and see.
If the harness does have a short, you will need to have someone probe the harness since I do not believe the harness can be easily replaced. I think it is part of a much larger harness assembly. Once the short is found it should be easy to fix.
If the harness does have a short, you will need to have someone probe the harness since I do not believe the harness can be easily replaced. I think it is part of a much larger harness assembly. Once the short is found it should be easy to fix.
01-05-2006, 10:51 AM
#7
Let me repeat...>
CEL = Code
What is it?
Bad MAF or Bad Temp sensor can both be causes of this. The ECU is commanding LIMP mode because something is not right. Measure block 32 to check the MAF induced adaptation. Temp sensor won't throw a code or CEL though.
You can also unplug your MAF and see how it runs..
What is it?
Bad MAF or Bad Temp sensor can both be causes of this. The ECU is commanding LIMP mode because something is not right. Measure block 32 to check the MAF induced adaptation. Temp sensor won't throw a code or CEL though.
You can also unplug your MAF and see how it runs..
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01-05-2006, 10:56 AM
#8
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Let me repeat (nothing out of the ordinary)
Nothing came up that would indicate the MAF is bad. Even when disconnecting the MAF sensor I still had the issue. I had disconnected my MAF while up in Tennessee before I replaced it with another one and never had boost loss.
The vag was showing something funky like the light adjustment sensor. I don't see that causing boost loss. No idea why the CEL came on and went off and didn't flag anything on the VAG. Mind you, I also had it vag'd the third time and dropped it off at my stealership to have one of the guys I know there check it. Still found nothing. (shrugs) gremlin!
The vag was showing something funky like the light adjustment sensor. I don't see that causing boost loss. No idea why the CEL came on and went off and didn't flag anything on the VAG. Mind you, I also had it vag'd the third time and dropped it off at my stealership to have one of the guys I know there check it. Still found nothing. (shrugs) gremlin!
01-05-2006, 11:00 AM
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Thanks RoberTT... I will have to try and probe it like the other gentleman said
and see what happens, once I get the car out. It just hit me, I know I am going to get it out of the shop and the darn thing is going to have this issue. (shrugs)
We replaced the thermostat, however the temp sensor has not yet been installed. From Schwing, I am assuming this could be the problem too. I hope the hell that is it aye! I can't deal with much more of this stuff.
We replaced the thermostat, however the temp sensor has not yet been installed. From Schwing, I am assuming this could be the problem too. I hope the hell that is it aye! I can't deal with much more of this stuff.