Air/Fuel mixture, manual adjustments possible? |
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Air/Fuel mixture, manual adjustments possible? |
newto914s |
Sep 22 2004, 08:51 AM
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#1
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Senior Member Group: Members Posts: 561 Joined: 16-February 04 From: Thornton, CO Member No.: 1,663 |
I was wondering if their is anyway to manualy adjust the air/fuel mixture on a 2L with stock d-jet fuel injection. I really feel like my car is running rich and I hear a good sized sucking nose coming from my throtle plate.
It sounds and feels like my car can't breath. Thanks |
ArtechnikA |
Sep 22 2004, 09:00 AM
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#2
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rich herzog Group: Members Posts: 7,390 Joined: 4-April 03 From: Salted Roads, PA Member No.: 513 Region Association: None |
fix whatever's broken, and the AFR will be magically correct.
likely suspects: Manifold pressure sensor, head temperature sensor, plenum temperature sensor. |
mike_the_man |
Sep 22 2004, 09:03 AM
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#3
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I like stuff! Group: Members Posts: 1,338 Joined: 11-June 03 From: Regina, Saskatchewan, Canada Member No.: 809 |
Take a look through Brad Ander's web page. Pretty well everything you need to know about D-jet is explained here.
D-Jet web page Let us know if you have any questions after that. It should answer most of them, I hope. |
newto914s |
Sep 22 2004, 09:15 AM
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#4
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Senior Member Group: Members Posts: 561 Joined: 16-February 04 From: Thornton, CO Member No.: 1,663 |
Thanks Mike, I've seen Brad's site before. I'll take a good look this time.
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Bleyseng |
Sep 22 2004, 10:02 AM
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#5
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Aircooled Baby! Group: Members Posts: 13,036 Joined: 27-December 02 From: Seattle, Washington (for now) Member No.: 24 Region Association: Pacific Northwest |
Yes, it can be done but only after everything else is checked that it is working properly and in spec. This is a hard wired FI and works very well when its set up just like it was when it left the factory.
Make sure they aren't any vacuum leaks anywhere. Make sure the FI parts match their specific year. (ECU,MPS,CHT) Taking apart a MPS and adjusting the A/F mix can be done but its not easy. Geoff |
mike_the_man |
Sep 22 2004, 10:58 AM
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#6
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I like stuff! Group: Members Posts: 1,338 Joined: 11-June 03 From: Regina, Saskatchewan, Canada Member No.: 809 |
You can also adjust the idle mixture using the knob on the ECU. Right = richer, left = leaner. Without the right tools, adjusting the MPS is just guess work. I believe that Geoff (Bleyseng) could adjust your MPS if it comes down to that.
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newto914s |
Sep 22 2004, 11:18 AM
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#7
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Senior Member Group: Members Posts: 561 Joined: 16-February 04 From: Thornton, CO Member No.: 1,663 |
Is it possible to confuse the idle mixture knob with the idle adjustment knob(i.e. raise the idle, or appear to do so)?
I left my car at my father house for a couple of weeks and he did some work on it. He's a good mechanic(owned and mantained an old bug and a volvo p1800) and taught me a lot about cars. I know he raise the ideal while the car was with him, it cured the stalling problem, and the car had been running more iratically before I left it with him, but in a different way(no sucking sound). I figure he might have been turning the wrong screw to raise the idle and upset the mixture in the process, or maybe that's not possible? |
Demick |
Sep 22 2004, 11:21 AM
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#8
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Ernie made me do it! Group: Benefactors Posts: 2,312 Joined: 6-February 03 From: Pleasanton, CA Member No.: 257 |
If it is running to rich or too lean, then there is probably a problem with one or more components in the FI system, or something is mismatched, or something not hooked up right.
So first make sure everything is working properly to start with. After that - if you want to make across the board changes to the mixture, that is most easily done by altering the fuel pressure slightly. But if you want to customize the mixture at different loads, you can only do that with adjustments to the MPS - and even then you are quite limited in how the profile can be altered. First step would be to get a wide band O2 sensor so you really know what your engine is doing. Only then can you make educated changes to the F.I. system. Demick |
Demick |
Sep 22 2004, 11:25 AM
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#9
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Ernie made me do it! Group: Benefactors Posts: 2,312 Joined: 6-February 03 From: Pleasanton, CA Member No.: 257 |
Don't be concerned too much with the sucking sound. It is simply the sound of air being sucked through the idle speed bypass port. Sometimes this can be quite noisy.
Demick |
mike_the_man |
Sep 22 2004, 11:33 AM
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#10
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I like stuff! Group: Members Posts: 1,338 Joined: 11-June 03 From: Regina, Saskatchewan, Canada Member No.: 809 |
QUOTE(newto914s @ Sep 22 2004, 09:18 AM) Is it possible to confuse the idle mixture knob with the idle adjustment knob(i.e. raise the idle, or appear to do so)? The idle adjustment screw is on the throttle body. Cranking it out will raise the idle, cranking it in will lower the idle. The idle mixture adjustement is on top of the ECU, which is located on the firewall, under the battery. It should be pretty tough to get these two confused. Adjusting the idle mixture will definitely change the RPMs at idle though. The only way to properly set it is to use an O2 sensor, or some other type of exhaust gas analyzer. Check all FI components and make sure there are no vaccuum leaks. Then set the idle mixture, and then you should be able to adjust the idle speed properly. Good luck, |
Bleyseng |
Sep 22 2004, 11:47 AM
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#11
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Aircooled Baby! Group: Members Posts: 13,036 Joined: 27-December 02 From: Seattle, Washington (for now) Member No.: 24 Region Association: Pacific Northwest |
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newto914s |
Sep 22 2004, 12:49 PM
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#12
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Senior Member Group: Members Posts: 561 Joined: 16-February 04 From: Thornton, CO Member No.: 1,663 |
Thanks again Mike! I'm on it. I have been planning on changing all my vacuum hoses. I just haven't had a chance to go out and messure them all. It would be nice if their was a kit that had all the hoses pre-cut to the standard messurements. Right (IMG:style_emoticons/default/wink.gif) I just need to suck it up and pull out the tape measure.
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mike_the_man |
Sep 22 2004, 01:21 PM
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#13
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I like stuff! Group: Members Posts: 1,338 Joined: 11-June 03 From: Regina, Saskatchewan, Canada Member No.: 809 |
I believe they have all the lengths and sizes for hoses on the Pelican site. Ahh, here it is.
Hose lengths |
newto914s |
Sep 23 2004, 06:11 AM
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#14
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Senior Member Group: Members Posts: 561 Joined: 16-February 04 From: Thornton, CO Member No.: 1,663 |
I've seen that diagram a million times and never noticed it had all the hose lenths under it. Thanks
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