74 2.0L, Running Very Rich, owner quite confused, need diagnostic help |
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74 2.0L, Running Very Rich, owner quite confused, need diagnostic help |
drumsticks2112 |
Sep 20 2009, 12:56 PM
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#1
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Newbie Group: Members Posts: 7 Joined: 29-October 08 From: New London Member No.: 9,704 Region Association: Upper MidWest |
Car fires without a problem, but idles quite rough, and runs very rich, so much so that when the it settles down to normal idles, it floods out. MPS was replaced with a used but tested one recently. When it was last running ( a year ago) it ran a little rich, but nothing like this.
As of now, the CHT is not connected. When it is connected, the RPMs jump up to 4000 and stay there. When the CHT is bypassed with direct grounding of the harness, the results are the same as with the sensor being disconnected. I have no reason to suspect the injectors, FPR, Decel Valve, or the MPS. Any and all advice is welcome. -Todd |
CHAZT54 |
Sep 23 2009, 12:41 PM
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#2
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CHAZT54 Group: Members Posts: 19 Joined: 29-December 08 From: New London, Wisconsin Member No.: 9,878 Region Association: Upper MidWest |
I am working with drumsticks on this car and have done the following in the last 24 hrs to track down the source of this problem;
I replaced the vac. hose going to the MPS - there seemed to be good vaccum on the MPS end of the hose when running and connecting it to the MPS while running had minimal effect- still flooding out. At the same time I connected the hd temp sensor lead to the inj. harness lead which makes the eng race immediately without moving the throttle body flap. ALSO - grounding the hd temp lead from the brain had NO effect. I am beginning to think we are barking up the wrong tree. This car ran pretty good a year ago, albeit a little rich, without the hd temp sensor being hooked up. In the process of restoring the car over the winter, we removed the throttle body and intake tubes for cleaning and painting and then re-assembled with new gaskets. No other EFI components were disturbed. The throttle valve sensor was recalibrated upon assembly. As stated before, the eng. fires right up but the plugs eventually drown in gasoline at idle. I have not yet checked the fuel pressure - possible source of the problem? We are frustrated and open to any and all advice. CHAZT54 |
greenie |
Sep 23 2009, 07:41 PM
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#3
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Senior Member Group: Members Posts: 873 Joined: 26-October 04 From: Trinidad Member No.: 3,013 Region Association: Pacific Northwest |
I am working with drumsticks on this car and have done the following in the last 24 hrs to track down the source of this problem; I replaced the vac. hose going to the MPS - there seemed to be good vaccum on the MPS end of the hose when running and connecting it to the MPS while running had minimal effect- still flooding out. At the same time I connected the hd temp sensor lead to the inj. harness lead which makes the eng race immediately without moving the throttle body flap. ALSO - grounding the hd temp lead from the brain had NO effect. I am beginning to think we are barking up the wrong tree. This car ran pretty good a year ago, albeit a little rich, without the hd temp sensor being hooked up. In the process of restoring the car over the winter, we removed the throttle body and intake tubes for cleaning and painting and then re-assembled with new gaskets. No other EFI components were disturbed. The throttle valve sensor was recalibrated upon assembly. As stated before, the eng. fires right up but the plugs eventually drown in gasoline at idle. I have not yet checked the fuel pressure - possible source of the problem? We are frustrated and open to any and all advice. CHAZT54 My advice, I fought an intermittent rich condition for a long time... I bought and installed a new CHT which was defective from Bosch. I will always check new parts now before I install them. Pull the CHT , test the resistance at cold & hot temperatures using your stove top and a pan of hot water. Cold it should measure 2,000 to 3000 ohms. Hot it should measure less than 1000 ohms. Trust me the car will not run correct without this sensor functioning properly. |
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