Feeling rich? One for the FI guys! |
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Feeling rich? One for the FI guys! |
Rod |
Sep 16 2019, 03:24 PM
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#1
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Senior Member Group: Members Posts: 616 Joined: 1-January 08 From: Farnham UK Member No.: 8,526 Region Association: England |
Hi all, it’s a FI diagnosis I’m after, please help.
1973 1.7L standard FI system. When hot after a long run, I have a really rubbish tick-over and car wants to stall. I thought it would be MPS as mine has already been opened by a PO, but it reads 94 ohms on the outer coils and 398ohms on the inner terminals. It seems to hold vacuum too (only tried sucking on it, don’t have a gauge) so can I rule that out?? I really want some further checks to do as it’s running so rich I can see smoke at a hot idle and it’s difficult getting it to pull away without bogging down (only when hot - it’s great when cold!!) So it’s a hot only problem I’m having. Thanks for any help. |
rjames |
Sep 17 2019, 06:46 PM
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#2
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I'm made of metal Group: Members Posts: 3,951 Joined: 24-July 05 From: Shoreline, WA Member No.: 4,467 Region Association: Pacific Northwest |
The MPS you get from Jeff will still most likely need to be adjusted to get the correct AFR for your engine. I just went through this myself. Tangerine Racing sells the MPS adjustment tools, but you will need an O2 sensor to know where your at. Plex makes a grood/affordable one that connects to your phone via Bluetooth if you don’t want to install a gauge.
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Rod |
Sep 18 2019, 05:25 AM
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#3
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Senior Member Group: Members Posts: 616 Joined: 1-January 08 From: Farnham UK Member No.: 8,526 Region Association: England |
The MPS you get from Jeff will still most likely need to be adjusted to get the correct AFR for your engine. I just went through this myself. Tangerine Racing sells the MPS adjustment tools, but you will need an O2 sensor to know where your at. Plex makes a grood/affordable one that connects to your phone via Bluetooth if you don’t want to install a gauge. My car is a factory standard 1.7 and I want this one to remain this way. Do I really need to set the MPS to this specific car? Are there not factory 1.7 settings that Jeff knows about? If they were sealed and set at the factory and teh car is standard I don't understand why the extra adjustment might be necessary.....? |
JeffBowlsby |
Sep 18 2019, 05:45 AM
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#4
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914 Wiring Harnesses Group: Members Posts: 8,532 Joined: 7-January 03 From: San Ramon CA Member No.: 104 Region Association: None |
The MPS you get from Jeff will still most likely need to be adjusted to get the correct AFR for your engine. I just went through this myself. Tangerine Racing sells the MPS adjustment tools, but you will need an O2 sensor to know where your at. Plex makes a grood/affordable one that connects to your phone via Bluetooth if you don’t want to install a gauge. My car is a factory standard 1.7 and I want this one to remain this way. Do I really need to set the MPS to this specific car? Are there not factory 1.7 settings that Jeff knows about? If they were sealed and set at the factory and teh car is standard I don't understand why the extra adjustment might be necessary.....? Hopefully things will be plug N play, but...The unknown is not the MPS values, its the condition and needs of the rest of the engine and its injection system. Sometimes, when a new component is installed, it becomes evident that other adjustments to the engine or its FI system have been made to compensate for some condition that needs further adjustment to work well with the new component. Each engine is different, and if adjustments are needed (they are not needed every time) you may be able to make simple adjustments if necessary such as to fuel pressure, the air bleed screw, or the idle mixture ECU knob, injector flow rates (clean them or replace leaky ones!) or the ignition system, etc. This explanation may clarify: "MPS calibration notes: Rebuilt MPS are calibrated to the known values of NOS MPS’s. These values are verified to be generally accurate for the specified engines, but may not be precisely correct for your engine, because your engine may not be in the same state of tune, wear or condition as a factory new reference engine used to determine the NOS MPS calibration values. Consider that the MPS calibration provided is as close as possible, but for optimum performance your engine/fuel injection system should be evaluated on a dyno or exhaust gas analyzer and adjusted accordingly by a qualified technician. So that the MPS can be accessed easily for adjustment, the outer MPS stop receives only a drop of clear nail polish to hold it in place and not a full epoxy seal." |
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