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Car will only run if i feather the throttle!

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Old 12-15-13, 11:55 AM
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Car will only run if i feather the throttle!

ok, so i have a 1990 rx-7 vert with a turbo 2 swap. car ran fine for about a year and then the clutch went out. replaced the clutch and bolted everything back together. car would start and die after 5 seconds. did some searching and jumped the fuel test connection at the passenger strut tower. car fired up and maintained idle. Test drove the car, drove about a mile and it died. EGI fuse was blown, replaced EGI fuse and car starts and runs. Get home and buzzing from dash, low coolant. find the leak and repair then refill coolant. try to start the car again, goes to 500rpm and dies immediately. try again while feathering the gas, get it up to 2000rpm, idles by itself for a second and then dies. start again by feathering the gas and same thing. i can keep it running but if i let off the gas it dies and if i peg the gas it dies. i have no idea what is going on with my car! please help!
Old 12-15-13, 04:17 PM
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It would appear you have a vacuum leak. And where was your coolant leak? Sharing this info will help to diagnose your problem for if you had to remove certain things to make the repair then that might give some insight as to what also might be causing your problem. If you had to remove the water pump or temporarily remove the alternator then it would point to the Water Thermosensor as a possible cause.

Last edited by satch; 12-15-13 at 04:20 PM.
Old 12-16-13, 12:36 PM
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Possibly OMP limp mode. Did you delete the OMP?
Old 12-16-13, 01:18 PM
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Leak

The leak was going through the firewall above the intercooler, it had a loose connection which was tightened. i did not remove the alternator or the water pump and i checked all my vacuum hoses tight. Im new to the rotary world so what is OMP limp mode?
Old 12-16-13, 01:28 PM
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Oil Metering Pump limp mode shouldn't affect idle but would restrict the engine from running at too high of an rpm.

You should check for error codes. Ground the single wired check connector near the lead coil (wire is Orange). Then w/key to on the CEL (check engine light) will flash any error codes.

http://www.banzai-racing.com/FD&S5_error_codes.htm
Old 12-16-13, 01:41 PM
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Yeah, retread the first post and it doesn't sound like limp mode. The limp mode will allow the engine to Starr, idle, and run well up to about 50% throttle. Any more throttle and the ECU starts cutting ignition.
Old 12-17-13, 11:01 PM
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Ok, so i grounded the diagnostics wire to the neg battery terminal and the check engine light did not blink at all. Since my last post i replaced the fuel filter and the fuel pump and verified my tuning on my power FC commander. It seems to me like there is a fuel distribution problem since the engine will rev when i initially push the throttle but if i hold it down it will bog out and die. Im at a complete loss. . .
Old 12-17-13, 11:44 PM
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Originally Posted by clintb06
Ok, so i grounded the diagnostics wire to the neg battery terminal and the check engine light did not blink at all. Since my last post i replaced the fuel filter and the fuel pump and verified my tuning on my power FC commander. It seems to me like there is a fuel distribution problem since the engine will rev when i initially push the throttle but if i hold it down it will bog out and die. Im at a complete loss. . .
WAIT a second!
you have a PFC on the car?.why didn't you state that off the bat instead later?
This is a whole different ball game now.
THIS is why you should state all modifications.The check engine light would be integrated with the STOCK ECU and throw codes if something is wrong.
You have a PFC..you should be able to get some kind of data off your PFC to pinpoint the problem.
Unless we have a couple PFC guys cruising up here in this section I can only suggest to Get your Post count up and make your way to the Power PFC section (engine management section) where your problem could be addressed more by better qualified people.
Old 12-18-13, 10:32 AM
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What are your afrs ? Did the car ever overheat? if so how hot did it get when you fixed the leak , did you have to remove any plugs of vacume lines when you fixed the leak ?
Old 12-18-13, 03:06 PM
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The car didnt overheat. i drove it about half a mile and the EGI fuse blew, during this i noticed coolant under the car. i then replaced the fuse and drove home where i tightened the hose clamp. I didnt remove anything, just used a screwdriver to tighten it.
Old 12-18-13, 03:07 PM
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Originally Posted by misterstyx69
WAIT a second!
you have a PFC on the car?.why didn't you state that off the bat instead later?
This is a whole different ball game now.
THIS is why you should state all modifications.The check engine light would be integrated with the STOCK ECU and throw codes if something is wrong.
You have a PFC..you should be able to get some kind of data off your PFC to pinpoint the problem.
Unless we have a couple PFC guys cruising up here in this section I can only suggest to Get your Post count up and make your way to the Power PFC section (engine management section) where your problem could be addressed more by better qualified people.
Sorry about that, like i said, im new to all of this
Old 12-21-13, 10:28 PM
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Ok so new update that may help you help me. I decided to use a multi-meter and test my TPS based on the FSM under the fuel and emissions section it says my resistance readings in narrow range closed should be .8 to 1.2 Kohms and 4 - 6 Kohms at full throttle. Closed my reading is 1.5 Kohms and full throttle its in the MEGAohms. . . but my full range is reading properly . . .could this cause my car not to run without feathering the throttle?
Old 12-23-13, 09:02 AM
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Set the Green/Red wire of the TPS to 1 voltDC w/key to on after the car has been driven for 20 minutes. This is an easy way to set the sensor to spec per the FSM.
Old 12-23-13, 11:34 PM
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I'm having the same problem. I gotta find the answer
Old 12-29-13, 04:23 PM
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do i adjust the voltage the same way that i adjust the resistance on the low end?
Old 12-29-13, 09:08 PM
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Red wire of meter to the G/R wire of the TPS and the Black meter lead to the battery negative terminal. Meter set to DCV and key to on and use the adjustment screw to set the sensor. Everything is plugged in.
Old 12-30-13, 11:24 PM
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Originally Posted by satch
Set the Green/Red wire of the TPS to 1 voltDC w/key to on after the car has been driven for 20 minutes. This is an easy way to set the sensor to spec per the FSM.
Thanks for this tip, Satch. I was just looking a tuning the throttle properly. Mine was kind of miss-calibrated when I got it.
Old 01-02-14, 06:55 PM
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ok, tried adjusting went fully clockwise and only able to get 1.34Vdc.
Old 01-02-14, 09:34 PM
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And you did this immediately after the engine was run till it was as hot as it could get?
Old 01-03-14, 01:05 PM
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yes, although this was a hard process since i had to feather the throttle for 15 minutes
Old 01-04-14, 05:02 PM
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Ok another update, i tried to warm the car up again to double check the adjustment and as the car started to heat up it seemed to bog down even more than it was before. when i first start the car i can feather the throttle and it has a split second rev and then it will bog down and as i crossed into the lower portion of the engine temp it wouldnt even rev like it was. im at a complete loss as to what could have happened out of nowhere to cause this. even other TPS problems i have seen arent quite like this
Old 01-04-14, 09:07 PM
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Check the Water Thermosensor and make sure the bulb for the CEL is good.
Old 01-06-14, 10:13 PM
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Thermosensor or check the timing happens to me then it took a crap on me in the middle of a shift lol
Old 01-07-14, 05:52 PM
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ok so today i was trying to work on the car and had my jeep jumping it. ran it for 10 minutes or so feathering the throttle and took the jumpers off. removed the neg terminal and checked volts on the battery. 12vDC. . . connected neg terminal and tried starting ,. . . nothing. . . checked voltage again and got 8vdc. disconnected neg terminal and watched it go back up to 11.8vdc reconnected neg terminal and dropped automatically to 8vdc and went down slowly. could this be the cause of my problem? any ideas of where the ground could be? please help!
Old 01-07-14, 07:05 PM
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The battery ground runs to the driver fender where it is bolted to the fender and then it runs to the starter. Cleaning the connections at the battery terminal, fender and starter might be worth doing.


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