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Discussion Starter #1
Hey all I have a 1986 D-21 with a FI 2.4L. When coming to a stop I push the clutch in and the idle drops like it wants to cut off then idles rough for a few seconds then back to normal. I have new 02 sensor coolant temp sensor thermo wax kit cleaned MAF ecu says throttle / idle switch. Went to the junk yard got a TPS and still same thing. Any help in the right direction would be greatly appreciated
 

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Hardbody Freak
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check all vacumn and check the bpt valve..it it the one right b4 the egr valve..

also check the fuel pressure regualator vacumn..some time moving it to a manifold source solves this prob..
 

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Discussion Starter #5
Thanks for your reply.if you dont mind me asking what is the bpt valve and if you are facing the throttle body which side is it on.I have checked all vacuum lines numerous times.If i route the fuel pressure regulator to a manifold source what do I do with the ends that is coming out of the top of the throttle body going to the fuel pressure regulator.Again thanks for any help you offer.
 

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Discussion Starter #7
ok thanks what am i checking the bpt valve for and I will re-route the vacuum this evening and post back
 

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Hardbody Freak
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i am a little tired ...

so my first reponse to you should have been to try a tune up..

plugs wires cap and rotor fuel filter air filter and breather elemet.

even an oil change ...
 

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Discussion Starter #9
Ok here is a list of all i have done thus far
Nissan Wires - NGK Plugs
Distributor - Cap - Rotor Button
Set Timing
Compression Test
Thermostat - Heater Core
Engine Coolant sensor - To the computer
New fuel filter
TBI cleaned
New TBI gaskets
FI filters & o-rings
Used TPS per Vehicle computer
What am I checking on the BTP
 

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Hardbody Freak
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check the bpt for operation.

with the truck running (you might have to idle it up for this )

pull the vacumn for the bpt ..note the effect..

put vacumn back on and pull the otherside vacum not e the effect ..and is the vacumn coming staight thru..

also check egr function..
 

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Discussion Starter #12
Pulled vacuum on top of bpt engine ran rough pulled lower vacuum no effect. No difference when hooking up the fuel pressure regulator to manifold
 

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Discussion Starter #16
I just pulled it off the TBI and placed the other one on. I lined the old screw marks up on the one from the junk yard and tightrned it down
 

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Hardbody Freak
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you noticed it has oblong screw holes..

it can be adjusted..

there is a proceedure..but try lossenening the screws just enough so you can tap the tps toward the longer part of the oblong..

just a tap ..do not get crazy and move it too far..

then start and test its idle problem ..

do it a couple of times to see if it helps..
 

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Discussion Starter #18
I want to say thanks for your time trying to help me get this truck rite. I had heard of a procedure of adjusting the TPS but I am far from a mechanic. I did notice the oblong screw holes. Should I take the TBI off to adjust the tPS or can it be done on the truck. There is only about a quarter inch adjustment either way correct.
 

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Discussion Starter #20
Ok I will try when I get home. Truck is parked in the garage didn't drive today hoping to get the problem fixed. Post back later
 
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