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Throttle Position Sensor Solution For 85-87 Crx Or Civic Si


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#16
crxracer87si

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Ignition Timing? 



#17
kedwards

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I have 4-5 Si throttle bodies on my shelf with TPSs. $15 each, plus shipping from 23437. I could dremel the screw head slots and remove them, if needed. I also have a similar number of idle control valve units.

 

I still have 2 TPSs. 1 has the oval plug and the other has the round-ish plug. I sold the others after following the above directions to un-screw them from the throttle bodies. BTW, I hear similar vintage EFI Honda motorcycles used the same TPS.


Keith A. Edwards
Suffolk, VA
1.75 1st gen. CRXs
former ECHC H5 Champion


#18
1985 CRX SI

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I can tell you from my experience that the round plug has been on all of the EW3 1985 SI's I have had. The flat or oval plug has been on my (1986) EW4 Si's  and (1987) D15a3 Si's 



#19
Sinub

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Voltage is .527 closed and 4.289 at WOT. Numbers change nice and smooth along with throttle operation. Impedance seems good. Voltage seems good. Puzzling. Now I'm really confused as to what is causing the bog and hesitation.

 

Those readings sound about right. I noticed you said you were going to replace the fuel filter. Did you do that yet? 

I've had a bad fuel filter with similar symptoms. Another last resort would be changing the fuel pressure regulator that's on the fuel rail. 



#20
Ocabrera1966

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Well, replaced the fuel pump and filter. Car refused to start - turned over, but would not start. Disconnected the battery, when I reconnected it a few minutes later, it started and ran just fine. The hesitation was gone. About an hour later, I started it again, and it started fright away. Pulled it out to the driveway and let it idle while I went back into the garage to get something. As I walked up to the car, it started to sputter, and died. Again, now it turns over, but will not start!!!
 
I can hear the fuel pump running and priming
There's fuel pressure at the filter
I disconnected the battery again and waited, but still does not start
There's spark at the plugs

Edited by Ocabrera1966, 23 September 2018 - 08:09 AM.


#21
1985 CRX SI

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Is the pressure at the filter within spec?



#22
Ocabrera1966

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There is NO pressure at the filter now. Pulled the pump from the car, disconnected the hard line, but kept the tank line and electrical connections on. Pump primes, but no fuel from the pump. Repeated the test several times, no fuel. Ok, put the original pump back on. Same story - primes, not pulling any fuel!

First thought - Im out of gas! I dont think so, I filled the tank about a week ago, and drove the car maybe 30 miles tops. Maybe a clogged screen filter in the tank?

Edited by Ocabrera1966, 23 September 2018 - 08:18 AM.


#23
1985 CRX SI

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Yes in-tank filter clogged (common problem). I I run an inline plastic filter (G3 Fram) before the pump. Got rid of the in-tank filter.



#24
1985 CRX SI

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https://smile.amazon...=g3 fram filter



#25
Ocabrera1966

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Update: I put in 2 gallons of fuel and primed the pump a few times until I saw fuel at the filer pressure relief screw. Guess what? It started! I drove it around the block a few times, and it ran fine, except for the occasional bog at 3k, but no where near as bad as it was before. I went around the corner and filled up the tank, and it only took 1.7 gallons to bring it to the overflow point, so I don't think I really was out of fuel. 

 

Thanks for the tip about the internal filter Leadfoot, and to the rest of you guys for your suggestions. Sounds like replacing the filter and pump were part of the problem, with the internal filter needing to be done next. 

 

If I can get it to my Honda specialist, I'll add that to his list of things to do aside from setting the timing and checking the condition of the timing belt. I also need new oil pan and valve cover gaskets replaced as well.  



#26
1985 CRX SI

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You are welcome Granny



#27
PuddleSkipper

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Yes in-tank filter clogged (common problem). I I run an inline plastic filter (G3 Fram) before the pump. Got ride of the in-tank filter.


Nice, I'm definitely going to do that now!

#28
Ocabrera1966

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Having a local shop drop the tank and have a go at either cleaning the strainer or bypassing it with an external filter before the pump. I took the car out last night and it started and drove well. A slight hesitation at 3k, but nothing major. The PGM FI light cam on (code 1 on the ECU). The o2 sensor has been replaced, but I'm going to check the wire going back to the ECU to make sure there's continuity. 



#29
1985 CRX SI

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Code 1 Insufficient fuel is one of the possible.



#30
Ocabrera1966

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Ah! I hope thats it. It got towed to the shop this morning because I let it idle in the driveway (its sloped) and it died and would not start again. Tow truck dropped it off at 10:00 AM. I gave the shop a full explanation about the fuel system, the filter, the pump, and the strainer bypass, but I havent heard back yet.

Edited by Ocabrera1966, 27 September 2018 - 05:58 PM.