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Fuel problem diagnosis


tturnpaw
02-21-2005, 10:55 PM
Ive got an issue with my 87 prelude. It has good spark and i bought a new fuel pump and regulator but yet it still doesnt start. It fires on all cylinders when turned over then dies. every once in a while it will run 4 about 20 secs or so. whats the common issue it could b with these cars? im new 2 imports (i own a mustang) and im figurin it out. i also replaced the timing belt. any help would b appreciated. sadly im a noob.

Prelewd
02-22-2005, 03:14 AM
is your timing belt on the right teeth? is the timing correct? honda engines/cars are just like any others..

GV280Z
02-22-2005, 04:55 AM
I had the same problem, I narrowed it down to one or all of these three major factors, and I did replace all three on mine and it eventually did the trick: (my car would cut off immediately after starting, OR if it ran, once a LITTLE gas was applied, engine would die)

A. Throttle Angle Sensor gone bad (located on throttle body, requires replacement of throttle body since the sensor is rivoted on.) New throttle body from dealership: $450 (replace this one last if the first two don't fix it)

B. Bad ECU found under (on my 86) the driver's side rear passenger trim panel; If you remove the ashtray, and look down through the hole, you should be able to see the ECU. You have to remove the trim on the left rear panel to access it: used ECU from foreign junk yard: $100

C. Idle Control Motor located on the back of the intake with two hoses running to it on the bottom (these carry radiator fluid to warm the internals up to operating temperature) There will be a little metal plate on top held in place by two screws. The part itself is held onto the back of the intake by three small bolts and is around 4 inches long: New Idle Control motor from Dealership: $100

Also, you can turn on the key and then remove that left rear ashtray and look down at your ecu in there, right on top will be an led flashing a number of times and then a pause, then it flashes the same number of times.

These are trouble codes. Count the flashes and then look up what that
certain number of flashes means in a service manual you can get at an auto parts store, that may help in determining your problem.

Greg

tturnpaw
02-22-2005, 04:10 PM
ya i changed the timing belt and it was a little old (original from 210,000 miles ago) and it fired right up when i did 4 about 20 secs. thanx greg i appreciate ur help and im pretty sure i can fix this dam problem! i was gettin close 2 sendin it off of a cliff. ttyl thanx again.

tturnpaw
02-22-2005, 04:36 PM
ok i checked the ECU. its not flashing at all. so do u think that would mean that the ECU is bad or that its not mechanical? does the computer have sensors for all of those things? thanx

GV280Z
02-23-2005, 01:35 AM
Did you have the ignition turned on when you checked it?

Maybe it could actually be something like a fuel pump or a relay gone bad, maybe a bad connection on the fuel pump, I'm sure it's electric but don't know where it's located. Probably in the fuel tank.

I'm not sure if the ECU has a sensor for the fuel pump, but it does have one for the egr valve, the throttle angle, and a bunch of other things that I don't really know..:(

Greg

tturnpaw
02-23-2005, 08:04 PM
ok its not the pump or connection. i checked it all with a test light and its fine. its an external pump and electric, and i think that the "sock" or the screen in the tank could be clogged. Ya the ignition was on.(IM NOT A DUMBASS!) and today i replaced the throttle body and the other sensor u were talkin about-dont remember which one it was, but it was next 2 the throttle body on the back of the intake next 2 the throttle position sensor. now the ecu blinks 5 times. i looked on the net and all i could find was that it was the map sensor. i need to get a manual that lists the diagnostic definitions in it, because its so universal on the net im not 2 sure what 2 think. i doubt its a fuel problem anymore. thanx

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