Hi guys, Nice forum you have so I decided to join up and talk shop:wave:

I have a problem with my 1.8 Accord which is getting progressively worse.


The idle was hunting and sticking at 1200rpms, I replaced the idle control valve and the fast idle valve as well, the problem persisted, I replaced the idle control valves again from another car, same issue.

A week later the RPM needle started jumping and the engine began to cut out when heated up, I replaced the ignition amp in the distributor with a new one, I also replaced the ignition coil with a new one, same problem.
I have replaced the engine coolant sensors both A and B

My brother thinks its the TPS throttle position sensor as he was getting a reading of 5.5 volts, he told me that is should be 5 volts?

He told me to replace the whole throttle body, not just the TP sensor from a used one, but I don't agree, I suspect the crank shaft sensor, the only problem is my car is OBD1 and does not flash a code for this.

Plus I'm not sure where the Crank shaft position sensor is? I have seen some people say its behind the crank shaft pully, which looks like a nightmare of a job, but then some says it in the distributor?

You guys sure know your Accords so any advice would be great as I'm running out of money real fast:dunno:

Shadow Works:

Being of Scottish descent, on my paternal side, I give you a hearty "Hoot, Man!" :yes: Aye, may I go out of my way, to try to help a fellow "High Lander?" :thmsup: :)

Sir, you don't mention what model (LX, EX, etc.) of car you have, and what the mileage is. :dunno:

NOT being sure of the outside-market cars, I will GUESS that your CAS (Crank Angle Sensor) is located inside the distributor. IF so...

A blown camshaft seal WILL contaminate the inside of the distributor with oil, fast enough, causing engine malfunction/failure.

Yes, you may need to replace the entire throttle body unit as (I THINK) the TAS/TPI (Throttle Angle Sensor/Throttle Position Indicator) is built into the unit.

ONE MORE THING, before you invest a ton of money: Check the IAT (Intake Air Temperature) sensor. It's located somewhere, on the intake manifold. If defective, it CAN cause an erratic and/or "wandering" idle condition.

ONE MORE THING, before you invest a ton of money: Check the IAT (Intake Air Temperature) sensor. It's located somewhere, on the intake manifold. If defective, it CAN cause an erratic and/or "wandering" idle condition.


Thanks for your reply Wardenr, my cars is a LX, 97k miles.

It turns out blown intake manifold gasket which I repaired but the jumping rpm needle remains so I replaced the whole TB and TAS/TPS sensor, still had the jumping needle, I replaced the whole distributor from a known working unit, it worked after that, but then I put on the new ignition amp and ignition coil and it wouldn't even start! I quickly put the ignition coil and ignition amp back in, it starts but the rpm needle started jumping again.


Both distributors have zero oil in them as the crank shaft seal O-Ring is in good condition.


Is there a test for the intake temperature sensor? is it possible to damage the crank angle sensor by using the wrong ignition amplifier or ignition coil?

Is there a test for the intake temperature sensor? is it possible to damage the crank angle sensor by using the wrong ignition amplifier or ignition coil?

Shadow Works:

SOMEWHERE, there is the IAT sensor, installed on your intake manifold. YES, there is a test, typically using a VTVOM, to give you an Ohm range, to determine if it's good or defective. Typically it has two (2) Phillips-head screws fastening it, with a two-conductor connector, with a green (?) (plastic) cap. Look on the (left) driver's side. Else check the exploded diagrams in the Service Manual.

Using the wrong coil is NOT a good idea. :thumbsdow However, and that said, I don't think it will blow anything inside the distributor. Being essentially half of the ancient "Kettering" style ignition system, the coil fires after it gets a signal from the (Hall-Effect) ignitor unit. (Instead of points-and-condensor, you've got a transducer, breaking an electro-magnetic field.) That said, we get involved with impedence issues, nevermind voltage. Put the CORRECT coil on your car.

You use the term "ignition amplifier" with my NOT understanding precisely what you mean. In modern, transistorized distributors, you've got a distributor cap, with a rotor button, a reluctor, and the ignitor unit, inside.

Aside from all of this, it is quite possible you have a faulty/defective ECU/PCM (as in, the computer). Run a DTC (Diagnostical Trouble Code) test to see what (if any) "Error Codes" are indicated. Right offhand, I don't remember if your car uses OBD-1 or OBD-2 protocols. Either way, you've got a "Diag" connector under the dash, else you can count the number of LED "blinks" on the ECU...to provide said information.

SOMEWHERE, there is the IAT sensor, installed on your intake manifold. YES, there is a test, typically using a VTVOM, to give you an Ohm range, to determine if it's good or defective.

Do you happen to know what the Impedance is on a good IAT sensor?

I tried to remove it using a stubby Philips but there is precious little space for my shovels, I'll remove the intake again I have a new intake gasket on order. I made a temporary gasket from PU sealant, the kind using on bonding windscreens, this corrected the hunting idle at least.


Using the wrong coil is NOT a good idea.
That said, we get involved with impedence issues, nevermind voltage. Put the CORRECT coil on your car.

When I said the wrong coil what I meant was its an after market coil, its not a Honda part but the parts guy swore it was the same unit, the igniter is a Motoquip? unit, its also not an original part but again I was told its the same thing, is it possible that the igniter damaged something or blew the coil? when I put that on it just wouldn't start, not sure what its done to the ignition coil or God forbid the ECU. I can get another ECU from a breakers yard but I don't know anything about programming keys, its not like I can just swap out ECU and use the same key right?



it is quite possible you have a faulty/defective ECU/PCM (as in, the computer). Run a DTC (Diagnostical Trouble Code), I don't remember if your car uses OBD-1 or OBD-2 protocols.

The car has OBD1 with the flash codes in the dash but it registers no fault. I think I may just buy a new distributor to eliminate any doubt as I can't be driving my sisters Nissan Micra any longer, its acceleration makes me feel constipated.

Shadow Works:

Taking your issues, one by one...

Regrettably, I do not know resistance (Ohm) values on your IAT sensor. Given the symptoms you indicate, given the mileage and AGE of your car, that is my FIRST suspected component malfunction/failure. Not being hideously expensive, I suggest you replace it.

I am loathe (opposed) to using most aftermarket coils. Remember that you're building electrons, across a grid, which determines "cycle" (or "recovery") time. It's just an oil-filled capacitor. Correct? In the case of an aftermarket coil, if I don't know the size of the coil, the winding structure, etcetera, then I don't know how "fast" or how "slow" the coil operates. I also don't know what the coil is throwing at the spark plugs, in the way of amplified, secondary voltage. Too little? The plugs foul, engine runs like horse manure. Too much? Plugs FRY, prematurely. Issues with gap control. Possible "hot spots." Either way, too little or too much "electricity" is a BAD situation.

As far as the ECU (Main Computer), I don't know what to tell you except to say, yank it out and have it tested...by your Honda dealer.

Replacing the distributor unit...with a NEW one...is a good idea. While pricey from Honda, well worth the expense.

In the case of electrical issues, involving aftermarket and/or salvage yard parts, you are really "shooting in the dark." Bear in mind that I live in the United States, and you (ostensibly) reside in Scotland. Thus, I am not familiar with the UK-version cars. I regret that I've not been of more help to you, Sir.