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Discussion Starter · #42 · (Edited)
I have amplified the sound from the videos and re-encoded them for you.

Ruff idling:



Stalling; restarting with key held on start, then accelerating at 100%:



See how in the first video the idle bounces, and in the second video it stalls, then I need to keep the starter motor going to get it to start and then when it starts and I accelerate at 100% the RPM struggles to climb while making a ruff sound.....
 

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Ok so heres the thing. A vacuum leak would not cause the engine to not rev. The car would drive normal with an active vacuum leak. If it was a small leak, it would definitely drive fine but the idle would be messy. If it was a large leak, the idle would rev up immediately and the idle will surge up and down as the idle control valve tries to compensate.

If this thing is falling on its face, after getting warm, maybe something to do with the map sensor, maybe tps sensor. Id start with the map sensor.
 

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Discussion Starter · #45 · (Edited)
I read that too- a vacuum leak would not cause the engine to not rev.

So today I tested the coolant temperature gauge sender and temperature coolant sensor.

The gauge sender may have passed, but the temperature coolant sensor failed.

The shop manual says to test the resistance of the coolant temperature gauge sender when the engine is cold and then when the engine is running and the fans come on. At cold, the resistance should be 142 ohms and at hot it should be between 32-40 ohms. It then goes on to say if the readings are substantially different then to replace the gauge sender. I got 163 ohms at cold and 67 ohms at hot.

The shop manual says to warm up the engine and check the resistance of the temperature coolant sensor when the fans come on. The resistance should be between 200-400 ohms. I got 150 ohms, so the sensor is bad according to the manual. In reality I don't have any problems, so I will leave it. It also crept up to 170 ohms within 20 seconds after testing.

Now for the more interesting part...

I sprayed a mist of water all around the throttle body, on the vacuum hoses on the right of the throttle body, on the pipes on the valve cover and on the vacuum hoses on the left of the throttle body; no response. I then thought I had nothing to lose so I sprayed a mist of water into the pipe that sucks in air behind the right headlight, and then twenty seconds later the car started coughing and running like shit as per this problem, so I am thinking the problem is either the EACV or the throttle angle sensor.

What do you think?

Here is a video of the engine idling bouncing. I couldn't get the car to stall today as I ran out of time but I am sure the cause of the bouncing idle is the same as the stalling and ruff acceleration.

https://filesharing24.com/download-...2BvV%2FeAPDmoHXLmJmO5rB8j74a91O7odfE96A%3D%3D
 

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We used to get a can of spray LP-S and spray all the hoses that go to the intake, not the intake air pipe to the plenum, and vacuum system, (you can use starting fluid but use a very small spritz, remember it's ether and it will catch fire and can burn) The idle will go up if there is an air leak.
My idle system has been going bonkers on both my 91s. It's becoming a huge pain in the ass to diagnose just what the cause is. The maintenance manual gives so many variations because the vacuum and fuel system is so overly complicated. In my opinion.

Cheers
nigel
 

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I was able to find a used MAP sensor, they don't exist and are stupid expensive, if you can find one, so i'm gonna try that as well.
Mine is throwing a code 4 to add to the mix, also i'm gonna try and do a EACV cleaning this weekend at the same time to try and get this thing to run the way it used to.

Cheers
nigel
 

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Discussion Starter · #50 ·
The problem is with my throttle angle sensor, its not making that noise when you turn the key to ignition. When I removed my engine wire harness and put it back in, the plug got jammed and I had to use a bit of force to get it out under the throttle body. There is also a lot of pull on it and perhaps the connection has become lose. I'm going to go outside now and run a voltage check on it. I'm not getting a ECU code 7 for it, so that's a good sign the connection is good. Perhaps the problem is mechanical.
 

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Discussion Starter · #51 ·
Got 4.95 volts on that circuit and there's also heaps of play on the wire so its not under stress which is a relief.

The throttle angle sensor is not the thing I was looking for. There's no way that 5 volt ECU circuit could have enough torque to close the butterfly I don't think.
 

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Discussion Starter · #52 ·
So I'm just reading the troubleshooting page for the EACV and it says to check for a click energised. That must be the click I'm not hearing, so that's further evidence my EACV has gone bad.

When I put my engine wire harness back on, I noticed the terminals on the EACV looked bad. One of them has green corrosion on it, even after cleaning it with degreaser as I ran out of contact cleaner. Tomorrow I am going to clean it with contact cleaner.

So the computer is right, EACV problem, ECU code 14.
 

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I’ve tried to find a new EACV and so far there’s none which is why I was wondering if a removal, cleaning and reinstallation will help or do the job ?
I’m so sick of chasing these idle problems !

Cheers
nigel
 

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Discussion Starter · #55 ·
How come you haven't done it yet? A simple clean is perhaps all you need. I'll be pulling mine off tomorrow night if contact cleaner doesn't solve it. I'll take some photo's for you if I remember to. I'm pretty sure I just have dirty terminals though.
 

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Discussion Starter · #57 ·
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The shop manual says to replace the EACV if you don't measure between 8 to 15 ohms between the two EACV terminals. I measured 48 ohms.

I just blasted the terminals and plug twice with contact cleaner, cleaned the terminals with cotton tips and then blasted the terminals and plug again. The contact cleaner is junk quality but its all I could afford at the shops that were open. It's suppose to be fast drying, it's not, hence me killing time here. :)
 

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Discussion Starter · #58 ·
So I reconnected the plug to the EACV, turned to ignition and didn't hear anything. Then started the engine and then shut it off.

Pulled the clock fuse for 10 seconds which was suppose to clear the volatile memory in the ECU. After putting it back in and turning to ignition, heard the EACV click but the ECU codes were still flashing. Started the engine, shut it off and then pulled the fuse again- this time for 30 seconds. Still the ECU was flashing, so started the car and drove it around and really heated it up, turned it off and on multiple times, thrashed it. No more ruff idling, though the RPM needle bounces a teeny bit, but the engines is not knocking anymore like it was before, and there is no more stalling and no more acceleration issues.

I don't know what to think...

Did pulling the fuse clear something in the ECU? I was under the impression this car is so old it doesn't store engine calibration data, and even if it did, the ECU codes are still present which is an indication that nothing cleared.

Did cleaning the EACV terminals fix it, and the EACV require the engine to start to get itself moving?

Is the problem still there and just isn't showing itself yet?

Time will tell.....
 

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Removed, cleaned and re installed the EACV today and no change to the idle. It still sux.
Re set the computer and there was a code 14 there so thinking the EGR valve is stuck also. Will clean that soon but it shouldn’t make it run shitty.
Found a used MAP sensor. It has different the last four numbers in the p/n, 0821 so it’s different than the one that was in it. If doesn’t fit the OEM screw hole so I connected the air line and stuffed it in the vacuum box. No #4 code on the way home but the idle is fucked up still. Way fast. After I drive it a bit to be sure it’s getting hot and no leaks I’ll re set the idle, again and hope. It does drag way down, 800 if the a/c is on but goes back up to 1500 with the a/c off.
I’m getting so tired of chasing this idle problem. I’ve done so much to fix it and no good result.

Cheers
nigel
 

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so thinking the EGR valve is stuck also. Will clean that soon but it shouldn’t make it run shitty.
Actually thats not true. If your EGR valve is stuck open, even a little bit, then that is essentially a vacuum leak, except you are sucking in exhaust gas. This absolutely can cause a bad idle. The EGR valve is not supposed to open at idle. Its only supposed to open while you are driving.

What is code 14 specifically? I dont have the OBD1 stuff memorized anymore.
 
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