was hoping one of the tech guys could help me. I made a post already in my vehicle specific forum. thanks.

http://htarchive.org/showthread.php?t=2770264

 

Do you know if it goes into VTEC when the problem occurs?

 

yes vtec activates.

 

You do know that factory tachs are not always spot on the true RPM of the engine, especially on a fast rev-up. Are you absolutely sure there's a problem with the rev limit, or is it possible that the needle hasn't made it to the engine's true RPM before the limiter kicks in?
But if you're sure there's something else going on then okay. Well you did cap, rotor, and wires. You checked plugs, coil, & distributor. Checked your ignition timing. Did you jump the SCS connector when checking/setting ignition timing and use a timing light? Just making sure... Does it misfire/pop or anything like that when it's acting up, or just seems to lose power? If it's missing, then I'd still look into ignition system (including ECU) or fuel supply. Didn't see anywhere that you checked the fuel pressure or quality. Bad gas can cause some odd things. The ECU could be the cause since you stated that when you put in the other and removed the limiter it seemed fine.
If it isn't missing just losing power, check air supply, take off your intake tube completely and see if it still persists. Do you still have a cat on it? It's possible it's beginning to clog, that too will cause odd problems, but if it seemed to go away after removing rev limiter, then I doubt it. However, I still think it's an ignition or fuel issue. Cam timing would be a very consistent occurance. Pretty much anything mechanical would be very consistent.
If you find or test anything further, keep us updated. I'm sure you'll get to the bottom of this eventually, hopefully sooner than later.

 

thanks for your input. I just checked the ignition timing again, with a timing gun and the wire shorted by the ecu. Timing is good. No missing or popping.

Im still using the chipped PR3 ecu I just turned the rev limiter on. I would think it could be the tach but when it works properly it never has a problem getting to the redline.. when the problem happens it has to fight its way through the tach. I dont have anything to test fuel pressure or quality, but its all 93 octane in my tank. The pump has also recently been replaced.

Really the only possibility I can think of at this point is dirty fuel injectors

 

Check the PGM-FI Main Relay...
http://www.tegger.com/hondafaq/mainrelay.html 94

 

Not to start anything, but if you don't already, maybe try avoiding the green gas stations... It's a possibility... When did this start? Recently? After maybe a refuel?

 

This problem has been happening for months

fcm, you always give solid advice so I pulled out the main relay.



while i had it out i went ahead and retouched that first joint at the bottom and most of the other ones.

I would have never thought that it could be the main relay, how did you come to that conclusion? If I had a bad joint wouldn't i notice a problem during normal driving as well? Anways thanks for the advice, time for a test drive.

 

problem still exist after checking main relay.

 

Pix is a little blurry but I see at least one more connection that may be a problem, I would just go ahead and redo them all.

The PGM-FI Main Relay may not be the problem, however problems with the PGM-FI Main Relay are common and it is always best to eliminate it as soon as possible as it is easy and cheap to do.

How about the fuses that power the PGM-FI Main Relay, there are 3 of them, one is in play only during cranking to start the other two should be replaced with new ones just to eliminate them as the problem, inspect the fuse "legs" for heat damage, [discolored] or melted or discolored plastic where legs exit housing.

If heat is indicated the fuse box terminals will have to be checked, cleaned and re-tightened.

The next thing I would want to know is, what is causing the problem, is it spark, [timing] or is it fuel, [my guess]?
What is the fuel pressure when the "bogging" occurs?
What is the voltage at the injectors when "bogging" occurs?
Both the above could be caused by a defective PGM-FI Main Relay, do you have access to a new or known working PGM-FI Main Relay you can try, maybe out of a friends car you can swap with? 94

 

Okay luckily for me I didnt remount the main relay again, its too much of a pain to get to. I redid all the other points and i still get four clicks: 1st @ dash lights on: then a second click a couple seconds later, third click on start, fourth click on release. Checked all the fuses they seem fine and I changed them.

I wouldnt think its ignition timing or mechanical timing, I checked both.

When it comes to spark the same problem happened with a new dizzy from distributor king. However I do think its weird that all the terminals in my dizzy cap get whitish-yellow/manilla colored corrosion on them very fast. Within days of driving.

As for fuel pressure I have no way of testing it at all. I also dont know how to test the voltage while I am driving. I dont have access to another main relay. The one i have is already a new replacement from a few years ago.

The weirdest thing is that if i remove the rev limiter its seems better. I did this for about a month and I dont remember the problem happening. What should my next step be?

 

If removing the rev limiter seems to solve the problem then maybe the ECU/ECM is the problem, [rev limiter], I can't remember if you said you changed out the ECU/ECM

$20-$50 will get you a fuel pressure gauge, I have a B&M on my 94LS, [around $30] I once had to see the pressure under load so I removed my hood and turned the gauge around so I could see it while driving.

I have tested voltage under load and intermittent electrical problems by running a temporary lead from a lead in engine bay into the car and connecting a multimeter to it, sometimes just a 12V bulb, [telltale/idiot light], in your case a multimeter is needed. 94

 

I have a virgin pw0 and socketed pr3 ecu.

 

Have you swapped it out with a known working ecu, [easiest way to eliminate it as the problem]?

 

well i cant check fuel pressure until I get a gauge. and advanced didn't have any.

as for as voltage im still not really sure how to rig up some wires to test injector voltage. I don't want to mess anything up further.

I would guess that I jam a wire in where engine harness connects to the injector? and bring that wire into the car and ground voltmeter? Im assuming that when the voltmeter is in volt mode that it has ?infinite resistance? so it wont be stealing any current from the injectors?

 

Yes I have and tested the pw0 in another car. its working fine.

 

Then I can only suggest you find a way to monitor fuel pressure and voltage at injectors under load.

If you eliminate or confirm fuel as the problem it will narrow down things quite a bit.

I assume you have made sure connections to engine sensors, valves and solenoids are good, [clean and tight]. 94

 

okay I finally got some time to work on my car today.

I test the fuel pressure, its seems good to me. Its

30psi @ idle
40psi @ idle with regulator disconnected
38psi under wot

 

all the connections are clean and tight on engine.

removing the rev limiter no longer seems to help.

the problem seems to happen everytime now.

As for as testing the voltage I cant figure out where to test it from. the only access to a voltage source I see is the individual injector connectors and they look like they fit pretty snug.

 

Well, 30 PSI with regulator hose connected & 40 PSI with hose disconnected are both at the bottom limit of spec. It's possible that you are getting low on fuel pressure at that high on an RPM. Watch the fuel pressure gauge while the cutting out is occurring and see if the fuel pressure is low or dropping off. You could have a fuel filter clogging, fuel pump not strong enough, or fuel pressure regulator relieving too much pressure. I personally would start with adjusting the fuel pressure up.

 

Ditto the above^^^.
With pretty much everything else eliminated and relatively low fuel pressure readings I would be looking at the fuel system.

When was the last time the fuel filter was changed?

I do agree it is more likely the FPR or fuel pump, as mentioned, knowing what the fuel pressure is when problem occurs under load would be worth knowing. 94

 

The fuel filter has been changed a couple months ago after the problem started.

The fuel pump has also been changed recently. I changed it bc of this problem and it did not fix the problem.

I should have been more specific when i posted the fuel pressure results. The fuel pressure is constant at 38psi under wide open throttle up to and during the major power loss. until i release the gas pedal. I took off my hood like you suggested and had my friend hold the gauge in his hand while i drove.

It doesnt seem like a fuel pressure problem unless 38psi is too low??? Also as suggested how could I adjust the fuel pressure? I was under the impression the regulator was non adjustable.

 

I couldnt figure out how to adjust fuel pressure so i put a crimp in return hose and test drove with same results.

I also test the voltage at pump, i get .35v @ on position with motor off, with a 12v spike for a few seconds when first turn to on position.

 

Adjusting fuel pressure properly can only be done by modifying/replacing the fuel pressure regulator with an adjustable one. Yes crimping the return line will cause a rise in fuel pressure, but if you crimp it completely it will peg the fuel pressure.

You need to test the voltage at the fuel pump with the engine running. The 2 second on then off voltage to the pump at "key on" is the fuel pump priming. Once the key is cycled to "start" position and the engine is running the main relay will (is supposed to) keep steady voltage supplied to the fuel pump.

The other is checking the voltage to the injectors they are supposed to have a steady voltage to them also with key on & engine off or running. This was talked about before, and you decided it to be a difficult task to accomplish, which it isn't simple but do-able.

edit:
Again, since the bottom of spec is 40 PSI at idle with the vacuum hose disconnected & pinched/plugged shut, it may be a low fuel pressure issue. You are asking for a lot out of an injector at that high of an RPM. The injector has very very little time to spray fuel into the port during that very brief moment in time that it has at 8000 RPM. If your fuel pressure is low, which your readings indicate it is borderline for a stock civic, then the force behind the fuel that does get sprayed into the port will be lower and thus you'll get less fuel sprayed in during that split second the injector is open.
I'm not saying that IS your problem, but it IS something that you should address reguardless. You could run a risk of running lean in high RPM's so not only do you have the most physical stress on the engine from loads & rotation & friction, but you're adding another heat producing element with a leaner mixture. Maybe that's whats caused this problem, running a touch lean, causing your spark plugs (especially if they aren't the proper type or heat range) to over heat & pre-ignite the mixture or causing detonation, both of which aren't good for the engine.
Just some thoughts...

 

I got a huge clue on this problem today. I was running some road test and the motor rev'd to 8k smoothly and right when i was about to release the gas out of no where the needle skipped immediately back down to 7k.

At this point Im not sure what to do. swap clusters?