Can't find my old thread. Here's the deal. 1999 Prelude w/95K. Car has a lot of trouble starting cold. Colder it is, worse it is. More than 24hrs. and it needs a jump because it'll take 150-250 cranks to get it started. Only thing that will get it started is pump the hell out of the gas then hold it to the floor.

I pulled the injectors out and put them into a rag (still connected to rail) to check if they were leaking fuel. Not leaking. Electrical parts have been replaced (battery, cap, rotor, plugs ect.). Engine is acting like it's flooded itself I guess. Once warm it runs OK. I had trouble getting it to hold idle today though.

It's been to Honda already, they don't know what the problem is. They charged me $176 for the cap and rotor. The only thing they did do is figure out how to start it (pump the **** out of the gas). Any ideas what to check next?

 

Just took the car out. Held idle and drove fine.

2 questions here.

1. What on this engine controls cold weather startup as a choke does on a carbuerator? Where can I find a diagram and/or what parts control this. If I have to get another intake, throttle body, whatever, I'll do it. Whatever controls cold weather startup is 99% most likely my problem.

2. Where is the 2nd fuel pump, the one the controls fuel when the engine is running? The primary fuel pump is engaging, for sure, I almost got a facefull of gas. The 2nd pump is kicking on but only after I drive away. I hear it when I pull out of where I park, usually. I didn't hear it kick on when it wasn't holding idle/stalling. It did kick on when I took it out a few minutes ago and it ran fine. Also, which fuel line is which? I'm assuming the one large bolted one is the primary (startup) line and the other with the filter right there is the one that supplies after startup?

One other thing. Vtec is kicking in but when I hit about 6K-6500 the engine jumps and that's it, power cuts out. I don't want to say it's a rev limit because it's different. It's a violent skip that shakes the whole drivetrain. Never had this problem before. It would just have a warning "beep" to remind me to upshift right before 8K.

 

do you have a CEL? i don't know whats wrong but it sounds like your ecu is in limp mode if it cuts power at 6,500.

 

Well the thing located under your TB controls your Cold Starts. It may need to be cleaned or replaced.

If you want I have replacements for 35 dollars shipped.

As for the fuel pump, you only have one. The fuel pump is attached at the gas tank and pumps fuel to the fuel filter, and the fuel filter pumps to your fuel rail. You have a fuel pressure gauge that automacticly adjusts your fuel pressure. And then from the Fuel Pressure regulator, it syphions the exess gas back down the fuel return line to the fuel tank or fuel pump, I forget where it goes.

 

I have a CEL that's been checked 3 times and cleared each time. It's "transaxle clutch disc #2 slip" though, nothing to do with the current problem. Also, I think limp mode is more like 2500 rpms. 6500 is enough to blow most "normal" engines. I've never seen a limp mode in a Honda but in a GM 4cyl. it was real low, like enough to do 25mph. and that's it.

 

Yes, I'd like to get one if you have one. I'm assuming it's the valve on the drivers side under the TB?

As for the fuel pressure, that could be an issue as well. I know I fuel to the rail coming in from the line with the large nut. The other must be the return you speak of. Has 2 10mm nuts on it and comes off teh back side of the rail? That had what I thought was a filter on it but maybe that's the regulator? That might be something worth looking into replacing as well for me. The car is acting like it's flooding itself, perhaps that regulator is not working properly.

 

Saw that link in another thread for the Helms manuals. All set now. Have all sorts of crap to check now. Looks like a bad crank position sensor would give me these symtoms as well.

 

Try this next time. When the car sits for a while, immediately put the gas pedal to the floor. Crank it and see how quickly it starts. Just be ready to take your foot off the gas pedal quickly once it starts. There's a button that putting the gas pedal to the floor that cuts off the fuel pump.

That should let you know if it is flooding.

Also, what mods do you have? Happen to be running an MSD ignition?

 

Also - look into a bad MAP (manifold air pressure) sensor. This will cause a bad mixture problem when the engine is cold.

 

The cold engine operation is amazingly basic. Right where the plastic intake tube attached to the intake manifold, there is a Cold Air Valve. It is a piece of "wax" that changes sizes (grows) as the temperature goes up. Basically, it leaks air around the throttle plate when the engine is cold.

Fuel mixture is controlled exclusively by the MAP sensor when cold and heavily when hot. After a few minutes of operation, the O2 sensor is used to add a fudge factor to the factory MAP mixture settings. So, MAP determines how much air is going into the engine and the ECU looks up to see how much fuel is needed. Once warmed up, the O2 sensor updates the offset needed to make the car run as designed.

If you replace the MAP sensor - be sure to disconnect the battery for a couple minutes so that the ECU tables will reload from factory. It takes 80-200 miles of variable driving to get the ECU tables completely re-adjusted after a major engine or sensor change. Operation and mileage will vary considerably during that time.... But that is why an engine with 200K miles will run nearly as good now days as a brand new one. The MAP/O2 method is pretty cool - Thanks to Robert Bosch.

 

my 96 s prelude was having this problem. i would crank the **** out of it and hit the gas and it would start to crank. after that it would run fine at perfect idle and everything. it would just take me forever on those cold starts. what i did was give it a whole tune up. i also switched the external coil out with another one. after i did that it starts up perfect, even on the cold days here. so you might check that. wires and your coil.

 

Hmm - the vtec problem you mentioned makes me think that maybe the vtec is stuck ON or is having problems. I don't have vtec on mine, so I don't know much about it's behavior.

Mine is 94 Si and fuel cuts off at around 6500 rpm redline. I think I would have parts in the street at 8000.