It's James

Sorry for the length, but every detail is neccessary to understand the problem.

I have a 1990 Honda CRX si with a b16a2 engine transplant. It has an Si-R-II ECU, Place Racing external VTEC controller, and an APEXi S-AFC + some more mods.

I came back from college for winter break and my car has developed a strange problem. While I was away, my car recieved new axles and intermediate shaft, as well as battery relocation to the trunk. My car had been started up at least once every 1 1/2 weeks while i was away and did not act out of the ordinary.

Here is the problem:
I picked up my car on a friday night. The car drove fine except when i would give it more than 2/3 throttle. The car would vibrate like crazy (the whole dash would wickedly rattle as well as the driver's side door) until i let off the gas. Also, if i reved it past 3250-3500 rpms the car would also begin to rattle slightly.

The next day i drove it back to my garage to have it checked out. On the way there, If i maintained a certain speed, the rpms would spike sporadically. Ex. I would be going 40mph at in 4th gear, however the rpms would spike from a normal 3000 rpms every few seconds for a split second at a time. And, everytime it would spike, the car would slightly buck. By the time I had made it to my shop, any pressing on the gas would just result in the car dying, as opposed to idling like it normally should.

I figure that the rattling it was doing on friday night, was due to the rpms spiking very rapidly when i would give it 2/3 or more throttle. They spiked so quickly that instead of just making the car buck like it did the next morning, it caused the car to rattle violently because the spikes came in such quick succesion.

Now, what does this mean? That's the problem. I'm not quite sure. Neither is my mechanic. We think it is either a faulty MAP sensor, or distributor. My mechanic has been trying to figure out what it is the past week and has noticed that it only happens when it is hot, not when its cold. Therefore, he thinks it might be the distribtutor, even though the symptoms would lead one to believe it is the MAP sensor.

Before I left for school, when i was driving the car on a daily basis, the car had a similar problem which would occur. The problem was that every once and a while, (not every time, but quite often) when I gave the car full throttle, between 4000 and 5000 rpms, in either 3rd or 4th gear, the car just "fell on its face." I got no throttle response. Pressing the gas pedal gave no effect. Shifting to another gear did nothing either. I then had to turn the car off, and then back on again to regain throttle response.

No one could come up with answer for that problem either. And since it only happened occasionally, i for the most part ignorned it. However, now that i can't drive the car at all, I need an answer ASAP. Could you PLEASE tell me if you have any idea as to what this is. I would be very thankful.

GreenChromeCRX

spark plugs or your distributor. Ignition problem is likely.

stevel

I have no idea if this will fix your problem but I've had problems similiar to yours and it's been the 02 sensor both times. Test the 02 sensor with a voltmeter, it should fluctuate between .4-.9 volts when the car is running. Check all the wiring and connections to the O2 sensor. Mine would do it only sporadically and it turned out the wires had pulled out of the O2 sensor connector just enough to lose connection every once in a while and cause the car to buck. Check it out...it's worth a shot.

s

tinkerbell

maybe voltage drop from battery re-location causing ECU and electroniccs to fail?

waht gauge (thickness) wire was used?

t..

PS the shaking/vibration could be from intermediate shaft not being torqued to specs...

pkek

make sure yoru mounts are still good.

check yoru clutch if it needs to be replaced replace it.

bad gas?


[Modified by pkek, 2:56 PM 1/7/2003]

Nameless RB26

Is your engine grounded correctly?

brian g

Timinng belt or distributor.

brian g

It's James

thanks for all of the responses guys. I'll let you know what works.

nsxmatt

pennies_hatchie

iTrader: (1)

i had almost the same problem...
where my rpm shot up every other second ex: from 3k to 4k...
turns out my dizzy was falling off, so i just screwed it back on and the problem was no more..
good luck