90crvtec

OK, I just bought a CRX that's had lot of work done to it. Here is what I know about the car so far.

CR/VTEC Swap
MSD SCI Ignition
B16 Head and Intake Manifold
Appears to have stock fuel rail and injectors
Supposed to have a two stage ECU that allows you to switch between Spoon and Mugen programming (I have no idea how this works).

Basically, my problem is that under light to medium acceleration the car stutters or hesitates, almost feels like the AC is one but I don't have AC. I have pulled all the plugs, they're new (NGK V-power) and they all looked fine (they were a little black, so it might be running rich??). I also have a fuel pressure regulator, I have tried adjusting fuel pressure anywhere from 58PSI to about 36PSI, in all cases the hesitation did not go away. I have checked the timing on the car, it is at 16 degrees. If I open the car up there is no hesitation at all, it pulls very strongly to redline. Its only under light to medium loads that it hesitates. I can make the hesitation briefly go away by goosing the throttle and adding a little more gas, the hesitation will stop for maybe 20 seconds and then come back. I'm going crazy trying to figure out what this is. Any advice or suggestions would be greatly appreciated.

I am new to these forums and I had tried using the search feature to find posts asking similar questions to this but I could not. If my question has already been addressed I apologize for the repetitive post.

Quitripin

check you ignition timing

90crvtec

Do you mean by moving the distributor with a timing light? Or are you talking about ignition timing on the MSD?

Quitripin

distributor, make sure you use the jumper to set it back to base time and check your timing

90crvtec

Car is currently set at 16 degrees, this is the correct base time isn't it? I had read somewhere that 16 degrees was the stock timing. If its not then what should I set it at? Thanks for the replies.

90crvtec

I also noticed the car does not have the MAP sensor plugged in and does not appear to have a plug for the MAP sensor. What does this sensor do? Could this be the cause of my hesitation/stumble at lower RPMs?

EDIT: It has a MAP sensor on the firewall, there is another map sensor just above the throttle body (similar to a teg GSR TB I think) that is unplugged. However, it does not appear to be necessary. I have noticed that the stuttering/hesitation starts in at about 3500RPM, it is most prevalent at this engine speed although it can happen anywhere in the rev range before VTEC. When the car hesitates you can hear a gurgling sound through the exhaust, almost like the engine is being smothered.





Modified by 90crvtec at 5:46 PM 5/20/2005

WHITFIELD-TUNED

you definetly need a map sensor also check the valve adjustment if they are too tight (holding the valve open) then this would cause lower rpm hesitation but would not be so noticable at higher rpm ore at WOT.

90crvtec

Thanks for all the replies, I'll be checking everything that was mentioned here. I pulled the distributor cap/rotor yesterday. Its an MSD cap so the stock honda coil has been removed and my distributor is wired to fire through the MSD SCI ignition. However, both the cap and the rotor had badly corroded contact points, there was even some weird stuff laying in the bottom of the distributor cap (it looked like the contact points in the distributor cap were falling apart and landing in the bottom). I'll have a new MSD cap/rotor on monday. Hopefully this will fix my issue. Thanks again for all the great info, I'll make this place my stop for honda information from now on.

WHITFIELD-TUNED

kool deal and just a note* we (hookups) have had a lot of issues with the SCI MSD we recc the regular MSD 6A or better yet the digital6 plus.

90crvtec

What about just going back to stock honda distributor? I'm not boosted and I have no plans of running forced induction or NOS. It seems like the stock setup is the easiest and most trouble free way to go (not to mention its one less item that I'd have cluttering up my engine bay vs having an MSD box and coil).

90crvtec

Hey I figured it out! Did some searching on these forums for 'hesitation' and came up with a bunch of things to check. So I just started checking each item that applied to my car. Around midnight last night I finally got to the O2 sensors, I just switch them and it works great! It looks like whoever wired the car just had the O2s backwards, a quick swap of the wiring at the header fixed the problem and now the car runs perfect. Idles much smoother and no bogging/hesitation in any gear at any RPM. Thanks again to all who posted.