Hi guys!

What is a MAP Sensor?

 

Personally I'd suggest a 4 step plan. I'm no mechanic or mastermind at dealing with dealers but this is based on my own common sense. Each step is a result of the previous one failing

1) Do as you suggest and try describing the problem
2) Take a Honda mechanic out for a drive to the same corner
3) Take a Honda Master Tech out for a drive to the same corner
4) Ask for the black box recorder that Vixen is currently investigating for her own intermittent issues. The Institute at Langley told us about it.

 

IIRC, there is a fuel filter buried in the top of the tank.

You could try changing it.

 

I've experienced the same problem on the M20 (bear with me....). Between J3 (M25) and J2 (A20) southbound you go uphill for 2-3 miles and then enter a long sweeping LH bend. A couple of times when I've have VTECed all the way up, I got halfway around the bend and the car lost power dramatically, throttle does nothing and both times I had to put hazards on and move to the LH lane, once the revs had dropped to 3-4k it came to life again.

Only happens when really powering up the hill, so I had attributed it to oil surge, or perhaps a fueling issue caused by the long period of lateral/ vertical force (needless to say I tend to back off a bit when going up there now).

 

It's either fuel starvation or, as you say, a loss of spark.
might also try to check the following:


1) do it top down - can you smell unburned fuel?
2) could it be something to do with the senors which cut the ignition when the car thinks your about to have an accident? (not sure S2000 is fitted with these but they are not uncommon.)
3) check the fuel pump
4) Tachymetric relay might be faulty (rev limiter relay)

 

have u had the recall work done ?

 

Sounds like the ignition is being cut.

Try fitting a wideband sensor temporarily, this should reveal more of what is going on.

DarkBlueMark may be able to help you further.

 

Thanks for the useful responses guys!

yep, all recall work has been carried out!

Excuse my ignorance, but what does a wideband sensor do?

 

Hello! Dont know how much I can add to this but will share what little I know.

Nick, there is a fuel filter on the bottom / intke of the fuel pump but if blocked you would see it most of the time or high up the rev range where you need more fuel.

Its tricky to diagnose any problems without any diagnostic info but a few things to note. Best was it to try and eliminate problems 1st.

I have heard of fuel surge causing probs on other cars. Saxo Boy had a well documented incident with it on his scoob, when running a fairly low fuel level. Try and rule that one out.

As we all know, VTEC engagement is dependant on oil pressure, and any low level, slosh etc, could interrupt the engagement and not allow it to re-engage until everything is clear again. Interestingly the VTEC oil pressure switch is on the right hand side of the block, if viewed from the drivers seat. Both of you quote the prob on a left hand bend so there shouldnt be any prob there, as the oil will be shifted to the right side of the pan / block.

Heat - I do think this is a problem on the S, but ive only ever experienced it when pulling away in traffic.

Emissions - some cars, such as the Subaru, have an interesting feature to get them around emissions testing. If you hold the revs at 4000 then floor it, you only get half boostand very little power. I dont know if the S has anything similar.

If the engine revs die and you have your foot down, there's either no fuel going in or no spark. It feels to me like there is a lack of fuel. This is what I have seen when Simon referred to my Wideband. The lambda sensor plays a big part in the fuelling (not on VTEC though) and operates on a 0-1v scale. Its commonly called a narrowband and is great for the car's needs, but not good if you want to accurrately measure the fuelling. A wideband (what I have) is 0-5v so you can log a better resolution from it.

What ive seen on mine when pulling away when you get hesitation, is throttle open, very lean mixture - no fuel going in, and detonation. I think its the MAP misreading due to heat.

So back to your problem, if the revs are dropping, there's prob fuel being cut. The main culprits for me would be the MAP (could be under-reading) TPS (could be slack cable or voltage drop so ECU thinks throttle is shut therefore cuts fuel)

So although I cant say what it is, hopefully the above longwinded load of words might provoke some thought???

Addition: My personal view is you need may need a new MAP. I get flamed from some people when I suggest a sensor could fail but given the amount of oil mist that they are subject to, I can see why. I had hesitiation quite a lot, replaced the map and its all fine now.

Can you do a test? Take the MAP off and tap it firm but gently with a screwdriver, to knock any crap out. Put it back on and repeat your test above. Let me know

MB

 

Mark, thanks for the advice...

What's a TPS and how does this affect things?