Misfire when between 2-3k revs

Blarge · Post by **Blarge** » Thu Dec 18, 2014 12:22 am

Hi All,

Hope you all can help I have come to a dead end investigating this misfire issue with my lude. I have been experiencing a misfire between 2-3k when driving my Prelude SI Vtec 93 BB4 for several months and after many trips to the garages the issue is still present. It seems unless they plug it into a scan tool and replace a part they are stumped!

The car is standard other than the EGR has been blanked recently by a garage and the brakes have been changed to EBC turbo grooved with Red stuff. During the investigation the following have been replaced with new:

Spark plugs NGK New
HT leads New
Rotar arm New
Dizzy Cap New
Coil New
Catalytic converter & Downpipe OEM New As it was leaking after a recent pothole damage

- lambda sensor was confirmed by the garage to be fine. But I do have a new one that I could fit.
Injectors were checked at the garage and confirmed to be working fine
Vac leaks have been checked for and fixed as there was a minor hole in the bottom of the air filter pipe.
Compression test has been performed and confirmed to be fine across all the cylinders
EGR blanked by garage as they advised this could be causing the problem

Problem: When under load the car appears to stumble at 2-3k but seems to recover if you accelerate through it. If you carry on driving you after about 15-20 miles will get the Cel light (Depending on traffic) normally while driving through average speed camera's on the M5 and it gives P0301 a miss fire on 1 according to the garage. I did have a wet spark plug in Cylinder 1 before I changed them but this hasn't been seen again. I have also removed and rechecked the connections on all the ignition parts. Coolant level is also correct. Not sure if this is related but was also informed the car is running rich not sure if this could be causing the problem?

I will be changing the fuel filter tomorrow and have cleaned out the throttle body but plan on removing the whole intake and cleaning it all out in the next few weeks. I am currently not sure what to check next? Could the MAP sensor be at fault or low fuel pressure and indicate a bad fuel pump or even a thermo sensor I remember seeing that causing a car to run rich?

Any ideas will be greatly received as I have been trying to get the car running properly for a few months

Thanks,

Ben

K30DPC · Post by **K30DPC** » Thu Dec 18, 2014 1:28 am

P0301 is something that we won't probably recognize. Do selfdiagnosis first as this will bring the light on real engine condition.

Are replacement parts genuine or aftermarket? I had similar problems with aftermarket distributor cap.

Also coil even new is very sensitive and can be easily damaged.

I'm also thinking about sensors in dizzy but somebody here will know better

Post by **Drax** » Thu Dec 18, 2014 8:46 am

valve clearances

bennyboy · Post by **bennyboy** » Thu Dec 18, 2014 8:59 am

Igniter/ICM worth a check too?

Post by **vanzep** » Thu Dec 18, 2014 9:06 am

I would have the distributor timing checked. Your looking for about 15 +/- 2 degrees advance on TDC
All 4th gen preludes tend to run rich

Why was the egr blanked off - seems an odd thing to do unless your upgrading your inlet manifold etc

bennyboy · Post by **bennyboy** » Thu Dec 18, 2014 9:11 am

Also, how old is the dizzy itself, is it the original?
I recently had to replace mine as it killed my engine (Have a look at the latter pages of my profile, in my sig)

Rare circumstances, but the point is all the sleeving on the dizzy wires had cracked and split with age, which caused misfires.
I think we might start to see a few more issues like this on cars running 20 odd year old dizzys...

Post by **Merlin** » Thu Dec 18, 2014 9:23 am

vanzep wrote:I would have the distributor timing checked.

This !!!!!

How to here - http://www.ludegeneration.co.uk/honda-p ... 11854.html

damon · Post by **damon** » Thu Dec 18, 2014 12:33 pm

My prelude does this and is also jerky to drive, I change everything and still the same so my valve clearances are next it be done with the help off @drax

Blarge · Post by **Blarge** » Fri Dec 19, 2014 3:02 pm

Hi All,

Thanks for the reply's below I have answered your questions and comments:

@@K30DPC All the parts were OEM and fitted by a garage and just replaced to rule out a problem the car run better with them fitted but it didn't resolve the underlying problem. I do take it on board and will look at getting a dizzy cap but will take a look inside it as well as there might be an oil leak from the dizzy. All the parts were purchased from http://www.importcarparts.co.uk/

@@Drax Yes I agreed these need doing, the engine did run well before this problem happened. I have just received the feeler gauge and gasket to perform this. Is it quite an easy job to do as I've seen lots of you-tube video's on it? Any idea the valve clearances for the H22A engine? A lot of the guides I see mention other H22A models but not the import one.

@@bennyboy Yes I did wonder if the ICM was on it's way out, I have seen a replacement one on EuroCar parts and thought it might be wise to replace as I've done the rest of the ignition parts. In regards to if the dizzy is the original I'm not sure I have checked the work the previous owners have had on it but see no mention of it. I have checked the cables and they do look new could the contacts have moisture in it cause something similar? Maybe some dielectric grease on the connectors? I have noticed a small oil leak just above it so it might be worth taking of and replacing the O rings when I'm investigating it. When you replaced yours where did you source yours?

@@vanzep Yes I agree checking the timing wouldn't hurt, I do need to get a timing light though. Could it have been knocked when the garage replaced the cap etc? The EGR was blanked of under advisement of the garage, Is this something that needs to remain on the H22A engines?

@@Merlin Thanks for the information and link I will give it a go at the weekend providing I can get a timing light. Would a cheap one from Halford's be worthwhile our should I spend a little more for the extra features? Reason I ask is I've got a few classic cars being worked on at the moment. One is a practical nut and bolt rebuild 1970 Mg Midget and suspect the engine will be looked at soon even though its only got 30k genuine miles on it.

@@damon Seems you have a similar problem, I did wonder if this could also be fuel related and have the garage replacing the fuel filter for me next week as it seems a fiddly job and they only want 20 quid for the hassle

.It's also another to rule out as being the problem.

Thanks,

Ben

Post by **Drax** » Fri Dec 19, 2014 3:12 pm

good man, sounds like you have it all in hand, fair play

link on how to adjust your VC;
http://www.ludegeneration.co.uk/honda-p ... t5116.html

if you lived near North Wales, id happily offer to come and do it for you