Persistent Cold Start & Misfire Issue – Need Guidance

[Jakku41]

Hi guys,


Sorry in advance for the long post — this has been an ongoing issue with my '99 Prelude for the past 9 months, and I’m not ready to throw in the towel just yet. Hoping some Honda gurus can help point me in the right direction.


The issue started after fitting an AEM V2 intake in place of the stock one. On the first test drive, I noticed under load (around 2k rpm, slight incline), the engine would hold at 2k rpm with no response to throttle. After ~2 seconds, it would suddenly come to life and rev normally. This only happened early in the drive and went away once warm. Left the car parked for a few weeks — drove fine next time. A month later, issue returned just as before.


I suspected weak spark under load and replaced plugs, HT leads, dizzy cap, rotor arm, and coil pack. That resolved the hesitation, but shortly after introduced a cold start issue — longer cranking, delayed ignition, and initially firing on what felt like only 2 cylinders. After a few minutes warming up, all 4 cylinders kick in and it idles fine around 800rpm.


The next morning: same again — no ignition for a while, then fires up weakly on 2 cylinders, smooths out after warming. Took it to a local garage. They checked ignition, fuel, wiring, grounds — no fault codes, no obvious cause. Eventually, the car wouldn’t even turn over.


Towed it home and put the OEM intake back on to get back to baseline. Replaced the flat battery, sent the full distributor assembly off for testing (came back fine), reinstalled correct NGK plugs and leads. Still the same: crank, no fire, then eventually 2 cylinders, warming to all 4 with smooth idle. However there is a light coloured smoke from the exhaust.


Interestingly, the problem worsens in colder temps. On cooler mornings (15°C), it takes ages to start and only runs on 2 cylinders at first. On warmer days (23°C), it starts quicker and runs on all 4 sooner. Brand new plugs are already showing carbon build-up.


I checked and reset ignition timing to 15° BTDC per service manual — no improvement. Logged data using Hondash ECU reader — only notable difference between a good start and a bad one is coolant temp. MAP and injector data are consistent. Compression test show consistency through out all cylinders.


So far, spark is confirmed good, intake is back to stock, fuel seems OK, and ECU shows no errors. I’m starting to think this is temp-related — cold fuel atomisation, weak wiring in cold, maybe a sensor acting up in low temps?


If anyone’s had a similar issue or has suggestions on what to check next, I’d really appreciate it. I’ve got big plans for this car, and I just want to get it running properly again!

[vanzep]

There is a know fault with 5th gen ignition barrel - they did issue a recall. Normally it just cuts out completely when driving but it could possibly be worth looking into. The other item is the main/fuel relay located under dash on drivers side - these can cause issues due to dry solder joints - easy to fix.
Couple of other things I can think of is to run some fuel line cleaner through and see if this improves starting/running and check that the alternator is charging the battery so you should see approx 12.5 volts at the battery and approx 14.4 volts at the alternator with engine running.

[Jakku41]

There is a know fault with 5th gen ignition barrel - they did issue a recall. Normally it just cuts out completely when driving but it could possibly be worth looking into. The other item is the main/fuel relay located under dash on drivers side - these can cause issues due to dry solder joints - easy to fix.
Couple of other things I can think of is to run some fuel line cleaner through and see if this improves starting/running and check that the alternator is charging the battery so you should see approx 12.5 volts at the battery and approx 14.4 volts at the alternator with engine running.

Thanks for the response, I'll have a look into those I didn't know about the ignition barrel issue before. The main relay issue I had heard of but it seemed as though warm conditions were the crux for that unlike my cold temp issues but I think I'll need to check it too just to make sure.
The car has been sitting with the same fuel in its tank for a while now so that probably isn't helping much. The alternator is definitely charging the battery like you said the 14.4v shows on the data logger when running which at least covers the battery being an issue .

[Scott560]

I would do a compression check first.

If it's low consider checking/setting the valve clearances as a quick win.

I'd check the air filter to see if any of it has been ingested, is ilthis the one that has the water proof sock thing inside the filter that sailor/Hans recently posted about getting sucked into the inlet?

[Scott560]

Ah just read you did a compression test. Have you done both cold and hot ones? Cold is probably most important.

When you replaced the ignition coil, did you be sure to refit the tiny spring that links the coil output to the dizzy cap? It's so easy for it to fly off...

Has the car had any other work done recently? Been sitting around for a long time perhaps?

You could have an injector stuck open perhaps.

is this H22 engine? Where are you based, you might someone nearby with spares to help diagnose...

Cheers

Scott

[Jakku41]

Ah just read you did a compression test. Have you done both cold and hot ones? Cold is probably most important.

When you replaced the ignition coil, did you be sure to refit the tiny spring that links the coil output to the dizzy cap? It's so easy for it to fly off...

Has the car had any other work done recently? Been sitting around for a long time perhaps?

You could have an injector stuck open perhaps.

is this H22 engine? Where are you based, you might someone nearby with spares to help diagnose...

Cheers

Scott

Hi Scott thanks for the reply!

The intake it all clear I've removed everything up to the throttle body which i would assume should be clear.

The compression test was done when the engines was up to temp which now you've said makes more sense to do a cold test as thats more representative of the issue condition. Yes the spring was installed back on I made sure of that.

All previous work I had done that was engine related was fitting new headers and exhaust but its had that done for about a year since the problem started. It's been sitting a while for now but prior to the issues it was ran every other week. I was thinking of getting the plugs tested if there was nothing glaringly obvious from my listed issues.

Yes it's a H22A5 and I'm based Cambridgeshire area around Ely if you've got any good Honda specialists nearby you would recommend?