Throttle body air filter clip screw

[jaxabin]

I think I've stripped the screw, any ideas on how to get it out? Was going to clean intake manifold but I guess not today

Apparently its a 5.5mm bolt? I've ordered some sockets since I only had 4.5mm but not 5.5mm

[CRC]

I've never heard of a 5.5 mm head bolt, but stand to be corrected.

Are you sure it's not a 6 mm head bolt that has corroded away slightly, or a socket that's not quite as accurately made as it might be?

[jaxabin]

I've never heard of a 5.5 mm head bolt, but stand to be corrected.

Are you sure it's not a 6 mm head bolt that has corroded away slightly, or a socket that's not quite as accurately made as it might be?

I'm not too sure to be honest, my next biggest is 7mm so I can't really test it out. Will see with 5.5mm when it comes, but I saw a thread here and a youtube video that said 5.5mm too, the manual on hondafitjazz (something like that) doesnt seem to specify either

[jaxabin]

I cant quite make out which one its supposed to be? APparently there's some 6mm bolts in attachment:

part 17


https://www.parts-honda.uk/honda-cars/assignment_spare_parts/90001P0A000

I think that sounds about right then, luckily I got a set of the sockets so I'll have 6mm too. I don't know why it looks like a screw too? Maybe its a screw and bolt at the same time but the screw got ruined over time. Wonder what they looked at in the engine before

[CRC]

There is a commonly used screw / bolt that is used one jubilee clips for tightening round hoses and this generally takes a 7 mm socket but it also has a crosshead screwdriver slot formed in the head. Often, you'll find that this is best fitted by a "Japanese spec screwdriver" which fits the slots much more securely that a Philips or a Posidrive screwdriver.

My brother worked at a Honda main agent for years and I remember him telling me that Honda never used a 13 mm head  nut or bolt, and, to this day, I don't recall finding one.

[aphybrid]

5.5 mm does exist.
eBay & amazon

[Lord Voltermore]

My brother worked at a Honda main agent for years and I remember him telling me that Honda never used a 13 mm head  nut or bolt, and, to this day, I don't recall finding one.

For anyone interested here is a pasting of the google AI overview on the subject

 Asian vehicles—particularly Japanese-manufactured cars—frequently use smaller bolt head sizes compared to American or European standards (DIN/ANSI). This is due to adherence to the JIS (Japanese Industrial Standard), which commonly uses smaller heads to allow for tighter packaging of components.
Key Differences in Bolt Head Sizes:
M8 Fastener: JIS standards typically use a 12mm hex head, whereas DIN/ANSI standards usually use 13mm.
M10 Fastener: JIS standards typically use a 14mm hex head, while others often use 17mm.
Common Sizes: Japanese cars are renowned for heavily utilizing 8mm, 10mm, 12mm, 14mm, 17mm, and 19mm sockets and wrenches.
13mm Rarity: It is common to find that a 13mm bolt simply does not exist on many Japanese vehicles, often replaced by 12mm or 14mm.
JIS Screws: Japanese cars use specialized Phillips-type screws (JIS) that have smaller heads compared to standard ISO/Phillips screws, which often causes standard tools to strip them.

These smaller heads often feature a flange at the base to ensure proper clamping force despite the smaller tool surface.

[jaxabin]

5.5mm worked

I tried to remove the intake manifold and it was harder work for me, I managed to do most of it (with the help of ex-mechanic housemate) but couldn't take the last bolt, so just put things back together where I could and planning to just get a mechanic to check it out and do it all for me

(I seem to not tighten bolts enough because now I have a high RPM I think due to the throttle body not being tightened enough?)

Its way harder than it seems for a non mechanic like me, but I think I might try later tomorrow depending if the mechanic has availability.

the bolt im struggling with is the last middle one, its hard to reach so just gave up after a while, i think if i had more time I'd be able to I think but i started a bit late in the day

[cavosavosk]

It was originally 6mm but you stripped it yeah  , it happens. Good thing you got it out.

About the higher RPM, it also can be a reason of you messing with the throttle body, the car needs to relearn the idle and set itself correctly. It happens when you disconnect the battery or do smth with throttle body. But tighten up the bolts too. Just needs like 5 minutes of idling once the engine is warmed up.

[jaxabin]

It was originally 6mm but you stripped it yeah  , it happens. Good thing you got it out.

About the higher RPM, it also can be a reason of you messing with the throttle body, the car needs to relearn the idle and set itself correctly. It happens when you disconnect the battery or do smth with throttle body. But tighten up the bolts too. Just needs like 5 minutes of idling once the engine is warmed up.

yes I thought this too but it still jumps between 1k and 2k rpm, I'll take it to a local mechanic and see what they say

I didn't put all the bolts back properly either so I think it's best to just ask someone else to clean the intake and put it back together even if it costs a few hundred quid

The only other thing I want to do is change the battery too, maybe that fixes my EGR issue after reading other people who said changing the battery helped, it's a really old one by now that came with the car and I think only changed once with the reciepts I've seen

[Lord Voltermore]

Paying maybe 10% of the current value of the car to get the  job done wouldnt appeal to me .
If you've rounded off the hex heads making them difficult to remove, or tighten up properly there are alternative solutions.

Any you cant remove  maybe cut a slot in the head using a small hacksaw blade, dremel  etc. so they can be removed using a  screwdriver.  .  Although the hex is japanese standard 5.5m  the chances are the bolt thread itself is M3 so  alternative replacments should be readily available, even in diy shops. Use a removed bolt as a pattern for replacments .  (Make  sure they are high tensile steel often marked 8.8, not mild steel marked 4.6/4.8. ) The replacment will probably have the european 6mm hex  but should still fit.

[jaxabin]

Paying maybe 10% of the current value of the car to get the  job done wouldnt appeal to me .
If you've rounded off the hex heads making them difficult to remove, or tighten up properly there are alternative solutions.

Any you cant remove  maybe cut a slot in the head using a small hacksaw blade, dremel  etc. so they can be removed using a  screwdriver.  .  Although the hex is japanese standard 5.5m  the chances are the bolt thread itself is M3 so  alternative replacments should be readily available, even in diy shops. Use a removed bolt as a pattern for replacments .  (Make  sure they are high tensile steel often marked 8.8, not mild steel marked 4.6/4.8. ) The replacment will probably have the european 6mm hex  but should still fit.

yeah I think if it was any other car I wouldn't bother but it has sentimental value, my first car, driven to france etc, few moves, lots of memories. It's been very very reliable anyway and doesn't look like it's rusting yet so will plan to drive it as long as possible, couldn't have asked for a better car tbh

better the devil you know and all that I guess

the bolts seem fine, they get off well but i think its a skill issue for me in the harder to reach places. so hopefully it's all sealed up and done tomorrow and the intake is cleared a bit and see where it goes from there, i think when i'm really prepared to buy a new car/ have a second then I'll start diy-ing on it a lot more as projects, just don't really have the patience right now because i still need it

[jaxabin]

Really smooth now! 

He said it was the EGR plate was blocked off, no more rough idle or anything! Hopefully other people who have the EGR P0401 issue get their intake manifold looked at if the EGR valve cleaning doesn't do anything for them too