Hesitation on my V6 Collie

[AndycruiserguyLomas]

This might require a bit of help from overseas where the V6 Prado/Colorado is a bit more common.
The Collie starts up and runs fine but when it's warm it has a hesitation for a second before it sets off from a tickover, as you would set off from a junction or entering a roundabout from a standstill. After the slight hesitation it sets off with plenty of power and above tickover it runs fine. It feels like the enrichment it needs isn't there for half a second.
It will do this if it's stood with the bonnet open and you manually snap the throttle open.
The plugs have done less than 20K.
Although its ODB1 it has been scanned and showing nothing amiss although it is basic.
It's run on Shell V power nearly always.

As I understand it enrichment is achieved by drawing fumes collected in the charcoal canister opened by a valve when required, I may be wrong on this but the valve works and when powered up remotely it makes no difference. The inlet pipe to the canister the rear isn't blocked and when the canister is bypassed completely ie.connected straight to the inlet manifold it still hesitates.

I may be looking in the wrong place as I don't understand the workings of the V6 as I do the diesels but do understand the fundamentals.

There may be a simple solution to this I just need pointing in the right direction.

I think there is a fuel filter somewhere along the line I replaced 20K miles ago which I might investigate.

Back to the drawing board as they say.

Thanks.

 

[stumog]

Does it have a airflow meter or something similar? I have had problems on similar age golfs where the afm needs a clean. Also problem with a vaccum line having a slight crack that closed up with more pressure

 

[AndycruiserguyLomas]

Yep it has a MAF sensor, like a 2 wire thing. I can't see any perished vac lines, there aren't a lot on it TBF.

 

[MODVRS]

When I had idling issues with mine it was down to a clogged up IAC valve (idle air control) and a bit of carbon build up around the throttle butterfly. If it's not been cleaned in a long time it might be worth popping the throttle body off and giving it a good clean. The IAC is on the bottom of the throttle body and has coolant pipes on either side.

 

[AndycruiserguyLomas]

This sounds like somewhere to investigate, many thanks.

 

[MikeJak]

I have the V6 too, it does need a bit of throttle on take off but no real hesitation.
they are relatively simple engines... air-sprak-fuel are
air is pretty easy, check the air filter is clean, clean the maf sensor (can make a big difference) cleaning the IAC valve under the throttle is also a good call. the butterfly is less likely to need cleaning as long as your CVP on the valve cover is working, you shouldn't get much oily air in the throttle and upper plenum at all.
o the back of the throttle body you have the throttle position sensor, mine was giving a laggy feel when the sensor went but it does store a code if the sensor is outside teh paramethers.

spark I assume is good if you don't have any misfires?

fuel is a bit trickier as it's deeper in the engine, I don't have much experience with that but read that running some injector cleaner regularly does help. I haven't done it yet.

the 5VZFE is very common in the USA, Tacoma and 3rd Gen 4Runner (and a few others) run it so there is a lot of info in state side forums.

 

[AndycruiserguyLomas]

Well, having well thought about it and going back to fundamentals I thought this must be a fuel issue. Having steamed out all the old petrol in the tank when I bought it years ago I thought about what I hadn't done, having replaced the in tank fuel pump.
When I serviced it up I didn't change the fuel filter. One dually ordered from Amayama ( £48.00) I fitted tonight and Hey Presto smooth running was restored, beautifully smooth again and no hesitation.

I'm back in love with it.

Next job, air con.

 

[AndycruiserguyLomas]

Bumping back onto this thread I have finally got to the bottom of this problem. Having sought advice from several garages all with different diagnosis from wrong fuel pressure, fume canister, vacuum hose split, throttle body clean, water temp sensor, plugs, leads, MAF sensor clean, all of which I checked out.
Watching a You Tube vid about a guy trying to start an Alfa which had been stood several years which would start then stop he disconnected the MAF sensor and it ran perfectly. I did the same and low and behold it ran perfectly with the engine management light on.
New genuine MAF sensor obtained and fitted and..... perfection, drives like a dream. One noticeable difference is it smells a lot less rich from the exhaust.

Re. fitting the fuel filter. I thought it was cured but not as the case was. See previous post.

The offending item.

 

[MODVRS]

How much was the new sensor and where did you source it please? I've had some bother with MOT emissions and think a new one might be in order for next time. Genuine part the only way to go I think.

 

[MikeJak]

Sorry I missed this… I’d have suggested cleaning the MAF as one of the first things….
If you have fuel, air and spark then the classics are dirty maf sensor or faulty tps or, for rough idle, dirty iac valve.
As the 5VZFE is quite rare over here I often find great info on Us 3rd gen 4Runner forums.
Timmy the tool man videos on YouTube are a fantastic resource.
Test the old maf, it may just need a clean and you have a spare to keep..

 

[MODVRS]

Thanks for that. I've looked at cleaning the MAF but the wires are well shrouded and I didn't want to break it. I cleaned the throttle body and IAC valve last year (they were pretty clean to start with). MOT man suggested looking for intake/exhaust leaks which I will do this year. If a MAF doesn't require a mortgage I'm inclined to give it a go anyway. Not investigated the TPS, will look into testing that. The car runs fine it's just the CO at idle come MOT time.

I'm a great fan of Timmy's videos; followed his advice on several jobs.

 

[AndycruiserguyLomas]

How much was the new sensor and where did you source it please?

I got a genuine one from Ebay from a seller in the Philippines. it was about £50 posted.
They are from £25 from Amazon but I went genuine. One thing to bear in mind is that they changed type somewhere around mid 99 so it's worth taking your part number as a reference. Toyodiy said mine should be the latter type from chassis number but the earlier type was fitted and the new one seems to be doing the same job. I did clean the old one but it didn't restore it.
What year is yours?

 

[MODVRS]

Thanks for the info. Mine's an early one I think, 1997. Will search for a part number if it ever stops raining.

 

[AndycruiserguyLomas]

Will search for a part number if it ever stops raining.

99% it will be the same as the one I bought. Part number is on the pic. I'd still check on Toyodiy from your chassis number though.

 

[MikeJak]

I clean regularly the maf with a specific cleaner (highly volatile and no oil) and works well.
A malfunctioning maf or tps should throw a code, usually without cel light but the code will still show if you jump the contacts.
Good shout about the different maf, I think one has a 3 pin plug and one 4, made for different version ecu, the tps has a similar variance.
For specific part numbers someone told me about Toyota parts catalog - [Leaving Land Cruiser Club]
If you put your vin it will bring up the exact build sheet of the truck.. allegedly with the exact parts fitted. So far it has been reliable with some pretty niche parts ( transmission valve body gaskets to name one… same trans can have 19different gasket layout!!)

Agree Timmy is great!

Nice to see some love for the v6, the 5VZfe is a great engine in my opinion..

 

[MODVRS]

Looks like I have a different version

 

[AndycruiserguyLomas]

Looks like I have a different version

Toyodiy tells me that's what should be on mine. Maybe in a previous life ( when it had a front end bump) a second hand air box off a different year was cobbled in as part of the repair. It works though.