Hyundai -v hard cold start

Pauley2

Have a 99 Hyundai Lantra 1.6 that was lying up for a few months. Jumped it and got it going no problem. Was using it for a few days with no issues at all (although I did replace the battery). However one morning it barely started - cranked fine, but just didn't fire up. It eventually started after about 15 tries...

Once it starts it runs perfectly and will start again no bother as long as it's not allowed cool down to much.

Thought it may have been a bad coil, so replaced that along with the spark plugs and plug leads but still the problem remains. If it were an older car it's almost as if you were trying to start it without giving it choke(!). I'm starting to wonder if the computer thinks wrongly that it's warm enough to not do whatever it would normally would to start from cold. The Temp gauge works OK, but is there another sensor somewhere that the computer relies on that could be bad?...

All help appreciated!

andyseadog

id say its either the key antenna or the crank sensor.

is the check engine light on?

bmw535d

since you sorted the spark id say its a fuel problem, seems that when you let it sit it air locks itself, even though its petrol.

colm_mcm

My money is on camshaft or crank sensor

Pauley2

...just to follow up for anyone who's interested.

I left the car with a dealer for diagnosis. Keep in mind that right up to the time I got it down there the problem was consistent i.e. it cranked OK but just barely started.

Anyway the dealer couldn't look at it right away so it sat there for 2 days (indoors). When they finally did get around to looking at it they couldn't find anything wrong!!! It started right up and behaved just as it should have. I left it overnight with them again to see if the problem returned the next morning but it didn't.

One thing the dealer did was check for engine codes - there was only one (which I wasn't aware of as for some reason there's no "check engine" light in my Hyundai...), the crank sensor, but they had no way of knowing how old it was and it wasn't misbehaving at the time. They also said that in many cases when the crank sensor goes the car usually either stops dead unexpectedly or refuses to start at all.

The only other thing they thought MAY be an issue was the presence of a plastic store card on the keyring. They said that they sometimes interfere with the key security system and advised I take it off (which puzzles me because I thought that if an unauthorised key was used, that the car wouldn't even turn over - or that there'd be some sort of warning...). They also recommended I try the spare key.

So, in essence no fault found and no parts replaced, yet with the exception of ONE time since (it had been cold and damp, engine off for about 6 hrs) the car has been OK.

I searched all over the web and there seems to be lots of Hyundai owners with similar problems. Many point to the crank sensor or improper installation of it so I made sure mine was in tight (it was). I also disconnected it from the harness, cleaned the contacts and reconnected it. I'm also using the spare key (minus store card) and no problems since.

However I don't trust it though... If it goes again I'll try the crank sensor seen as it's cheap enough (about €50) and relatively easy to replace...

Thanks to all who responded...

Pauley2

...more follow up:

The symptoms appeared again (intermittant prolonged cranking before start). This time I replaced the Crank Position sensor and, seen as the part was only another €12, I also replaced the Engine Management temp sensor. Both were very easy to change. All in all I had both done in under 30 mins.

So far so good but it may still be too early to tell.

Question though: I've seen temp sensors described as having both Black and Blue "tops". The one I removed had a black top, but the one supplied as a replacement came with a Blue top.

What's the worst that could happen if I ended up with the wrong one installed? (car seems to run just fine).

Tx

sth_safal

Pauley2 wrote: »

...more follow up:

The symptoms appeared again (intermittant prolonged cranking before start). This time I replaced the Crank Position sensor and, seen as the part was only another €12, I also replaced the Engine Management temp sensor. Both were very easy to change. All in all I had both done in under 30 mins.

So far so good but it may still be too early to tell.

Question though: I've seen temp sensors described as having both Black and Blue "tops". The one I removed had a black top, but the one supplied as a replacement came with a Blue top.

What's the worst that could happen if I ended up with the wrong one installed? (car seems to run just fine).

Tx

Sorry for bringing this old thread up but just wondering, did you find solution to the problem? Was it Crank Sensor or something else. I am having a similar problem with my hyundai coupe...

Pauley2

Interesting to see this again...!

As I had bought both the CPS and temp sensor (buying both by spending the extra €12 for the temp sensor took me to the €50 threshold for free shipping) and as it was easier to install both at the same time, I just did that.

Bit of a shotgun approach I know, but I didn't have the time to definitively troubleshoot such an intermittent problem and I was getting wary of being stranded.

I can't tell you for sure which failed (I suspect the CPS) but as the temp sensor was so cheap and accessible it did no harm to replace it anyway - and the car's been perfect since...

Good Luck!

sth_safal

Pauley2 wrote: »

Interesting to see this again...!

As I had bought both the CPS and temp sensor (buying both by spending the extra €12 for the temp sensor took me to the €50 threshold for free shipping) and as it was easier to install both at the same time, I just did that.

Bit of a shotgun approach I know, but I didn't have the time to definitively troubleshoot such an intermittent problem and I was getting wary of being stranded.

I can't tell you for sure which failed (I suspect the CPS) but as the temp sensor was so cheap and accessible it did no harm to replace it anyway - and the car's been perfect since...

Good Luck!

Thanks for the quick reply. I just got CPS for my car from Rathgar Motor Factors. I hope it fixes the problem. My local garage keep insisting on the immobilizer but from what I have learnt from many forums, I want to try CPS before spending hundreds on Immobilizer and key.

Thanks again for the confirmation.