Help: Car takes 4-5seconds to turn off.

Woody_FX

Hi Guys.

Driving a Jeep Cherokee 4L Petrol. 1997.

The jeep takes about 4-5 seconds from when the key is turned to the 'off' position to turn off. I didnt take this as a problem, more a quirk of the Jeep.

But a mechanic today said it is a real problem since ignition switchs are very important to the running of the vechial.

A different mechanic replaced the ignition switch a week ago. Obviously he noticed this didnt fix the problem and said nothing to
me about it. I noticed the 400$ charge on the reciept. Seems he didnt know what to do after the problem persisted after getting me to buy the part.

Any idea what might be causing this kind of delayed shutting off of the engine?

Car intermitantly loses power while driving so maybe they are related. Fuel pump was relplaced previouly so i am guessing this problem has been there for a while and that replaced part didnt solve that problem.

Something electrical faulty? Some sensor?

Thanks guys
W

Yakult

Did it do this from the start (from when you bought it?)

mik_da_man

I've only seen this on cars with turbo timers - which i'm guessing your jeep does not have??....

Drummerboy08

Mmm i was just thinkin turbo timer myself.. I drove an MR2 once that was running outside the house for ages!

I doubt the Jeep is fitted with one, but is there a similar system installed in these that would cause the engine to stay running?

Woody_FX

No there is no turbo on the Jeep.

I bought it used so i dont know but i doubt it was doing this from when it first came out of the factory.

Anybody else got a guess as to whats happening?

Saab Ed

I hope someone with better mechanical knowledge sees this and has a better explanation but as far as I know on a petrol car when this happens its because of a large carbon build up on the head which continues to ignite after the fuel has been cut off. Proper way to fix it is to take the head off or drive the nuts out of it with a fuel additive. DONT TAKE THIS AS GOSPEL

Woody_FX

Sorry for asking?

But what is the head you are refering to when you say there is a possible build up of carbon? They replaced some part of the ignition system last week.

Saab Ed

The head is the top of the engine. Not rocket science for a mechanic but a big enough job. Where abouts are you and maybe somebody here can suggest someone good in your area to help you out.

Woody_FX

Saab Ed wrote: »

Where abouts are you and maybe somebody here can suggest someone good in your area to help you out.

Arlie Beach in Australia. I am guessing nobody can suggest anybody.

Could the same carbon deposits becausing the intermitant loss of power effect? Driving along then engine revs down slowly and not much responce coming from the trottle.

Thanks Saab Ed you just might be right.

Anan1

Saab Ed wrote: »

I hope someone with better mechanical knowledge sees this and has a better explanation but as far as I know on a petrol car when this happens its because of a large carbon build up on the head which continues to ignite after the fuel has been cut off. Proper way to fix it is to take the head off or drive the nuts out of it with a fuel additive. DONT TAKE THIS AS GOSPEL

This was my first thought too, again not Gospel.

Saab Ed

Im just not 100% sure on that but no doubt carbon build up would hinder performance. Maybe the carbon build up is giving bad readings to the emissions sensors and thats whats causing your loss of power. As an attempt at a cheap fix that wont damage anything try a bottle of fuel additive and a quarter bottle of 2-stroke oil mixed with a full tank and take it on a good long hard run. One thing for sure its not an ignition switch.

Del2005

Woody_FX wrote: »

Hi Guys.

Driving a Jeep Cherokee 4L Petrol. 1997.

The jeep takes about 4-5 seconds from when the key is turned to the 'off' position to turn off. I didnt take this as a problem, more a quirk of the Jeep.

Woody_FX wrote: »

Arlie Beach in Australia. I am guessing nobody can suggest anybody.

Generally engines which do that are knackered and the fact that it's a 12 year old American engine being driven in Oz makes me think it has huge milage on it. May be better to try and source a 2nd hand engine. And burn down the place that charged you 400.

itarumaa

Once I had an old 205 that didnt run anymore and the reason was carbon build up as well.

You could try to drive the car hard for long period of time, it usually helps but it can also damage the engine because that carbon might go somewhere it should not be. The idea is to use large gear and floor it and therefore take out as much power out of the engine as long as possible. I am not 100% sure how to do this with automatic tough, since I assume you Jeep is automatic one.

Or another option is...and if you try this and damage your engine, dont come to complain to me:)

Basically you use water to clean up the engine, but if you don´t know what you are doing then...

See this video:

This has been tested and it works but again if you put too much water then you will damage the engine.

Woody_FX

*oh jesus*

Ok i'll go have a chat with the mech. I dnt care about the 4 second delay in the engine cutting off, he just seemed to think it was serious.

I'll go have chat to him tomorrow. Really hope its not a sign the engine is knackered.

200k miles on the engine. -.-

Thanks for the help guys.

Omcd

When it starts running on for about 10 - 20 seconds it becomes a pain. Like an old Sierra I had years ago. That went to the scrapyard. 150K on the clock, which was a lot back then.