Sometimes car starts fine...sometime car cranks a lot before starting

Hi Car People - A few months ago, I had a starting issue that I resolved after replacing the battery, starter motor, starter relay and switch plunger cylinder. Things were perfect until my son got in the car yesterday and turned the key. My 2007 Jeep Liberty cranked excessively before turning over. My son did his business, got back in his car and it started right up. He drove to the car wash, shut the car off to go inside to pay and again the car cranked excessively before starting. This morning, he went to start his car to check things out and it started up but he says he thinks it’s not starting the way it used to. He used the word “weak” start…more cranks to turn over than the past.

I hoping it’s a bad tank of gas but haven’t replaced the fuel pump YET… I say fuel pump because I think everything else associated with starting is new…

You know how it is, if the mechanics can’t recreate the problem then they can’t fix it. I’m trying to be proactive so my son doesn’t get stranded someplace. Any words of wisdom would be appreciated.

Thanks for your help.

Cranking and turning over are the same thing. What you describe is an engine that cranks/turns over, but does not start and run right away.

Try the “key dance” before starting the car: turn the key to Run, not all the way to Start. The fuel pump should run for a couple seconds. You may hear it. Turn key Off then back to Run a few times. Each time the fuel pump runs and brings fuel and fuel pressure to the engine. Now turn the key all the way to Start. Does it start right up? And keep running?

Next time you do a cold start after the Jeep has sat for a while… turn the key to ON but not all the way to crank. Turn it back off. Do this 3 or 4 times before going all the way to crank. If it starts right up each time you do this, a check valve in the fuel pump is leaking OR a fuel injector is leaking off the residual pressure the car needs for a quick start. A pressure test can confirm this.

Try a bottle of injector cleaner in the gas tank first. If that doesn’t clear things up, a new fuel pump may be in order.

edit… @shanonia types faster than I do!!

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Thanks @shanonia. I’ll report back after he does the “key dance”.

Thanks @Mustangman. I’ll try a bottle of injector cleaner. The car uses regular unleaded gas. Do you think filling up with super unleaded the next time would help? The car has almost 165K miles so it’s probably time to replace the fuel pump…

Premium fuel doesn’t contain any more detergents than regular so no. Injector cleaner is the way to go.

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Complete waste of money.

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That’s what I thought but wanted an expert’s opinion. Thanks

That seems to be the consensus. Thanks for the confirmation NYBo

If you have no fuel pressure (as noted) the car is not going to start. The check ball can cause fuel pressure to be lost or the pump not running. Priming with the key as suggested will tell you if the check ball is likely hanging up and releasing pressure while parked. I also had an injector once that would stay open intermittently that would cause the loss in pressure. That required the dealer doing an injector cleaning. So those are the likely causes. Two involve the fuel pump replacement.

Thanks for taking the time to respond Bing. I guess the next logical step before bringing it to the mechanic is to buy a bottle of injector cleaner and put it in the gas tank. Probably not the same thing as having the mechanic clean the injectors but it’s worth a try. Unfortunately, until the 15 year old fuel pump gets replaced, I’m always going be worried when turning the key that the car won’t start (The only definitive way to know what’s wrong with it). I suppose that’s why I buy towing insurance and what rideshare apps are for:). Enjoy your weekend.
Rob

Knowing the results of the “key dance” can help diagnose the problem. And if it works, and the driver(s) do it, you don’t need to replace any parts.

In my 1999 Civic, the key dance has been needed a few times, especially when the gas tank is near empty.

Thanks shanonia- I know the key dance is going to be the first tool on my son’s tool belt should the car excessively crank without turning over. Hopefully, the fuel injector cleaner will resolve the problem but, like I said, the old fuel pump is a low hanging fruit that is going to haunt me.

I’ll be sure to keep you and everyone else posted on how this story ends someday. I’m not getting rid of the car…

I don’t think that will resolve the problem. The gas now has additives that keep the injectors clean, not like the old days.

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To be clear, if it is cranking it is turning over. Same thing.

Starting and running, that’s what you want the car to do.

I always thought “turning over” meant the car started. Sorry for the confusion. The car sometimes starts right away and other times I have to hold the key in the start position for several seconds before it starts.

I’m thinking you’re probably right and have scheduled an appointment to have it looked at on Wednesday. Hopefully, the car will act up for the mechanic or the mechanic can outsmart the car and figure out what’s wrong. I have a feeling it’s going to be a big bucks repair- it usually is with a 15 years old car…

I’ll keep you posted

Thanks

No need to apologize. “Turning over” is often used in place of “starting” but it is a confusing usage.

“Start” is universally understood but “turn over” - as we see here - leads to the question, “Do you mean the crankshaft is turning, the pistons are going up and down, etc. but the engine is not starting, or do you mean the crankshaft is turning, the pistons are going up and down, etc. and the engine is starting.”

Tester

That article starts out well, but later uses “turn over” when what is meant is “start” — the same problem it sets out to solve!

Will a clogged fuel filter keep an engine from turning over? Will worn spark plugs? Sheeesh.

I don’t remember which factory service manual it was, could have been the 68 Dodge or 74 Olds, but they had several pages of sounds and symptom definitions to help the mechanic communicate with the customer. Difference between chuggle, etc. Who knows who destroyed the language.