Inconsistent Starting

[Bstrom]

I've been having an inconsistent starting experience with my '99 with 184k miles.

It had new plugs put in about 2k miles ago and I just replaced the plug wires with NGKs.

I cleaned the TB and MAF a couple weeks ago with no changes in measured fuel mileage. It runs fine with no issues and gets 18-20mpg consistently.

Sometimes it starts immediately on the first crank, sometimes it doesn't unless I hold the key over longer than I like - about 3 seconds. It may be me.

Are there any other components involved in this process that are potential culprits? Cam sensor, O2 sensor? Before the plug wires were changed, if I turned the key all the way off and tried again it would start better. May be my imagination but that seems to help.

Any ideas?

 

[stir_fry_boy]

Fuel Filter.

 

[Bstrom]

Fuel Filter.

Forgot to mention. I've already changed it.

My battery is 4 years 9 months old and about 100 amps below spec. Starts and runs fine routinely, just seems slightly sluggish. Would that much of a drop be enough to inhibit snappy starting?

 

[TXRick]

Battery cable tight and clean?

 

[Bstrom]

Battery cable tight and clean?

Yup...this vehicle is in great shape, just seems weak in the start department. I've eliminated all the maintenance items as causes, I believe.

On the battery, what is the lowest amp reading before swapping out supposed to be? We got any battery experts here?

 

[JRZEE2000TR4LTD]

I've been having an inconsistent starting experience with my '99 with 184k miles.

It had new plugs put in about 2k miles ago and I just replaced the plug wires with NGKs.

I cleaned the TB and MAF a couple weeks ago with no changes in measured fuel mileage. It runs fine with no issues and gets 18-20mpg consistently.

Sometimes it starts immediately on the first crank, sometimes it doesn't unless I hold the key over longer than I like - about 3 seconds. It may be me.

Are there any other components involved in this process that are potential culprits? Cam sensor, O2 sensor? Before the plug wires were changed, if I turned the key all the way off and tried again it would start better. May be my imagination but that seems to help.

Any ideas?

IAC or MAF IMHO

 

[Singtoe]

Your fuel pump is bad.

 

[4eigner]

Your fuel pump is bad.

Might want to do a fuel pressure check before he goes diving in on parts.

 

[Bstrom]

Your fuel pump is bad.

Even if the vehicle runs without issues and gives correct fuel mileage? What would be wrong with it? Low pressure or something?

It idles perfectly at ~600rpm with AC off and ~750 rpm with it on. That should rule out the MAF too.

This may be more imaginary than anything else. My 20 year old Miata starts instantly with no hesitation. This 4R has high mileage so maybe I shouldn't expect perfect behavior.

I might just go ahead and replace the battery since it will need to be in a little while. I put one of those beastly 7-year Bosch models in my F-150 and it made a difference. Cranking amps might be low enough on the 4R to prevent a clean start.

 

[Singtoe]

http://www.toyota-4runner.org/3rd-gen-t4rs/90760-engine-cranks-3-times-too-long-6.html

 

[rdracer66]

Could it not be all the recent questions regarding this where most seem to make it sound like the contacts need replacing. I have the same issue lately and thinking about doing this version. Not even taking the who start out just the front so i can replace the contacts and plunger. I hear it fixes most of the problems. worth a shot and prices around $40 i think for the 3 pience at the local steeler ship

 

[Idle Beak]

I've been having an inconsistent starting experience with my '99 with 184k miles.

It had new plugs put in about 2k miles ago and I just replaced the plug wires with NGKs.

I cleaned the TB and MAF a couple weeks ago with no changes in measured fuel mileage. It runs fine with no issues and gets 18-20mpg consistently.

Sometimes it starts immediately on the first crank, sometimes it doesn't unless I hold the key over longer than I like - about 3 seconds. It may be me.

Are there any other components involved in this process that are potential culprits? Cam sensor, O2 sensor? Before the plug wires were changed, if I turned the key all the way off and tried again it would start better. May be my imagination but that seems to help.

Any ideas?

I have had the same problem with mine ever since I have owned it. Nothingi have tried has fixed it. I just deal with it cause it doesn't change the performance of my truck.

 

[St Runner]

First issue would be fuel delivery. If your fuel pressure is good after it warms up and has been running for a while the next thing I would do is upgrade your ground. I know everyone just rolls their eyes at this but it is important that your secondary grounds are working well. My theory is this , when starting which is your biggest draw by far on both the positive and the ground, if your ground is maxed out, all the functions for the engine to start(ecu sensors etc) will be weaker than they would while running. You can test this out by bump starting if you have a manual and then stopping and crank start it. If it fires as soon as you drop the clutch but cranks for a while when you use the starter you should upgrade your ground. Autos are harder to test but if it takes 5 second of cranking to start, crank it for 3 and then let off the key. If it fires as soon as you let off the key you have a weak ground. This is just my opinion but I upgraded my ground on my tacoma and it cut the cranking time down to normal. I followed a thread on ttora and even if you don't do the big three a ground upgrade will help.

 

[jeremyc74]

Fuel pump is a reasonable place to start.

The pump itself may be fine but there's a check valve on the inlet, and if that goes bad it allows fuel to drain back out of the line and into the tank. Then when you try to start it the pump has to fill the line up before you get the proper amount of fuel pressure at the rail, and it can cause long cranks.

I'd put a gauge on it that you can see from inside and keep an eye on the pressure at start up. If that's the problem you'll likely be able to see a difference in pressure between a normal start and a long one.

 

[cashmoney]

Long shot is starter contacts. Cheaper than a fuel pump and easier to replace.

 

[Singtoe]

Long shot is starter contacts. Cheaper than a fuel pump and easier to replace.

That is a way long shot - Like shooting a terrorist in Syria from NC with an AR15.

The OP is not saying that it won't start, he is saying that it takes many too long to start. Like the engine is cranking over but not firing up.

 

[cashmoney]

I know what he's saying. But it's still worth a check. If they are making a weak contact it might cause a weak start.

 

[Bstrom]

First issue would be fuel delivery. If your fuel pressure is good after it warms up and has been running for a while the next thing I would do is upgrade your ground. I know everyone just rolls their eyes at this but it is important that your secondary grounds are working well. My theory is this , when starting which is your biggest draw by far on both the positive and the ground, if your ground is maxed out, all the functions for the engine to start(ecu sensors etc) will be weaker than they would while running. You can test this out by bump starting if you have a manual and then stopping and crank start it. If it fires as soon as you drop the clutch but cranks for a while when you use the starter you should upgrade your ground. Autos are harder to test but if it takes 5 second of cranking to start, crank it for 3 and then let off the key. If it fires as soon as you let off the key you have a weak ground. This is just my opinion but I upgraded my ground on my tacoma and it cut the cranking time down to normal. I followed a thread on ttora and even if you don't do the big three a ground upgrade will help.

I was just reading up on the Big 3 and you might be right. Between an aging battery and potentially worn starter contacts, that makes a lot of sense since it usually cranks and starts right up without delay if I turn it off and try again.

Hopefully the pump is not an issue as it is another item that does not show up in the records as being replaced yet. Will take care of these electrical connections first and see what happens. I will also be installing a Bosch 850 cranking amp battery today or tomorrow after confirming my 9/11 battery is on its way out. Thanks a lot guys, this is why I come here to learn from the best!

PS: how does one check fuel pressure, BTW? And assuming that check valve is an issue, can simply turning on the ignition and letting the pump pressurize the line compensate for the valve drain back condition?