Hard start after truck being warm

Hello all,

Question, have a 95 taco
2.4 2WD

-new battery with connector's
-Solid alternator (charges battery per multimeter
- starter (clicks over and hasn’t failed to start truck)
-Replaced the FPR and rubber vaccum hose
-New valve cover (no leaks)

my question is. On a few instances when the truck is warm and I turn it off to either run into the store or let it sit for 10 min or so. I’d say a hand full of times when I fire up the truck is has a hard/ struggle start.
It’s hard to explain.

I was thinking of replacing the ignition cylinder next due to the part being cheap with my city discount and easy to replace. the key can give me a slightly issue when I have to insert it into the opening.

a lot of info I seen was saying it was the FPR or fuel injectors(have no misfires or codes or running lean symptoms) and lastly could be a fuel tank not suppl to my proper pressure.

like I said the truck has never not cranked over. just on a small number of instances it has a momentary hesitation then fires up.
Still within 3 seconds
any info or ideas I’m all ears

thank you for your patience. It’s difficult to explain lol.

 

If she has a tach... look at the tach when she fires up normally and see if it bounces and then when it doesnt start see if the tach acts differently. If she does have a tach and the tach does not wiggle the usual starting place is the crankshaft position sensor (CKP), they break down due to age and heat, so do the injectors and the camshaft position sensor and the engine temp sensor and the...

If she doesnt have a tach, and this is reproducable on a consistant basis drive her to an O Reillys or an Auto zone and have them scan her for codes both pending and current, not all codes will turn on the check engine light. If there scan tool is sophisticted enough and can show live data have them display engine RPM. Crank her over and see if it displays anything, it will be a low reading as the starter can only put a few hundered RPM's of revolution into the motor. If it does show an RPM signal that doesnt mean that the CKP passes the test it just passes the Go no GO test, the signal can be so weak that the powertrain control module (PCM) doesnt recognise it. A signal from the CKP and starter is used to tell the PCM that the motor is attempted to be started, turn on the fuel pump via the shut off relay. The other tests for things to check like camshaft position sensor require different tools that arnt usually avalible outside a competent diagnosticans toolbox, this is where people start throwing parts at it.

When and if you do have to replace a part use Toyota only parts, too many times an issues have been retraced to aftermarket parts.

 

Awesome man I’ll keep this info if I need to get detailed into looking into this matter.
I just went out to my truck right now and fired it up with no issue. (It was sitting for about 4 hours since I ran it). I Ran it for about 1 minute then turned it off and sit for about 2 mins and restarted it after with no issue/hesitation.

Maybe the cpu needs cycles to register the new fuel pressure regulator I installed last night. I only drove it about 20 miles since then. I also disconnected the negative battery port when I installed the new one as a precaution.


I’ll see how it starts does when I drive from work to the gym later and let the truck sit then restart it.

Thoughts ?

 

The CPU does not monitor the fuel pressure in this application.

As the electronic components age the resistance values internally change and while they might pass the ohm meter test there might not be a strong enough signal getting to the PCM for it to even see it, we are talking very low voltages that can only be measure with an oscilloscpe by viewing the pattern, its amplitude and the difference between the peaks and valleys.

 

tacotony

i went thru the same issue
search: "hot no start"

host of issues and solutions
some super easy coolant temp sensor or CKP(like glasmisman states)
some more involved (leaking injectors)

i have quite a few threads wrestling with this issue.
turned out mine was injectors(212k)

and
i wish i listened to other seasoned members about certain AM parts
i blew $60 on some fleabay injectors...fixed my hot no start issue but a host of new codes/hesitation issues
sent my OE old injectors to Motorwest to be RM'd.........
fixed!

 

I appreciate all the help

I’ll keep the fuel injectors in mind

like I mentioned the truck kicks over.
I just took a video of it but don’t know how to upload it on here. Says “video has no extension” .

 

Control car


How long was the turn around for the RM of fuel injectors ?

could a bad fuel filter be an issue ? mines the OEM 202k lol

 

Glamisman

I was looking up the CKP and I might honestly change it out and the alternator as well since you practically gotta take out the alternator to access the ckp lmfao

not to difficult of a repair.

 

4days
CA to TX

one of my injectors so bad they had to charge me a $25 core
$125 total

when you call, human answers, no hold.
Good people

 

https://www.tacomaworld.com/threads/2-4l-2rz-injector-installation-a-tip-and-question.818472/

 

Okay so today I got a P0170 code for bank 1 running lean. Smh ‍♂️ going to clean MAF first and replace PCV hose since it looked kinked when I looked under hood after code came on. Have freeze frame data that came up. I’ll post date later.
Have a feeling this could be the culprit to my hesitate start after truck was warm.

 

Update : new fuel filter/fuel pump/injectors were cleaned and functioning properly per mechanic who is very reputable/ new fuel pressure regulator. Still getting sluggish start when truck is warm and turned off for a short period of time.

am I missing something but the last part of this fuel system would be the CRANK position sensor correct ?


All parts replaced were OEM parts

 

When it does fire up (after hard start) does it smoke?

 

Lights off


No smoke at all. Truck runs amazing with perfect fuel trim ratios.
Checked battery/alternator as a precaution and all perfect.

I only have issues when I’ve been running the truck and I noticed when the AC is on is when I’ll have the most issues trying to crank the truck on after it’s been sitting for 5-20 mins then firing it back up. It’ll have a “sluggish turn over” not electrical but more of a fuel delivery issue if that makes sense.

replaced fuel filter/fuel pump/fuel pressure regulator/ injectors were cleaned and no issues (tested by my mechanic who is really good on Toyotas)
Only other thing I haven’t done is the CRANK position sensor.

 

Glamisman


I’m starting to believe it’s the CKPs lol
After placing everything but that lol

 

Could be... other than replacing it the only other way is to scope it and see if the amplitude of the sine wave is high enough for the PCM to detect. The only other thing that I can think of and I hate mentioning it... the motor could be so worn that there is insuffiscent compression warm to promote combustion.

 

I’ll replace it. I get a fat discount on parts with my city discount. lol

Totally understand, I know the block is good. Leak and pressure test conducted and engine is insanely strong. Have a feeling it’s the CKP. Truck has along of power and no misfire at all. I watch the live data and all my data is in spec. THANKFULLY lol

 

Does it start OK if the AC is not on when cranking? That's a lot of extra load.

 

Wow MadNachos on to what I was guessing


https://www.tacomaworld.com/threads/96-hard-to-start-after-running-a-c.44400/

Freakin another 95???? WTH

 

Okay everyone lol after two weeks of driving and changing out the fuel injectors and CPS my truck hasn’t been turning over much better and drives way better

I can safely say it was the injectors.