Starting issue -- Cold fine, hot fine, Warm cranks forever and finally starts

[Pano Anthos]

So I have scoured the threads on staring issues for my LX-450. 255K miles but new rebuilt engine, new suspension, new radiator.

• Engine starts great cold, great hot (turn off and then turn on),
• but if it sits 1 hour, just cranks. If I jam the pedal down and hold for 15 seconds or more, it finally breaks through. Standard lights on starting.
• Runs like a champ when it fires (races to 2K and then drops down). Never shuts off. Idle is perfect 800 or so. No misfiring felt. Acceleration all good. No CEL when running or in idle.

Took it to Toyota. Diagnostic said

• "Idle speed control valve closes at times. EGR Exhaust Circulating Valve Closes when both are closed it Carbon builds up which causes the start issue.

So I took it to cruiserparts, who I have used for years and like and who replaced the following:

1. EFI relay replaced
2. Fuel pressure regulator replaced
3. idle speed control valve replaced
4. egr valve replaced
5. spark plugs replaced

Ran great for two days and then acted up again. Definitely feels like spark not fuel. Ran well probably because spark plugs were clean. Now no longer.

Specialist thought it might be thermostat. That the thermostat is not registering engine heat (but it is temp gauge running says engine and coolant fine). Also says it could be wiring harness which will cost $$$ to replace. Ready to do that if necessary.

On forums I have seen:

• fusible link relay
  
• intake throttle hoses
• harness
• distributor

Directionally, where should I go with this. I am not a mechanic but care enough to read up and want to get it fixed but cannot do the work myself.

 

[jonheld]

You need to determine what you're missing during the crank-no start. Fuel or spark? "feels like spark" is not an answer.
When the issue occurs, do you get a "check engine" lamp BEFORE you crank the starter?
There are temperature sensors that feed information to the ECU. Different from what feeds the dash gauge.
No such thing as a "fusible link relay".
Torn intake tube may be a possibility and is simple to check.
What about cap/rotor? how old are they? Condition?
Plug wires?
Before you go into rebuild mode, check the simple things first.

 

[Pano Anthos]

You need to determine what you're missing during the crank-no start. Fuel or spark? "feels like spark" is not an answer.
When the issue occurs, do you get a "check engine" lamp BEFORE you crank the starter?
There are temperature sensors that feed information to the ECU. Different from what feeds the dash gauge.
No such thing as a "fusible link relay".
Torn intake tube may be a possibility and is simple to check.
What about cap/rotor? how old are they? Condition?
Plug wires?
Before you go into rebuild mode, check the simple things first.

**********
Thanks for your fast reply.
I have a check engine light when I turn the ignition key before cranking the starter. Sorry for the dumb question but can i get codes before the starter cranks?
I meant fusible link per this link. Sorry
96 LX450 - Intermittent No Start. Turns over but won't start
Plug wires are new
Will check cap/rotor
Thnx

 

[Tools R Us]

Sounds like they did the shotgun, replace random parts and hope thing, rather than proper diagnoses. The key to run, check for CEL light thing, confirms power to the ECU. If the light is on, chances are good that the fusible link, relay, etc, are good. If/when the ECU isn't getting power, fuel, ignition, etc, are not going to work.

 

[Pano Anthos]

Sounds like they did the shotgun, replace random parts and hope thing, rather than proper diagnoses. The key to run, check for CEL light thing, confirms power to the ECU. If the light is on, chances are good that the fusible link, relay, etc, are good. If/when the ECU isn't getting power, fuel, ignition, etc, are not going to work.

CEL stays on throughout the crank process.
I can smell gas and when it turns over the initially (when it does not start) it actually runs very rough and then shuts off within seconds.
Then when I crank long enough with gas pedal depressed, it fires up and after a little roughness, clears out and runs great.
Ill get these guys on it.
Separately, given your years on IH8MUD do you have any favorite mechanics in the eastern MA area. Always looking for closer support than NH.

 

[jonheld]

CEL stays on throughout the crank process.
I can smell gas and when it turns over the initially (when it does not start) it actually runs very rough and then shuts off within seconds.
Then when I crank long enough with gas pedal depressed, it fires up and after a little roughness, clears out and runs great.
Ill get these guys on it.
Separately, given your years on IH8MUD do you have any favorite mechanics in the eastern MA area. Always looking for closer support than NH.

So are you stating that it cranks, catches briefly, then dies when you release the key from the start position? That is pointing to a torn intake tube. Again, one of the simplest things to check.
If you're looking for local help, get in touch with the Yankee Toys. They are a great bunch of folks in the New England area. They have a club forum here:
MA/NH- Yankee Toys

 

[Pano Anthos]

Yes. It catches, rumbles (feels like misfiring) and sputters and then dies. On subsequent ignition tries, i have to crank it for close to 30 seconds with my foot to the floor in order for it to catch.
And only when the engine is warm. Hot or cold it starts fine. But if I run it for 15 minutes around town, then have it sit for an hour, i get the rumble, die and then have to crank forever.
I'll get that looked at and report back for the forum.
Meanwhile, I will reach out to them.
Thnx and have a great day.

 

[Pano Anthos]

SO I tracked the issue down. There is a thermostat on the engine block that was malfunctioning. When the engine was cold obviously the thermostat did not register anything. But when the engine warmed up, it was still not registering and thus over supplying gas to an engine that was not cold.

 

[Andrew Bluemel]

I have a similar problem to you with slightly different issues. Mine does the same thing starts cold and hot fine but warm has issues. But mine I can crank it for 5 seconds let off and try it again and it will fire up. It also doesn't seem like it's getting to much fuel as when it grabs it is completely fine.

 

[Pano Anthos]

Might be worth checking that thermostat.

 

[Andrew Bluemel]

Might be worth checking that thermostat.

Agreed. Where is the location of that thermostat and how did you tell it was defective?

Thank you