hard to start 1hz when at running temp (1 Viewer)
- Thread starter stuch
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Tapage
Club 4X4 Panamá
start checking your batts not only for V but for amps under load .. ( starter )
Does it make a difference if you give it some throttle?
I havent heard of this happening before. There is only a few things that it can be.
Air in the system but that is usually there when left overnight.
Your fuel cut solenoid is not functioning for some reason when warm.
Your fuel pump doesnt get full pressure when warm.
Does it make any smoke when you turn it over warm?
Air in the system but that is usually there when left overnight.
Your fuel cut solenoid is not functioning for some reason when warm.
Your fuel pump doesnt get full pressure when warm.
Does it make any smoke when you turn it over warm?
Hmm when I checked my manual about this it lists 5 probable causes when a hot engine is difficult to start when hot:
1. STA signal circuit
2. Injection nozzle
3. Fuel filter
4. Emissions ECU
5. Injection Pump
Could be #1. Starter Signal Malfunction. Here's the decription from the manual I have on the circuit:
when the engine is being cranked, the intake air flow is slow, so fuel vaporization is poor. A rich mixture is therefore necessary in order to achieve good start ability. While the engine is being cranked, the battery positive voltage is applied to terminal STA of the emission ECU. The starter signal is mainly used to increase the fuel injection volume for the starting injection control and after start injection control.
1. STA signal circuit
2. Injection nozzle
3. Fuel filter
4. Emissions ECU
5. Injection Pump
Could be #1. Starter Signal Malfunction. Here's the decription from the manual I have on the circuit:
when the engine is being cranked, the intake air flow is slow, so fuel vaporization is poor. A rich mixture is therefore necessary in order to achieve good start ability. While the engine is being cranked, the battery positive voltage is applied to terminal STA of the emission ECU. The starter signal is mainly used to increase the fuel injection volume for the starting injection control and after start injection control.
Which manual is this one?
Factory 1HZ Engine Repair Manual Supplement. Dated for 1998
HTH. If this does turn out to be the issue I can post more photos from the manual
HTH. If this does turn out to be the issue I can post more photos from the manual
Its probably not in my older manual.
This was why I asked if giving it some throttle helped,as this is basically what the ECU is doing if Im reading it correctly.
Wouldn't giving it throttle continue to push more fuel into the chamber with the wrong F/A ratio though? if it takes 6-8 seconds to fire up it to would be doing the same thing, right? As you keep turning it over the pump keeps pushing more fuel in there until it starts, much the same as pushing the pedal a few times. This would be effective on a cold engine but it seems a hot engine specifically asks for a rich mixture.
I'm certainly no expert and I am getting this from my manual while inserting my own logic but by the sounds of things if your engine is hot and you want it to start right away then it need the proper amount of fuel with the right A/F ratio. Anything else is going to make the engine work harder than it should and delay starting.
IF this is the problem then you would have no starter signal to the emission ECU (located under the dash on the passenger side). The trouble area will be:
open or short in starter signal circuit
open or short in ignition switch or starter relay circuit
emission ECU
I posted a wiring diagram which should help to test these items
I'm certainly no expert and I am getting this from my manual while inserting my own logic but by the sounds of things if your engine is hot and you want it to start right away then it need the proper amount of fuel with the right A/F ratio. Anything else is going to make the engine work harder than it should and delay starting.
IF this is the problem then you would have no starter signal to the emission ECU (located under the dash on the passenger side). The trouble area will be:
open or short in starter signal circuit
open or short in ignition switch or starter relay circuit
emission ECU
I posted a wiring diagram which should help to test these items
Possibly,but older diesels including 1HZ pre 99 start ok without changing the A/F ratio AFAIK.
I'd be looking at your injection pump. I believe that it is a rotary which when hot if it is worn or leaking internally on the low pressure lift side will present the symptoms that you describe.
My thoughts also,but with 190000klms I thought it a bit early for this scenario.
Another cause could be heat expansion is letting in a small pocket of air into the pump.
That sounds like starving for fuel, white smoke, change both fuel filters, blow the line backwards to the tank to clear tank filter, does it do it on both tanks?
I would do what aussie25 suggests and also check the fine mesh filter under the banjo bolt on the pump.
If its not that Im starting to think its a worn pump .When the pumps warms up,it expands and loses the high tolerances it needs to compress the fuel.
Other symptoms can be losing top speed as the engine gets hotter.
Squash
SILVER Star
Someone else also added a clear hose to tank return line...this showed bubbles and a cure.
IP was sucking air, his was an "O"ring
IP was sucking air, his was an "O"ring
