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Occasional hard start , bad idle 240 kjet turbo

T

TimS

Member
Joined
Dec 18, 2017
Car starts fine from cold and runs great. Sometimes, if you stop for about an hour and try to start, it will crank over and idle rough for a few moments and stall out or stumble when you put it in gear and dies . If you start it and rev it up (1500), it will hold rpm and then clear out and eventually run fine. I can't seem to nail down why. When it happens I have cycled the key and can hear the fuel pump running.
When its running normal, I have pulled the lift pump fuse and the car runs fine for a moment and then stumbles and dies. I put the fuse back in and it starts fine.
Once it clears up/out everything is fine, you can stop and start it and all is good.
 
If the transfer pump in the tank is working. The next thought I had is this is the classic symptom of a bad accumulator next to the fuel pump.
 
Sounds like you might have an injector leaking and flooding a cylinder after shut down. Do you have a pressure gauge to check control and rest pressures?

The accumulator will leak externally if the diaphragm is bad. If it has a small hose barb on it that goes back to the tank disconnect it and see if fuel is coming out.
 
My Kjet car has been hard to start for years....

Fires easily when cold (I assume the cold start injector helps), I can leave mine for an hour and it fires, 2-4 hours and things get iffy..

One thing I have noticed is that during the much colder winter months here in TX, I have significantly less issues. The 100F summer months are the worst. I think with my car the fuel is being boiled causing vapor lock...

Buy as hiperfauto stated above; you need to check pressures...
 
Check the pressures and check the injectors for leaking as suggested above. For those cold months your car probably needs the extra fuel. In the summer it's probably causing some flooding.

You'll get vapor lock if the intank pump isn't working.
 
As always with the Kjet, "check fuel pressure". Does the WUR slowly leak down pressure as it cools off? Like I start at 40psi on shutdown and then overnite as it cools off the pressure slowly drops. A cold morning start should be down in the 20 psi at 40-50 dgs.
A lightly leaking injector wouldn't affect how it runs? I easily passed smog back in Dec.
And what do I do if for a leaky injector? Remove and clean or run some sort of cleaner in the fuel?
Oddly I've got/made a fitting to tap off the pressure line at the distributor so I can get fuel pressure but haven't been able to program an arduino to make a history bar graph of the value.
 
Your description is mixing up rest pressure and control pressure. Rest pressure is when you shut down and watch the decay of fuel pressure referenced to a time. For example it should retain 20psi after 40 minutes of shut down. Control pressure will start low say about 29psi and slowly rise to about 48psi once fully warmed up. You check rest pressure by putting the gauge setup in system pressure test position to watch the decay after shut down. You measure control pressure by having the gauge valve in the open position for flow to the WUR and to the gauge.
 
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