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Matt, Mechanical Engineer
Category: UK Car
Satisfied Customers: 21631
Experience:  BEng hons Mech engineering, in auto industry 22 years
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Dear Randall:My Kia Sedona 2008 started idling funny about

Customer Question

Dear Randall:
My Kia Sedona 2008 started idling funny about 1,5 year ago: irregularly at 750 rpm, then regularly at 900 rpm por 3-4 seconds once every minute or so, and always with the engine already warmed up. After a few attempts to clean injectors with cleaning fluids added to the gas, it seemed to improve, but soon afterwards it began to sound as it the engine were working on three cylinders. Then, about four weeks ago it began to start with increasing difficulty: it cranked, but it would take more and more to start, until it did not start at all. At that point, we got it working a couple of times by hand-priming the system with the rubber bulb by the gas filter; then, the mechanic used a touch of propane in the air admission, and it worked. Now, the minivan is parked. Interestingly enough, the engine has NEVER STOPPED while it is running: once you get it to start, it keeps going. ¿What to you think?
Submitted: 2 years ago.
Category: UK Car
Expert:  Matt replied 2 years ago.
Hello If you haven't already then I'd replace the fuel filter I'd check that you're getting full power to the glow-plugs, they pull a lot of current so take care when checking but see if the relay is clicking when the ignition is turned on first and also check the fuse if this is OK check to see if the engine earth strap is also OK.If the plugs haven't been changed in the last 20K then they may have to be replaced.You can test the glow-plugs with a multimeter by measuring the resistance across the plug ( between the power connection and the body) it should be around 4-8ohms if its tending to infinity / open circuit the plug is faulty or by using a clip on current clamp, either on the supply wire to glow plugs or onto engine earth, with glow plug light on you should see 15-20amps for each glow plug fitted, 4 cylinders would be approximately 60-80amps.
Customer: replied 2 years ago.
Dear Matt:Thank you for your answer. The mechanic here says that he already changed the fuel filter, checked the relay, fuse and earth connections, and verified the plugs. The starter cranks fine and he has also cleaned and calibrated the injectors, but when the engine is cold he can only get it to work by blowing a little propane in the air admission. Once the engine starts, it runs quite well and does not stop.
Expert:  Matt replied 2 years ago.
Hello If the EGR valve isstuck open then this too can effect starting so try disconnecting it to see if this helps or changes anything Could also be an injector leaking fuel back through the overspill pipe, so not getting enough fuel pressure to tell ECU to fire the injectors, this is trickier to find and you’ll need the garage to do a ‘run back’ test to identify which one is the issue
Customer: replied 2 years ago.
Dear Matt:Juan -my mechanic here- says thanks. He was retesting the injectors, and will look into what you last suggested next. By the way, he asked me to comment to you a couple of things:1. My minivan does not have an electrical high pressure fuel pump, so he tried an external one to test this part of the system: it did not work.2. When he puts the injection in the testing bank, each injector seems to perform as it is supposed to.3. He feels that the engine does not start because the initial four-injector fuel blow is not occurring.One more thing. When I was coming home after this conversation, I recalled that a few times and while I was just starting to drive -usually in my parking lot-, the minivan suddenly began to accelerate by itself, so I had to step on the braking pedal. ¿What do you think?
Expert:  Matt replied 2 years ago.
Ok if its accelerating on its own then its likely that's getting extra fuel from somewhere
this could be diesel dribbling from a leaking injector
but more likely is the engine breathing in engine oil and running off that
The first thing I'd check is the crankcase pressure relief valve (PCV) these are sprung loaded and are only meant to 'burp' excess pressure every now and then. The exiting gas is piped back to the inlet, however should the valve stick open then the engine tends to suck the air out of the crankcase all the time and this carries oil over with it.
If you remove the air intake pipe and look inside where the crankcase breather is plumbed in you may find evidence of oil.
If you do find oil replace the valve
Expert:  Matt replied 2 years ago.
do you still need help?
Customer: replied 1 year ago.
Dear Matt:Sorry for the delay in letting you know. The "run back test" was positive, so the mechanic here got a repair kit for the injectors, and now EVERYTHING is fine. He... ¡and I! say THANK YOU.
Expert:  Matt replied 1 year ago.
Glad to have helped
Please can you ensure that you give a rating for my advice , otherwise I don't get paid
Best regards
Expert:  Matt replied 1 year ago.
do you still need help?