Wierd run on "dieseling" problem
Thread Starter
Melting Slicks
Joined: Aug 2000
Posts: 2,388
Likes: 42
From: Murrysville PA
Wierd run on "dieseling" problem
I let the 89 idle this afternoon since it was hot today. I wanted to see how hot it got while idling with the AC wide open after I cleaned the rad. last fall. It crept up to about 200. I turned the motor off and then turned the key on without starting. The temp climbed to 220. I started it and it knocked when it first fired up and the temp went down to 213. I let it run for a while and then shut it off again. Turned the key back on and the temp went to 240 with the motor off. I stated it again and this time it labored to turn over acting as if it was hot. The temp started to come down with it running but when I shut it off, the motor was dieseling and knocking and backfiring. With fuel injected motors I thought this was not possible.
The manual says that a leaky injector is the cause for this. Anyone else have this problem? Does anyone elses temp climb real high as soon as you turn off the motor?
Thanks,
Jason
The manual says that a leaky injector is the cause for this. Anyone else have this problem? Does anyone elses temp climb real high as soon as you turn off the motor?
Thanks,
Jason
Burning Brakes
Joined: Nov 1999
Posts: 859
Likes: 17
From: Houston TX
Re: Wierd run on "dieseling" problem (89vette)
Well, as for heating up, when you shut off your engine, the water pump isn't turning any more. So the coolant stays still, and it still soaks up the heat from the engine, but it doesn't get to flow through the radiator any more because the pump isn't turning. Since the temp sensor on your 89 is below the thermostat in the system, it will show the temperature of the coolant inside of the engine.
As for the "dieseling" effect, I believe that a leaky injector can cause that to happen. Too bad you don't have a later model, you could scan the different O2 sensors to see if one bank was rich and one lean. Only way to see if one is leaking on an 89 is to pull them and check... and with a Super Ram or T.P.I. that ain't fun. Mabey somebody else will have some other suggestions.
:seeya
As for the "dieseling" effect, I believe that a leaky injector can cause that to happen. Too bad you don't have a later model, you could scan the different O2 sensors to see if one bank was rich and one lean. Only way to see if one is leaking on an 89 is to pull them and check... and with a Super Ram or T.P.I. that ain't fun. Mabey somebody else will have some other suggestions.
:seeya
Pro
Joined: Sep 2001
Posts: 743
Likes: 4
From: Guyton GA
Re: Wierd run on "dieseling" problem (89vette)
If it only diesels for a couple seconds, then it is probably just a little fuel vapor left in the intake port. You could hook-up a fuel pressure gage and turn the key switch to "on". Then switch it to "off " and watch for a pressure bleed down. Your dieseling hot spot could be caused by carbon build up, feathered valves, or wrong plug heat range.
