Location: Houston
Posts: 706
My VIN: 16113
Club(s): (SCDC) (DCUK)
Location: Northern NJ
Posts: 8,570
My VIN: 10757 1st place Concourse 1998
Hunting when cold is not a symptom, They All Do That (TADT). It should settle down quickly but it won't get smooth till it warms up a little at least. The CPR (aka warm-up regulator) is like a choke on a carbureated car. It makes the motor run rich and is not very adjustable. How bad it runs and how long it runs bad is a function of the ambient temperature and the calibration of the CPR. If it takes a while it is probably because the heater inside the CPR is burnt up. Very common. That heater speeds up the CPR to shorten the warm-up cycle and reduce emissions.
David Teitelbaum
I'll stick with my non hunting from cold and warm car then
RIP Rob van de Veer Top bloke
I say Sir, I must be mad, one loves fixing K-Jet !
Make sure there's plenty in the tank for the weekend chaps....
Does your fuel pump relay operate for a second or 2 when you put your key in to position 2 ?
If not, try linking out the fuel pump relay to operate the fuel pump for a couple of seconds then reinstate the fuel pump relay. If that initial surge you experience goes, I'd recommend you buy the solid state relay that Dave sells.
My own car still uses the original black fuel pump relay and it does operate the fuel pump this way.
Some cars do, some don't, but K jetronic should ideally have this function to prime the fuel system.
Fwiw, I strip down and recalibrate CPR's to oem spec. It's not hard, you just need a fuel pressure gauge, a temperature gauge, a hammer and a drift. As long as the lower diaphragms are in good condition you might as well do it yourself.
Last edited by NckT; 10-10-2017 at 03:06 PM.
RIP Rob van de Veer Top bloke
I say Sir, I must be mad, one loves fixing K-Jet !
Make sure there's plenty in the tank for the weekend chaps....
Location: Rochester, NY
Posts: 2,405
My VIN: 01049
My car was K-Jet for the first five years of my ownership. It never hunted either cold or warm at idle, and I have personally witnessed numerous similar DeLoreans. This idea that they all hunt is bollocks.
-Mike
My engine twists my frame.
1981 DeLorean, Carb LS4 swap completed
1999 Corvette, cam/headers/intake manifold, 400 rwhp
2005 Elise, stock
2016 Chevy Cruze
Location: Florida: Pinellas County
Posts: 2,096
My VIN: 5003 Never placed Concourse
Club(s): (DCF)
I have to agree, back in the K-jet days mine always hunted when it was cold. Yet, I knew another owner whose car never hunted up/down even in the middle of winter. The only way I could get mine to run "ok" was to disconnect the full throttle enrichment switch and put a jumper in the harness side connector.
-----Dan B.
As a Brit, the use of this slang word makes me smile, as the main meaning of it over here is not just related to "rubbish" / "wrong" / "incorrect"
https://en.m.wikipedia.org/wiki/Bollocks
And that Sir, is the dogs bollocks
RIP Rob van de Veer Top bloke
I say Sir, I must be mad, one loves fixing K-Jet !
Make sure there's plenty in the tank for the weekend chaps....
Yes some cars always prime the system with the key on using the OEM RPM relay. The OEM RPM relay does not have a circuit designed to do that, it just happens to see and ignition pulse when the key is turned on.
My car never hunts. It did when I first bought it. I even have the three brass screws fully closed. I do have a wideband O2 unit so that heated sensor may help reduce hunting problems. But hunting cold the lambda is not even changing mixture.
Dave M vin 03572
http://dm-eng.weebly.com/
I think that would be irrelevant as the ecu would only go open loop when the lambda switch would go open circuit once the coolant water temperate goes above 80c.
RIP Rob van de Veer Top bloke
I say Sir, I must be mad, one loves fixing K-Jet !
Make sure there's plenty in the tank for the weekend chaps....