Engine dieseling

[XTCshri2222]

I have had dieseling issues, but it was not a primary concern since i had alot of other bugs, but they are all fixed now and i now want to fix the dieseling issue before i do a final tune. What would cause the motor to keep running for a few seconds after ignition is killed, I realized how severe the dieseling was when i was running on 3 cylinders when my igniter took a dump, and the motor just showed symptoms of a simple misfire. The plug was not even saturated in fuel like i was expecting to see. It was running 3 cylinders and dieseling cyl 4.

[Fleemer]

usually cause by leaky injectors or an idle thats too high. (cutting engine when at like 3krpm instead of waiting :P)

My GFs carbed 323 did it all the time until i turned the idle down form 1500 to 800 (where it should have been)

[XTCshri2222]

my idle is only 600-800rpms, and I dont have a injector leak my fuel presure takes a bit to 0 out.

[XTCshri2222]

anyone? any ca geniuses? i know there a few here lol

[lexrob]

If idle and fuel are good, possibly from hot spots (carbon build-up,cyl.head is to hottt low coolant/air in system) causing ignition after. lol ignition.

or .... possibly throwin it out there timing/valve adj. issue .... nahhhh.

thats all I got.....

[lexrob]

leaky inj. could do it ....... cause it to go lean which = hotter = hotspots

If im not mistaken you should hold fuel pressure for a while ... like 30sec. someone clarify.

[XTCshri2222]

I'm good on carbon build up motor runs clean, hot spots i checked for with my laser temp gauge, injectors are new venoms doubt their leaking and my fuel pressure is holding, im leaning to timing, but i hate doing timing, specially since that's one thing i personally haven't done yet, and I don't wanna borrow my buddy's timing light since he's anal about his tools lol, I guess I gotta buy one.

[ca18detgabby]

dieseling is likely an issue with the tune....... I know bad eproms are notorious for doing this.

[sjbsuperman1425]

my engine does this too, all stock except full exhaust and front mount. i never really looked into it, but after i turn the key off, it will take a second or two to fully shut off and will shake right before it does.

how long is fuel pressure supposed to be held at 28psi after priming? i checked a week ago but forgot the results..

[lexrob]

timings easy man... not to shur on a CA but normally jump service conect lossen up dist. and point and turn ... adv. slightly even gives some pref. gain normally +2deg. to factory spec. but will make it run a little hotter.. well turbo might complicate that theory anyways......

Check grounds(put thick wire from engine to frame)read your plugs... for incorrect heat range blistering ect.

put an sr in it ..... j/k

[dattodude]

Yeah ..check earths and disconnect any thermo fans you've fitted yourself.

I know that a good thermo fan can keep enough 12v to the ignition relay to hold it open for a few seconds. If you don't wire up your fan relay properly, then this can happen.

[XTCshri2222]

I have my fans running on constant power.

i hooked up a timing light to the looped wire and to power and ground, i tried 2 differnt timing lights and i could not get the timing light to flash

[XTCshri2222]

m

my engine does this too, all stock except full exhaust and front mount. i never really looked into it, but after i turn the key off, it will take a second or two to fully shut off and will shake right before it does.

how long is fuel pressure supposed to be held at 28psi after priming? i checked a week ago but forgot the results..

mine dose the same thing

[sjbsuperman1425]

sometimes it doesn't do it though..like yesterday, i put my CD player and speakers in and when i turned it off after checking everything, if shut right off..no waiting??

could this problem be coupled with a running rich problem and hard to start "sometimes"? if thats the case, i think it could be timing or a fuel injector leak for me

[cadence_1]

I guess this all depends on what you mean by dieseling. But If you have your fans hard wired like was stated above (at least in my case) when I shut my ignition off, while the fans are spinning down they are inducing a voltage which was keeping my car running. Run the fans properly with relays. This should fix that problem.

Hope this helps.

[KEMP]

mine does this as well but its only because my elec. fan is wired into the fuel pump to turn on with ignition, when i unplug the fan the car does not deisel

where else could i wire my fan?

[boost_boy]

mine does this as well but its only because my elec. fan is wired into the fuel pump to turn on with ignition, when i unplug the fan the car does not deisel

where else could i wire my fan?

You guys shouldn't be wiring items that significantly lowers voltage to critical components; especially connecting the to the fuel pump or ignition circuitry. You'll end-up robbing much needed power from your ignition and/or your fuel pump which will cause either poor performance or at worst, some melted pistons (Depending on your performance levels).

Dee

[sjbsuperman1425]

i wired my elec. fan and thermo switch right to the battery. it doesn't draw as much power as it used to..but i guess in the end, i can deal with this lol it doesn't bother me that much haha xD

[dattodude]

Kemp, this requires an ASCII wiring diagram:

This is using a normally OPEN relay.The trick is to 'switch the earth on', and use the best connections you can to reduce the load on IGN.

A lot of people make the mistake of looping 12V from pin 1 to 3, and connecting 2 to earth, and connecting 4 to the FANs (and earthing the fans independently.

Alternatively, you can add an additional relay to control a FRESH high current wire from the battery. This gives a clean 12V feed for things like FANs and Intercooler spray systems.

Caveat: I'm not an auto-electrician, but I did wire up my whole car and CA18 from scratch, including aftermarket ECU and CDI.