Re: [DML] Poor idol on DMC.

[Soma576@xxxx]

In a message dated 2/10/03 10:47:42 AM Central Standard Time, 
mwwilber2003@xxxx writes:


> I have an 81 DMC and when it get running for about 10 min or so it 
> starts to idol very poorly. The oil pressure and RPM's go up and down 
> while sitting at a stop. When I get going again it goes away, but 
> every time I stop again it comes back. I thought that it might need a 
> tune-up but maybe something else. Any ideas??? Thanks 
> mwwilber2003@xxxxx Please let me know what you might think this 
> could be.

Hello - 

i have this same problem from time to time and i think i have tried 
everything!
things to check:
1. check all vacuum lines for proper connection and free of cracks or damage
2. replace spark plugs, wires, cap, rotor. gap properly!
3. check timing
4. check ignition advance solenoid for proper operation (located adjacent to 
rear of fuel distributer)
5. check and/or replace fuel injectors
6. check gas tank parts for loose/collapsed/kinked hoses. check fuel pump for 
proper flow (2 liters in 30 sec? check the shop manual, i forget)
7. replace fuel filter
8. check intake manifold and W-pipe for tightness
9. check brass tube from idle motor for o-ring tightness and alignment 
(common problem, easily fixed with patience)
10. send your entire fuel system from the firewall to the injectors to Rob 
Grady for cleaning and testing (about $350 labor + parts).
11. check idle speed microswitch for proper connection and proper operation 
when car is at idle.
12. make sure the frequency valve buzzes and the idle motor hums
13. check CO mixture plug for vacuum leaks
14. check and adjust valve clearance 
15. replace Lambda sensor
16. absolute last resort - adjust CO mixture (have an experienced owner do 
this one!)

that's about all i can think of. a wascally idle can be caused by so many 
damn things that it's tough to track down right away. if you go thru this 
list you will probably get to the problem, but if you are like me, you will 
have done everything (except having a computerized CO adjustment) w/o getting 
the idle to settle down all of the time. unfortunately, a slightly wobbly 
idle is a CHARACTERISTIC of this engine that is caused by the lambda system 
constantly making adjustments. it shouldn't be very extreme though. 

Martin made a post last year giving instructions on how to dial out the idle 
with the brass screws, but this should not be done unless you are positive 
that EVERYTHING including the CO adjustment is 100% perfect. 

Good luck, and happy tweaking!
Andy

Soma576@xxxx
1982 DeLorean DMC-12 VIN#11596
Fargo, ND 58102


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