1988 2.5 Wont Idle! (Page 1/1)
88 Fiero Notchie MAY 02, 05:38 PM
Hey yall, Ive been having issues recently with both of my 88 fieros base with the 2.5. It wont hold and idle and pops and misses but sorta smooths out with the increase of rpm. All sensors are new but I changed the Igntion control module to change it when it crapped out on my over the summer (issues Im having were present before I changed it) Is it possible to get the timing wrong if the engine spins on you?
Fuel inector is also very audible when its running.

Thank you.

[This message has been edited by 88 Fiero Notchie (edited 05-02-2022).]

skywurz MAY 02, 05:43 PM
Check your vacuum lines. Bad idle on these has always been bad vacuum for me
88 Fiero Notchie MAY 02, 06:03 PM
If I am correct, it only needs the map sensor to run and all the other lines can be capped?
skywurz MAY 02, 06:36 PM
Uhh That would disable cruse control if you have it and bypass evap and probably cause some issues with the evap system. Never heard of someone doing this. Also you have to have vac to the EGR.
theogre MAY 02, 07:30 PM
"Bad" ICM often was or cause by bad coil(s), plug wire(s) or even plug(s).
"Bad" coils may pass whatever test w/ Ω meter etc and still have short windings or carbon tracks between HV and LV coils.

Does ICM have the shield? No, then ICM can short out even cause a fire.
See my Cave, DIS Ignition

Blocking vac lines can cause other problems.
Like ERG need to work or engine get can miss during accel and other issues.
See my Cave, Vac Leaks

Note: some engines may have extra vac ports anywhere on intake that must be capped. Other have "screw in" vac plugs that could get loose and leak but is very rare.

------------------
Dr. Ian Malcolm: Yeah, but your scientists were so preoccupied with whether or not they could, they didn't stop to think if they should.
(Jurassic Park)

The Ogre's Fiero Cave

88 Fiero Notchie MAY 02, 08:14 PM
My Icm went bad becuase I decided to give my engine bay a wash and didnt quite cover the coils good enough. I replaced the ICM and the coils. Coils are MSD. No my car doesnt have that plate come to think of it. I applied the goop it came with. Ill work on making a plate tomarrow.
The MAT is the only sensor thats not new. Ill tst that tomarrow too. Is there a place I can buy one if this turns up bad? I looked and could find one on rock auto or the local auto zones.