1990 Wrangler YJ 2.5 liter with TBI --What Next? - JeepForum.com
Search  
Sign Up   Today's Posts
User: Pass: Remember?
Advertise Here
Jeep Home Jeep Forum Jeep Classifieds Jeep Registry JeepSpace Jeep Reviews Jeep Gallery Jeep Clubs Jeep Groups Jeep Videos Jeep Events Jeep Articles
Go Back JeepForum.com > Models > Jeep Wrangler Forums > YJ Wrangler Technical Forum > 1990 Wrangler YJ 2.5 liter with TBI --What Next?

FS: 2007-2013 Jeep Wrangler "HALO" Angel Eye KitIntroducing MONSTALINER™ UV Permanent DIY Roll On Bed LineFS: Wranger BRIGHT License Plate LED! Just $3! Great value

Reply
Unread 09-12-2013, 12:02 AM   #1
Calpastor
Registered User
 
Join Date: Aug 2010
Location: Farmersville, CA
Posts: 10
1990 Wrangler YJ 2.5 liter with TBI --What Next?

Started stalling, backfiring, idling rough...
I changed plugs, wires, cap, rotor - No change
New Battery - No change
New coil - No change
New Fuel Pump and Filter - No change
New Crank Position Sensor - No change

Calpastor is offline   Reply With Quote
Unread 09-12-2013, 05:43 AM   #2
Que89YJ
Web Wheeler
1989 YJ Wrangler 
 
Join Date: Apr 2008
Location: Detroit, Michigan
Posts: 14,565
Does it make any difference in the way it runs hot or cold?
Que89YJ is offline   Reply With Quote
Unread 09-13-2013, 11:24 PM   #3
Calpastor
Registered User
 
Join Date: Aug 2010
Location: Farmersville, CA
Posts: 10
Cold runs better...but warms quickly and then runs bad...
I replaced throttle body injector today - No change
What's this part?


image-4204404700.jpg
Calpastor is offline   Reply With Quote
Unread 09-14-2013, 12:46 AM   #4
ShArKtRaInEr
Registered User
1989 YJ Wrangler 
 
Join Date: Oct 2012
Location: , Maui
Posts: 22
Check for vacuum leaks, like behind the engine where the trans meets. There is a junction there. Also you can check the oxygen sensor and throttle position switch at the back of the throttle body.

That photo is the idle speed motor. You can reset/retract it with a little 9V battery, the two center pins are where you connect after disconnecting the harness.
ShArKtRaInEr is offline   Reply With Quote
Unread 09-14-2013, 04:52 AM   #5
Que89YJ
Web Wheeler
1989 YJ Wrangler 
 
Join Date: Apr 2008
Location: Detroit, Michigan
Posts: 14,565
If there is a big difference hot to cold then o2 or coolant temp sensor. Not the one for the guage. Can't figure out where you took the pic?
Que89YJ is offline   Reply With Quote
Unread 09-14-2013, 10:49 AM   #6
Calpastor
Registered User
 
Join Date: Aug 2010
Location: Farmersville, CA
Posts: 10
Not a big difference hot to cold.

I do have an exhaust leak...could that cause the proble?
I may replace TPS today...what about EGR? Could that creat idle issues?
Pic was Idle Control Motor
Calpastor is offline   Reply With Quote
Unread 09-14-2013, 10:47 PM   #7
Calpastor
Registered User
 
Join Date: Aug 2010
Location: Farmersville, CA
Posts: 10
Added new throttle position sensor - still rough idle
I have an exhaust leak on exhaust manifold...couple bolts missing, could that create a vacuum leak?
I'm also wondering about EGR valve, but it's about 110 to replace. Ouch!
Calpastor is offline   Reply With Quote
Unread 09-14-2013, 11:52 PM   #8
Que89YJ
Web Wheeler
1989 YJ Wrangler 
 
Join Date: Apr 2008
Location: Detroit, Michigan
Posts: 14,565
The exhaust leak is throwing off the o2 sensor causing you to run rich and throwing off the calibration. On the pre 91 yj there is a setup procedure that must be done for the tps, ais, and wot when replacing.
Que89YJ is offline   Reply With Quote
Unread 09-16-2013, 12:09 AM   #9
Calpastor
Registered User
 
Join Date: Aug 2010
Location: Farmersville, CA
Posts: 10
I'll update after that.
Calpastor is offline   Reply With Quote
Unread 09-30-2013, 09:21 PM   #10
Calpastor
Registered User
 
Join Date: Aug 2010
Location: Farmersville, CA
Posts: 10
Ok...
Feeling dumb, and angry.

Bad Spark Plug! Not cracked, not broken. I changed plugs, wires, rotor, and cap when my engine started running rough. And it didn't help. My mechanic removed plugs and tested them and found one that just was a dud. Running like a champ now!
Calpastor is offline   Reply With Quote
Unread 09-30-2013, 09:59 PM   #11
Chrisnvegas
Web Wheeler
1992 YJ Wrangler 
 
Join Date: Dec 2012
Location: Las Vegas, Nv
Posts: 1,039
That was one expensive spark plug!
__________________
Do not write in this area, for office use only.
Chrisnvegas is online now   Reply With Quote




Jeep, Wrangler, Cherokee, Grand Cherokee, and other models are copyrighted and trademarked to Jeep/Chrysler Corporation. JeepForum.com is not in any way associated with Jeep or the Chrysler Corp.