Hesitation and stumbling when warm
08-23-2004, 02:12 PM
#1
Rennlist Member
Thread Starter
Join Date: Oct 2002
Location: Sunny Californina
Posts: 206
Likes: 0
Received 0 Likes
on
0 Posts
Hesitation and stumbling when warm
Cut aribox, car idle rough when cold and sluggish when warm under 3,000rpm.
Latest update, I retaped the airbox to test original configuration, the car idle better now and drove fine when cold, but when warm it display same sluggish revving syptoms, major hesitation when stomping pedal at idle, slight backfiring, engine feels like it's missing under 3,000rpm.
I think I have two problems:
1) With drill airbox I could not reset ecu because of the jump oxygen sensor status, thus bad idle when cold
2) Something is wrong with ignition system becuase it performs bad when warm, either the:
Wires
coil
coil control unit
Distributor cap
Distributor rotor
Any suggestions? Could it be some fuel system relay? Fuel filter is new.
My car has straight exhaust, no cats or heat exchangers, it doesn't have a oxygen sensor either. How to reset DME with jump oxygen sensor setting?
Latest update, I retaped the airbox to test original configuration, the car idle better now and drove fine when cold, but when warm it display same sluggish revving syptoms, major hesitation when stomping pedal at idle, slight backfiring, engine feels like it's missing under 3,000rpm.
I think I have two problems:
1) With drill airbox I could not reset ecu because of the jump oxygen sensor status, thus bad idle when cold
2) Something is wrong with ignition system becuase it performs bad when warm, either the:
Wires
coil
coil control unit
Distributor cap
Distributor rotor
Any suggestions? Could it be some fuel system relay? Fuel filter is new.
My car has straight exhaust, no cats or heat exchangers, it doesn't have a oxygen sensor either. How to reset DME with jump oxygen sensor setting?
08-23-2004, 08:16 PM
#2
Burning Brakes
Join Date: May 2003
Location: N. OC, CA
Posts: 1,060
Likes: 0
Received 0 Likes
on
0 Posts
I believe DME reset should be the same even if your O2 sensors are jumped. Aside from what you've already listed, I would also look into replacing the DME relay, cleaning the ISV & Air Flow Meter. A gunked up ISV & Air Flow Meter are usually the culprit for rough idle and hesitations. Here's a very descriptive DIY Instruction written by DavidI. https://rennlist.com/forums/showthre...t=ISV+cleaning
08-23-2004, 11:59 PM
#3
Technical Guru
Rennlist Member
Rennlist Member
Without an O2 sensor there is nothing to provide feedback to the DME for adjusting the short & long term fuel trim tables so resetting the DME will probably not help here.
Did all your problems occur only AFTER you drilled your airbox?
Did all your problems occur only AFTER you drilled your airbox?
08-24-2004, 03:39 AM
#5
Rennlist Member
Thread Starter
Join Date: Oct 2002
Location: Sunny Californina
Posts: 206
Likes: 0
Received 0 Likes
on
0 Posts
I gave it some thought and realize the hestitation when warm might had been present before drilling the airbox. I recall that the car was much more alive when I first got it several months ago, suspect the degradation in performance might be iignition related.
08-24-2004, 06:40 PM
#6
Addict
Rennlist Member
Rennlist Member
Join Date: Sep 2002
Location: Jacksonville Fl
Posts: 114
Likes: 0
Received 0 Likes
on
0 Posts
If you’re still thinking ignition, there are a couple of ways to check it out without just buying new parts right off. I had the same problem a month ago. Disconnect one coil wire at a time, start it and see if it idles. One of my coils was bad. Mine idled on the secondary coil but would hesitate and die on the main coil. 2 new coils was what fixed mine. The Bentley book has the values to check the resistance of the wires, distributor cap, and rotor. Just some ideas you might try, hope this helps. Mark