Author |
Topic: 2,3 engine hesitation and seldom misfire (Read 932 times) |
|
ottopmh
Junior Member
I'm a YaBB newbie!
Posts: 53
|
 |
2,3 engine hesitation and seldom misfire
« on: Oct 12th, 2006, 8:39am » |
 Quote  Modify
|
Hi all,
Long story, but that's only for everyone's benefit Trying to explain as thoroughly as possible.
1996 2,3 manual, 125000 kilometers on the clock.
1) Engine wandering when idling after a cold start. It starts wandering 20 to 40 seconds after being started up. Revs are varying between 750 – 1200. It stops right after a light touch on the accelerator. Just press it so that gauge indicates some response and wandering stops. (does not wander when it's COLD, last winter tried at -27C and no wandering... had to do it as there was no electricity available for block heater)
2) When accelerating (doesn’t matter on which gear) more aggressively, let’s say throttle from around 50% to fully open, the engine starts hesitating at 3000rpm. Not always, but usually. I wouldn’t say that it jerks, but something like that only much softer. Accelerates still, but not as it is supposed to. At around 4000rpm it wants to go again. It’s very willing also below 3000rpm. If I press the pedal as it accelerates, so I’m constantly giving it more and more as it goes, it jerks very rarely.
3) Misfire when pressing accelerator _quickly_. When starting to accelerate, typically after a gear change when revs are around 2000, there will be a misfire if pedal is pressed quickly. Feels like only one spark would be missed. This does not happen every time though. Easy way to reproduce this is to use engine braking, for example with second gear from 3000rpm to 2000, and the suddenly kick the pedal again. This does not happen when accelerator is pressed more slowly. It can be pressed all the way down and no misfire. More or less related to the speed of opening the throttle and happens only when throttle is opening, not when foot is held down (then it usually will hesitate as previously described).
4) Hesitating when revving on neutral. If it revs (with the help of my foot) for example 2000rpm and I kick the pedal it responses immediately. But when doing it from idle the engine will hesitate a short moment before it revs.
These symptoms do not make driving hard. I’m just avoiding opening throttle quickly. No probs with that – and if I have to do so the misfire won’t appear every time. Only thing that is, say annoying, is the number 2. Luckily it doesn’t happen every time either.
What would you suggest? I’ve not done anything so far, just thought this over and over again. I’d start from the TPS as the speed of accelerator movement seems to play a big part here. Can TPS be opened and cleared? Usually potentiometers are pretty well sealed…
Or am I now facing the situation that I should order a PWM cable and start using computer with my car too? I’m using it enough at work…
All tips and hints are appreciated!
Otto
|
|
 IP Logged |
|
|
|
Jonnycab
Senior Member
Former owner of 2.3 Ultima Facelift saloon
Posts: 3900
|
|
Re: 2,3 engine hesitation and seldom misfire
« Reply #1 on: Oct 12th, 2006, 9:21am » |
Quote Modify
|
Have you checked the ignition coils, plug leads & wiring for cracking?
I had a misfire once which ended up being the coils.
|
|
IP Logged |
|
|
|
ottopmh
Junior Member
I'm a YaBB newbie!
Posts: 53
|
|
Re: 2,3 engine hesitation and seldom misfire
« Reply #2 on: Oct 12th, 2006, 11:23am » |
Quote Modify
|
Haven't checked anything related to this problem yet as I said. But it's about the time before it will (most propably) get any worse.
Plug leads and wiring - I will check.
But how can I tell if a coil is fine or not if it looks "normal"? I quess that there aren't. Please correct me if I'm wrong.
Tomorrow my wife will take the car to visit her grandma and will stay there for one week. So I'm just gathering ideas for the time being...
|
|
IP Logged |
|
|
|
ottopmh
Junior Member
I'm a YaBB newbie!
Posts: 53
|
|
Re: 2,3 engine hesitation and seldom misfire
« Reply #3 on: Oct 12th, 2006, 11:27am » |
Quote Modify
|
b****r...
"I quess that there aren't...."
I quess that there is no way to reliably judge the condition of a coil by examining it externally. That's what I meant
|
|
IP Logged |
|
|
|
Dave2302
Senior Member
2006 Mercedes S55 AMG, Retired Barefoot Waterskier
Posts: 1119
|
|
Re: 2,3 engine hesitation and seldom misfire
« Reply #4 on: Oct 12th, 2006, 1:02pm » |
Quote Modify
|
Hi there,
Get it scanned, or get a lead and scan it. Thats the best place to start. Work from there, and I'm sure it will be something simple like a plug, a lead or maybe coil. The best way to test the coil is with a HT load Tester load it up and see if it will break down. This is basically a variable gap spark plug, your coil should be able to give good sparks up to about a 4mm gap. Regards Dave
|
|
IP Logged |
Dave "The 'ol Bear" ex Footer !
|
|
|
GrahamT
Full Member
I'm a YaBB newbie!
Posts: 108
|
|
Re: 2,3 engine hesitation and seldom misfire
« Reply #5 on: Oct 13th, 2006, 12:45am » |
Quote Modify
|
Firstly, clean the MAF, instructions on the site.
Secondly, an easy way to check condition of the coils and plug leads is to run the car in the dark and see if you can see any little lightning strikes, sparks where the HT is finding a path to earth.
Final quick, cheap and easy is to put a new set of spark plugs in.
After that you're into ODB scans or changing components randomly!
I'd start with the TPS or maybe the IACV. (you could try cleaning the IACV but success rate is not very high).
Good luck,
Graham
|
|
IP Logged |
|
|
|
Octavian_P
Senior Member
 
Posts: 1126
|
|
Re: 2,3 engine hesitation and seldom misfire
« Reply #6 on: Oct 14th, 2006, 10:08am » |
Quote Modify
|
1) The IACV gets cloged, i had same problems with mine, a good squirt of carbcleaner and some light oil on the shaft did the job.
3) I have the same problem, i belive is HT lead / coil related, as i did scaned it with obd, and have new sparg plugs
|
|
IP Logged |
2.0 16V Ultima|2.3 16V Ghia|2.9 24V Cosworth Ghia
|
|
|
ottopmh
Junior Member
I'm a YaBB newbie!
Posts: 53
|
|
Re: 2,3 engine hesitation and seldom misfire
« Reply #7 on: Oct 30th, 2006, 6:30am » |
Quote Modify
|
Thanks for good advices!
Started with the easiest ones and the problems seem to be cured!
MAF was surprisingly dirty, carb cleaner did the job.
Spark plugs were propably original as the condition was what it was... As said there's now 126000 kilometers on the clock.
No hesitation, no misfire and it feels that it doesn't think when revving on neutral either.
Don't know yet about idle wandering after cold start. It was really bad after the fixes (semi warm), but that must have been due to the fact that I forgot to disconnect the battery. As the MAF was so dirty it might have been a good idea to reset the whole system by disconnecting battery. After 10 minutes and few kilometers it stopped wandering. Let's see what it says after next cold start.
Let's hope that it stays like this
BTW - everything looked as shiny as new under the head cover. No cracks at the leads what so ever.
|
|
IP Logged |
|
|
|
|
Home
Help
Search
Members
Login
Reply
Send Topic
Print