tb42 misfire
Submitted: Monday, Jan 27, 2003 at 13:38
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stephenj
i have a1991 ford maverick ,auto,petrol/gas which has a misfire when at idle and in gear (approx 750 rpm). seems to be worse when on lpg, temp doesn't seem to make a difference . tb42 is carby and has about 145000 km .any ideas ?
Reply By: stephenj - Monday, Jan 27, 2003 at 13:47
Monday, Jan 27, 2003 at 13:47
forgot to mention have replaced , plugs ,points , rotor , cap , condensor ,plug leads , coil.
AnswerID:
11921
Follow Up By: Oziexplorer - Monday, Jan 27, 2003 at 14:06
Monday, Jan 27, 2003 at 14:06
Have you checked the compression on each cylinder?
FollowupID:
6815
Reply By: stephenj - Monday, Jan 27, 2003 at 16:04
Monday, Jan 27, 2003 at 16:04
no , i have not . but misfire not always there
AnswerID:
11925
Follow Up By: Oziexplorer - Monday, Jan 27, 2003 at 16:34
Monday, Jan 27, 2003 at 16:34
That does not matter if the misfire is not always there.
Shock horror, could also be a head gasket with a very small water leak. Are you using any water at all?
A compression
test is always a must, especially with everything else you have done. I always like to keep an annual or twice yearly
check on compression on petrol engines. Really gives you an indication when that rebuild is getting imminent.
FollowupID:
6821
Reply By: ThePublican - Monday, Jan 27, 2003 at 17:58
Monday, Jan 27, 2003 at 17:58
If around
Brisbane get your vehicle of to Hycraft Auto at Clontarf on the
Redcliffe peninsular, gas experts, dyno reports pre and post tune,4way gas analysis ect.
AnswerID:
11932
Follow Up By: Stephenj - Tuesday, Jan 28, 2003 at 09:03
Tuesday, Jan 28, 2003 at 09:03
live in north qld, about a hour north of
townsville , but thanks for the reply
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6858
Reply By: stephenj - Monday, Jan 27, 2003 at 18:02
Monday, Jan 27, 2003 at 18:02
not using any water,i'll get a compression
test done and go from there,thanks for the suggestion
AnswerID:
11933
Reply By: tour boy - Tuesday, Jan 28, 2003 at 06:52
Tuesday, Jan 28, 2003 at 06:52
Another operator had this problem. Turned out to be the head.
AnswerID:
11970
Follow Up By: Stephenj - Tuesday, Jan 28, 2003 at 09:18
Tuesday, Jan 28, 2003 at 09:18
thanks for reply tour boy . i'll go and see my local mechanic and get him to do a few checks. i actualy spoke to the nissan dealer about this little problem and the only things they could come up with was replace the rotor , because they thought the rev limiter was faulty , and they also said to disconect the tacho as it might have a short. both of these things did not work , so they said learn to live with it
. not saying all nissan dealers are like this , with the learn to live with it attitude. went to ford first ( being a ford maverick) as soon as i mentioned maverick ,went no further got told go to nissan.
FollowupID:
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Reply By: Rowdy - Tuesday, Jan 28, 2003 at 18:39
Tuesday, Jan 28, 2003 at 18:39
Possible cause could be valve recession as LPG is a dry fuel and valve seats wear more rapidly than when on petrol and valve stems are more prone to sticking. If valves have recessed into the head they can cause a miss or hesitation at or just above idle, especially if hardened seats and valves are not fitted. This was a problem in the early years of LPG conversions before unleaded fuel was used and valves and
seat quality was not as good.
Rowdy
AnswerID:
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Follow Up By: Stephenj - Tuesday, Jan 28, 2003 at 20:06
Tuesday, Jan 28, 2003 at 20:06
thanks rowdy, i'll get the mechanic to
check that as
well.
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Reply By: kezza - Tuesday, Jan 28, 2003 at 23:27
Tuesday, Jan 28, 2003 at 23:27
Ill go with rowdy - valves!!
kes
AnswerID:
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Reply By: Member - Steven - Wednesday, Jan 29, 2003 at 19:22
Wednesday, Jan 29, 2003 at 19:22
stephen
does it backfire if under load .i have an 89 patrol same motor brother in law a mechanic spent hours trying to find problem came
home from
alice springs 2002 bloody thing backfired every 40 ks finally went to a place called performance ignition nunawading melb web site as above i think i will look it up and post an addon any way they sold me an extended rotor button $55 also guy behind counter said if on gas open tappit settings normally .32?mm open to .5 mm we settled on .42 mm have not had 1 backfire , miss, burp , fart or other hiccup since installing and getting better fuel consumption
steve
AnswerID:
12095
Follow Up By: Stephenj - Thursday, Jan 30, 2003 at 15:50
Thursday, Jan 30, 2003 at 15:50
sometimes under load around the 80 - 90 khm range and i'll try the tappits at that setting.
thanks
FollowupID:
7055
Follow Up By: Member - Steven - Thursday, Jan 30, 2003 at 20:50
Thursday, Jan 30, 2003 at 20:50
stephen probably better to trythe extended rotor button i think this is the main part as it shortens the distance the spark has to jump to fire steve
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Follow Up By: Stephenj - Thursday, Jan 30, 2003 at 21:08
Thursday, Jan 30, 2003 at 21:08
steven , i have sent a email to performance ignition regarding the rotor and waiting for reply , thanks for the information and reply.
regards stephen j.
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Follow Up By: Stephenj - Thursday, Feb 13, 2003 at 10:50
Thursday, Feb 13, 2003 at 10:50
final word , had mechanic do compression
check ,
check for head crack, and also
check valve recess . all ok . i have installed extended rotor from performance ignitionmelb , no more misfire at idle under load or at 80-90km .so far so good .the rotor seems to have fixed the problem , but when the budget allows a electronic conversion will be put in place . so thanks to everyone who replied your advice was extremly welcome.
regards stephenj.
FollowupID:
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Reply By: Ferret - Wednesday, Jan 29, 2003 at 23:16
Wednesday, Jan 29, 2003 at 23:16
Toss the dizzy and replace with electronic ignition
AnswerID:
12119
Follow Up By: Stephenj - Thursday, Jan 30, 2003 at 15:52
Thursday, Jan 30, 2003 at 15:52
ferret ,can i use a nissan one from an electronic ignition model , or do i have to use a conversion of the aftermarket type ?
FollowupID:
7056
Reply By: Member - Steven - Thursday, Feb 13, 2003 at 21:11
Thursday, Feb 13, 2003 at 21:11
stephen hopefully you will find economy increases as
well glad you found problem and cure i have had my rotor in about 3 months and no problems (touch wood ) see you on the road steve
AnswerID:
13067