Misfire ?? Help Needed

[madbrian]

Have you tried a simple cure like disconnecting the battery for a period long enough to clear out all of the adaptives in the controller and then seeing if the problem is still there after you reconnect?

yes, have tried that. seems to solve problem for a couple of miles but then returns.

as it is an intermittent fault i do not know if it has made a difference or not ?

 

[GTSnake]

So it runs great after you disconnect the battery for awhile then comes back? That can't be a fuel issue then. It's back to electrical.

Just to eliminate one factor swap out the battery.

 

[white out]

sounds like ecu. disconnecting the battery would reset it.

Nick

 

[MARKL488]

Unplug the speed sensor on the trans it is located below the reverse lock out below the the shifter on the left side of the trans. The 5 volt feed to this sensor also feeds the coils, if it is creating disturbance it will cause a driveability problem but still work the speedometer. It will turn on the engine light when you unplug it but if the problem goes away you know what causes without buying a sensor

 

[madbrian]

Unplug the speed sensor on the trans it is located below the reverse lock out below the the shifter on the left side of the trans. The 5 volt feed to this sensor also feeds the coils, if it is creating disturbance it will cause a driveability problem but still work the speedometer. It will turn on the engine light when you unplug it but if the problem goes away you know what causes without buying a sensor

now we might be getting there.

this is next on my list and if no difference battery on order as soon as possible.

 

[madbrian]

Unplug the speed sensor on the trans it is located below the reverse lock out below the the shifter on the left side of the trans. The 5 volt feed to this sensor also feeds the coils, if it is creating disturbance it will cause a driveability problem but still work the speedometer. It will turn on the engine light when you unplug it but if the problem goes away you know what causes without buying a sensor

can any one please give me the part number for this sensor
thanks!

 

[AZTVR]

Unplug the speed sensor on the trans it is located below the reverse lock out below the the shifter on the left side of the trans.

can any one please give me the part number for this sensor
thanks!

See page 37 of the linked parts manual:

http://www.roeracing.com/OE-Parts/1999_Viper.pdf​

 

[madbrian]

See page 37 of the linked parts manual:

http://www.roeracing.com/OE-Parts/1999_Viper.pdf​

Thanks Jim

 

[madbrian]

update -

not had chance to check speed sensor yet and awaiting new battery
just took car for a drive.

from idle to 2.5 thousand revs , pressing gas pedal slowly the car jerks and bucks creating clunking etc from diff area.

from idle to 5,000 stepping on it the car runs faultless .

any ideas?[media]http://forums.viperclub.org/images/smilies/confused.gif[/media]

 

[Bobpantax]

I think that you should follow through on the speed sensor before posting again.

 

[madbrian]

speed sensor is next, would have done it today but had no pit or ramp available.
do you have to remove the metal chassis plate to get at it?

 

[InjectTheVenom]

update -

not had chance to check speed sensor yet and awaiting new battery
just took car for a drive.

from idle to 2.5 thousand revs , pressing gas pedal slowly the car jerks and bucks creating clunking etc from diff area.

from idle to 5,000 stepping on it the car runs faultless .

any ideas?

Sounds exactly like my 4 cyl turbo car when you pull the vacuum hose from the recirculation valve.. severe bucking/jerking with occasional clunking and if you keep laying into the go pedal the reward is a check engine light.
I know, totally different cars, but still...

 

[twinkie]

has the intake manifold ever been off the car?

i maybe stuck on stupid, but it has definite symptoms of a vacuum leak.

How is the car at idle?

 

[madbrian]

the car is perfect on idle.
the inlet has been off but re fitted correctly as i thought it might have been the problem.

if it was a battery problem would this happen at low revs or higher revs.
at what revs does the alternator kick in or am i barking at the wrong tree?

 

[99 R/T 10]

I would bet it is the speed sensor or Throttle position sensor(TPS).

 

[madbrian]

tps is new and i am waiting for the use of a ramp to change the speed sensor.

i am getting too old for lying under the car on axle stands on a freezing cold concrete floor.

can i change the speed sensor without removal of the chassis plate?

 

[twinkie]

if it was a battery problem would this happen at low revs or higher revs.
at what revs does the alternator kick in or am i barking at the wrong tree?

you maybe barking up the wrong tree... I believe the other members were meaning when the battery is low some vipers tend to do weird things.

 

[Bobpantax]

Mark L said:

Unplug the speed sensor on the trans it is located below the reverse lock out below the the shifter on the left side of the trans. The 5 volt feed to this sensor also feeds the coils, if it is creating disturbance it will cause a driveability problem but still work the speedometer. It will turn on the engine light when you unplug it but if the problem goes away you know what causes without buying a sensor.

You have to remove the metal plate to get at it.

 

[madbrian]

Have you tried a simple cure like disconnecting the battery for a period long enough to clear out all of the adaptives in the controller and then seeing if the problem is still there after you reconnect?

yes , done that and no change.

 

[madbrian]

just changed vehicle speed sensor and no surprise, the problem is still there.

do you think it is possible that 1 injector is staying open and wetting the plug as the car runs great when i give it gun.

would only 1 dodgy injector cause lots of bucking, surging etc at low revs?

 

[plumcrazy]

Replace the battery yet or just disconnect it ?

Have tried to call a few of the good tuners/techs we have here like Tator, Woodhouse, tom sessions, Dc, DLM etc ?

 

[madbrian]

Replace the battery yet or just disconnect it ?

Have tried to call a few of the good tuners/techs we have here like Tator, Woodhouse, tom sessions, Dc, DLM etc ?

i have only disconnected it.

is a bad battery likely to cause low down rev problems or problems higher up in the revs?

thanks!

 

[madbrian]

i have only disconnected it.

is a bad battery likely to cause low down rev problems or problems higher up in the revs?

thanks!

 

[1TONY1]

Replace the battery first. Then if you want I can check/clean your injectors.

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[bluesrt]

what about the plug wires/have seen wires make a car buck at meadium throttle and run like a scaulded dog under full throttle,and also pur at idle,if its not throwing a code-more than likely its mechanical keep in mind,and also maybe not throwing a code due to its not acting bad long enough to throw a code-if you can make it run bad till the light triggers,it might help steer you in a better direction.you also need a fuel guage hooked up when the car bucks,the guage should stay still at psi, if it drops even a little-no good-a heathy pump should rise in psi at any throttle romp.but staying at a correct spec psi will do.

 

[madbrian]

Replace the battery first. Then if you want I can check/clean your injectors.

You must be registered for see images

thanks, new battery being fitted today .
i will get in touch if it's the injectors.

 

[madbrian]

what about the plug wires/have seen wires make a car buck at meadium throttle and run like a scaulded dog under full throttle,and also pur at idle,if its not throwing a code-more than likely its mechanical keep in mind,and also maybe not throwing a code due to its not acting bad long enough to throw a code-if you can make it run bad till the light triggers,it might help steer you in a better direction.you also need a fuel guage hooked up when the car bucks,the guage should stay still at psi, if it drops even a little-no good-a heathy pump should rise in psi at any throttle romp.but staying at a correct spec psi will do.

i had a new set of msd leads and was not happy with the connectors ,i thought this might be the problem.
i replaced them with a new set of mopar performance leads.
result no difference.
after the battery, the next test will be the fuel pump.
thanks everyone for all the advice and help.

 

[madbrian]

new battery fitted today.

things are going from bad to worse.

as soon as i drove it, violent bucking , missing etc.
took it for a 30 minute very fast drive through the gears and now the car is back to the same as before i changed the battery.

when i step on it the car runs great.
all my problems are at low revs.

would a fuel pump be bad even though it has plenty of fuel supply when it is needed for maximum power?

thanks

 

[bluesrt]

new battery fitted today.

things are going from bad to worse.

as soon as i drove it, violent bucking , missing etc.
took it for a 30 minute very fast drive through the gears and now the car is back to the same as before i changed the battery.

when i step on it the car runs great.
all my problems are at low revs.

would a fuel pump be bad even though it has plenty of fuel supply when it is needed for maximum power?

thanks

more than likely no. but you still need to see it working on a guage when the car malfunctions just for your head so you can rule it out.

 

[bluesrt]

does the car have turbo boost?