Backfiring at hwy cruising

[BoostedTtype]

My 87 T will backfire out of the exhaust when I let off the gas anywhere around 55-65 mph.. It kinds bucks and misses also around those mph on the highway..

Car is stock with 77k on it. Fresh Autolite 23's and kirban wires

Any suggestions on what I should take a look at..

 

[dagojoe]

reply

i had a friend whose car did the same thing...turned out the harmonic ballencer was bad and loose and it got the crank sensor really bad...may be a good place to start....good luck...

 

[Fachie Motion]

Cam sensor.

 

[TurboDave]

More likely crank sensor/balancer related rather than cam sensor. Or possibly something going whacko in the ign. module.

Question for the OP, When did this symptom start? Did it just start doing it on it's own? or did it follow some work done on the car?

 

[SCOOBY DOO]

If you have a Scanmaster...post numbers.

 

[BoostedTtype]

I recently bought the car and this is how it ran when I got it.. I changed the plugs and wires and no change..

Its a bit sluggish on acceleration also.. Seems kinda strange that it always happens at the same speeds... Last week it backfired loud enough to scare me into parking it until I can get this resolved...

Sorry no scanmaster yet..

Can someone tell me how to test the cam and crank sensor? Or even where they are?? A pic would be great

I work on my own cars most the time but Im still noob at the turbo6 stuff...

 

[whitehot1]

Sounds like a problem with the ignition module or coil pack or maybe both.

This site can help you with troubleshooting and can show you where the parts are located on the engine and a lot of other info as well.

Vortex Buicks

 

[fc227]

Backfiring though the exhaust ?

 

[TurboBuRick]

More likely crank sensor/balancer related rather than cam sensor. Or possibly something going whacko in the ign. module.

Question for the OP, When did this symptom start? Did it just start doing it on it's own? or did it follow some work done on the car?

X2

 

[speedskills]

Timing chain maybe. My GN had the same miles when all the sudden it backfired twice and died. Tore all the teeth off the cam sprocket. If you haven't done the TC its a good time to goto a double roller. You'll learn a lot about these cars doing it yourself.

 

[PTS]

Had the same problem last week, Car would buck at around 50-55mph. Ignition module was loose on the bracket that holds it in place. Make sure its tight, there are 3 nuts that hold it together underneath. Thats how it is grounded.

 

[BoostedTtype]

Backfiring though the exhaust ?

Yes it backfires through the exhaust

 

[standupjskiguy]

In the wife's 85 T-type a similar symptom was caused by a mis=adjusted cam sensor. We had a new timing chain put on and the guy didn't set the cam sensor right. It would backfire and buck at 55-60 mph. We took it back and he adjusted it by hand and said if it's OK you needn't come back. (duh) It seemed OK but later I noticed it did the same thing only at a higher speed. (65-70) I took it to the Buick dealer and had them set it by the book and then it was fine. The cam sensor it in the front of the engine. It is in the spot that a distributor used to be in. I see there is a post on how to set it.

 

[BoostedTtype]

Ok went to tinker with it today.. I noticed that is very hesitant on initial takeoff.. If I nail the gas it hiccups a bit before acceleration.. i.e. it kinda pauses or takes a deep breath before takeoff .... After that the car runs decent until 55mph and then the backfiring begins... I assume these issues are related...

 

[whitehot1]

You could post your location.

There may be some turbo regal owners/members that live close to you that could help with troubleshooting and may even have some spare parts to let you try to make it easier.

Also did you go to the vortex web site i posted earlier? There really is a lot of good information on that site.

http://www.vortexbuicks-etc.com/31_thru_34.htm

 

[BoostedTtype]

Im located in Southern Maryland near Virginia... Yes I went on Vortex earlier.. I checked out all the locations for the sensors.. Very handy info.... Thanks for the site info

 

[BoostedTtype]

I want to thank everyone for their help thus far.. I tested the cam sensor Today.. I started the car and unhooked it and went for a drive.. No major issues... hesitation went away and the 55 mph backfiring stopped.. You guys are awesome!!!!

Do You guys think its bad or set wrong... What should I do?

Also where can I purchase a cam sensor at? Whats the going price for one?

 

[TurboDave]

It could have been set wrong. Possibly 180 out. It'll run that way but does funky stuff.

 

[turbo nasty]

Check the reluctor cup in the cam sensor (under cap). Could be a loose screw and or the tab tht holds the cup in position sheared and now the timing is off.

 

[BoostedTtype]

Ok will do.. I plan on taking the cap off tomorrow to see whats going on.. If everything inside is fine is there a possiblilty that the unit is still bad?