grand national starting problems and back firing though the throtle body

165

Asked by May 05, 2010 at 09:42 PM about the Buick Grand National

Question type: Maintenance & Repair

the back fireingonly happens when you stomp on it and a pop and a cloud of smoke comes from the air filter. the other thing is the car will start fine first time but when you drive to llike a 7-11 and you turn it off it wont start it just cranks like its out of gas but if you let it sit for about 30 miniutes or a little more it fires rite up somone said maybe a crank sensor so can somone please help me with some info thank you so much

16 Answers

10,675

Sounds more like the Idle control valve. Mounts in the throttle body, reads air/fuel mixtures and adjusts fuel to compensate. The car is running rich and timing may be off a bit too.

165

ya thats one thing i havent tried yet is the idle control valve

1 of 1 people found this helpful.
15

let us know if this helps I am having the same issue with my 84 GN

1 of 1 people found this helpful.

bad crank sensor sounds right,is your GN supercharged,if so check the haromic balancer for a crack in it.

1 of 1 people found this helpful.
15

do u know a good place where you can buy the crank sensor and what is a good price for it i called auto zone and they told me $130 is that a good price?

Dont buy elecetral parts at auto zone or advance auto,get one from a indepent parts store.$130.00 is high,I never paied more than $40.00 for one.

1 of 1 people found this helpful.
15

do u know any place online that sales them i have been looking and can only find them as low as $99

dang thats high,i get my parts at a private owned parts store,where you at,modle of car engine super charged or not,i can get it and send it to you

15

i live in Fresno CA do u have a paypal

yes,checked on one today for the v6 supercharged,45.99 + tax=48.23,is yours the v6,need to know your engine size.

340

If you are backfiring through the intake and popping under wide open throttle, you are over boosting. This is very dangerous to a GN. Can cause anything from blown headgaskets to a window in the block. This can be caused by a number of problems. How much boost are you running? How much fuel pressure? What year is the car? Give me some more info and we will try to figure it out. In the mean time......stay out of the throttle!

5 of 5 people found this helpful.
340

By the way if it is a GN it is not Supercharged. No such thing! Only Turbocharged with a 3.8 V-6.

1 of 1 people found this helpful.
10

can the calliote converter cause the check engine light to come on and loose idle and cause engine to sputter and when you give gas it stops sputtering when idle can the calliot converter cause that? and where can i find a new brake component?

1 of 1 people found this helpful.
340

Agreed. There is no such thing as a Supercharged GN or T-Type. They are all Turbocharged!

55

they are all V-6 turbocharged unless it is an 87 which is intercooled aswell. check you air to fuel ratio, timing and check to see if your turbo is properly spooling up

2 of 2 people found this helpful.
340

84-85 is non-intercooled. 86-87 are all intercooled.......

2 of 2 people found this helpful.

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