Running rough... need help
Thread Starter
5th Gear
Joined: May 2005
Posts: 5
Likes: 0
From: macomb mi
Running rough... need help
well my cousin has a 1991 vette ... automatic and under 40,000 miles
he just gave it a lil tune up including plugs, wires, oil change, fuel filter.. and still when you step on the gas it bogs and takes a minute to clear up and then it will take off... like it is running real rich kinda...
is there anything that would cause a problem like this maybe the speed density sensor? bad gasket somewhere?
could the fuel injectors be getting a lil clogged or possibly a computer problem or bad chip? it is 100% stock meaning no performance parts so i would think the chip or computer could be the problem... can anyone offer a good direction to start?
he just gave it a lil tune up including plugs, wires, oil change, fuel filter.. and still when you step on the gas it bogs and takes a minute to clear up and then it will take off... like it is running real rich kinda...
is there anything that would cause a problem like this maybe the speed density sensor? bad gasket somewhere?
could the fuel injectors be getting a lil clogged or possibly a computer problem or bad chip? it is 100% stock meaning no performance parts so i would think the chip or computer could be the problem... can anyone offer a good direction to start?
Safety Car
Joined: Aug 2002
Posts: 4,812
Likes: 1
From: New Albany IN
St. Jude Donor '03-'04-'06-'08-'09
Did he/she just bring it out of storage from the winter? If so, gas could go bad or get water in it. Mine did to the point of rusting the fuel pump. Had to replace that..ran great.
Thread Starter
5th Gear
Joined: May 2005
Posts: 5
Likes: 0
From: macomb mi
well it is kindof in all time storage... it gets driven very very little since he just had a child and another on the way... bad fuel pump would cause a bog down like this? i thought maybe it wouldnt be able to keep up when the RPMS get going... hmm
anyway to test for this or is it a thing you kinda have to replace ?
is it real simple to do... just drop the tank or is the exhaust in the way of everything... how much does a good replacement pump run? 250$?
i did a fuel pump on my grand national and it was really really easy and pretty cheap for a good one... should i expect the vette to be more of a hassle?
anyway to test for this or is it a thing you kinda have to replace ?
is it real simple to do... just drop the tank or is the exhaust in the way of everything... how much does a good replacement pump run? 250$?
i did a fuel pump on my grand national and it was really really easy and pretty cheap for a good one... should i expect the vette to be more of a hassle?
Thread Starter
5th Gear
Joined: May 2005
Posts: 5
Likes: 0
From: macomb mi
hmm well that makes sense to get a scanner but where could i possibly get one of them... does autozone or advanced auto or anything rent them out or would he have to take it into a dealer to get it properly diagnosed?
i didnt think the fuel pump would cause a bog
thanks for the help and replies
i didnt think the fuel pump would cause a bog
thanks for the help and replies
Safety Car
Joined: Aug 2002
Posts: 4,812
Likes: 1
From: New Albany IN
St. Jude Donor '03-'04-'06-'08-'09
Yes...my fuel pump did cause mine to bog when acelerating and it would even stop running at times. The pump was puttig out pressure but not enough. The easiest way to check is to hook a fuel pressure gauge to the schrader valve on the fuel rail and see what it does. Youcan also check for a leaky injector this way too.
If it is the pump, you pull it from the top where the gas cap is...not hard at all.
If it is the pump, you pull it from the top where the gas cap is...not hard at all.
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Racer
Joined: Jan 2005
Posts: 312
Likes: 0
From: Las Vegas / Scotland
Autozone will plug a scanner in for him but it's well worth buying one if he has the money - very useful things.
They may also test the fuel pressure for him but a garage can do that and it's fairly easy as Bruthish says at the schrader valve. The fuel pressure should be between 30-40 psi (someone can you give you the accurate figure) and if it drops fairly quickly then suspect a leaking injector. It may have gummed up due to lack of use. A new set of injectors is around $200 and fairly easy to install.
They may also test the fuel pressure for him but a garage can do that and it's fairly easy as Bruthish says at the schrader valve. The fuel pressure should be between 30-40 psi (someone can you give you the accurate figure) and if it drops fairly quickly then suspect a leaking injector. It may have gummed up due to lack of use. A new set of injectors is around $200 and fairly easy to install.
Le Mans Master
Joined: Dec 2002
Posts: 6,715
Likes: 2
From: Santa Teresa New Mexico
Originally Posted by TurboGn87
well my cousin has a 1991 vette ... automatic and under 40,000 miles
he just gave it a lil tune up including plugs, wires, oil change, fuel filter.. and still when you step on the gas it bogs and takes a minute to clear up and then it will take off... like it is running real rich kinda...
is there anything that would cause a problem like this maybe the speed density sensor? bad gasket somewhere?
could the fuel injectors be getting a lil clogged or possibly a computer problem or bad chip? it is 100% stock meaning no performance parts so i would think the chip or computer could be the problem... can anyone offer a good direction to start?
he just gave it a lil tune up including plugs, wires, oil change, fuel filter.. and still when you step on the gas it bogs and takes a minute to clear up and then it will take off... like it is running real rich kinda...
is there anything that would cause a problem like this maybe the speed density sensor? bad gasket somewhere?
could the fuel injectors be getting a lil clogged or possibly a computer problem or bad chip? it is 100% stock meaning no performance parts so i would think the chip or computer could be the problem... can anyone offer a good direction to start?
How did it run before the "tune up"?
Le Mans Master
Joined: Oct 2003
Posts: 6,130
Likes: 2
From: seattle WA
I'd run some SeaFoam thru it first-great for cleaning injectors and carbon removal. You HAVE to keep the RPMs up around 1000 when sucking it thru the vacumn line-or it will kill the engine. I don't follow direction-I put 1/2 in fuel tank and 1/2 thru vacumn line-I don't put it in the oil. It might mist your 02-but it burns off and disconnecting the battery will clear the code-if you get one. Hey-it's cheap and doesn't hurt a thing-just might cure the problem.
BTW-a fuel pump and new sock for my 87 was less than $100 from Auto Zone, and it takes about 1/2 hour.No dropping the tank-just replaced thru where you fill her up.
BTW-a fuel pump and new sock for my 87 was less than $100 from Auto Zone, and it takes about 1/2 hour.No dropping the tank-just replaced thru where you fill her up.
Last edited by rick lambert; May 9, 2005 at 01:10 PM.