'87 2.5 4 cyl backfire

I'm havin trouble. My fiero was sittin for a few months and recently I put
it back on the road. Anyways, It was driving fine, but now it's backfiring
during acceleration. I've checked the plug wires, O2 sensor, EGR, but I
really don't have a clue what's goin on. It runs fine under high RPM
driving, but if I go to punch it it starts to backfire and as is it's
missing or something. It's backfiring out of the carb too. Anyone have any
clue what's goin on?

Well The problem isn't fixed. I re checked all the vacuum hoses and stuff,
and they're alright...... I can't figure it out.

Maybe a coil pack? I dunno. Anyone have any clue?


"Chris B" <cbabchuk@globallivingspace.com> wrote in message
news:U_YMc.110797$od7.101798@pd7tw3no...
> I'm havin trouble. My fiero was sittin for a few months and recently I
put
> it back on the road. Anyways, It was driving fine, but now it's
backfiring
> during acceleration. I've checked the plug wires, O2 sensor, EGR, but I
> really don't have a clue what's goin on. It runs fine under high RPM
> driving, but if I go to punch it it starts to backfire and as is it's
> missing or something. It's backfiring out of the carb too. Anyone have
any
> clue what's goin on?
>
>

I had a similar problem with my SC3800 (also has a DIS ignition), in my
case is turned out to be a flaky ign module. It would accelerate fine
when cold but as soon as it warmed up I could cruise at speed but if I
accelerated too quickly it would miss and backfire.

Chris B wrote:
> Well The problem isn't fixed. I re checked all the vacuum hoses and stuff,
> and they're alright...... I can't figure it out.
>
> Maybe a coil pack? I dunno. Anyone have any clue?
>
>
> "Chris B" <cbabchuk@globallivingspace.com> wrote in message
> news:U_YMc.110797$od7.101798@pd7tw3no...
>
>>I'm havin trouble. My fiero was sittin for a few months and recently I
>
> put
>
>>it back on the road. Anyways, It was driving fine, but now it's
>
> backfiring
>
>>during acceleration. I've checked the plug wires, O2 sensor, EGR, but I
>>really don't have a clue what's goin on. It runs fine under high RPM
>>driving, but if I go to punch it it starts to backfire and as is it's
>>missing or something. It's backfiring out of the carb too. Anyone have
>
> any
>
>>clue what's goin on?
>>
>>
>
>
>
>

Check the Crank Position Sensor:

In fact, take out the module and coils, for the price of the CPS, and the
amount of times they go bad. It's worth just replacing it. While you have it
apart, then check your coils as per manual directions, I don't remember and
do this all the time. Plus, it would take two pages to type it all in.

My bet would be the Crank Position Sensor, especially if it wicked out any
oil when you remove it from the module. Then you might want to consider
swapping the module too.

Refinish King


"Chris B" <cbabchuk@globallivingspace.com> wrote in message
news:99CNc.124834$od7.49243@pd7tw3no...
> Well The problem isn't fixed. I re checked all the vacuum hoses and
stuff,
> and they're alright...... I can't figure it out.
>
> Maybe a coil pack? I dunno. Anyone have any clue?
>
>
> "Chris B" <cbabchuk@globallivingspace.com> wrote in message
> news:U_YMc.110797$od7.101798@pd7tw3no...
> > I'm havin trouble. My fiero was sittin for a few months and recently I
> put
> > it back on the road. Anyways, It was driving fine, but now it's
> backfiring
> > during acceleration. I've checked the plug wires, O2 sensor, EGR, but I
> > really don't have a clue what's goin on. It runs fine under high RPM
> > driving, but if I go to punch it it starts to backfire and as is it's
> > missing or something. It's backfiring out of the carb too. Anyone have
> any
> > clue what's goin on?
> >
> >
>
>

Check fuel pressure......low presure will act like a lean condition and
backfire will occur......

Hi:

I have an '87 SE 2.5 and have something you may check. Attached to the
air cleaner is a sensor and a cable connects to that sensor. If the
connection is intermittent, it can cause the problem that you describe.
In my case, I was able to clean the contacts by removing and replacing
the cable, then - magic- the engine run great.

I have a California car, and so far have been unable to replace that
sensor since it is not in the parts manuals at auto stores. I have had
the car for 12 years and it still runs great. Good luck!

Chris B wrote:
> I'm havin trouble. My fiero was sittin for a few months and recently I put
> it back on the road. Anyways, It was driving fine, but now it's backfiring
> during acceleration. I've checked the plug wires, O2 sensor, EGR, but I
> really don't have a clue what's goin on. It runs fine under high RPM
> driving, but if I go to punch it it starts to backfire and as is it's
> missing or something. It's backfiring out of the carb too. Anyone have any
> clue what's goin on?
>
>

> I have a California car, and so far have been unable to replace that
> sensor since it is not in the parts manuals at auto stores. I have
> had the car for 12 years and it still runs great. Good luck!

This should be the MAP sensor, same as used by about a gazillion GM
cars. Standard Motor Products AS5 or ACDelco 2131545 for instance. If
local suppliers don't have it, try www.rockauto.com
--
Robert W. Hughes (Bob)
BackYard Engineering
29:40.237N, 95:28.726W or perhaps 30:55.265N, 95:20.590W
Houston, Texas "The city with too much Oxygen"
rwhughe@oplink.net