Fuel pump colamity

1,275

Asked by Oct 03, 2012 at 05:24 PM about the Pontiac Firebird

Question type: Maintenance & Repair

I have a 1999 Pontiac Firebird with the 3.8 v 6. Im haveing fuel pump issues. this will make the third time swaping the fuel pump/sending unit.   The unit keep burning up and im not letting it get below a quarter of a tank. The engine is also missfiring heavly at idle but smooth out mostly at high way speeds. At idle it  the exhaust smells raw fuel. I have changed the battery, altenator (which was checked and inspected), coil packs, spark plugs, and wires. Im running out of options on diagnoseing the issue and a certified mechanic tells me its your altenator. I dont know if it is the computer gone haywire or fuel injectors, loss of compression or what, All i can tell you is the day this started i was sitting at mcds  on the internet for a while with the car running  and it started hesitating and died on the way home and this will make the third time with the fuel pump/ sending unit and second time with trans seeing that the engine was acting up and cause the trans to shift hard and lose two bands in the trans for second and overdrive. anyyyy takers on helping me diagnose this would greatly be appreciatedddddddd

3 Answers

33,365

#1 what is the voltage coming out of the TPS with the key on engine off? Should be .5V +-.05. The TPS could flood the engine thinking the gas pedal is pushed down further requiring more gas, it will also make the car shift super hard. #2 what is the fuel pressure with the key on engine off? Should 50-60PSI. Apply 15 inches of vacuum to the fuel pressure regulator and the fuel pressure should drop to about 40 PSI +-5. There are so many possibilities. As for the alternator I'm guessing someone is really trying to sell an alternator.

33,365

Ohh and a bad regulator will keep the pump under strain because excess pressure can't be let off. BTW its excellent that you know about the fact that the gas IS what keeps the pump cool and prolongs its life. Make sure your friends and family know.

1,545

In regards to what fuel level you're keeping in the tank, interesting point is that the shape of the tank means that 1/4 tank is closer to the 1/2 mark on the gauge, 1/2 tank is 3/4 mark on gauge, 3/4 tank is at the full mark. Case in point, when my needle was on E, I put in 3.5 gallons and the needle jumped to 1/2 on the gauge. When the needle was a bit between the 1/2 and 3/4 mark, closer to the latter, I filled up the tank and it took about 8 gallons.

Your Answer

Add photo
Firebird

Looking for a Used Firebird in your area?

CarGurus has 730 nationwide Firebird listings starting at $1,800.

ZIP:

Search Pontiac Firebird Questions

Pontiac Firebird Experts

#1 Samuel Moore
Samuel Moore
Reputation 930
#2 dandyoun
dandyoun
Reputation 780
#3 John Saffrahn
John Saffrahn
Reputation 700
View All

Related Models For Sale

Used Chevrolet Camaro
152 Great Deals out of 32,722 listings starting at $1,995
Used Ford Mustang
365 Great Deals out of 46,760 listings starting at $1,500
Used Chevrolet Corvette
95 Great Deals out of 20,164 listings starting at $3,495
Used Pontiac GTO
4 Great Deals out of 432 listings starting at $5,995
Used Dodge Challenger
116 Great Deals out of 24,009 listings starting at $9,350
Used Dodge Charger
279 Great Deals out of 26,758 listings starting at $2,250
Used Pontiac G8
18 Great Deals out of 334 listings starting at $4,995
Used Ford Mustang SVT Cobra
274 listings starting at $6,335
Used Chevrolet Monte Carlo
12 Great Deals out of 1,393 listings starting at $1,995
Used Pontiac Grand Prix
21 Great Deals out of 2,843 listings starting at $1,995
Used Chevrolet Silverado 1500
1,731 Great Deals out of 166,808 listings starting at $1,800
Used Chevrolet Impala
520 Great Deals out of 28,982 listings starting at $1,100
Used Ford F-150
2,223 Great Deals out of 208,132 listings starting at $1,499
Used Nissan 350Z
51 Great Deals out of 1,191 listings starting at $3,995