Fuel pump colamity

1,235

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

32,445

#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.

32,445

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.

1,525

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 783 nationwide Firebird listings starting at $2,000.

ZIP:

Search Pontiac Firebird Questions

Pontiac Firebird Experts

#1 Samuel Moore
Samuel Moore
Reputation 920
#2 dandyoun
dandyoun
Reputation 780
#3 Justin Hatfield
Justin Hatfield
Reputation 730
View All

Related Models For Sale

Used Chevrolet Camaro
216 Great Deals out of 36,428 listings starting at $1,250
Used Ford Mustang
318 Great Deals out of 43,871 listings starting at $2,000
Used Chevrolet Corvette
142 Great Deals out of 20,320 listings starting at $3,995
Used Pontiac GTO
6 Great Deals out of 447 listings starting at $5,995
Used Dodge Challenger
201 Great Deals out of 24,191 listings starting at $8,495
Used Dodge Charger
289 Great Deals out of 28,291 listings starting at $1,997
Used Pontiac G8
14 Great Deals out of 366 listings starting at $6,500
Used Ford Mustang SVT Cobra
4 Great Deals out of 278 listings starting at $6,500
Used Chevrolet Silverado 1500
2,059 Great Deals out of 149,545 listings starting at $1,995
Used Ford F-150
2,467 Great Deals out of 208,740 listings starting at $1,000
Used Pontiac Grand Prix
31 Great Deals out of 3,312 listings starting at $950
Used Chevrolet Impala
647 Great Deals out of 31,513 listings starting at $1,300
Used Chevrolet Monte Carlo
7 Great Deals out of 1,503 listings starting at $2,000
Used BMW 3 Series
1,228 Great Deals out of 35,974 listings starting at $1,233
Used Nissan 350Z
76 Great Deals out of 1,411 listings starting at $1,600