Ok this has been addressed in other threads but i need some fresh eyes and ideas.

my trans am is a 1986 5.0 305 fi auto.

the car usually starts up ok after sitting over night.

but the car doesn't like going on errands

meaning it doesn't like being parked then quickly re-started if I'm only in the store for a few mins then come back out and go run some more errands.

either randomly through out the month or when i do my errands i will get an engine light if the car has been started/parked then quickly re-started and its a code 54

lot voltage at the fuel pump.


but this has been an issue and i'm finally just getting fed up with it.

Sometimes it turns right over with no complaints if I've just parked it and recently started it back up from doing a quick store run.

the CTS sensor for the ECM and cold start switch sensor was replaced maybe 4-5 yrs ago just to get it over with when i was doing engine work.

the new relays for the fuel pump are around the same age along with an oil pump switch.


so I've read that there could be issues with CTS and that could be a reason for my hot start problems.

I'm hoping its not the fuel pump but why for years would i randomly get a code 54 the car sits over winter. and I've been driving it for 6yrs. when i turn the key i here the pump running/priming.



any ideas?

 

Maybe the pump is bad/going, the wiring to it is going/bad. How many miles on the car/pump? And I DON'T KNOW if this could be an issue with it or not, how old is the battery? maybe it's not charging to its potential when driving (weak/bad alt, old battery) until it take some time (overnight/cold start) to build up and send enough power to it. Just some food for though. Hope this helps!

 

i appreciate the response as far as i know the car has 125,000 miles on it, i bought it at 102,000. 6 years ago.

the pump as far as i know is original from 1986.

but the battery and alternator are 2yrs or less new. and the starter was just replaced again because i bought a bad brand that only lasted a yr and put a better one in with a warranty this time.

all the sensors except for the fuel gauge sensor and knock sensor has been replaced.

the mass air flow sensor is a refurbished one cuz they are so damn expensive from 5yrs ago. the iac is a few years new and calibrated along with the tps to .54v

k@n cold air induction air filter kit.

and brand new aftermarket 19lb injectors.

spark plugs and cables are about 5yrs old.

and the car starts up usually no problem and i can drive around park and start up again ok, but especially if its running hot or on a hot day it gives me trouble if i park and start it up again within a few minutes or under a half hour because my errand didn't take long.

and then it takes a 2nd try or more to get it to turn over and usually gives me a code 54.

then the next time i start it up the code would be gone and started up fine

 

What's the stock lb for the injectors? I know these pumps are okay normally when adding bigger injectors, BUT since this car is 26 years old I think it may be time for a new fuel pump, or at least to check the wires going to the pump/the pump itself. And if the fuel pump is bad mine as well upgrade it.

There is an easy way to get easy access to the pump without dropping the tank. Which is to cut a hole under the carpet in the backseat/trunk area and it's right there. A lot of people see this as hacking or destroying a car, but if done right it can look professional. I have a hole wing nutted with a piece of painted steel and a gasket there so its got an easily accessible opening to the pump, and it wont leak. Plus its covered by carpet so no one sees it.

Also, I know some cars have trouble retaining pressure in the fuel lines so it would cause an unreasonable amount of cranking/few attempts to get it started.

There are also some mistakes that can be done while starting right after you shut down (not saying you're doing it. It happens) On TBI and Carbed cars it can start with your foot on the gas to aid in starting, but on TPI or and newer fuel injected cars(at least GM), this will cause the car to take a long time to turn over if it does at all. Also, if you stall the car(Even I do this on my truck) by letting on the clutch or riding it until it stalls (not depressing the clutch when stopping) it will cause the engine to become flooded a little, and harder to start. Side note, with your injectors (if they are bigger) they may be flooding your engine a little causing your harder starting (but since you have the code tripping this is most likely not the case).

Good luck!

 

they are the same size injectors, 19lb is stock for a 305 v8 FI.

i know about cutting the hole in the trunk area, I'm just trying to avoid the pump for as long as i can if i don't have to replace it. i have the money i just either don't wana hack up the trunk area or i don't wana pay for the labor to drop the tank.

but i appreciate your input i will double check the wiring under the carpet and the engine bay.

i just find it so weird it start up fine most of the time and drives like a champ but just randomly throw me a code 54 and have a little trouble getting started when I've been driving it and stopping it all day

 

I know what your saying about spending the money for something that may not even need to be replaced.

I've just done a little more research, and there is a 5 pin connector going to the fuel pump relay. Check that out as it is fault some times and causes harder starts/not priming fuel right away.

Also, I forgot to mention, double check all of your vacuum lines. I can't believe I didn't think of this to add before, but I mixed up some vacuum lines before/some were cracked, and it caused the car to not start right. But it also had idle problems. I hope it all works out and if you have any more questions feel free to ask!

 

yea i have some "patch jobs" on cracked vacuum lines and the idle is a little high like 900 in park once warm but i could never get it down no matter wat matenience i did. but like i said the car drives fine, no rough surging idle or chugging or sluggish response, it just goes!

and the relays and connectors were replaced a few yrs ago also.

this car was in rough shape when i bought it so i just through parts at it because it just needed everything or was going to soon.

the car looks and runs great its just that damn code 54 that randomly pops up and if it was always there then i would say ok the pump is bad. but because its random and even when the code is there, the car drives the same. no difference.

anyways i appreciate your help and input I'm going to have to find time to just go through the vacuum lines and double check wiring just to rule them out.

thanks again

 

Yeah No problem, and just a tip on the vacuum lines. It's like $4 at pepboys for some windshield washer tubing and they can be used for vacuum lines. Just match up as best as you can. get some tiny zips and a cutter. Cut the old vacuum lines leaving a little of the hard plastic still in the connector for it (about 2 inches) and slide over the new rubber line about .5" then zip tie it to secure it. Only about $5 and its better than trying to find/order new custom fit lines that cost more. And the cool thing is these are flexible and can be re routed

 

Im having the same problem. It runs great starts just fine except when its hot. i have to let it sit for 10 min then it will start again. I have a new battery and new GM fuel pump. I've done the fuel system check everything is good. Did you find any fix to your problem?

 

turns out i didn't replace my fuel pump, so i finally did. the wires at the connector were a mess, plus the previous owner plugged in a fan relay in place of fuel relay. so new wire connectors and new proper relay

haven't had an engine light or code 54 since. but i randomly am having trouble when i try to leave work at night. when there is a lot of moisture and dew in the air and on the car windows. i think moisture is seeping into the sides my spark plugs where they screw into the block. whenever i get around to replacing them for matienence ill put some stuff on the threads when i screw them in