Hi, I have an 86 TA-305 TPI and am having a fuel problem. Car fell on its face last time I drove it and and with my fathers help I barely got it home. tested the fuel pressure at the regulator and it was 30psi (should be around 40). We then ran the car and the pressure gradually dropped after a couple minutes from 30 all the way down to 5 until the car stalled out. fuel pump was replaced a while back so we started by pulling the fuel filter and it was extremely clogged up. I know this is at least part of the problem, I haven't put a new one on yet as the store was closed on a Sunday night. However, this is not the first time this has happened. A while back going down to the shore, the same thing happened. We gave the car a while to cool down, took it to a shop and they found nothing, the car ran great ever since until now. Any ideas of what else this could be? I feel like the filter would not be the only problem and if it was i feel as if the problem would have gotten gradually worse not happen all of a sudden again. I am concerned the problem may come back even if the filter is replaced. Anyone experience something similar or have any ideas? Any help would be appreciated. Thanks All!

 

I can be going down the road 55-65 MPH go to pass a car put the peddle to the floor it drops 500-1000 rpm car looses speed lift the peddle a 1/4 of the way up it runs good and picks up speed I am new to tune port injection oh yea check engine light comes on let car sit for 5 min shut off upon start up engine light is off runs fine go full throttle same thing happens and it doesn't do it all the time please help I really don't want to go to a carberator

 

Sounds like a similar problem. TPI is very very sensitive. I have the check engine come on as well but I think it's because of rough idle or low fuel pressure. All I can tell u is check everything fuel related. Check fuel pressure at the regulator as I did, should be about 38psi I believe. I changed all my injectors as well in the past, Check fuel filter because that's easy (as long as it comes off) might as well replace it anyway. I am hoping I do not have to pull the tank out of the car again as there is no access door. Check what the code is too, as that may give u an a better idea of what the problem is. It may just be pulling a code because the car is running rough. I should also add that when my fuel pump kicks on now, it sounds very different, the last time it sounded like it was almost stuck or fuel was clogged, however I don't know if this is the pump, or just a clogged up system that makes it sound different because the fuel isn't flowing as well. Any help anyone?

 

There is a fuel filter in the tank that probably is getting clogged. Did you clean the tank when you replaced the pump? Sounds like another "Drop the Tank " time. If you are not a 'purest' when you drop the tank, put in a hatch. If not invest in a lift.

 

Would u happen to know exactly where to cut an access hole to get to the tank without dropping it from the bottom?

 

The clogged filter may have smoked your new pump, if they were both in there for a while.

There is only a sock on the bottom of the pump for an 'in-tank filter'. Your tank would have to be absolutely filthy for that to become an issue.

Put the pressure gauge on it again, start it, and let it run. What is pressure doing when the engine quits?

 

Hi Ploegi, appreciate your response. Fuel Filter has been replaced and the engine is holding fuel pressure. even bumped it up a bit since it was low. It is sitting at just under 40 at idle and hasnt been an issue. I plan to run the car to E, and then check the filter again to see if there is still anything clogging it up from the tank. When the engine did quit before, it was at 30 pds and dropped all the way to 5 before stalling out completely.

 

That's interesting..... I have seen 'floaties' wrap themselves around the sock before, but, that was because someone put something into the tank that shouldn't have gone in there.

 

There are YouTube videos on cutting a port, and plenty of discussion on how to do it and if you should do it. I do know that 20 psi won't hack it with a TPI. Our pump was replaced with a TBI pump, because a parts guy made a mistake and we couldn't get the car out of the drive. Your problem sounds as if your regulator is crap. You say you bumped the pressure, how did you do that? DO you have an aftermarket adjustable regulator? The original manual says "the regulator is set for 36 psi across the injectors at all operating conditions". The regulator controls pressure by bleeding fuel back to the tank. Pressure against an internal spring controls this bleed. If the regulator seals are bad (not replaceable) it will not control pressure.
Elsewhere in this forum, it suggests that an adjustable regulator running at 50 psi is the ultimate pressure for max power with a stock engine. Don't know, as I have not done that, however, I do know the engine runs like crap with low pressure.

 

bop11, yes i have an aftermarket regulator, fuel pressure is now sitting at 36 at idle and upon goosing the throttle, will jump to 40 pounds. car runs great. idle is smoother than before. However, i do have different injectors on the car, i believe they are slightly bigger than stock, i cant recall because i have changed them twice and don't remember if I put stock injectors in last time. I am also running a mild cam, ported heads, headers and a full flowmaster exhaust, the car is far from stock but has a brand new 305 motor in it. The regulator should be fine as it is fairly new and the fuel pressure has been holding up great since replacing the filter. Car seems to run great at idle and under any acceleration so i think the fuel pressure is fine at 36. I will be sure to post an update in the future.

 

i thought i read that you replaced the fuel pump recently. maybe that jostled up some gunk when you did it. if it is getting past the sock and not the filter, IMO it must be some pretty fine stuff. if the filter seems to have fixed it, then great, but i'd be weary of this happening again. my pops had a Mazda pickup he had to do a fuel filter on atleast 2x a week cuz the tank was rotting away and clogging the filter. He had to do it on his way to work twice. obviously this isnt that bad, but the possibility of a rotting tank is always there, although i rarely read about that here. good luck with this issue!