Longshot08

So after the first few 100+ degree weeks here in AZ, I suspect my fuel pump finally said enough is enough.


I would notice a definite louder whine from time to time after longer drives in the past year but I didn't want to believe it. Last night after filling up at the gas station the car starts but idles roughly, stumbles, then shuts off. Starts up a couple more times but cant get car to stay running even while flooring throttle. Crank on the starter (new) with no joy. Also don't hear a fuel pump prime like I normally do after the 10-15 second pause between start attempts. So I play around with the fuel pressure relay for about 5 minutes, and generally poke and prod under hood. After that car starts after a few cranks and I keep it above 2000 rpm at all times (was suspecting MAF sensor again...) enroute home.


Drive car to work today. Bit of a hard start this morning (80ish degrees OAT), but get it started and drive in to work. After sitting for about 40 minutes same exact problem from last night occurs. Car wont start. Get a ride from a friend.


So the PO said he had the fuel pump replaced which would make it a 3-4 year old pump now, which is why I wanted to believe so hard that it just COULDN'T be the pump going bad despite all the warning signs.


I'm pretty sure the pump is toast but feel free to chime in to give me validation because I'm going to order the BOSCH 69218 from Rock Auto based on a very strong suspicion (real scientific method here). Guess this is the kick in the pants to get the fuel gauge working too.

GeneralDisorder

iTrader: (1)

Don't order a pump yet.

I have never seen a pump fail in that manner. Typically the pump will get a bad spot in the commutator and will fail to start turning. If you do get them spinning by banging on the tank, etc then they will keep going till they stop in the bad spot again.

Also if it were a pressure problem then the car would (in all likelyhood) idle but not take any load or have very poor performance the faster you try to go (more fuel demand).

Check the rail pressure. You may have a fuel problem but it is not likely to be the pump.

When you do need a pump, hit me up. I can get you a 255 LPH pump for less than $100. Also completely silent.

Rick

Longshot08

battman

iTrader: (2)

failing fuel pump + hot weather/fuel= exact problem you are experiencing. go ahead and replace it and move on.

Longshot08

So brings up another question... I plan on building the motor to a 400-450 hp level once all the gremlins are gone and it has a good coat of paint. Will the Bosch stock replacement support that goal or should I consider an updgrade to the 255LPH range mentioned earlier? Haven't done the math to calculate the fuel flow, pressure, and injector size requirements yet but if I have to replace the pump now I want to go with something that will support future mods to that level.

GeneralDisorder

iTrader: (1)

The Bosch pump might but I can't find any real specs on it. For the difference of ~$40 why take the risk?

I just tore down a cheap turbine pump today at the shop actually. In-tank pump pulled from a 99 Ford Ranger. Someone had been in there and replaced it with a cheap Chinese pump I think - though the truck had only 78k on it. The plastic turbine impeller had begun to erode away and it must have jammed up because the hub of the turbine wheel stripped out and was free spinning - lost all pressure.

If you have the ability you can watch current draw on the pump. If you watch it with a scope you can see the waveform and pick out any bad commutator bars, etc.

In my experience bad in-tank pumps either work, or they do not work. Its probably possible to envision a way for them to only partially work or fail when hot but it would have to be something like a motor winding failure, etc. Since they are submerged in gasoline they don't typically get extremely hot - not enough to damage the windings anyway.

If this has been seen in the older stock pumps I would love to see what happened inside that results in that type of failure.

GD

bluegrassz

iTrader: (3)

I had sort of the same problem once. Turned out to be a 50 cent piece of fuel hose in the tank on the pump. I had a split in it and would not hold sufficient pressure. The split must have opened up when the pump was warm. then closed when cool.

chazman

iTrader: (4)

Wow, no kidding! At that point though, you might as well swap the pump.

My '85 has the screeching fuel pump syndrome too. Really bugs me.

bluegrassz

iTrader: (3)

The pump was almost new at the time. I had already spent $300 on egr valve, gaskets plus fuel pressure tester just to find out a 50 cent fuel line. Lesson learned. Always replace the short fuel line when in the tank. Always.

KyleF

I have had a few vehicles get weak pumps that you wouldn't even notice until upper RPMs. I have had one that required you keep the throttle open to keep the air velocity up because the low pressure was resulting in poor atomization.

Not sure where the statement of "works or doesn't" came from, but I have had many cars get weak. No it was not the sock, no it was not the filter... been there done that. It was pumps on their way out. All "cars" were thirdgens with different FI motors.

If you want to get to 500hp, no the stock pump won't work. Not sure how you plan to build a 500hp TPI... maybe 500 ft-lbs. Your factory Injectors won't get you there. Usually on a stock motor producing 225hp they are running 80% duty cycle. How is that going to get you 2X the hp without being able to supply 2X the fuel?

chazman

iTrader: (4)

Good to know.

Longshot08

I said 400-450, and I wasn't asking about fuel injectors, I was specifically referring to the fuel pump since I have to replace it now. Fuel injectors and supporting modifications will come once I get there but since I need a fuel pump now...


Like I said, I haven't done the research yet to figure out what flow rate I need from the fuel pump in order to support the planned 400-450 hp range and I was being lazy asking for someone who's done it already to chime in with what they went with. Probably just going to take GD up on his offer.

Longshot08

Definitely bad fuel pump. Its completely done now. Had to tow the GTA home yesterday.

Davidgou

iTrader: (2)

Yup, just went thru that myself. Replaced fuel tank, sending unit and fuel pump.

GeneralDisorder

iTrader: (1)

Interesting. But on a vehicle this old anything is possible. My experience with in-tank fuel pumps is largely on stuff made in the last 20 years and cars that haven't got any serious tank corrosion, etc. 9 out of 10 just stop working with little or no warning.

GD

Longshot08

Longshot08

KyleF

Addressed the pump in the first sentence, wasn't a lot to say there. No, it won't.

I jumped into what you were saying you wanted to do with your car and a TPI is just not a high horsepower set up. It was developed to make torque and when trying to double your HP, you are going to need fuel modification from back to front and will probably require a change in intakes or major modifications for higher RPM airflow. HP is not everything, HP and Torque can do the same thing based off of gearing. Hence why there are Diesels running 900 ft-lbs but only a little over 300hp. Hp is calculated from torque, and as they say Hp sell cars and Torque wins races.

Longshot08

You said a STOCK pump. I get that a STOCK pump will not support that (even though there have been claims). I am thinking about getting the Bosch 69218, which is better then stock. So not a STOCK pump.

Says better then stock. What does that mean? I don't know. But it's not a STOCK pump we are talking about. So with respect, it was not addressed. I may be missing something here though. Do you have the flow rates for the Bosch 69218? If you do I would love to see it because I still cannot find what its output is.

I found a Bosch PDF that,claims A fuel pump they make flows 265 LPH at 600kpa at 13 volts but it doesn't say what specific model it is. Is that all of them, some of them, better then stock ones? Idk. But I'm leaning towards getting the Bosch NOW anyways because I've read a number of good reviews on it across a few different vehicles and its the closest alligator right now. If it becomes the weak link later after modifications then I'll address it then I suppose. Thanks for the responses.