WonkoTheSane

iTrader: (2)

Yesterday, for the first time in about three months, my car started and ran! I was happy..

Today, it's back to what it was doing before:

If i press the button to start it, the car will turn over, and start, but die before the RPMs reach 1500.. reliably. I can go out and do that 20 times in a row.

I'm pretty much down to the fuel pump, either it's dying, or the connection is bad. I've tried a new ECU, I've checked all my grounds, got my injectors cleaned by Cruzin' Performance, etc.

I'm thinking that it might be the fuel pump itself or the elctrical connections going to it. I haven't had a chance to verify this yet, as it's rather cold out there this week, but I was hoping that someone has had this problem before.

Thanks!

Fitness Stain

car starting up and then dying was exactly what happened to me when my afm was poo

the afm will shut down fuel supply or whatever if certain conditions are met ... try a diff afm if you have one handy and see if that works

WonkoTheSane

iTrader: (2)

It does the same thing whether I jumper the fuel pump jumper or not... still think it's the AFM?

JamesBong

Have you checked your fuel pressure? Low fuel pressure is a good sign of a bad pump, or a bad fuel pressure regulator.

WAYNE88N/A

Rip back the carpet at the rear left strut tower, and backprobe the blue (I think) wire at the HARNESS side of the connector (leave the connector connected). Read for voltage, to ground. My meter leads are long enough to do this and allow the meter to be seen from the driver's seat, yours should be too. Key on, the voltage should be around 12. During start, the voltage will fall to between 9 and 10v, then assume alternator voltage ranges.

What I'm getting at here is you want to see whether it is the actual fuel pump crapping out on you, or the circuit feeding the pump.

Obviously, if the voltage falls to 0 (or close) right before she shuts down on you, it's not the pump, it's the circuit...

Remember that the circuit opening relay (near the steering column) has 2 coils- one energized with the key to start (obviously works in your case), and one energized by the AFM door (providing the ground)...

WonkoTheSane

iTrader: (2)

Thanks for the tips, Wayne - I'll check this out tomorrow.

JamesBong - I don't have have a pressure check, although yesterday it was flowing pretty consistantly (I checked when I put the fuel injectors in) But yesterday the car ran for about 20 minutes, too... I'll see if I can dig up a pressure meter.

BlaCkPlaGUE

The inconsistancy that your telling us here would indicate to me that it is a bad connection to the pump. It starts and dies, then starts and stays on for 20 minutes.

Check your fuel filter as well, if its clogged enoughe you'll have good pressure after it for about 10 seconds and then there won't be enoughe pressure behind the injectors, let alone fuel. Its fairly obvious that you need to do a pressure check, so see if you can di up that meter.

RotaryEvolution

iTrader: (30)

he said 20 times not minutes =P


i would go with Wayne's suggestion also, best to try and isolate the problem rather than keep throwing parts at it.

WonkoTheSane

iTrader: (2)

I actually said both Yesterday it started right up after I put the cleaned injectors in, it ran for 20 minutes or so before it died.


The second time was in reference to the fact that it will start to rev the engine and die by the time it reaches 1500 RPM (About 3/4 second or so).. It does this every time..

How much does one of those pressure checkers cost?

RotaryEvolution

iTrader: (30)

a basic voltmeter from radio shack is probably about $8-20.

JamesBong

I had intermittant good moments when my fuel pump died on my Jeep. So it still could be the pump. These immersion pumps are lubricated by the fuel running through them. They can fail slowly, making it not so obvious what the problem is. Definately check all of the cheap solutions first. Wireing, fuel filter, pressure regulator (check that vacuum line to it too).

Keep us updated, and good luck!

WonkoTheSane

iTrader: (2)

Yeah, but why go with cheap voltmeters when you have Flukes?

I just need to get off my lazy (read: Warm) butt and do it.. I'm going to wait until it's light out tomorrow..

RotaryEvolution

iTrader: (30)

well then yea... you can get a nice fluke for about $100

WonkoTheSane

iTrader: (2)

Alright, got a chance to probe the fuel pump.. you were right, it was the blue wire.. when I metered it, it did exactly as you described, started out at 14v (I have a charger on the car), dropped to 10V while cranking, then right back up to 14V..

While I was playing with it and watching the ranges as I cranked the car, the car actually ran for 20 seconds or so.. then it shut off like all the other times.. I cannot reliably replicate this. Every other time (before and since that one isolated incidence) it has turned over, started running then died before it hit 1500 RPM..

What about the fuel pump relay? I'm looking in the haynes and FSM for information on that.. anything I should look for with that?

Or, what's the deal with the FPR (Fuel Pressure Regulator)? How do I check that one without a pressure guage?

PS - How much does a fuel system pressure gauge cost?

JamesBong

It's been a while since I got mine, but it was less than a fluke meter. I'm guessing about $25 maybe. Of course, you still have to hook up a tee inline with the supply to check it. It's not that big of a deal though. It's all spelled out in the FSM.

jhammons01

Guys, I don't know anything about this subject but may I add something??? When I was getting ready to pull my motor. The FSM said to depressurise the fuel system. I unhooked the connector under the coils on the Shock tower. This was supposed to kill the fuel pump. I did this while the motor was running. Well it ran and ran and ran, I started checking my work and looking at this forum to see if I did it right, it seemed like at least 7-10 minutes before the car shut down. I even turned it off and started it again.

What I am saying is that if it was the afm shutting the pump down wouldn't it run like mine did......until the fuel rail ran out of pressure??

RotaryEvolution

iTrader: (30)

the rail only takes a few seconds to depressurize and kill the engine, sounds like that was not the right connector or the FSM has a wierd way of depressurizing the system.

back to the subject, double check your grounds as they can cause all kinds of wierd issues with the electronic control systems of the car. i don't mean just the engine grounds but i mean the negative battery terminal and where the ground wire connects to the starter. i had some wierd issues with my car recently and i found that my wires inside the terminal had a tiny bit of corrosion on them causing these problems. the terminal i installed is only about a month old and already had issues with its connection to the wires, i will be doing a writeup on regrounding the negative side soon as i can get some part numbers for my project. i never see this emphasized but it almost as much of a problem as the ground points on the engine it seems.

WonkoTheSane

iTrader: (2)

Jhammons01 - According to the Haynes manual, you should pull the connector that is on the rear shock tower (where your speakers are mounted)< the one that Wayne described to me.. It sounds like you pulled your trailing coils, which means you were only running on your main spark plugs, you basically just unhooked your auxillary spark plugs.

Karack - Good point about the grounding.. I'll have to triple check that tomorrow..

I'm almost positive at this point it's related to the fuel pressure in the system, whether the pump simply is not pumping properly or not. I ran into this Gem in the Haynes manual, page 124 where it was talking about checking the pressure. it tells you how to jumper the fuel pump jumper (by the airbox), and then "you should hear a whirring sound for a few seconds. 1) If there is no whirring sound, there is a problem in the fuel pump circuit. Check the EGI main fuse fuse first. 2) If the whirring sound continues for a long period of time, the fuel system is probably not pressurizing properly. Check the fuel system as described below..

If you jumper mine, you will hear the fuel pump for as long as you want to listen. I'm working on rigging up a fuel system pressure check. I was running into leaks, and as soon as the sunset, it dropped down to about 0 degrees, so that ended my fun for tonight....

I'm pretty sure it's something related to the fuel pressure, though. And I should be able to check it tomorrow or saturday..

More on this story as it develops.

RotaryEvolution

iTrader: (30)

yep, always best to check with an actual pressure guage on the fuel system rather than relying on the sound of the pump. i don't think the test is entirely accurate though, it sais the pump should run then shut off, mine runs continously like yours but i drive mine everyday with no problems, maybe mine is abnormal as well but this should not cause low fuel pressure for a starting problem.

JamesBong

I think the implication is that if it needs to keep pumping, there may be a pressure leak somewhere. I havn't tried this test though.

WonkoTheSane

iTrader: (2)

I think you're right, JamesBong..

Wait, Karack - did you remove your pulsation dampener, too? I wonder if that was supposed to be a restriction? mine is gone.. but I remember it flowing continuously even before it was removed, so that's probably not it..

jhammons01

Son of a gun, I guess your right. I looked and looked and that connector was the only thing I could see that looked remotely like that Photo in the Haynes manual....but it didn't add up. Learn somthing new everyday

OBTW.......Nevermind

RotaryEvolution

iTrader: (30)

my PD is still in place but i plan on replacing it with a BB soon.

WonkoTheSane

iTrader: (2)

Alright guys, I got some new information that I need help on.. I've been basically dead with a flu since friday, today was the first time i've been off the couch for more than 5 minutes... so I went and worked on the 7 I'm not an addict, though... really

I got a gauge hacked into my fuel system, here's what I found: When the car is turned on, and the fuel pump is jumpered, I'll pull 32 PSI.. when I crank, and it turns over, it drops down as low as 28 PSI..

The Haynes manual says that a fuel system should be between 34 and 40 PSI.

Should I look into rewiring my fuel pump?

eage8

iTrader: (9)

the same thing happened to me when my TID was loose, you might just have a giant vacuum leak somewhere...

-Myk