Hey! I have a 1989 RS with a TBI 305... and she don't run. Problem started in the fall, but I had her parked all winter without any time to take a look at it. I've got the time now, so I want to get to work. It's a project car and I have big dreams for it, but for right now I just want to get it running.

The problem in the fall was the car would run fine for a while, then just stall. Sometimes it'd start up again, sometimes it would take several tries. It got progressively worse until it wouldnt start at all.

Now I'm new to working on engines, and not overly mechanically inclined... the way I understand it there needs to be a certain amount of fuel pressure in the line to allow the throttle body to work, and if its just under that threshold it wont. Is that correct?

My first task is going to be checking to make sure there is power running to the fuel pump, second will be a pressure gauge or somesuch on the fuel line.. after that it gets more messy. The fuel pump was previously replaced a year and a half ago, and some of my friends think it might be a dirty tank fouling up the pump.

I'd appreciate any help you can give me for checking the voltage to the pump, checking the pressure, and whatever else it takes.

 

I should also mention I replaced the fuel filter in the fall after the problem started, didn't help.

 

What's the quickest way to see if the fuel pump is working... see if the fuel flows from the line, and then check the pressure with a gauge?

 

why isnt anyone helping this poor guy??? as far as i know theres no way to check pressure without a pressure gauge or relief valve. go to autozone and get one for like 10 bucks. very simple. you should bealbe to hear your pump run when you hit the key. if not, you'll have to check all connections and wires and filters ect. to see if they are in proper order. i dont think checking the volts will answer your question, either that pump is dead or alive. if you wanna see if its pumping just pull your fuel filter have a buddy turn the key. it should pump

 

yeah I just meant checking the volts to the pump, to determine if its a break in the system, or the pump itself. thanks for the help. I didnt hear the pump the last few times... I just have to figure out where all the wires and relays and whatnot are now to check them all.

 

other than the following link, i suggest you get a haynes or chilton manual (suggest chilton, i'm agrivated at haynes right now) and it will explain the procedures and tools you will need to check the prussure. I would also suggest getting used to wiring schematics, as the sooner you do, they will become your friend. I'm going thru hell right now trying to figure out my fuel issues between the relay and the ECM. anyways here it goes, this is how to diagnose your fuel's electrical system. I know of another page, i will post that as soon as i find it...that goes step by step.

http://www.austinthirdgen.org/index.php?pid=35

 

thanks, yeah I have a haynes manual right now, and it hasn't been overly helpful thus far.

 

ECU is under the passenger side of the dash, fuel pump relay is on the driver side of the car, to the right of the brake booster (should be two relays, one for radiator fan one for fuel pump, you want the one with 5 wires not 4, can explain further if needed). Fuel pump gets power and guage signal via plug in rear axle hump, unplug that plug, and up at the relay, yuo will see a thick tan with white wire, supply 12V there and then you can go to the back of the car and test what was the tan wire when it was plugged in for voltage to see how the current is, there should be much if any drop in voltage.

https://www.thirdgen.org/forums/v6/1...hlight=code+54

that is about as complete of a guide you can get! Any other questions feel free to ask,

the following is all the wiring diagrams for all years and then some. It should get you started in diagnosing.

http://www.austinthirdgen.org/index.php?pid=19
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and thats why i hate the haynes manual
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one sure fire way to check connectivity is to check the ALDL, put 12V to the bottom right hole and it will activate the fuel pump...otherwise use other sites i provided for diagnostics

 

first off figure out if the pump is priming, if not you can check your wiring and all that or you can see if its just the pump, depends on what kind of work you're into, be sure to check all your fuses etc, the basics, if you find that it isnt the wiring once you drop the tank and pull the pump you can just run 2 wires from a battery to the leads on the pump, it mihgt be locked up.

Just start with the basic question, can you hear it prime when you turn the key on and when you turn it off? it sounds like a humming

 

ok i got back out there today, and the pump is priming. Yesterday we gave it a go and it didn't seem to be priming, but there was a lot of background noise. If it consistenly keeps priming but not starting, what is the next thing to look at?

 

ok, my next question is that i might have missed it in what you have said above, but what leads you to completely believe it's a fuel problem? Have you checked your spark plugs, all the other obvious things? Sure it's not an ignition problem? Just curious. From my understanding...optomily it runs on like 11-14 PSI??? may be just shy of being right there, but from my understanding it can run on 8-10 PSI...it's just not going to run well and may stall out, so really, it could be fuel pressure, i would suggest testing pressure reguardless. If your pressure checks out and it primes for 2 seconds once the ignition is on as it should, then i would suggest to then go into the ignition systems.

 

The fuel pump gave me problems a year and a half ago, I do believe it was replaced at the time... I can't remember anymore, I didn't do any of the work on it.

So the next step is testing the pressure, I'll get a gauge on there hopefully tomorrow evening. Does anyone know what getting a pressure gauge on the line permanantly would entail?

If it turns out not to be the fuel system, then its on to other things I suppose.

 

you could skip the pressure test FOR NOW and see if there is even any fuel getting to the throttle body by disconnecting the line form the TB and see if its pumping fuel out there, but you probably will do a FPC with a gauge so your next step would be to test the fuel pressure reg, if you can manage to get the engine running crimp the return fuel line and if it runs better you should probably change your reg.

Like 84redta said, BE SURE its fuel related. Check your plugs, make sure they're sparking....just dont shock yourself, granted its a good wake up call but it sucks. Check your firing order on the distrubutor, plugs, wires, cap and rotor etc. If the fuel system checks out fine you'll kick yourself for concentrating on it.

also see if you have ANY codes, stored or new, even if the SES light isnt on, if you havent cleared them they could give you an idea of what may have happened

 

yea if you test the pressure and it comes back normal, and you've replaced the fuel filter, and all your hard lines look good, we can rule out fuel system.

Next i would probably check your ignition systems and plugs, wires, cap, and such. Anything faulty there you could get some of the problems your experiencing. It would just be helpful to rule it out system by system.
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didn't think of that, check the simple things, make sure that all your plugs are plugged in securely and are in the right order. I've had a v6 ford probe running on 5 cylinders that were completely not pluged in right and everyone thought it was a blown headgasket from the white smoke coming out the back, lol.

 

Its the simple things that can kill you though. No matter what problem you have, always rule it out in the simplest order, number one rule to being a tech. Dont overlook ANYTHING i was told my enigne was getting ready to give out on me about 2 weeks ago, turns out my number 8 plug was shot, caused difficult starting, bad idle fluxuating tach, etc. changed out my plugs and now its back to being a champion. Is there ANYTHING that you did before this started happening? Did a plug job? Tune up? anything? Or did it happen out of the blue?>

 

Aye, it was running great for almost a year before the problem started and no one has touched the ignition system or any of that jazz so far as I know, but I will definitely test that out.

Edit: yeah the problem just happened out of the blue, she ran great and then the engine randomly started cutting out.

As for codes, the previous owner hacked up the electronics, I don't have the light for the code, or even a socket for that light... and that has been a serious frustration.

 

if your handy with electrical id say pull up a wiring diagram, trace it to the SES light and then wire in a new one, as long as you have the ALDL port and the light you should be fine

 

Well we threw a fuel pressure gauge on there, it's between 9 and 13 psi, sitting at 11 or so generally I believe. That's in the acceptable range according to my haynes manual.

Tomorrow hopefully I'll check all the wires and the distributor and whatnot. The guy at the store where we picked up the pressure gauge said to look at the ignition module, apparently he had a similar problem and that was it.

But I dunno!

 

at this day in age at ~20 or so years, our ignition items like to act fishy at times. At least that ruled out dropping the gas tank and that headache!

 

Well, I haven't gotten a chance to take a look at my car since we figured it's not the fuel pump.

I'm pretty frustrated at trying to puzzle out possible causes for this problem, and I'm also pretty frustrated at my near complete lack of knowledge in how to test so many of these possible causes.

So to list possible causes:
Distributor/rotor whatever the hell else is connected to that
The ECM
Ignition module.

First things first, I'll test it for spark. Is there any way to do this by ones self? I don't think I'll have anyone around that can give me a hand tomorrow.

I'm also going to call about getting the ignition module tested. If I can get it tested that's an easy way to rule that out.


*sigh* I wish I learned this stuff growing up. I hate not knowing

 

OK, first thing let's do, is sit down and take a deep breath. Calm down, forget everything you've done or heard, and get ready to become logical. The "scattergun" "maybe it's this, maybe it's that" approach will get you nowhere fast, except to an empty bank account and a bus fare.

Now... engines require 3 things in order to run: compression, air/fuel mixture in reasonable proportion, and spark at the right time. 3 "magic ingredients". Fixing a no-start is SUPER EASY, all you gotta do is figure out which of the "magic 3" disappeared, and restore it. So, divide your efforts up first, into tests to determine which one is missing.

Step 1, is compression. I'm not talking so much here about the kind you "test" with a gauge, so much as, that the valves open and close at the right times, and the pistons go up and down.Compression doesn't act like that. The single most common cause of a lack of it, is a timing set failure; specifically, the teeth on the cam sprocket all break off, and the cam (which works the valves) quits turning in the correct relationship to the crank. This is a yes/no type of thing; either it works, or it doesn't. It doesn't work fine, then slowy diminsh, then stop, then suddenly for no reason start working again, and so on. Eliminate it from consideration.

OK, now we're down to 2 "magic ingredients". Fuel/air, and spark. Which one is easier to "fake"?

Right: FUEL. Pour an ounce or so of gas into the throttle body, and try to start it. If it starts up, runs somewhat, and then stalls again, then you now know that fuel is the missing ingredient. If it is unaffected, i.e. still doesn't start, then fuel isn't the problem, and it's time to move to spark.

If it's a fuel problem, then the only possibilities are the pump, the relay for it, the filter, the injectors, the ECM, and the wiring & fuses and such. Probably not the ECM; it's like compression above, it's a works/ doesn't work kind of deal. It doesn't fade in and out, or get worse from sitting. It might work when cold, then start malfunctioning when hot, but even THAT is EXTREMELY rare. Same for wiring and fuses: works/doesn't, not fade in and out. Eliminate those things too. That leaves the pump, the relay, the filter, and the injectors. You know the relay works, because you can hear the pump running. Eliminate that. You're down to pump, filter, & injectors. You can just chang ethe filter, probably should anyway, if you haven't lately. Change it out, and eliminate it. You're now left with pump and injectors. At this point, you'll need to check the fuel pressure; get one of these, or equivalent. You should see 12-13 lbs cranking, maybe 9 or so running at idle. If you don't see that, it's the pump; if you do, it's the injectors. You can buy rebuilt injectors from that same place, or any of dozens of others; they don't cost a whole lot. Or, you could go to the junkyard and gank one off a car. But doing that, who knows whether they're any good or not. If you don't see pressure, then you need a pump.You'd remember, believe that.... or, if your memory is as bad as mine, go back and look at your check register. Remember that one month that you were suddenly REAL POOR? I'd look in that month's checks and see if there's a fuel pump in there. If you didn't write a BIG check (probably $300-500), then it didn't get replaced. Not taht replacing it THEN, guarantees that it's good NOW; but if the car has had this problem since before whenever it would have been replaced, and replacing it didn't fix it, then ... it probably wasn't bad before, and it's probably not bad now.

OK fine, fuel system is now fully eliminated from consideration, and known working perfect. We now know we have compression, and fuel. All that's left, is spark. The last "magic ingredient".

Don't worry about "testing" the spark; at this point, you already KNOW, you either have it, or you don't.

The parts in the ignition system are the spark plugs, wires, distributor cap, rotor, coil, module, and pickup coil. Using the same logical procedure as the fuel system, eliminate them as potential causes, one at a time, starting with the most likely, cheapest, and easiest ones first.

If you haven't tuned up the car for a while, that would be the first thing to do. A set of spark plugs, a distributor cap, and a rotor. Like the fuel filter, these are wear parts which REQUIRE periodic maintenance. If they haven't had their maintenance this period, maintain them. Not worth troubleshooting: just put new ones in. Did that fix it?

OK, all that's left is the module, coil, and pickup coil. Modules are electronic, and fit the works/doesn't paradigm. Again, might work cold and fail hot, or might have worked at one time and now is broke; but doesn't just fade in and out. However, if you've gon through EVERYTHING ELSE, and you know for certain that you have fuel and good spark plugs and rotor and all that, then try just replacing it.

Now there's nothing left but the coil and the pickup coil. The main coil is tough to test, because it can "test" just fine with an ohmmeter or something, but can fail to properly generate or contain the high voltage spark. The pickup coil does "test" fairly easily though; it should show a few hundred ohms of resistance, probably 600 to 1000 ohms or so, and it should not change when bending, shaking, GENTLY pulling, or otherwise disturbing it little wires.

Not so bad, eh?

 

OK!

I had a response here all written up, then I foolishly browsed away from the window without posting :/ kinda dumb. So here goes round two.

Checked my reciepts, The fuel pump was most definitely replaced.
Replaced the fuel filter a couple months ago, car has done nothing but sit and get towed to my new place since then.
Put a pressure gauge on the line, reading about 11 when cranking, car no longer starts so I cant see what it is at when idling.

If I'm tracking you right, this means the last thing to check for fuel system is the injectors. Is there an easy way to test these? By myself? And how much do they cost generally to replace.

I think I had more to write but I forgot it.

 

If the injectors are working, you'll be able to see and smell gas.

Did it run when you poured some gas in it?

Click on the link for the adapter; look at that seller's store. He has them. Far from the only source, just the first one I found without more than about 2 clicks and typing 2 words; so by all means, check around, if it turns out you need some.

 

more than likely the injectors are not bad. you are getting fuel pressure you said. can you get the car to turn over? if you can turn it over, pour a little gas into the intake, does it run for a second??
if it does run for a second, good.
have you ruled out the VATS.

 

OEM replacement injectors should be around 50-70 dollars a piece to replace, or like someone else said buy a remanufactured one or pull it off a junked car, but its most likely not the injector. i would think its obvious but i just wanted to make sure you checked your fuel pump and fuel injector fuses?