For some background, my car is an '88 GT 5-speed that I picked up last year with 16k miles on it. It had sat for 19 years, but it had the gas drained, fuel pump and filter replaced, and injectors cleaned before it was started. It drove great for the 3k miles I drove it last year, then started to develop this issue...
Symptoms: - I would hear the fuel pump whining when the gas level was below 1/2. Filling up would silence it. - It had a hard time starting once last year, followed by trying to stall out while driving. I got it into a parking lot - bucking and snorting at about 3mph. I sat there for a while, then it started back up and drove like nothing ever happened. - The car sat over the (warm) winter and I drove it on the roads around my neighborhood. It died after about 3-4 miles of driving. After several attempts to restart, it finally did, bucking about, and I got it back in the garage. - I started the car up last week and washed it, then went for a ride. I made it about 4 miles and it was running great, but then stuttered and died. I tried to start it every 10 min for an hour, then again an hour later, all to no avail. I managed to find someone to pick me up so I could go get my truck and trailer and tow the car home. Not a fun night. - I still have the car on the trailer in my driveway and I started diagnosis today, based on research I did utilizing the search function of this forum. Here's what I found: - Fuel pump primed. I could hear it and I confirmed the voltage (10.x) at Pin G on the ALCL. That might be less than 12V because my battery had been weakened. - I figured "what the hell", and tried to start it. It started, ran with a weak idle for 5 sec, then died (on cold start fuel?). It did this 3 times (I gave no throttle input) and then did run continuously. However, when trying to rev it (after warming for a min), it would not pull past 3500 rpm. It did not want to accept full throttle revs. I shut it down after another minute or two. - I started the car up again and it now ran fine. It would accept full throttle revs (I took it as high as 5k or a little more). I ran it for 20 or 30 min, revving it occasionally, and it purred away, as if it was mocking me for not being able to catch it misbehaving!
I will accept any and all help I can get here, but here is all I can come up with at the moment... I am pointing at the fuel system, first of all. I initially was suspecting the fuel pump, itself, but it seems to be running at the moment. I am now suspecting that some debris from the bottom of the tank may be wreaking havoc. I am thinking of changing the fuel filter, as it may have become clogged by stuff from the bottom of a 19 yr old tank coming loose, but the sock filter on the pump should catch anything big enough to clog the system, I would think...
Any other ideas, suggestions, or advice? I want to get back to enjoying driving this car! THANK YOU
If you haven't already, I'd also recommend pulling off the distributor cap and look down in there. Could be pick up coil or ignition module giving up the ghost, or even the coil going bad. While not likely, check the catalytic converter and exhaust system for any restrictions. Might be backing up thwe exhaust gasses choking the car out, after revving it a few times may have cleared it out until it clogs again... just thinking out loud,
Ok, I got it all hooked up. Fortunately, I had it all from previous stuff with my racecar. Here are the results:
- Ignition ON: 2 sec cycle of fuel pump - Built up to about 10psi, then dropped back to near-0. - START/RUN: Built up to ~36psi and stabilized there. - Revving Engine: Fluctuated between ~32-37psi. - Engine OFF: Dropped to 0psi within 5 sec, fuel drained back into fuel rail.
This doesn't seem bad to me. What say you guys? Thanks!
Yep, sounds like regulator leakage, but there is also one other possibility. Having sat that long (19 years) there is a rubber hose , which connects the pump itself to the metal line leaving the tank. Over time, these rubber/neoprene hoses begin to dryrot and/or deteriorate, and sometimes, even burst completely. It's been my experience tho, on 2 different Fieros--that they bleed off a little pressurized fuel thru age caused porosity or a pin hole or 2, which could also account for your quick bleed down of fuel pressure after shutting the engine off. IF the fuel pressure test procedure is the same for both the 2.5 and the 2,8, there is a 2nd part to the fuel pressure test. You squeeze down on the rubber part of the feul return line, and watch your gage at the same time. The pressure should begin to quickly increase. Doing the return fuel line pinch-off part of the fuel pressure test is "supossed" to eliminate the regulator from the troubleshooting list of possibilities, but that can also (if that previously mentioned line is soft and weak) result in blowing that line completely apart. The presmise behind the return line pinch-off is that if the problem is in the tank components, nothing that is done to the return line will increase fuel pressure, but if you pinch it off a little, and the pressure comes up to normal, the problem is in the regulator. Do NOT hold a pinch on that line for very long at alll--you can damage other compnents by doing so, as a good pump is quite capable of producing more pressure than they can withstand.
And of course, if you do have to drop the tank to replace that 2" long hose, go ahead and replace the pump while you have it out-- with a quality replacement part.
[This message has been edited by maryjane (edited 04-26-2012).]
It might be your ignition coil and/or module. Seems like the car starts fine when cold but dies after getting warm which is a sign of slow electrical death. I would think that if the fuel pump was truly faulty, it would act up all the time and not just when hot/cold. When you experience this condition, when trying to start watch the tach...does the needle pulse with the starter? If it stays dormant, it's either the coil or the module (can't remember which one). Ive had this before where it would stumble and die. I would just replace these parts anyway - cheap insurance.
/\ true as well. Usually, a module will just die completely, but I have had them crap out when driving, the engine won't start, then once the engine and module cool down, that sucker will fire right off and run for a while longer, till it warms up again. Sit, wait 15-20 minutes, then it's down the road a few more miles---rinse/repeat till I got home and changed the offending module.
As far as the fuel system either being good or bad all the time, that's almost always true with the pump itself, but not neccessarily with the regulator.
Hey guys, thanks a lot for the responses. I will try pinching off the return line tonight and see if the pressure goes up. Do you guys know the spec for the pressure regulator? I mean, what pressure is it set to?
maryjane, as mentioned in my original post, the fuel pump was replaced before I picked up the car, along with the filter (AC Delco parts) and having the injectors cleaned. I would hope that they wouldn't have re-installed the new pump with a cracked or crumbling hose. These guys were too anal for that. However, I will keep that in the back of my head...
I fiddled with the car tonight. I located the FPR under the intake manifold (may be obvious to you all, but I don't know these cars at all so everything is new! lol). However, I couldn't find any rubber fuel lines between the fuel rail and at least to the filter. They were hard lines except there seemed to be a shrouded section that ran down the RR wheel well. I haven't tried to pull it off yet. Is this the rubber line you were talking about, maryjane?
Now it seems like my battery is fried, too. I noticed the other day that the Volt light was on. I had put a charger on the battery since I figured I had worn it down when I had been stranded and kept trying to restart it. I put it on the charger the other night, over night, but tonight it was dead. The fuel pump was weak and it would barely turn the engine once. It wouldn't start it. I was initially thinking it was the alternator, but since I had a charger on the battery and it didn't seem to hold the charge, I'm now thinking the battery could have had some cells go dead or something. It was new as of a year ago, but who knows.
Ok things are getting weird... I mentioned that the battery wasn't holding charge. Well, I took it out and took it to AutoZone and they tested it. It tested 11.4V, but 0% charge. And this was after I've had a charger on it (while it was in the car) for the previous 20 hours. I figured the battery was simply not taking a charge. However, I thought I'd put a charger on the battery with it sitting outside of the car and see what it does. Well wouldn't you know... it starts soaking up the juice (as far as I can tell from my charger).
So, I go start looking at the battery cable wiring and put my multimeter on it to make sure I have continuity and a good ground. I got the beep to confirm I have continuity between the negative battery wire and a rear strut bolt. Great. Then I put it on the positive cable and check it ground and...... it beeps. WTF? I check and re-check. I have continuity between the positive battery wire and ground. Also between the + battery wire and the - battery wire.
Now, I'm not an electrical guy. Someone please tell me I'm an idiot and this would be normal when the battery is not in the car, but I'm suspecting that something is shorted out. Starter or alternator? No idea. The weird thing is that my electrical stuff was working in the car, but it didn't have enough juice to turn the engine. I would think that, if I had a short as bad as I'm thinking I do, I would be burning up wiring. No?
I don't know what the resistance threshold is on that beep, but yeah you must have a short somewhere. To narrow it down, try pulling fuses until you find one that "fixes" it. I did this once while watching an ammeter connected between the battery and cable. That way I could see how much current was being drawn. But the resistance test should be fine too. If you use an ammeter, leave the key off since apparently the problem is already there without turning anything on, and it's safer for the meter.
[This message has been edited by armos (edited 04-28-2012).]
The most common battery drainers on Fieros is a headlight motor that is not completely up or down - still drawing enough current to pull the battery down. This would also be enough load to give you the beep on your meter too.
If there was a real short the battery would be dead and/or your wires would melt. Ignore the beep. Measure the current with the ignition off - should be a few mA.
The battery won't take a charge when its hooked up in the car, which leads me to believe there is a short. Possibly internal to a component such as it is not burning up wires, maybe? Idk. The headlights haven't been turned on in quite a while and both motors are new as of last year.
Unfortunately, I don't have this problem of the car dying after 10 minutes of driving solved yet. I haven't had any time to focus on the car at all during the racing season, but as it winds down, I found myself with a free weekend. So, here's what I did...
It was sounding like either the fuel filter or the ignition module would be the first suspect items, so I picked up those parts and put them in first. I pulled off the fuel filter (which was replaced before the car was started when it was resurrected last Feb, 3000 miles ago). The fuel that drained out the INLET to the filter was very rusty, with lots of sediment.
When I replaced the ignition module, I found some corrosion in there. The plastic connector for the ignition module to the pickup was very broken apart and the cap contacts had some corrosion. I cleaned everything up best I could and put it back together (I now have replacement cap, rotor, and pickup ready to go in).
I also had an issue of the battery not charging... So, next I removed the alternator to go have it tested. What a biatch that was... I finally separated the alternator from the bracket while they were both off the block. I don't know why the repair manual tells me to take the bracket off with the alternator. Maybe just because that upper through-bolt would hit the exhaust heat shield? I would have saved myself a lot of heartache if I had just left the bracket in place, or decided to separate them from the get go. In any case, I had it tested today and it was confirmed bad. I replaced it and the Voltage light in the voltage meter went out when the car was started. The meter also showed about 14V, as opposed to about 12V before (just battery power). So, Alternator issue seems to be solved.
I went to drive the car after letting it fully warm up, to see if it would still try to die after 10 minutes like it was doing before. At first it was fine. Then, after about 5 minutes of driving, I was accelerating at full throttle in 2nd gear and it started lose power. It felt like it was leaning out. I kept trying this (I would back off as soon as t started losing power so as to not damage it). At first it wouldn't accelerate past 5k, then 4k, then it wouldn't pull past even 3k. Then I was turning around in a circle and, from idle, the engine died. It restarted on the first try, though. I got back home and, reversing into the garage, it died again. This time, it took probably 6 tries before it restarted without dying. And it idled and revved like nothing happened. I put 3 gal of gas in it (it as pretty low) and I took it back out. On a short stretch of road, tried accelerating in 1st gear, it wouldn't pull past 5k.
My feeling from the way the car was acting is that it was leaning out, which is indicating (to me) a fuel delivery issue. What I'm feeling could be different from what is actual, of course. But, going with that for now, I am going to drop the fuel filter again and see what the fuel in it looks like. I am thinking that the tank may be rusty and that it is sediment clogging the filter, but then settling back, allowing it to run for a while. I really don't want to drop the damn tank, but I'll do what I have to do. I'm hoping it's something (almost anything) else.
Does anyone have any ideas of any other things I should be looking into or what else this issue could be? Thanks
Did you ever clamp the return line to see if the fuel pressure held? You know the pressure should hold pretty close to 40ish after the engine is shut off. If it's still not right then that is one variable I would eliminate.
(and dropping the tank is not hard at all if you ever have to go there)
So, where I'm at now is that I think the rust in the tank is clogging the sock filter on the pump. It is consistent with the symptoms. I will drop the tank tonight and decide whether to clean/seal, replace with new (if I can find one), or take a chance on a used one. Any advice is welcome.
I would be going with dropping the tank especially since you said there was a bunch of rust in the line feeding the fuel filter. I have had to do this myself to a 86 I had and took the tank into a rad shop to have it steamed cleaned and relined.
It not holding fuel pressure is also something to be concerned with - but I would tend to suspect a bad injector (stuck open) first over the regulator - there are 7, 1 for each cylinder plus the cold start which is located feeding into the side of the intake kind of under the distributor. Although if you pinch off the return line and the pressure holds, then it would be the regulator. The rubber hose section for the fuel line is located near the battery. If you remove the plastic battery protector from between the battery and the engine they will be easy to see - you will just have to determine which is the feed/return which is obvious since the feed comes from the filter.
Future reference, you don't need to remove the alternator bracket and comes out the easiest through the wheel well.
Also, don't worry about the headlights motor comment - the 87 and 88's used a second generation motor and don't suffer from the 'battery drain' issues that the eariler years do (it's a different system).
So, the tank has TONS of rust particles in it. If I gathered it all up, I would probably have a whole hand full. What I was NOT expecting was the big plastic baffle inside the tank. I feel like it will make it difficult to get the tank fully cleaned out and sealed... Anyone have any advice on this, hopefully from direct experience with having cleaned and sealed a Fiero tank? Thanks
So, I found a clean tank here locally and I put it in last night. I can run the pump by hooking a 12v battery to the ALDL and it seems to run fine. However, the engine won't start and I have no fuel pressure at the rail. I am assuming that I kinked a line somewhere. I can't see any way I could have mixed up supply and return lines. I may find a line kinked above the tank... I will first disconnect at the filter and see if I get anything there when I run the pump. At least that will eliminate anything from there to the engine. I will report back, in case anyone cares. I guess this is more of a personal journal for me. Lol
Me too, i'm watching. I have an 88 Duke that was sitting forever too. I'm going through all the same things you are. Check out my Coupe link in my sig. You know with some thing like this, you really learn your way around the car. For me it's a labor of love.
I'm pretty sure you should hear the pump load up when you turn the key on. You know like its pumping gas then hits full pressure then stops. I know this is how my 3800SC sounds when I turn the key on. My 88 formula used to sound that way too when I would turn the key on. My 88 duke fuel pump won't load up towards the end of the pump cycle when I turn the key on. I'm suspecting a bad regulator due to all the rust (MUD) that was being pumped into the throttle body. I think there's a check valve also to keep pressure once its built up. I wonder if mine is working correctly. Someone mentioned you could have a stuck fuel injector leaking down your pressure too. I can see mine and its good. As far as the pump pressure goes on your car, yes it sounds like you have a bad pump.
I wish I could say "My Pleasure", but it has not been. LOL. However, I got the new pump today and ran it in water and it pushed the water out of the outlet, as it should. I needed to do that just to make sure I wasn't crazy. I reassembled the pump and sending unit and put it in the tank. Put power to it again and it is pushing fuel through the supply line to the engine. Time to put this biatch back in and hopefully get it started tonight!