84 4cyl. daily driver quit on the way to work. driving along at 50ish and she just shut down. towed home now looking for the culprit. 1/2 tank of fuel, pump runs when key is turned on, no fuel at all coming from the TBI. i deleted the fuable link thinking that might have died, no change. I'm happy to use the search but havent found the magic phrasing to get a useful answer. i just gassed up a few miles back. so i know im not out of gas. i hear the fuel pump so i assume that means its working. can someone point me to the next thing to check?
[EDIT] Started that message and got a phone call, so didn't send till after you replied...
Could be a quite a few different things.... I do not know if the 2.5 has a schrader valve or not to test fuel pressure, but check for fuel flow/pressure where it goes into the injector. This will narrow down a fuel line/filter problem. If no fuel flow, the cheapest to try first, would be the fuel filter. it's possible it's clogged enough to not allow fuel through.
If you are getting fuel to the injector, It could be the injector, wiring, or the computer, which sends the pulse to the injectors to fire. Check for a pulse first with a NOID light. This will tell you if the signal is coming from the computer. If it is getting a signal, it could be the injector went bad.
EDIT: You said you changed out the injector, so it is either a fuel flow problem, or the injector pulse. Easiest is to unhook the fuel and have someone tap the key to see if you are getting fuel to the injector. Use a individual size water bottle to put the line / hose into and catch the fuel.
If there is no fuel, you are narrowed down to something in the tank (Bad hose, fuel pump, clog) or the fuel filter.
[This message has been edited by JohnWPB (edited 09-27-2015).]
when i loosened the screws to swap the injector there was a small spray of fuel at the gasket so I'm assuming there is fuel pressure of some kind. starting to get a bad feeling because I'm thinking if there were a clogged filter wouldn't i have noticed some performance issues as it approached critical? just seems logical that the volume would drop as the clog got worse so i would expect starvation when accelerating. i suppose a chunk of something getting picked up by the pump might do me in but I'm starting to think ecm and that could be a real budget buster. if i can even find one at the yard (haven't seen a fiero there in a while, much less a similar 84). pardon my ignorance but how does a noid light work to check for pulse? edit: never mind, i looked it up, seems simple enough. now to call around and see if anyone i know has one before i buy it :-) . If it turns out to be the ECM, what are my options?
[This message has been edited by wolf63 (edited 09-27-2015).]
You seem to have a good grasp on troubleshooting it. The same thoughts went through my head, when I mentioned the fuel filter after reading your post. Clogged fuel filter is normally a slow process, that will give you warning. I did see that you just put gas in it before it died, so I came to the same conclusion that you did, that it is possible for a chunk of something to get lodged, not likely, but possible. It's a cheap fix, so a good place to start
The Fiero store has ECM's, so that is always a direct option. Another option is to post in the mall here on the forum a "Wanted to buy 84 ECM" and see who offers what and for how much.
Before I would buy purchase an ECM, I would try to get a hold of a NOID light and test for a signal. It would suck to put out the cash for an ECM, and that not be the problem. Harbor Freight has them for around $30 I think.......
Lastly, you can use a test light to test your injector pulse some times. To really see the pulse, it helps to do it when it is dark, or in a garage where you can turn the lights off. Bulbs in a standard test light will only dimly flicker when you do this. You will have to figure a way to get both the test light leads into the plug that goes onto the injector, and do NOT short them together. The pulse puts out around 5v, so you should be able to see it. If you have an LED test light, that may work better, as they do not have the filament that has to heat up to glow to produce light. You will need to have someone crank the car while you look at the test light, trust me, its impossible to do by yourself
Here is a video of the procedure:
Skip to 14:00 in the video
[This message has been edited by JohnWPB (edited 09-28-2015).]
update: i got a noid light and tested the injector signal. nope, nana, nuthin no lights no joy :-( so,next question is there anything i should check before i start hunting another ECM? i followed the wires until they disappeared into the loop. are there sensors that feed info to the ECM that could have failed? common wire failure points? i have an aftermarket oil pressure gauge and remember something about a fuel shut off if the oil pressure failed with a backup in the ECM. if the pressure sender failed would that confuse the ECM? bottom line, is there ANYTHING else i should check before investing in a new ECM?
84 4cyl. daily driver quit on the way to work. driving along at 50ish and she just shut down. towed home now looking for the culprit. 1/2 tank of fuel, pump runs when key is turned on, no fuel at all coming from the TBI. i deleted the fuable link thinking that might have died, no change. I'm happy to use the search but havent found the magic phrasing to get a useful answer. i just gassed up a few miles back. so i know im not out of gas. i hear the fuel pump so i assume that means its working. can someone point me to the next thing to check?
You can dump all the fuel you want but without spark it's a no go. Fuel air and fire spells fiero.
[Gall757] I'll check tach at crank in the morning and have a spare ICM i can put in if that's the case. i thought the ICM failing would cause no spark, i have no fuel. the injector emits zero fuel when cranking. i checked for injector signal with a noid light and go no indication of signal. are you saying the ECM gets its signal from the ICM and then signals the injector to fire or am i confused? [Silvertown] the issue isn't no spark (although i haven't checked) didn't see the need when there is definitely no fuel coming from the TBI injector.
[This message has been edited by wolf63 (edited 10-04-2015).]
[Gall757] I'll check tach at crank in the morning and have a spare ICM i can put in if that's the case. i thought the ICM failing would cause no spark, i have no fuel. the injector emits zero fuel when cranking. [Silvertown] the issue isn't no spark (although i haven't checked) didn't see the need when there is definitely no fuel.
I thought you said it sprayed out when you removed injector? If there is no pressure it will dribble out.
spray might be an overstatement, spurt maybe? i would say there was a small amount of fuel pressure when i backed off the crews to exchange injectors. no fuel at all from the injector itself
spray might be an overstatement, spurt maybe? i would say there was a small amount of fuel pressure when i backed off the crews to exchange injectors. no fuel at all from the injector itself
Yea, have a container and another person handy. Unhook the injector, and put the fuel line in a water bottle, preferably a 2 liter bottle, as the fuel pump will stay on for about 3 seconds when you tap the key to start. This is a free test to do, and should be done first.
If you have fuel pressure, which I bet that you do, as you said there is no injector pulse, and that is probably the culprit, not the fuel pump. The next step would probably be swapping out the ECM.
Before you disconnect anything you might try spraying some starter fluid in the throttle body. If the car starts and runs continuously you know you have good fuel pressure and spark and it's an ECM problem. I smoked an ECM in my 84 and it would not start on it's own, but if I started it with fluid it would continue running.
[Jscott] easy enough to try, however, i seem to remember reading that the duke has an initial 2 second "pump on" from the ECM then looks for a continuous pump signal from the the oil pressure sender circuit (mine wouldn't since its an aftermarket sender and gauge) there was a backup in the ECM that would keep the pump running if the oil pressure signal failed. i have assumed i was running on the secondary signal all along. I'm getting the initial signal since the pump comes on for 2 seconds at key-on, after that who knows since i haven't gotten it to start. since there is no fuel coming from the TBI I'm pretty sure she will only run while getting fuel poured in. BUT, I'll try it and see when happens. not about to ask for advice and then not follow it :-)
[Jscott] easy enough to try, however, i seem to remember reading that the duke has an initial 2 second "pump on" from the ECM then looks for a continuous pump signal from the the oil pressure sender circuit (mine wouldn't since its an aftermarket sender and gauge) there was a backup in the ECM that would keep the pump running if the oil pressure signal failed. i have assumed i was running on the secondary signal all along. I'm getting the initial signal since the pump comes on for 2 seconds at key-on, after that who knows since i haven't gotten it to start. since there is no fuel coming from the TBI I'm pretty sure she will only run while getting fuel poured in. BUT, I'll try it and see when happens. not about to ask for advice and then not follow it :-)
I can't explain every failure mode of the ECM, all I know is I was driving down the highway when all of the sudden white smoke started pouring out the center console and I nearly had to bail out, but the smoke subsided and I was able to drive home. When I got home the car cranked but would not start. I poured some fuel in and it started and continued running. So whatever smoked in the ECM would not allow the car to start but it would continue running. I got another ECM from a member on here for either $10 or free I can't remember, but it worked perfectly after that. Make sure you have all the fusable links in or your car will catch fire for real if there is a short.
