I recently purchased a barn find '85 GT. I thought that I had figured out the issue for why it refused to run. In this thread I went over why I thought it was the fuel pump and the symptoms I had. The post seemed to be met with agreement from other members. I replaced the pump,sending unit, and fuel filter with parts from the Fiero Store. I also cleaned the tank while I was at it. Today, I finished buttoning everything up(I didn't fully mount the tank, just the hoses and lines) and went to start the car. I primed it a few times and expected to hear a mighty roar! The awakening of a sleeping giant. nothing...nothing but cranking. Alright, enough theatrics The fuel pump is operating. I can hear it prime when I turn the ignition to on. While my dad and I were trying to get the car started, he placed a hand on the tank while I cranked the engine and could feel the pump working. I did disconnect the line coming out of the fuel filter and gas started spewing out so we have fuel movement. I know that the engine wants to start, too. We tried using a bit of starting fluid, to help get the engine fired up, and it sounded good when we'd get it going for a bit. Don't really know where to go from here. If the engine turns over well with starting fluid, we have spark and I assume compression. And I would think that fuel would no longer be an issue. Needless to say, no start. Any suggestions on what to look for next would be great. I was thinking plugged up fuel injectors.
We tried using a bit of starting fluid, to help get the engine fired up, and it sounded good when we'd get it going for a bit. Don't really know where to go from here. If the engine turns over well with starting fluid, we have spark and I assume compression. And I would think that fuel would no longer be an issue. Needless to say, no start. Any suggestions on what to look for next would be great. I was thinking plugged up fuel injectors.
Could be the injectors but try changing the fuel filter if you haven't done that already.
I recently purchased a barn find '85 GT. I thought that I had figured out the issue for why it refused to run. In this thread I went over why I thought it was the fuel pump and the symptoms I had. The post seemed to be met with agreement from other members. I replaced the pump,sending unit, and fuel filter with parts from the Fiero Store. I also cleaned the tank while I was at it. Today, I finished buttoning everything up(I didn't fully mount the tank, just the hoses and lines) and went to start the car. I primed it a few times and expected to hear a mighty roar! The awakening of a sleeping giant. nothing...nothing but cranking. Alright, enough theatrics The fuel pump is operating. I can hear it prime when I turn the ignition to on. While my dad and I were trying to get the car started, he placed a hand on the tank while I cranked the engine and could feel the pump working. I did disconnect the line coming out of the fuel filter and gas started spewing out so we have fuel movement. I know that the engine wants to start, too. We tried using a bit of starting fluid, to help get the engine fired up, and it sounded good when we'd get it going for a bit. Don't really know where to go from here. If the engine turns over well with starting fluid, we have spark and I assume compression. And I would think that fuel would no longer be an issue. Needless to say, no start. Any suggestions on what to look for next would be great. I was thinking plugged up fuel injectors.
ah the lovely crappy tbi injection. check fuel pressure and that the injectors spray at cranking speed, quick and dumb way to check pressure is to let it pressurize and then find the Schrader Valve and poke it with a screwdriver after you disconnect the coil on all sides, the fuel geyser should be around 4 to 6 inches tall. aka if it touches the decklid its perfect
I see no mention made of an actual fuel pressure reading.
I may be able to borrow a fuel pressure gauge from someone I know. Or I can test it how cartercarbaficionado suggested. What would the psi specs be?
I had checked those V6 fuses when I first tried getting the car to run and one was blown. I replaced it. I'll check both of them again. If the fuel pressure is good and both fuses aren't blown, would I need to move towards cleaning up the injectors?
The injectors.always have 12vdc on the pink wire with the key on. Check that first. The injectors fire when the ECU supplies a ground. The 2.8 is a bank fire design, that means that all of the injectors on one side of the engine open at the same time, and the sides alternate . You can check for voltage at the injector sub-harnes to engine harness plug. Separate the plug and probe the pink wires with the key on. You should see 12vdc. If you do, you can get a noid test light to check that the ECU is supplying the ground to fire the injector. If there is pulse on the noid light, and you have fuel pressure (≈40psi), chances are the injectors are plugged. I would spend the money to replace them, rather than try to clean them.
The fuel system can prime but if the ECM doesn't see spark, it won't run the fuel pump at crank.
I've seen this more than once. Disconnect the large harness that plugs into the ignition control module. Look into the end of it to be sure that all the clips inside are almost flush with the end. They should all be equal. I believe it's the 3rd from the right as you look at it when it's plugged in. That's the one that signals the fuel pump to run. The clips inside sometimes get pushed back into the harness end and they don't make contact.
The injectors.always have 12vdc on the pink wire with the key on. Check that first. The injectors fire when the ECU supplies a ground. The 2.8 is a bank fire design, that means that all of the injectors on one side of the engine open at the same time, and the sides alternate . You can check for voltage at the injector sub-harnes to engine harness plug. Separate the plug and probe the pink wires with the key on. You should see 12vdc. If you do, you can get a noid test light to check that the ECU is supplying the ground to fire the injector. If there is pulse on the noid light, and you have fuel pressure (≈40psi), chances are the injectors are plugged. I would spend the money to replace them, rather than try to clean them.
I will test for 12V and fuel pressure tonight. I'll check the V6 Injectors fuses, too. I'll update the thread.
Alright. I checked both V6 fuses and they were fine.
I did test pressure on the fuel rail(How cartercarbaficionado suggested). I primed the pump about 3 times and poked the schrader valve with a screwdriver. A 4-6 inch geyser shot up as he said it would.
As for checking the connector for voltage like olejoedad said, I became a bit confused.
Is this the correct connector? I tried following the harness that I could see the fuel injectors were connnected to under the upper intake. I tested the two wires I have arrows pointing to. The left wire showed no voltage when cranking. The right wire showed only 8V when cranking. Kinda stumped on this one
I was searching up threads about fuel injection to see if there have been issues similar to mine. While I was searching, I found this thread by Intel where he was diagnosing a no-start after his Fiero had been sitting a minute. His issue ended up being that the timing somehow went off while sitting. Don't think that's my problem.
Some of the tests he did intrigued me though. I removed a spark plug to see if there was fuel on it after cranking for about 4-5 seconds. Pulled it out and it was bone dry. Not even a scent of fuel. After this, I poked the schrader valve and gas shot out.
So I have fuel pressure at the rail but I don't have fuel coming out of the injectors? That leads me to believe it's that the injectors are not getting power or they are plugged up
Side note: Anyone know if I tested the correct connector I posted above? I haven't been able to find any info on the injector harness. If I can't figure it out, I'll just remove the upper intake which I assume I'll have to do either way.
Originally posted by cartercarbaficionado: ah the lovely crappy tbi injection. check fuel pressure and that the injectors spray at cranking speed, quick and dumb way to check pressure is to let it pressurize and then find the Schrader Valve and poke it with a screwdriver after you disconnect the coil on all sides, the fuel geyser should be around 4 to 6 inches tall. aka if it touches the decklid its perfect
His car is actually an MPFI-based system... 6 separate injectors with the injector directly in the intake manifold just before the intake port on the cyl head. Which... totally random here, but I've often wondered if there's any significant benefit to converting to an SFI system. Difference being, ours with MPFI, the valves have fuel that pools on top of the intake valve rather than being sprayed directly when the valve is opening. With SFI... it sprays each valve independently as the valve is getting ready to open. I don't know if this saves fuel, makes more efficient use of it, etc... but it's certainly a more modern take.
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Originally posted by jumpmonkey:
So I have fuel pressure at the rail but I don't have fuel coming out of the injectors? That leads me to believe it's that the injectors are not getting power or they are plugged up
Side note: Anyone know if I tested the correct connector I posted above? I haven't been able to find any info on the injector harness. If I can't figure it out, I'll just remove the upper intake which I assume I'll have to do either way.
Just a couple of things...
I *THINK* you said you tested spark, correct? You said... "If" you could start it with starting fluid, then it should be fine. But I didn't get a concrete answer (or I might have missed it, and I apologize). If you're able to start it with starting fluid, then the problem is ABSOLUTELY fuel delivery.
Here, let's do it the way I know best... like a computer program.
IF Car Starts = TRUE when you spray starting fluid, THEN ECM and SPARK are OK. (EDIT: It would also mean timing isn't too far off)
IF Fuel Pressure = ~38-42 PSI at the schrader valve, THEN fuel pump is OK
If you can confirm both of those for me as TRUE (as written), then I think we need to take a closer look at a few things.
- Have you confirmed you don't have any engine codes? - I'm thinking maybe plugged injectors?
... that is the right connector, and if you've tested both those wires and you see pulses, it means the injectors should be bank-firing (I'd need to double check, but I'm assuming those are the right to wires).
Does it feel like it's trying to start?
[This message has been edited by 82-T/A [At Work] (edited 05-04-2024).]
The two wires that carry power to the injectors in that plug are D and A. One is pink, the other is pink/white. The wires you have highlighted are D and E.
E is for the cold start injector, as is the tan wire F.
[This message has been edited by olejoedad (edited 05-04-2024).]
The two wires that carry power to the injectors in that plug are D and A. One is pink, the other is pink/white. The wires you have highlighted are D and E.
E is for the cold start injector, as is the tan wire F.
I assume the wires are in aplhabetical order, left to right from the picture I sent? The wires that carry power to the injectors are A and D. A pink wire and a pink/white wire. You said that the wires I have highlighted are D and E but E is clearly the pink/white you're referring to, right? I think I'm more confused, now haha
If you look closely at the plug, the letters are on the plug. You may have to clean it up some, but they are there.
The wire on the right side of your picture that you have marked is purple and white, it is in terminal E. Terminal A is on the far left.
The wire colors are affected by engine heat and may be discolored.
Alrighty. Got it this time! Both A and D are showing 10-11V when key ON. At this point, with verified power and fuel pressure at the rail, I'd assume that my injectors are all gummed up. If there's something else I should check before I remove the rail/injectors to be cleaned and flow tested, I'm all ears.
I'll do a resistance check on the injectors tonight. I also was able to get my hands on a noid light, so I'll test with that.
If those tests perform good and I end up needing to clean or get new injectors, which would be better? I've been struggling to find any for sale online at a fair price compared to getting them cleaned and flow tested. What's a company that you recommend for cleaning and flow testing?
Also, if I'm going to purchase injectors do I just need to look for any that have FJ9 at the start? Looking on RockAuto from a link recommended by Patrick in another thread, I see FJ936, FJ990, FJ996, etc. I'm not sure what the differences would be or if I should just go for whichever one is in my price range.
[This message has been edited by jumpmonkey (edited 05-06-2024).]
I've been struggling to find any for sale online at a fair price compared to getting them cleaned and flow tested.
I looked up what it cost me nine years ago to replace my injectors. It was $77.20... no, not for one, for all six... and that price included shipping. They appear to be a tad more expensive now!
I'm running the Standard Auto FJ9's in my 86 and they perform very well. But like Patrick, when I bought them several years ago, I paid less than $70 for a full set. New. FJ111's are the updated part number. My FJ9's were originally FJ6's.
[This message has been edited by fierofool (edited 05-07-2024).]
I was able to use a NOID test light on the injectors to verify that they are getting power. They lit up like a christmas tree on each injector.
I'll be removing the injectors soon to have them sent in and clean/flow tested. I found a place online that does each one for $22 bucks USD including adding new O-Rings. I think that will be my best bet.
They appear to be a tad more expensive now!
