Georgia Fiero Club Forum
All Things Fiero => Tech Tips, Tech Questions => Topic started by: Cyb3rw0lf on July 12, 2017, 07:30:04 pm
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Hi everyone!
Recently picked up an '86 GT that has been sitting for 15+ years, a nice replacement for the '84 3800 swap I had 5-6 years ago. The car was not running when I got it but apparently ran fine when parked. After cleaning the fuel tank, lines, injectors, and fuel rail, plus replacing the fuel pump, fuel filter, fuel pressure regulator, spark plugs, plug wires, pickup coil, coil, distributor cap, and rotor I cannot get the car to start. It turns over great and I know that I'm getting spark and fuel, and that the timing is correct but the car just refuses to start. Is there some kind of quirk that the 2.8 has that I am not aware of? Any ideas or suggestions would be extremely welcome.
Thanks,
Thomas
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Are the plugs wet or dry?
Do you smell fuel out the exhaust?
Have you tried spraying starter fluid into the intake?
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I forgot to check. Is it firing at all?
Other things to check would be the ICM, timing, and neutral safety switch. Perhaps the TCC on an auto.
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Wet plugs
Havn't sniffed the exhaust...Yet.
Forgot to mention that the ICM has been replaced, neutral safety switch isn't an issue as its a 4 speed.
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OK, not the TCC, either, then.
Are you sure the timing is correct?
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Have you checked the ground straps, and made sure that rodents haven't gotten to the wiring?
You did plug the connector for the ICM in, right? New ICMs are often bad. You may want to test yours, or even try the old one.
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Verify spark again by pulling the coil wire from the top of the distributor and putting a spark plug in it. If no spark, check to be sure the carbon contact didn't fall out of the cap. Then replace the wire and spray a couple of shots of carb or brake cleaner into the throttlebody and see if it tries to start. Also check Inj 1 and Inj 2 fuses, but you wouldn't have wet plugs if they were blown. Check the 4-wire harness end that plugs into the module to be sure that all the contacts are all the way up to the front of the harness. Any of those that have been pushed back into the harness can lose contact and cause a no-start condition.
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Is this the Fiero you bought back in May?
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Technically I got it in June but yes.
Ground straps are a very good thought that I'll double check on tomorrow, as far as I've seen though the only thing pointing to the car becoming a habitat was a long dried out wasp nest behind one of the rotors. The car was thankfully garage kept.
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Just checked and there is no grounding strap on the car at all, guess I know what I'm picking up tomorrow.
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There should be several. One small one as an integral part of the main ground wire. It attaches to the battery tray. A braided ground strap from the right hinge base to the engine. A heavy stranded wire from the left side of the chassis rail over to one of the main transmission bolts. I think there are also one or two that go between the engine and cradle.
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Just checked and there is no grounding strap on the car at all, guess I know what I'm picking up tomorrow.
Unlikely there are none.
I hope the brake calipers didn't lock up.
I'm hoping you changed the coolant and oil.
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The brakes were locked up but the calipers have been rebuilt to resolve the issue, all fluids have been flushed and changed of course.
I should have been more specific with what I state previously, the braided grounding strap typically going to the head/block is not present, I didn't notice a strap on the transmission either. The ground to the battery tray is there though as I replaced it when I replaced the rusted out tray.
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I'd perform a compression check. Sitting that long, it is likely that rust developed in the bore and subsequent cranking may have broken a ring or piston land. With an engine that has been sitting that long, before trying to crank it, I add marvel mystery oil (air tool mineral oil) to the cylinders to sit a few days, leave the plugs out, hand turn the engine over slowly a few turns with the harnonic damper nut, going back and forth over any spot where there is resistance. I'd then spin it over with the starter to sling as much oil out of the bores as possible through the plug holes before reinstalling to prevent a hydraulic lock situation.
Another possibility is the timing set is worn and the crank and cam are no longer synced. I don't remember if plastic or aluminum gears were ever used in the 2.8.
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Start with simple diagnosis first:
Key on, don't start position, listen for fuel pump sound for two seconds and subsequent click heard from fuel pump relay next to air filter canister. If no click, check relay. If click and no fuel pump noise, check fuel pump.
Another easy check for same: spray starter fluid into intake on body panel, should start if fuel is only issue.
Please try and post results.
Ron
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Any progress?
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Yes there has been some.... Much to my embarrassment it's a timing issue as I did not realize this crank has three timing marks on it. I'm now on the largest of the three but believe it to be 180 degrees off. I'll work on it this afternoon and update with results.
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Hey, it happens. Looking forward to the results.
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Timing is now set properly and the car will run temporarily when fuel is introduced to the throttle body but not otherwise. I've double checked everything from the pump up to the injectors and it was all OK until I checked if the injectors were getting a ground signal from the ECM to fire, which they are not. Any advice on where to move on from there? I checked the ECM grounds and found that they had voltage to them when attempting to start, but am unsure if its simply a change in resistance.
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So, it was getting fuel with the wrong timing, but not with the right timing? Is the fuel pump still running? We're back to checking for fuel pressure, or bad injectors.
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Old fuel filter? Engine block has good ground?
Please see our 'Tech Tips' for the proper timing procedure. Use the center mark on the balancer to set your timing.
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We assumed it was getting fuel due to wet plugs, apparently not so though. Fuel pump is good and runs, block has good ground and the fuel filter is new. As I said I currently have no pulsing ground signal to the injectors from the ECM so I don't know if they function or not, going to attempt grounding D15 & D16 from the ECM manually to check if the injectors fire, if so then it should be a wiring problem I believe.
Timing is now correct as per the GAfiero tech tips, which is also how I realized my timing mark problem.
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I should also note that this vehicle had various electrical uh.... "Modifications" that I've been working on restoring to the original configuration, at this point I think I've gotten them all but perhaps I missed one.
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Injectors fire when manually grounded and attempting to start, the car even ran (horribly) for a few moments before the screwy fuel/air ratio shut it down.
Bad ECM or perhaps whatever sensors the ECM uses to control the fuel timing?
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Current summary:
1. Timing is supposedly now correct
2. Injectors, ICM, ignition coil, pickup coil, rotor, cap, plugs, wires, fuel filter, fuel pump, FPR have been replaced
3. Engine grounds are good
4. Engine runs when starter fluid is sprayed into the intake
5. Engine runs badly briefly when injectors are grounded manually
6. The injectors do fire
7. The plugs were wet before timing was changed
8. The injector bank fuses were checked
I almost suspect either bad grounds or bad fuses. When you spray fuel into the throttle body, do you remove the intake hose? Just to get a baseline, are you doing the same thing as when manually grounding the injectors?
I don't remember. Did you replace the MAP sensor? I had to unplug mine and limp home, in another vehicle. I don't remember what the symptoms were, but running terribly.
Hmmm. Did you check/replace the IAC, and CTS? You didn't adjust that screw in the throttle body by the IAC, did you?
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You can check the IAC like this (http://www.fiero.nl/forum/Archives/Archive-000001/HTML/20120111-2-110197.html)
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The problem has been found!
Decided to go back to basics and ignore what my helper and I have seen to this point, worked through everything before finally pulling the injectors that we had "cleaned" and attempting to put pressure through them independently with poor results. So poor in fact that these injectors are done for and need replaced, before I go about this though I've seen several mentions online of replacing the stock injectors with those from other vehicles. Is there a particular reason for this besides performance? I'm mostly going for the best fuel mileage I can get at the moment.
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With the stock 86 ECM, it may not be able to efficiently operate some aftermarket or even GM factory injectors. Especially the MulTec style injectors. I would suggest that you go to a fuel injector sales and repair company and tell them you want 15# Pintel-style injectors. Give them the part number of your old injector as a cross-reference. I like these guys. They have been Fiero owners/racers.
https://fuelinjectorconnection.com/shop
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I'm glad you're making progress. I was wondering...
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Thankfully all of this chasing problems around has led to my replacing most other things that could go wrong in the future and lots of spares. :D
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Careful. Don't jinx yourself.
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...... Jinxed myself, RF brake line collapsed going up a hill on it's first time out, brake locked and the clutch blew :'(. Good thing I know how to drop a Fiero cradle..
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How does a brake line collapse? If the RF brake grabbed, the car should pull to the right.
As for the clutch, dunno why the brake line would affect the clutch.
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The car stalled on a hill when the brake locked, when we tried to get it moving again the clutch blew. Too much resistance.
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There could be two causes for the locked front brake. Front pistons are notorious for locking up after the cars have set for a period of time. The other would be the hoses, as you suspect. With age, they start to disintegrate inside, getting small flaps similar to fish scales. These flaps, depending upon which direction they break loose, act like check valves and can block fluid from going to the caliper, or returning from the caliper once pressure is applied. To identify the source of the problem, disconnect the brake line from the caliper. If it releases, it's the line. If not, it's the piston. Don't bother to rebuild the caliper. Just replace it.
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I've never had a brake seize while just driving. Usually, the brake seizes during use. A collapsed hose or stuck caliper do not cause the brake to apply. If the wheel won't turn, it could be a bearing.
I'm curious to know what you find.
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What became of this?
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I'm guessing that you've been busy enjoying the wonderful driving weather, but I'd like to read an update.