1986 Fiero SE V6 Won't Run. My mechanic friend and I just replaced the fuel filter and fuel pump in the gas tank. We have pressure at the rail. What happens is that the car starts right up and dies 2 seconds later. But... With my buddy in the engine bay working the throttle we can keep the engine running indefinitely but as soon as he lets go of working the throttle the engine dies. We have checked the idle air control valve and its spotless. Obviously we have fuel and spark. He thinks its a vacuum leak but cant pin point it. Any ideas? We're stumped/ (One early attempt he plugged a vacuum hose on the middle back (top) of the engine and it ran but high idle. We couldn't figure out where it goes? Maybe brake booster? Anyway we tried that agin and it didnt seem to help.)
Mine did this after replacing a broken injector. I had forgot to plug the vac lines into the intake and map sensor on the passenger side of the intake. You may want to just check those lines.
Same symptoms as my 1990 Ford Bronco, ran if you sprayed starting fluid in throttle body. I replaced it in Bronco and it ran and idled like a dream. Fiero had same problems. Also my Fiero had NO low end power, nothing. Keep in mind I haven't taken the Fiero out of my driveway since purchase cause it runs so bad. Its been getting worse and worse.
Update: ICV replaced. No real change. It starts hard, then idles really high, and dies. TPS on order.
Did you ever see if it would run with the diagnostics ports shorted?
I just tried this. Doing this, it wont even start at all. Just cranked. At least before it started and died. Now jumping the ports it doesn't even do that. Just cranks. tried 6X.
I just tried this. Doing this, it wont even start at all. Just cranked. At least before it started and died. Now jumping the ports it doesn't even do that. Just cranks. tried 6X.
If it runs without being put into diag mode, but won't after being put INTO diag mode...I'd definitely check the timing.
IAC replaced. No change. Have plenty of fuel pressure.
I know you replaced the IAC.
If you remove it, you can use your finger to control the air flow through the throttle body. That is what I am suggesting you try. If you do not have your finger on the hole, it should have a very high idle.
[This message has been edited by buddycraigg (edited 09-28-2021).]
If it runs without being put into diag mode, but won't after being put INTO diag mode...I'd definitely check the timing.
How do I check it when the idle is all over the place as its nursed manually by someone by the throttle cable connections? And what would cause the idle problem out of nowhere when it idles before but roughly?
If you remove it, you can use your finger to control the air flow through the throttle body. That is what I am suggesting you try. If you do not have your finger on the hole, it should have a very high idle.
I take it that both of those IAC"s were removed with Engine-Off/Key-Off. When key is turned off the plunger withdraws from the port to allow idle air for the next start. Just turn the key to start, no need to push on the gas pedal.
The old IAC shows plunger extended which would block idle air when trying to start the engine, however working the gas pedal at same time as cranking may successfully allow the engine to start but would kill the engine once foot leaves gas pedal.
Since neither one seems to work correctly it may be time to acquire an automotive multi-meter and check the harness connector for the IAC to see if you're getting the proper electrical signals.
I could be all wrong about this and I welcome others to jump in and set the record straight.
Spoon
------------------ "Kilgore Trout once wrote a short story which was a dialogue between two pieces of yeast. They were discussing the possible purposes of life as they ate sugar and suffocated in their own excrement. Because of their limited intelligence, they never came close to guessing that they were making champagne." - Kurt Vonnegut
I take it that both of those IAC"s were removed with Engine-Off/Key-Off. When key is turned off the plunger withdraws from the port to allow idle air for the next start. Just turn the key to start, no need to push on the gas pedal.
The old IAC shows plunger extended which would block idle air when trying to start the engine, however working the gas pedal at same time as cranking may successfully allow the engine to start but would kill the engine once foot leaves gas pedal.
Since neither one seems to work correctly it may be time to acquire an automotive multi-meter and check the harness connector for the IAC to see if you're getting the proper electrical signals.
I could be all wrong about this and I welcome others to jump in and set the record straight.
Spoon
The top one is taken out of the car after sitting for 24 hrs, not run. The bottom new one is shown as it looks right out the box. To recap; as it stands now, car starts after several attempts, idles very high a few seconds and dies. We haven't tried keeping it going manually by the throttle linkage... yet.
Ok so how do I test it and what reading am I looking for? Steve
------------------ "Kilgore Trout once wrote a short story which was a dialogue between two pieces of yeast. They were discussing the possible purposes of life as they ate sugar and suffocated in their own excrement. Because of their limited intelligence, they never came close to guessing that they were making champagne." - Kurt Vonnegut
Maybe check for a crack in the EGR pipe (esp where it attaches under the plenum) ?
Without disassembly we sprayed Starting Fluid the area and no change in RPM. So without taking that apart it doesn't seem to be that. Tube from what I can see is nice and clean, no rot but cant see it all.
Well a replacement TPS didnt do anything. Same. Engine starts hard then idles 3 seconds and dies. So my mechanic took the intake off looking for vacuum leaks. But we did find this...
[This message has been edited by 72and86 (edited 10-07-2021).]
Well the latest in the saga. Cleaned out the entire plentum and EGR port (see pic above). Checked EGR tube; spotless Replaced TPS Replaced Coolant Sensor Removed cat and checked it.
Still same result, nothing changed. Car starts hard, runs a few seconds and dies. As before it can run if someone is constantly feeding the throttle. But let go and it dies.
Running out of things to replace and nothing seems to improve it.
Check all vacuum line connections. This includes them being inserted too far into their connectors causing an obstruction. Particularly the hose off the EGR solenoid, the hose goes to the firewall then tastes a sharp left, I had a large leak at the connection causing a similar issue. Check the PCV valve for free movement as well, you have to have a vacuum leak somewhere
Also, have you replaced the vacuum lines with a stainless set or are you still running plastic? Those lines if original are almost guaranteed to have cracks
What is it... and how quickly does it drop when power to the fuel pump is cut?
Dont have a gauge. When we pressed the valve with the tip of a screwdriver, fuel came spraying out like a gieser. But I just ordered a gauge tester on eBay
What is this tube thats open directly below the wire cluster? Its against firewall left side (drivers) in back of V6 engine, My mechanic says its nothing, just a vent, possibly fuel return vent.
What is this tube thats open directly below the wire cluster?
About once a month someone asks about that pipe. Relevant thread Here.
quote
Originally posted by Patrick:
Hopefully that pipe was disconnected from your air filter canister during the recall (and the canister hole plugged), otherwise that uncapped pipe has been allowing outside unfiltered air to enter into the filtered side of your air intake system all these years.
Well the latest in the saga. Cleaned out the entire plentum and EGR port (see pic above). Checked EGR tube; spotless Replaced TPS Replaced Coolant Sensor Removed cat and checked it.
Still same result, nothing changed. Car starts hard, runs a few seconds and dies. As before it can run if someone is constantly feeding the throttle. But let go and it dies.
Running out of things to replace and nothing seems to improve it.
Stop buying stuff.
We need to diagnose the problem.
I cannot help anymore until you tell me what happened when you tried to make it idle with using your finger over the hole when you took the IACM out.
Ok the latest saga. I got 2 gallons of fresh gas and added it just in case. (When we changed fuel pumps, all of a sudden the gas gauge is not working right now and pegged on full! WTF?) Anyway the addition of fresh gas made it start and surge and hunt a little and die. Before it would only start and die. This is what it did before we replaced the fuel pump.
I tried jumping the 2 ODB ports with a paperclip and the engine wouldn't even start. Just cranked. I removed the paper clip. I tried it. It started and ran! First time in 3 weeks it actually ran without my foot nursing it on the gas pedal. It idled little rough but idled at 1500. Whoa, I thought, progress.
BUT... Then I remembered OMG!, that I put a rag in the throttle body to keep the critters out at night. I got out of the car, I pulled out the rag and idle surged way high, it quickly idled erratic and it died. This must be a clue.
Later with my mechanic we will try covering the IAC. I need an assistant.
BTW heres the 2 ICXs.
Doesn't that tube supply air that's been controlled/regulated by the IAC valve?
