Its a bit funny...but I wanted to drive the thunderchicken in the nice weather we had Fri. and Sat. since there was no salt on the road. So I go to start it and something has run the 9 month old battery down...AND the dang thing wont start.
The freaking injectors won't work.
So, I charge the battery and check the fuel pump for output...and yeah they're pressurizing the lines but the car wont fire. So, knowing that sometimes EEC IV provides a signal for the injectors based on a detection of spark discharge, I pull the No. 1 wire, stick a screw driver in it and try to ground it against the body. Needless to say the car is getting NO spark while the wife cranks. This goes on for a minute and just as I get ready to throw in the towel and swap the ignition module bolted to the distributor, suddenly I get spark and the injectors start working and the car starts up. I replace the wire and the car runs as happily as it ever has.
What the heck!
Anyone have any ideas as to what happened that would cause the car to not have spark?
I figure there was some corrosion under the cap where I haven't driven the car in a month or two to keep it out of the "brine" VDOT throws on the roads. I looked and didn't see any corrosion, but I know grounding the wire to the body to check for spark is what got it to start.
What year is it?
You also didn't specify if it's a 3.8 or a 5.0.
Check for ground to the ecm.
1984, 302. Its making the carburetor and plug-and-play distributor option look more and more appealing.
All you need is a Holley 500CFM 2bbl, a Mallory 4309 FP regulator, and a Dura Spark dist/ign box. Very simple.
And a mechanical fuel pump
Problem is likely in the dist(TFI or PIP), or could be coil or power to it, ign sw is famed for intermittent issues in these vehicles...
It's NOT going to be cap, rotor or plug wires...
Nope. That's why you need the regulator. It drops the pressure in the existing return system so you can run your desired pressure at the carb.
I know on my 83, I had a bad crank sensor that would intermittently make the car not start. But I think 84's got away from the EEC-III and crank sensors. It's something to consider if it's an early 84, maybe.
I was thinking the crank sensor thing also, not sure if your car has it though.
No, I have EEC IV... I am ready to drop in a points dizzy with petronix box and switch to the carb and 4 barrel intake with a Lokar TV cable and fuel pressure regulator.
The car has this awesome thing where it picks up a miss right after you first take off driving, I'd venture to guess when it switches from closed loop to open loop (or maybe from open to closed... cold operation to warm operation) and the miss gets worse and worse until the thing chokes itself out and dies on the road and you have to sit there for a few minutes and then when it does start back up it runs just fine. When it dies it gets so lean the cats will smoke and stink!
The pain in the ass part is it only does this every now and then.
Maybe the EGR's vacuum is referenced by a ported vacuum switch thats screwing up occasionally.
Anyway, after its last round of shenanigans I bring the car home and check the sensors and wiring and pulled the codes (EGR fault and system rich)... so I replaced O2 sensor and repaired the coolant temp sensor pig tail where I found the two wires running to it got naked... and I found the plug for the TFI has been replaced, the plug to the coolant temp sensor has been previously spliced, and the PIP wires have been spliced and now if you wiggle the PIP while the car is running it will shut off. So that's freaking great! And just to make matters WORSE, the thing does its little fake suicide routine on the side of the road AGAIN two days later.
So, it seems to me a mechanical means of fuel metering and simple ignition system is the way to go. Screw you CFI, which I have decided MUST mean "Cluster F$@# Injection"
How in the heck can you wiggle the PIP?
if you can I suppose you just found your problem.
The PIP is the in-line timing isolator...if you wiggle it while the car is running, the car dies because the splice on one side of it is right against the pig tail connector, That, I think, is the cause of the no-start issue. I just wonder about the other stupid-idity. Are you conflating the PIP and the TFI module that is connected to the distributor?
Tfi carries the signal of the pip. if that's dead, no spark or injectors.
No it isn't, that's the sprout(spark output), the PIP is inside the dist... You can toss the sprout in the gutter and it will still run, just no timing advance...
I'd think with a fresh TFI connector it may be just fine, worse case maybe repl the dist as well... There's a tach pulse signal in the TFI harness that feeds back to the ECM, if that is lost it will run like do do... Other than throttle body, and ECM, the electrical components for CFI are similar to a SEFI system...
Your right Turbo, Im a bit out of practice with my EEC IV lingo. The spout is what you wiggle and the car dies.
Anyway... The previous owners had a lot of problems with the car and intermittent drivability issues and they had a mechanic throw parts at it. I don't know what codes it has previously thrown but I've gotten an O2 sensor fault, so I replaced it because the sensor was original, and an EGR fault, so I cleaned it and the car rode better for a day. I need to run codes again... I just don't think it will explain away the cars tendency to act a fool every now and then.
I may make an EGR block off plate and stick it between the EGR and intake and see if that eliminates the super lean problem that the car has when it chokes out and dies... Lean-ness is what would make the Cats smoke - REALLY high exhaust temps due to too much oxygen in the air/fuel mixture.
I could have used that info 16 years ago so I could have fixed it and kept my first 5.0 T-bird.
And a mechanical fuel pump.
I doubt that's your problem, open EGR actually enriches the mixture, slightly...
I'd be looking at the vac & electrical connections at the MAP, it's only thing I've seen that will cherry cats, creates a too rich condition...
Because he doesn't read responses.
ah, shiznit I forgot that I already said that, and that is was also said that it wouldn't be necessary.
.....don't worry about it.....BTDT...Lol....:cheers:
Turbo, I fail to see how an open EGR would richen the air/fuel charge, especially when the ECM would think it to be closed? A stuck EGR is just adding extra air to the mix, potentially a 5/16" to 3/8" vacuum leak were it wide open, one so large I doubt the MAP can signal the injectors to increase injector duty cycle to compensate for as speed density fuel injection systems are limited in their ability to adapt to such problems.
Unfortunately I don't do this stuff everyday anymore... I am now an "extra hazard" sprinkler tech so I could very easily be wrong.
Hot Catalytic converters are a product of extremely high O2 levels in the combustion mix, thus a lean condition. Like with an furnace, it gets hotter when extra air is forced into a fire while the fuel levels for the fire remain the same, like when a black smith uses bellows to superheat his fire to better melt iron ore. A fire with more fuel and less oxygen is cooler.
There is no oxygen in the exhaust gas, so mixture goes slightly richer, cools exhaust reduces NOx emissions...
Believe me on the MAP, I've cherried the cats a couple times, a Turbo four will do same if the VAM sticks open... Got the T-Shirt for that one as well...