I know there's a similar thread already but I don't want to hijack that thread and although the symptoms might be similar, I don't think the problem is similar.
This started two days ago. When I started my car for the first time in the morning, it started up fine as usual but when I tried to drive away, it immediately started to sputter. It didn't die, it just sputtered and hardly accelerated. Easing up on the throttle made the sputtering go away. Every time I applied a bit more throttle, it began to sputter. At higher RPMs, it goes away. It doesn't feel like a single cylinder cutting out, but more a whole rail. I'll try to make an audio recording today so you can hear what it sounds like. The engine doesn't backfire but I do smell gas when it happens.
Two things that might be related to the problem:
1) The evening before, I washed the (outside of the) car with a pressure washer. I didn't experience any problems in the two minute drive from the car wash to my house however. But it could still be related. But in the days since, it has been pretty hot up here (86F - 90F) so I would expect any water to have evaporated by now. Although we also had some rainfall in the evenings but rainfall has never caused any problems other than a squeaking belt for a few seconds.
2) My tachometer started acting up a few weeks ago. I have my digital dashboard installed so I'm not sure the jumping tach is caused by the car (like due to a broken tach filter) or because some electrical issue with the dashboard. I hadn't troubleshot the tachometer yet because I didn't notice anything different with how the car drove.
I was thinking fuel pressure until I saw the bit about pressure washing. Try pulling off the distributor cap and checking for moisture. Water can stay in there for a while. Second, check all of your ignition control module under the distributor. Also check your spark plug leads for cracks, etc. I had a similar problem on an old ford 6 cylinder once. A buddy told me to check the wires in the dark with the engine running. I did and saw a couple of wire arcing . My problem got better when I replaced the wires. If this doesn't solve your problem, you may want to check the fuel pressure when the engine is under load.
Mike
BTW, any chance you got water in the tank with the pressure washer?
TPS and MAP should be looked at. Unplug connections and make sure they haven't corroded.
Wouldn't all those things cause the entire engine to cut out? I'm asking because it doesn't sound/feel like it's somehow not getting enough fuel, it sounds/feel like a few cylinders cutting out.
It doesn't feel like a single cylinder cutting out, but more a whole rail. I'll try to make an audio recording today so you can hear what it sounds like. The engine doesn't backfire but I do smell gas when it happens .
quote
Originally posted by Cliff Pennock:
Wouldn't all those things cause the entire engine to cut out? I'm asking because it doesn't sound/feel like it's somehow not getting enough fuel, it sounds/feel like a few cylinders cutting out.
If we're talking a fuel problem, maybe some water got into the fuel injection harness connector under the MAP. See in picture below. The one on my 87 GT is a wide flat connector unlike the one in this pic. The injectors run in TWO banks and there are TWO fuses in the fuse box (one for each bank, can't hurt to put new ones in).
[This message has been edited by fierosound (edited 08-17-2020).]
Stupid question but... did you pressure wash the engine?
I would check the coil and ignition module connections. I've had something similar happen to my duke when the tach started jumping around and it was sputtering unless I let off the gas. It was a loose signal connector to the coil. I've found they are very easily pulled off and the clips that hold them to the coil tend to break.
Stupid question but... did you pressure wash the engine?[quote]
No I didn't...
[quote]I would check the coil and ignition module connections. I've had something similar happen to my duke when the tach started jumping around and it was sputtering unless I let off the gas. It was a loose signal connector to the coil. I've found they are very easily pulled off and the clips that hold them to the coil tend to break.
I will check the connectors tomorrow.
Today I drove the car longer than a few minutes for the first time since this happened. When I just started it up, just touching the pedal would cause the engine to cut out. But with time, it does get better and after driving the car for a while it only happens during moderate acceleration. Easing up on the throttle and it will accelerate just fine. During kick-down, no problem either. But somewhere in between, it cuts out.
It's hard to explain. It's not at certain RPMs, it's also not at certain throttle positions. It's at certain acceleration.
If we're talking a fuel problem, maybe some water got into the fuel injection harness connector under the MAP. See in picture below. The one on my 87 GT is a wide flat connector unlike the one in this pic. The injectors run in TWO banks and there are TWO fuses in the fuse box (one for each bank, can't hurt to put new ones in).
If no condensation under the distributor cap, I would look for a shorting rotor(pencil like mark under the center contact tab) And listen to the coil to see if it sounds like it has a faint arcing in the E core. Both would show up more damp. Both will allow to reach up to a certain KV demand then short anything above that point. From the cap on out it would be random or all the time.
I wanted to clean the spark plug wires so I could spray some water resisting stuff on it.When I pulled the #3 wire, I just had the wire in my hand and the connector was still on the spark plug. I repaired the cable and put it back. Also the main distributor cable was terribly rusted at the distributor end. I was amazed I had some spark at all. I cleaned out the rust using a Dremel and refitted the cable.
I drove the car to see if that solved the problem. The first few minutes I thought the problem was indeed solved but after that it started to sputter again. Not as bad as before, but it still did it. I haven't checked cable #2, 4 and 6 yet, nor the inside of the distributor cap itself.
anytime you think have ignition problem first unplug tack filter then re test. if gone discon the tack from I-coil or ICM. shorten/damage tack or filter can cause many problems. see HEI in engine section in my cave.
------------------ Dr. Ian Malcolm: Yeah, but your scientists were so preoccupied with whether or not they could, they didn't stop to think if they should. (Jurassic Park)
You could try cleaning the perimeter posts - they look a little worn... & get the dust & debris out. I've done that many times in the last 36 years to eliminate mis-fire issues. It frequently delayed replacing the cap for months/years.
Replaced the distributor cap and rotor today. The first few minutes it seemed that the problem was still there but after the engine heated up a bit, it was almost completely gone. Only every now and then there was a slight sputter. So the increased spark seems to have helped a bit.
With the engine running, I wanted to make sure the spark plug wires where seated properly but upon touching the black rubber boot on the distributor cap side (which was wire #3), I immediately got a shock. The wires weren't wet or damp so I was a bit surprised that merely touching the boot would give me a shock.
Does that mean the wire might be faulty and isn't conducting the electricity as it is supposed to? I mean, if going through rubber and my body is the path of least resistance, then somebody must be wrong, no?
Also, the new cap + rotor apparently introduced a lot if electrical interference/noise since my digital dashboard is now constantly resetting itself and displaying wrong values.
Cliff, something I would suggest to prevent pulling the wires apart when removing the boot from the plug is to put a liberal amount of dielectric grease inside the opening in the boot. Then, use the metal shields on the boot. The metal shields are a good tool for twisting the boot to break any bond between it and the plug before pulling them off the plug. The dielectrc will prevent shorts on the front plugs, and will help reduce the possibility of the boot bonding to the plug. I learned the hard way when all of my front (2,4,6) boots broke in half. It's more than a PITA to get the end of the boot off those plugs.
I had the misfiring and tach jumping problem under acceleration for a long time. Checked and tested everything. Finally took some electronic cleaner and sprayed connections of ICM and distributor windings. Corrosion - green color . Darn it if it didnt stop it dead in its track! Still cant believe how simple a solution. Just something to know if it helps anybody.
[This message has been edited by fierobug20 (edited 08-31-2020).]
Finally took some electronic cleaner and sprayed connections of ICM and distributor windings. Corrosion - green color . Darn it if it didnt stop it dead in its track! Still cant believe how simple a solution. Just something to know if it helps anybody.
Yep, it's been mentioned here many times over the years, but definitely worthwhile repeating, that it's sometimes just a poor connection with the short wiring harness between the ICM and the ignition coil that can cause an issue.
[This message has been edited by Patrick (edited 09-01-2020).]
Cliff, verify there are no issues with the MAP sensor vacuum line. This is my new solution to everyone's low power issue cause it worked for me (I just posted about it). Certainly can't hurt to check it out.
Also check your spark plug leads for cracks, etc. I had a similar problem on an old ford 6 cylinder once. A buddy told me to check the wires in the dark with the engine running. I did and saw a couple of wire arcing .
Cliff, I hate to mention it but I told you so.. ;-)
So basically the car needs an old-fashioned tune-up? I'd replace the other usual while you're in the mood (fuel filter, air filter, PCV valve, etc.) and order a spare coil and ignition module if you don't have them already.
