Mechanic's opinion needed...

[thunderchicken]

Chrysler used the ignition to retrieve the codes. On/off in rapid succession 5 times and stop with key in on position. Codes would flash.

I know I didn't know that. Never really worked on very much older Chrysler stuff.
I did however have the GM 2 prong code key that would give light flash codes. I remember keeping it on a key chain just to keep from losing it. Lol

 

[d.kaufman]

He's in California so... Still a nice gesture!

Well I figure if you travel east of the pacific you'll eventually land in Indiana

 

[thunderchicken]

and some of the buicks and caddies with the digital climate control used those. Such a weird era. Just kinda do whatever.

Yep before the government got involved to force a standardized OBD system

 

[KG1]

A short Sunday drive.

Yeah if you keep it wide open on the freeway where it runs the best.

 

[Ark]

Yep before the government got involved to force a standardized OBD system

A rare good government move, IMO. The proprietary systems, as this thread illustrated, were nuts and rapidly became impossible for average people to service. I can read standardized OBDII with a phone and a $20 adapter.

 

[thunderchicken]

A rare good government move, IMO. The proprietary systems, as this thread illustrated, were nuts and rapidly became impossible for average people to service. I can read standardized OBDII with a phone and a $20 adapter.

Yes and also made it much better for tech's to not need scan tools for every make they work on

 

[Leo]

Could be lots of things as suggested. If you have to ask about the fuel filter, it has been too long since it was changed. Change it, and if it did not help, call it normal service and know that is ok.

Ignition, fuel, timing each thing you eliminate gets you closer to finding the answer.

Good luck

 

[bobzilla]

Could be lots of things as suggested. If you have to ask about the fuel filter, it has been too long since it was changed. Change it, and if it did not help, call it normal service and know that is ok.

Ignition, fuel, timing each thing you eliminate gets you closer to finding the answer.

Good luck

I would think fuel filter or clogged pick up screen would have the inverse problem. Higher speeds, more load, more fuel required for the higher speeds compared to the slower in town slogs.

 

[Brad69]

So the timing belt replacement interval is 60,000 miles.

The car has 125,000 miles.
It's over 30 years old I bet that belt is kinda Krispy.

If it has not been replaced you are probably making your own variable timing.

Even with your cavemen computer you would have a check engine light if it was a sensor.

Stop and go and low speed =slack in timing belt crappy performance.

High speed = timing belt tight no issues.

I will send a bill in the mail.

 

[thunderchicken]

So the timing belt replacement interval is 60,000 miles.

The car has 125,000 miles.
It's over 30 years old I bet that belt is kinda Krispy.

If it has not been replaced you are probably making your own variable timing.

Even with your cavemen computer you would have a check engine light if it was a sensor.

Stop and go and low speed =slack in timing belt crappy performance.

High speed = timing belt tight no issues.

I will send a bill in the mail.

Yes it should have had a timing belt a couple times in it's lifetime.
While timing is a possibility, it wouldn't be my first bet. IF the tech/shop that installed the replacement distributor probably set base timing and verified proper timing advance (vacuum IIRC), then that would indicate the belt isn't the cause of the concern. If it is a vacuum advance, as engine speed increases and timing advances, it would prove out the belt as the likely culprit. Unless, the timing belt was replaced and installed a tooth off to begin with and the tech setting timing didn't really know what he was doing. Which is very possible as I know several tech's who have never used a timing light. Now, it could still be old and crusty and in need of replacement.

Those caveman computers had a much slower response time than modern cars. Also, if the TPS (as an example) only has one dead spot it may not spend enough time in that dead spot to set a code and turn on the CE light.

Heck have someone check base timing and see where it's at. Seen plenty of people set timing wrong over the years.


Of course, I could be mistaken. It's been a long time since I worked on anything with such old school technology other than carbureted race engines and mechanical advance

 

[injb]

So the timing belt replacement interval is 60,000 miles.

The car has 125,000 miles.
It's over 30 years old I bet that belt is kinda Krispy.

If it has not been replaced you are probably making your own variable timing.

Even with your cavemen computer you would have a check engine light if it was a sensor.

Stop and go and low speed =slack in timing belt crappy performance.

High speed = timing belt tight no issues.

I will send a bill in the mail.

Even with modern cars you can have sensors causing problems and still not get check engine lights. It's bound to be possible on older cars that were less sensitive.

I can't imagine how a difference in timing belt tension would cause this. If the belt is slack enough to jump, it'll jump and it is not likely to fix itself since the crank only ever pulls the belt in one direction. If it was off by even one tooth the engine would run like crap. If it's not slack enough to jump then it's going to run fine. What am I missing?

 

[Brad69]

I agree that you won't always have a check engine light.

The shop replaced the distributor I assume that they diagnosed a timing issue?

The timing belt /chain symptoms varies on the type of engine.

Non interference engines tend to have very simple timing belts.


The flex in a old timing belt isn't enough to jump time. But it is enough to slightly effect timing.

Causing symptoms of rough idle,stumble,surge,low power,ect.

In the days of the dinosaur a engine called the small block Chevy. Had nylon timing gears that at about 100,000 would get sloppy and many were junked because of this.

 

[thunderchicken]

I agree that you won't always have a check engine light.

The shop replaced the distributor I assume that they diagnosed a timing issue?

The timing belt /chain symptoms varies on the type of engine.

Non interference engines tend to have very simple timing belts.


The flex in a old timing belt isn't enough to jump time. But it is enough to slightly effect timing.

Causing symptoms of rough idle,stumble,surge,low power,ect.

In the days of the dinosaur a engine called the small block Chevy. Had nylon timing gears that at about 100,000 would get sloppy and many were junked because of this.

I do wonder what logic the shop used to determine the distributor was bad. Did they think base timing was off or was the advance not working? Who knows lol.

It takes a lot of slack or belt stretch to get a cogged belt to jump. I would have to look it up to see what kind of belt tensioner it has.
Heck, I run a cogged belt for my dry sump oil pump and even it has to be floppy dickin around to even throw it off at 8 grand. Did that on they Dyno last week lol.

You're right that timing can cause all the problems you describe. But the OP's description was when it acts up it has no throttle response and feels like the engine died. That's why I'm inclined to think more likely either an ignition module, ignition coil or TPS is a more likely culprit. Someone mentioned replacing the IAC, but those can be cleaned up with a shot of brake clean and those almost never cause an issue while driving. They only control the amount of air entering the engine at idle.
A vacuum leak can cause similar problems too. The OP could use a small propane bottle (or brake or carb cleaner to looked for a vacuum leak even seen shaving cream used).

It's an interesting problem and I hope the OP shares what he tries and the results

 

[Lpherr]

I do wonder what logic the shop used to determine the distributor was bad. Did they think base timing was off or was the advance not working? Who knows lol.

It takes a lot of slack or belt stretch to get a cogged belt to jump. I would have to look it up to see what kind of belt tensioner it has.
Heck, I run a cogged belt for my dry sump oil pump and even it has to be floppy dickin around to even throw it off at 8 grand. Did that on they Dyno last week lol.

You're right that timing can cause all the problems you describe. But the OP's description was when it acts up it has no throttle response and feels like the engine died. That's why I'm inclined to think more likely either an ignition module, ignition coil or TPS is a more likely culprit. Someone mentioned replacing the IAC, but those can be cleaned up with a shot of brake clean and those almost never cause an issue while driving. They only control the amount of air entering the engine at idle.
A vacuum leak can cause similar problems too. The OP could use a small propane bottle (or brake or carb cleaner to looked for a vacuum leak even seen shaving cream used).

It's an interesting problem and I hope the OP shares what he tries and the results

You are correct; the IAC only affects idle. Driving in town or highway, there's no issues, but when coming to a stop, it will lurch and die.
And on a Ford, many people said not to bother with aftermarket IAC's because they won't work, or fail within a few miles. They were correct; I tried three brands, and it wouldn't run. Paid the price for Motorcraft, and has been perfect from the first start.

 

[thunderchicken]

You are correct; the IAC only affects idle. Driving in town or highway, there's no issues, but when coming to a stop, it will lurch and die.
And on a Ford, many people said not to bother with aftermarket IAC's because they won't work, or fail within a few miles. They were correct; I tried three brands, and it wouldn't run. Paid the price for Motorcraft, and has been perfect from the first start.

Yep, every manufacturer has some stuff that the aftermarket just doesn't support well at all.
I've spent most of my career working on Ford's (dealers and police dept) so yeah I try to use Motorcraft whenever I can, especially with electric/electronic parts.

 

[bobzilla]

Yep, every manufacturer has some stuff that the aftermarket just doesn't support well at all.
I've spent most of my career working on Ford's (dealers and police dept) so yeah I try to use Motorcraft whenever I can, especially with electric/electronic parts.

I get really lucky usually with my Korean crap. most of the offbrands are just reboxed oe stuff. It's always funny to open a box from one of the big box stores and inside is the OE part, half the time still in the OE bag with part number.

 

[Brad69]

@thunderchicken are you going to be racing next year?

 

[Ark]

You are correct; the IAC only affects idle. Driving in town or highway, there's no issues, but when coming to a stop, it will lurch and die.
And on a Ford, many people said not to bother with aftermarket IAC's because they won't work, or fail within a few miles. They were correct; I tried three brands, and it wouldn't run. Paid the price for Motorcraft, and has been perfect from the first start.

Coming to a stop and having to pin the throttle at 1500rpm is classic IAC failure. Been there and done that numerous times, but never struggled with aftermarket parts.

Once in a long while I got bad out of the box new parts. Those SUCK because they can send you on a total goose chase before you finally circle back and condemn your new parts store part.

 

[Leo]

I agree that you won't always have a check engine light.

The shop replaced the distributor I assume that they diagnosed a timing issue?

The timing belt /chain symptoms varies on the type of engine.

Non interference engines tend to have very simple timing belts.


The flex in a old timing belt isn't enough to jump time. But it is enough to slightly effect timing.

Causing symptoms of rough idle,stumble,surge,low power,ect.

In the days of the dinosaur a engine called the small block Chevy. Had nylon timing gears that at about 100,000 would get sloppy and many were junked because of this.

More than sloppy, they would break and you had to tow the car home, multiple GM V-8's lost that plastic toothed sprocket. And they all had leaky rear main seals also. Sometimes I would yank one for a seal, and just put a new timing set in at the same time, stay ahead of the game. That was when things were simple enough to be able to get it done on Saturday, and you could still have the car ready to drive Saturday night.

 

[Ark]

More than sloppy, they would break and you had to tow the car home, multiple GM V-8's lost that plastic toothed sprocket. And they all had leaky rear main seals also. Sometimes I would yank one for a seal, and just put a new timing set in at the same time, stay ahead of the game. That was when things were simple enough to be able to get it done on Saturday, and you could still have the car ready to drive Saturday night.

Some years of my dad's old Benz had plastic timing chain guides that would wear out, go out of time, and munch the engine. Using ANYTHING plastic, nylon, or rubber in a timing system is dumb as hell IMO. Seen plenty of timing chain motors go 250k without timing system service. I freaking hate timing belts of any kind.