[Bob ONeill]

Here's the issue.

1986 Daytona
2.5 TBI - 5 speed
319,000 miles

New spark plugs.

When cold it starts fine. Then when I get on it, it is missing something. It's like it is missing or starving for fuel or something, but only when cold.

Once it gets to operating temp it's fine.

Here's the thing...

I'm looking for solutions from folks who may have experienced this. I believe I know what will help but I need to pin point it rather than shotgun a bunch of unneeded parts.

Anyone have any experience with this who has solved it and who wants to share that wisdom?

 

[Bob Lincoln]

Bob, how many miles on the ignition rotor, dist cap and wires? You know that I had a sudden no-start in the last car in the fall, that turned out to be a burned rotor with only 20K miles on it. Usually I change them at 15K, but I hadn't gotten to it for a month or so, and it just died on me. These symptoms could be wearout of one of these parts.

 

[Bob ONeill]

The wires, cap and rotor have maybe 45,000 on them.

I figured that they might be the problem though I don't think it explains why it runs fine once warmed up. Still, I'll get some can change them. I've also got a spring that helps with the headlight adjustment that's snapped. I'll get it replaced this week along with the rotor, cap and wires. The TB.... that's another story. When I do that one I would love to change the injector but don't have the extra $100 or so laying around. I don't think the injector is bad though.

 

[Bob Lincoln]

Ignition demands more power when cold, so that makes sense.

At 15K miles, I remove and rotate the wire prongs in the cap to use the backside for another 15K miles, before replacing. They get charred, too.

My injector was still fine at 300K miles. I cleaned its intake screen at 210K miles, but it really didn't need it.

 

[russ93spirit]

What about performing a compression check on it when it's cold...then doing another when it's up to full operating temp? She does have a few miles on her...

 

[Bob ONeill]

Last test I did was all within spec and even across the board.

And, it doesn't smoke at all. That's not to say that at 319,000+ it doesn't burn a little but no smoke and the last time I had the head off (about 50,000 ago) I could still see a hint of crosshatch on the cylinder walls.

 

[JTE]

I'm just guessing, but is the heat stove hooked up to the air cleaner & vacuum motor working?

 

[Bob ONeill]

No, the heater pipe to the air box was removed and the port blocked off several years ago. I also removed the flapper valve in the air box to improve air flow. One more thing.... when I say the engine is cold I mean in south Florida the morning temps are in the high 60s in the winter. So, cold isn't really 'cold' only that the engine has not warmed up.

But, today with the temps in the mid '60s the car behaved great. No starving and it ran great. I do however suspect that when I change the cap, rotor and wires it will settle down quite a bit. And at 319,000 I think it's probably finally time that I rebuild the TB.
No, the heater pipe to the air box was removed and the port blocked off several years ago. I also removed the flapper valve in the air box to improve air flow. One more thing.... when I say the engine is cold I mean in south Florida the morning temps are in the high 60s in the winter. So, cold isn't really 'cold' only that the engine has not warmed up.

But, today with the temps in the mid '60s the car behaved great. No starving and it ran great. I do however suspect that when I change the cap, rotor and wires it will settle down quite a bit. And at 319,000 I think it's probably finally time that I rebuild the TB.

 

[soloflite]

AIS Bob, had same issue w/ my 89 N/A 2.5. solved my issue. Try cleaning it..

 

[soloflite]

Any joy on repair?

 

[Bob ONeill]

Not repaired yet. Gasket set not available (well it's available but $9 shipping to get it here). I've not done the other either but the problem has gone away, for now.

 

[jmcdoodle]

Having a similar issue with my 86 2.2 non turbo except my problem happens only when the engine is up to temp. I would be interested to see what's causing your issue, it may be similar in mine.

 

[Bob ONeill]

My problem is/was the harness piece behind the valve cover. While I have not yet tackled the actual repair I do wiggle the connector once in a while which helps. Also, when I run the car on a long run for a few weeks after it runs just great. I've been so busy for the past 6 months that I haven't even had time to put on the wires and cap/rotor etc. But this weekend I will have some time to do that and an oil change and.....

I'll pull the harness off the car and rework it. Also, it may be my AIS or the actual throttle body as I have not yet rebuilt that in the 27 years I've owned the car or at least I don't remember doing it.

But, it is running great most of the time. I'll post back after this weekend after I've had the chance to play with it further.

 

[dana44]

Considering the wires, as noted, humidity can be the actual cause, where idle is fine, start moving and the breeze under the hood messes with pushing the spark around along with the spark along the plug wires, then it warms up, humidity gone, tracks properly within the wires. Had a Dakota that was this temperamental with old wires, had to change the plug wires every other time I changed the plugs or it would act up badly, and yes, it would idle fine, stumble for about five minutes, then run fine, too.

 

[Bob ONeill]

I changed the oil today and finally installed the new cap, rotor and spark plug wires. The wires are shorter than the ones I had on the car but they did fit fine. These I got from NAPA. After I cranked it up and let the oil pressure come up things settled down nicely. I'm not sure why the idle float is not presenting at this time but I'm not complaining. It runs far better now and the high idle and idle float are not present, yet.

I still have not rebuilt the throttle body nor have I taken the harness out and given it the once over. For now if it's not broken, I'm not fixing it.