78SC acting sick

RazorRacer · 03-31-2004, 11:18 AM

Just got back from a 1600 mile trip. Here are the symptoms:

Car would not maintain idle and would die. So I increased the idle screw. Now it maintains idle.

It is rough on cold start-up. At first it could barely pull the weight of the car. It seems to be getting better each day. Weird huh?

Sometimes the engine has low power, even when warm.

The engine seems to get hotter, quicker now.

The main problem now is poor performance when cold. What should I check first?

TYIA

sammyg2 · 03-31-2004, 11:37 AM

My guess is Vacuum leaks.

Check your pop off valve if you have one, check all your hoses and your air box.

Jdub · 03-31-2004, 11:43 AM

Replace the gas filter as a matter of maint. and I'd dump the oil as well.

Maybe bad gas got in there - go to a station you trust.

Finally, the trip may have cleared out a bunch of crap. You may be in the market for a CO readjust. John Walker recommends 3.5% on the SC.

Best of luck,
John

LFogelson · LFogelson's Garage

check your oil cap. If the idle doesn't drop when you loosen it, then you have a vacuum leak. I was trying this test once, when I realized my cap

was loose from a late night oil top off. Also could be your frequency valve relay under the passenger seat.

juanbenae · juanbenae's Garage

im with jdub on this one. did you visit any rural type gas stations during this trip? i would try a fuel filter 1st. sounds alot like when my filter went south on me. it came on and got worse every mile i drove. the higher temps may be because it has been starved of fuel and is running lean.

RazorRacer · 03-31-2004, 03:54 PM

Normally removing the oil filler cap would cause the engine to slow down. Now it doesn't have much effect. How do you check for a vacuum leak?

I will also order a new fuel filter and replace it.

David · David's Garage

I think you should come by my house with some beer and we'll check the timing, vacuum, and fuel pressure.

limble · 03-31-2004, 05:46 PM

CIS. You might have to bleed the fuel system.
1.remove the air intake assebly
2. switch the ignition to on
3. Press the diaphram lever, you have to reach inside the air box, and push the airflow sensor upwards until it stops. Hold it for 5 seconds or until the injector valves can be heard to spray fuel.
4. Put everything back together and it should help rough idle.

This condition usually developed after hitting bumps. Wierd but true.

This might not be the solution to your problem but it might help other CIS owners.

If you don't have a pop-off valve installing one is a good idea

bigchillcar · bigchillcar's Garage

Quote:

sounds alot like when my filter went south on me. it came on and got worse every mile i drove. the higher temps may be because it has been starved of fuel and is running lean.

yes, this sounds reasonable...does sound like running lean if it's getting hot...restrictions in fuel delivery could cause this. after a long trip, you may have more quickly trapped debris in your filter than you would have normally. replace the fuel filter and drain the old one when you remove it to see what drains out.

i'd also check for vacuum leaks...spray some carb cleaner around the intake/air box area...removing the oil filler cap, you should hear some change in idle speed. sounds like you may have a combination of problems. i'm assuming your air filter is probably ok.
ryan