CFI smoke test question

[TLB_Nut]

Hi all I'm stuck troubleshooting a CFI engine. I can't seem to find to much info on troubleshooting them. I have a 85 Capri V8 Auto with CFI. I have replaced plugs, plug wires, rotor cap and rotor so far. Currently the car will not idle on its own until the engine warms up and then it is low and erratic. At anytime if I give it gas it immediately falls on its face and stalls out. I do have a code reader on the way (my multimeter is digital not analog and I am working solo, so seeing the check engine light is harder to try the "paper clip" method)

What little I have learned is that the CFI system is highly dependent on vacuum. So I am making a Smoke pot to test for leaks.

My question is where do I connect a smoke pot tester up to, to look for leaks in the system? All the info I can find on this is only about the EFI cars not the CFI set up. To add to the problem my car still has Smog system. I want to get it running correctly before I think about removing the Smog stuff and possibly converting to EFI in the future.

Thanks in advance for any help with this.

Scott

[4eyedblind]

Any vacuum line below the CFI throttle plates is fine. I try to block the throttle opening, if I can, to make it easier to see the smoke from other places. Usually boost rags and duct tape do it enough.

[mcb82gt]

Maybe the coolant temp sensor is bad.

[fgross2006]

Hi all I'm stuck troubleshooting a CFI engine. I can't seem to find to much info on troubleshooting them. I have a 85 Capri V8 Auto with CFI. I have replaced plugs, plug wires, rotor cap and rotor so far. Currently the car will not idle on its own until the engine warms up and then it is low and erratic. At anytime if I give it gas it immediately falls on its face and stalls out. I do have a code reader on the way (my multimeter is digital not analog and I am working solo, so seeing the check engine light is harder to try the "paper clip" method)

What little I have learned is that the CFI system is highly dependent on vacuum. So I am making a Smoke pot to test for leaks.

My question is where do I connect a smoke pot tester up to, to look for leaks in the system? All the info I can find on this is only about the EFI cars not the CFI set up. To add to the problem my car still has Smog system. I want to get it running correctly before I think about removing the Smog stuff and possibly converting to EFI in the future.

Thanks in advance for any help with this.

Scott

I have an 84 5.0 thats CFI. Its a tough one to troubleshoot but they run like a swiss watch when its all good.

I dont know offhand whats up with yours but I can tell you a few issues i had with mine and maybe something will help you.

First, get a good code reader. This is a great one. Cheap and you will be using it alot in the future. It will tell you whats the deal and theres no substitute for pulling codes. https://www.summitracing.com/parts/i...CABEgKcv_D_BwE

Definitely check vacuum to the dashpot. That controls the idle. My original wasnt holding vacuum anymore when i got it. I got lucky and found a NOS with matching part number a few years back. Look at your part number and start searching because that part is a dinosaur, they are already extinct.

Do a physical setting of your curb idle. See this link, post number 3 from Jeff. Thats it in a nutshell. Search it online and you can find written instructions from Ford on how to do it too. http://vb.foureyedpride.com/showthre...n-84-CFI-setup

Check voltage on your TPS, and make sure the connector is solid. Recently on mine I found the male connector to be faulty and I had to order an O2 sensor for an 86 just to cut off the pigtail to repair my TPS male connector.

Make sure your O2 is functioning properly and check that it is grounded to the back of the head on the passenger side. When I got my 84 it was running like a washing machine full of marbles. It drove me nuts until Jeff helped me determine that some idiot who worked on it prior to my owning it, and they grounded the O2 to the firewall. It might seem a harmless maneuver but it caused my car to buck back and forth at cruising speed. Also if you run a new O2, run the wires in a way that keeps them from lying on the header pipes. I had the O2 wire burn right through and the connector melt. I ran mine away from the headers and dropped through the control arm. Giving plenty of slack for movement and zip tied to keep it from flopping around. Two years now and its still in perfect condition.

Check the ECT. Mine went bad on me this summer. the car will run like crappola if the ECT is bad, or even when its on its way out. If you replace, get a genuine Motorcraft, as with all the sensors on our Mustangs. My car is always happier with Ford genuine parts.

Make sure all Emissions control stuff is working. When I got my car the TAB was jacked right into the heads and the TAD was removed.

In my opinion, just saying for the sake of it, I think you need to set your curb idle. I found that living in New York where we get drastic changes of season, compared to a place like LA where its Springtime/Summer weather all year round, this cars idle needs to be manually reset when the weather changes. At the beginning of this Spring my car was idling low enough to stall, after being garaged all winter and not run. I ran the car, brought it to full operating temp and set the idle as per Jeff's instructions. The car has run great all summer long. When we get NY winter I will have to reset it almost certainly.

[emerygt350]

Yeah, get that reader. You are working blind till you have that.

Careful with that dashpot, all it does is fast idle kick up, ac kickup, and on a really good day it might save you from a idle drop stall. Idle is set by the computer using timing, not the dashpot.

Between fgross myself jacook and xctasy we should be able to help you get it figured out.

[Haystack]

I use the paperclip method. A test light is preferred, but I've used old computer speakers, a buzzer from a broken timer, one time it was the middle of the night, so I just soldered some wires into an 1156 bulb I had laying around.

Even if the fancy scanner has a digital display, it wont tell you anything a buzzer doesn't.

[emerygt350]

except it is easy, only 30 bucks, and you don't need to keep track of flashes and stuff

I use mine all the time, just to monitor how the car is doing. If I had to use a paper clip and a broken speaker I wouldn't be so inclined to check for codes.