Have no check engine system

[Dwranger]

I have a 87 ranger xlt 4x4 2.9litre
Running a bit rough at idle was wanting to check for codes
But there is NO check engine circuit
Like not even a pin/wire to create a circuit

I'm not sure what I can do for codes without a check engine light
Has anyone seen this before?

I'm thinking it's my temp sensor not letting the ecm know temp of the engine so it stays in warm up mode

 

[bcschief]

Get yourself one of these Innova Ford OBD1 Code Reader (autozone.com)

 

[Dwranger]

Where do you plug that one in? Wonder if I can find that in Canada

 

[JohnG]

Up to a certain year Rangers did not have a dash light (my 86 doesn’t either).
You can pull codes manually using a test light or volt-ohm meter using the method shown on this page:

Testing EEC-IV Equipped Engines - The Ranger Station

The EEC-IV equipped engines use an older diagnostic system to monitor and report engine related malfunctions. This system is known as On Board Diagnostics (OBD-I). The Diagnostic Trouble Codes (DTC’s) are two or three digit numbers and can be … Continued

www.therangerstation.com

 

[rusty ol ranger]

If youre looking for the plug its in the engine compartment back by the firewall, passenger side. Theyll be a big goofy looking plug and a small single one. Pretty hard to miss, looks like a short pyramid with a flat top.

Get the code reader. I got one, much eaiser then other methods and worth the 30 bucks. They are on amazon too.

 

[Dwranger]

Up to a certain year Rangers did not have a dash light (my 86 doesn’t either).
You can pull codes manually using a test light or volt-ohm meter using the method shown on this page:

Testing EEC-IV Equipped Engines - The Ranger Station

The EEC-IV equipped engines use an older diagnostic system to monitor and report engine related malfunctions. This system is known as On Board Diagnostics (OBD-I). The Diagnostic Trouble Codes (DTC’s) are two or three digit numbers and can be … Continued

www.therangerstation.com

Awesome thank you very much I'm going to see what I come up with using those methods

 

[RonD]

ECT(engine coolant temp) sensor was added to fuel injected engines so computer could run Choke Mode on cold starts
ECT is always 2 wire 5volt sensor
Not to be confused with the 1 or 2 wire 12volt Temp Sender used since the 1940s for dash temp gauges

Carb engines, even with computers, had a Choke Plate for cold starts, can't use a choke plate with fuel injection, no Jets to suck in extra fuel from

If ECT, IAC Valve and computer are all working, then on cold start engine RPMs should be above 1,000rpm at idle
Then as engine/coolant warms up idle will slowly drop, "target" warm engine idle should be set after 5 to 8min depending on outside temp
650rpm on manual V6, 750rpm on automatic V6

Choke Mode causes computer to run a Richer fuel mix and higher idle

If ECT was the issue then engine would run poorly until it warmed up, no choke mode
OR
Engine would run fine cold then run poorly after warm up, choke is still applied

 

[Dwranger]

Yes thank you I now understand all of that
I'm waiting on parts
Air/charge sensor
Coolant temp sensor
Coolant sender

I've tried testing for codes as per what the others have suggested but no luck
Tried with a multimeter and just a test light
Gives no codes with test light the light just stays on with no change

 

[Dwranger]

Up to a certain year Rangers did not have a dash light (my 86 doesn’t either).
You can pull codes manually using a test light or volt-ohm meter using the method shown on this page:

Testing EEC-IV Equipped Engines - The Ranger Station

The EEC-IV equipped engines use an older diagnostic system to monitor and report engine related malfunctions. This system is known as On Board Diagnostics (OBD-I). The Diagnostic Trouble Codes (DTC’s) are two or three digit numbers and can be … Continued

www.therangerstation.com

I thank you for all this info
I tried both methods and got nothing
Double checked to be sure I was hooked up properly with the test light the light just stays on no flashing
Kind of a bummer as I was hoping to get some codes

 

[alwaysFlOoReD]

I thank you for all this info
I tried both methods and got nothing
Double checked to be sure I was hooked up properly with the test light the light just stays on no flashing
Kind of a bummer as I was hoping to get some codes

Take a pic and post of how you hooked up the meter/light.

 

[Dwranger]

I'll have to post that end off the week truck is all masked up ready for paint