Limp mode?

[Blacktop]

Hi all,
My ‘84 351w has a serious lack of power. It struggles to reach 65mph on a flat stretch of road and doesn’t want to rev. The slightest of inclines and I need to drop it down a gear. Could it be in limp mode? And if it is, how would I know? There’s no check engine light on. It’s a two barrel carb with computer control.

Thanks for any info,
Alan.

[BullnoseHunter02]

Only 2 things that come to my mind are the injectors and the fuel pump. Its a carburated engine so i dont think its gonna have injectors on it. Plz correct me if i am wrong though. Im bettng its probibly an issue with your fuel pump.

[Blacktop]

Thanks for the reply👍 I have a new fuel pump ready to go on. Also have a 4 barrel Holley and intake ready too but would prefer to fit that later when I junk all the smog, ignition and computer too.

Alan

[Gary Lewis]

You said it is a computer-controlled 2bbl, and those can easily go into limp-home mode if the computer detects something it doesn't like.

The way to know is to pull the codes.  The EEC-IV Testing page explains how to do that: Electrical/EEC-IV Testing.  But if that doesn't make sense let me know.

[Blacktop]

Thanks Gary, I’ll check it out 👍😊

[Ray Cecil]

I thought the title of this thread was Pimp Mode, to which I thought Id offer my advice. Seeing that its Limp Mode, and I don't have ED issues yet, I still can't offer advice.

[Blacktop]

😂😂😂

[Blacktop]

Ive just ordered a digital obd 1 reader from ebay. The computer and carb will be going eventually but hopefully I can get it sorted for now👍

[vjsimone]

No Engine Check Light until about 1988 on Trucks....

[Ray Cecil]

vjsimone wrote

No Engine Check Light until about 1988 on Trucks....

I would have sworn my 86 efi 302 has a CEL or SES light.

[vjsimone]

It has an "Extended Useful Life Indicator" Light?

http://www.garysgaragemahal.com/warning-indicators.html

[Gary Lewis]

Yes.  And initially it was called a Malfunction Indicator Light, and it did come about in '88.

Prior to that there was an Emissions light, and it functioned as explained here: http://www.garysgaragemahal.com/89-22-08-emissions-maintenance-warning-module.html

[Ray Cecil]

vjsimone wrote

It has an "Extended Useful Life Indicator" Light?

http://www.garysgaragemahal.com/warning-indicators.html

I thought you were mocking me, but then I read the diagram...sure as shoot...there is an Extended Useful Life indicator....

I dont own the truck anymore, but I thought there was a warning light of some sort.

[Steve83]

Blacktop wrote

Ive just ordered a digital obd 1 reader from ebay.

Try to cancel it.  These trucks are EEC-IV, and readers are extremely UNreliable on them.  It only takes a jumper wire & test light to get codes.  Click this, read the caption, and follow the relevant links in it:



Also...
Ford has no "limp mode".  It has HLOS & FMEM.  Neither causes the engine to run worse or with reduced power - both attempt to keep the engine running as well as possible for as long as possible.

[Ray Cecil]

Steve83 wrote

 ........It only takes a jumper wire & test light to get codes.....

Maybe this is what I was thinking about. I do remember making a jumper and using a test light. Maybe this is the "CEL" I was thinking of.

[vjsimone]

The light in the Cab may have been labeled "Emissions", I believe it was in 1987.

[Steve83]

The EMISSIONS light (EUL/IMS) is different from the CEL.

[vjsimone]

1987


1988


Not to be confused with the “Engine Warning Indicator” in the 1987 – 88 – 89 - ….92 – etc.


Thanks Gary for helping me upload these.  
I hope it is only the second time you have told me how, and not more.

[grumpin]

Steve83 wrote

Blacktop wrote

Ive just ordered a digital obd 1 reader from ebay.

Try to cancel it.  These trucks are EEC-IV, and readers are extremely UNreliable on them.  It only takes a jumper wire & test light to get codes.  Click this, read the caption, and follow the relevant links in it:

I have an Innova tester I use on my 1992 Bronco and it has worked well.

What do they do?

[Steve83]

grumpin wrote

What do they do?

Display spurious codes; often, codes that don't even apply to the vehicle.  Some also fail to display actual codes.  A jumper wire will never do either (when used as that caption describes).