Two Dumb Questions

Reply Subscribe

Thread Tools

Search this Thread

Nov 20, 2017 | 04:19 PM

esmit02

Thread Starter

New User

Joined: Oct 2017

Posts: 6

Likes: 0

Two Dumb Questions

Can anyone tell me where to find the ERG valve on a 1978 - 400M engine?

Could a faulty gas tank - sending unit be the reason a gas gauge does not work?

The Haynes and Chilton manuals are no help with above.

Thank you.

Nov 20, 2017 | 04:33 PM

Canus

Senior User

Joined: Apr 2012

Posts: 324

Likes: 0

From: Spencer Mountain, NC

Not sure about your first question. A faulty gas tank sending unit can indeed cause the gas gauge to not work. If your gas gauge always shows empty a quick test is to disconnect the wire from the sending unit and attach a jumper wire to a good ground. If the gauge registers full the sending unit is bad.

Nov 20, 2017 | 05:13 PM

HIO Silver

Fleet Owner

Joined: Dec 2009

Posts: 20,678

Likes: 82

From: NorCal

On the fuel gauge, it could be just a sunk float. About $3 to replace with a brass one..... a lil more for a nitrophyll (plastic) float.

Nov 20, 2017 | 05:31 PM

thatsrealnice

Laughing Gas

Joined: Oct 2009

Posts: 874

Likes: 56

From: Merlin, OR

Quote:

Originally Posted by esmit02

If your truck still has the original EGR valve, it is part of the carb spacer and has the EGR built into that aluminum spacer. It could have been removed long ago though. EGR would be behind the carb towards the firewall.

Nov 20, 2017 | 05:32 PM

Blue and White

Postmaster

Joined: Nov 2011

Posts: 2,553

Likes: 10

Step by step is best on the gas gauge. Grounding the sending wire (briefly) to see if the gauge pegs is a good first test to figure out if the sender is non functional.

My gauge did not work and the sender tested good... wiring was good also and other gauges worked. Diagnosis was a failed gas gauge in the dash. i opted to install an aftermarket gauge on the lower dash vs downtime and expense to re-work the cluster. Works fine.

Nov 20, 2017 | 05:35 PM

Filthy Beast

Postmaster

Joined: Mar 2011

Posts: 2,698

Likes: 7

From: Taxachusetts

Nov 20, 2017 | 05:40 PM

NumberDummy

Ford Parts Specialist

Joined: Nov 2006

Posts: 88,826

Likes: 785

From: Simi Valley, CA

Quote:

Originally Posted by esmit02

Can anyone tell me where to find the EGR valve on a 1978 - 400M engine?

No such thing as a 400M, it's just plain 'ol 400.

EGR (Exhaust Gas Recirculating) valve shown as 9D448 or 9D475 in parts catalog pic.

Quote:

Originally Posted by thatsrealnice

If your truck has the original EGR valve, it is part of the carb spacer and has the EGR built into that aluminum spacer.

As you can see, the EGR valve is a separate part and bolts to the carb spacer plate, it's not made as part of the carb spacer plate.

The original spacer plates were aluminum, heat caused them to burn out internally. 1977/78: Ford replaced the aluminum plates with cast iron plates for use as "service part replacements."