1988 Ford F-150 Error codes: 21, 51, 87, 34

GORMGORM

MEMBER
1988 FORD F-150

Engine Performance problem
1988 Ford F150 V8 Two Wheel Drive Automatic
5.0 302

The ford is stalling, black smoke on start up. Rough idle and dies at stop signs and in driveway.

I got a code reader and the above codes are displayed.

What is a ECT? And it's out of range? So is cooling temp sensor. Where on the engine is the cooling temp sensor? (Error code 21)

ECT sensor is out of range/circuit open. Where is the ECT on the engine? (Error code 51)

Fuel pump circuit failure. Where is the fuel pump circuit located? (Error code 87)

EGR Control circuit fault. EVAP control system fault/voltage higher than closed limit. Defective EDT pressure transducer sensor. (Error code 34). Where/what is/are the EVAP control on motor? And can any of these parts be cleaned instead of purchasing new?

3 Replies

MERLIN2021

MECHANIC
17,250 POSTS

Replace the ECT first, it acts like a choke on FI engines. I would look up the location for you, but you didnt put the engine size in your post, some are on top of the thermostat housing and have two wires the sensor with one wire is the temp sending unit. After you change the ECT, and replace it with engine cold. Erase the codes and see if any reset.

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Friday, November 6th, 2009 AT 2:55 AM

GORMGORM

MEMBER
2 POSTS

I replaced ECT, cleaned contacts, and cleared EEC memory using code reader, and truck will not start. I checked codes and they are: 21o, 22o, 22c.

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Friday, November 6th, 2009 AT 7:38 PM

MERLIN2021

MECHANIC
17,250 POSTS

21= ECT out of range still, 22 =MAP out of range, if you cleared the codes with a scantool, try removing negative cable for a few minutes, Fords need KAM cleared after repair, or they think they are still sick...if that doesnt work, we need to know if it has spark and fuel.
Start with the basics, and work your way up, Last tune up was? Wires plugs ALL filters? If all that is ok, check for a stuck EGR, then test fuel pump pressure, If it won't restart, determine what's missing, the engine needs three things to run, Spark at all plugs, gas to all cylinders, and compression in all cylinders, tho an engine may run lacking one in one cylinder, it won't run very well!
https://www.2carpros.com/car_repair_video/test_fuel_injection_pressure.htm
Go here and checkout our video.
https://www.2carpros.com/car_repair_video/test_engine_ignition_system.htm
and this one!

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Saturday, November 7th, 2009 AT 8:32 AM