Bronco Forum - Full Size Ford Bronco Forum banner

1 - 7 of 7 Posts

·
Registered
Joined
·
18 Posts
Discussion Starter #1
After having my 88 bronco die while driving it a few days ago it has been difficult to start it since. The engine turns over normally and I am getting a good spark. The only trouble codes I currently have are for the TPS and EGR both are stumping me. But they do not seem related to the starting ability of the engine. The only way I have found to start the engine while hot is to unplug the inertia switch start the engine and then quickly plug the inertia switch back in. I haven’t been able to figure out why this is working for me but it is. The switch is not triggered and it still works how it should. If I had to guess I’d say this has something to do with my fuel system. This morning I replaced my fuel pump relay and the bronco fired up great. Later in the day I began having the same issues I’d been having before replacing the relay. If anyone has any advice or ideas, as to why I can only start by unplugging the inertia switch then keep the engine running by plugging the switch back in, I would much appreciate it.
 

·
Premium Member
If it is not a Bronco, it's just not worth driving.....
Joined
·
1,487 Posts
...... The only trouble codes I currently have are for the TPS and EGR both are stumping me......

...... If I had to guess I’d say this has something to do with my fuel system. .......
I would say it is an issue with your two trouble codes. Both of them are involved in the fuel system. The EGR to a lesser degree, but it still is involved in what get sent to the intake. I would resolve those two issues that you do know are wrong with your engine and then see what happens with your truck. The TPS trouble code is a biggie. I would start there.
 
  • Like
Reactions: Trashboat

·
Super Moderator
Joined
·
26,007 Posts
Yo Buck,
Post the codes.
The intertia switch could be sketchy. Inspect wiring at the connector and look for corrosion from cowl water leaks.

Try jumping it out for a test. Re-connect it if issue isn't solved.
 

·
Registered
Joined
·
18 Posts
Discussion Starter #4
I would say it is an issue with your two trouble codes. Both of them are involved in the fuel system. The EGR to a lesser degree, but it still is involved in what get sent to the intake. I would resolve those two issues that you do know are wrong with your engine and then see what happens with your truck. The TPS trouble code is a biggie. I would start there.
I over looked the tps because I had been driving on it a good bit in the days before this. I’ve tested the sensor and it does not read differently when I open or close the throttle. Maybe bad sensor? I don’t know how well I tested the sensor. If you have any ideas on how I can perform another test I’d appreciate hearing them.
 

·
Registered
Joined
·
18 Posts
Discussion Starter #5
Yo Buck,
Post the codes.
The intertia switch could be sketchy. Inspect wiring at the connector and look for corrosion from cowl water leaks.

Try jumping it out for a test. Re-connect it if issue isn't solved.
I think I had codes 21,23,31, and 51. After I made this thread I ran codes again and got 51.
I may have fixed the ect sensor last night.
 

·
Registered
Joined
·
18 Posts
Discussion Starter #6
I think I had codes 21,23,31, and 51. After I made this thread I ran codes again and got 51.
I may have fixed the ect sensor last night.
Just ran codes again I have 23 and 31 now.
 

·
Super Moderator
Joined
·
26,007 Posts
Yo,
DTC 21 ECT out of self test range 0.3 to 3.7 volts; "... ECT is bad, engine not warmed up, bad thermostat, low coolant..Coolant is less than 50 deg F for KOEO, or less than 180 deg F for KOER, or greater than 250 deg F for either. If coolant temp is in proper range, suspect ECT sensor or it's connector/wiring..." read more
Source: by me at FSB 86 Bronco Need help pulling codes

Testing; "..."But due to its simplicity of design, the ECT is rarely at fault when problems occur. Before testing the ECT or any other EFI component perform a self-test, trouble codes received during test can be used as a diagnostic tool along with other indicators. To test an ECT sensor you will need a volt meter. You can test the ECT by back probing the harness while reading the voltage returning to the EEC. Or you can removing the connector completely and test the resistance between the 2 pins on the ECT..." READ MORE Source: by Ryan M at http://www.fuelinjectedford.com/images/eec04.gif

and to help testing on all codes; use these by Ryan

EEC IV Connector Pin Depiction Pic by Ryan M
& EEC IV PIN LEGEND @ Ford Fuel Injection
°°

DTC 23, see Bronco Forum - Full Size Ford Bronco Forum by SeattleFSB
TPS out of range or throttle set too high
Bad TPS, especially if not a Motorcraft unit
Dirty throttle body,
Has anyone turned the throttle body's "throttle plate stop screw."?
Visually inspect throttle linkage for binding or sticking.
Verify the throttle linkage is at mechanical/closed throttle. Check for binding throttle linkage, speed control linkage, if equipped
Vacuum line/electrical harness interference, etc.
Disconnect TP sensor vehicle harness connector. Inspect for damaged pins, corrosion, loose wires, etc.
¤•¤

DTC 31 CM EVP circuit has intermittently failed below minimum voltage of 0.24 volts.
EVP - EVP signal is/was out of range - EVP
EVR - (O, R, M) EVP signal is/was low - EVR
URL="http://web.archive.org/web/20110704111747/http://www.tomco-inc.com/Tech_Tips/ttt32.pdf"]EVR Testing, Ford; "....check the filter on the solenoid (Fig. 4, EVR filter shown). If this is clogged it will inhibit the venting of the solenoid; "...EVR Solenoids should be 20 to 70 ohms (100 to 135 ohms for 7.5L engines). A functional test can be performed on most applications by using a Scan Tool. Enter the Output State check and cycle the accelerator pedal. This will turn all the solenoids on and off. Using a DVOM monitor the voltage at the EGR solenoid(s). They should toggle from a high voltage to a low voltage. Typically this is stated in the manuals and scan tools as above 10.5 volts to below 2 volts. If the voltage does not toggle make sure that you have system voltage on the power side of the connector. If system voltage is present and the voltage does not cycle to the low side check the connector and wiring to the PCM. If the wiring and connector are okay the problem may be in the pin at the PCM or the driver in the computer itself..." READ MUCH MORE by Tomco.[/URL]
¤
DTC 51, if test needed, see Checking resistance and voltage on the ECT sensor
 
1 - 7 of 7 Posts
Top