Rebuilt 2.9l check engine light on after 6 miles of break in


GingerKing13

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I just recently had my 2.9l rebuilt for my 1988 ford ranger 4x4. Break in went well no leaks. However, check engine light just popped on after a test drive... Is this a problem and is there any way to figure out what the issue is? I went with a mechanical oil pressure guage leaving the oil pressure sensor wire unattached, is this the problem or would that not affect the check engine light?? Motor was completely rebuilt, bored .030 over oversized rings, etc.. This is the first engine ive ever taken out and put back in please help Thank you!
 


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Dirtman

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You could start by figuring out what the code is...
 

PetroleumJunkie412

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+1 for the codes. If you can get them for us, we can be of much more help.
 

Dirtman

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No, on the oil pressure sender, computer doesn't read that info

After warm up, 6min, it does need the O2 sensor hooked up or will set a code

Did you install a thermostat?
And is the engine warming up?
Another code can be set if engine temp doesn't get above 150deg within a certain time, 5-6min
 

GingerKing13

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Okay thank you guys for the Input and I got the codes!!!!

from Memory (m)
18- ignition tach signal erratic

41-system lean for more than 15 seconds

96- Fuel pump relay or battery power feed was open - Power / Fuel Pump Circuits

this test was done with the engine off and key at on position.

When i started the truck up yesterday it was idling like shit jumping from 400-1100rpms but settled out after 3 minutes or less. Could this be the cause to my Number 18 Code?
As far as system lean, i did not replace the o2 sensor so i will get one and see if it throws that code again.

but the code 96 is tough because i hear the high pressure pump prime as it should and pump in tank run should i swap the relay for a new one and clear the codes then run again??

thank you guys for your help!!!
 

PetroleumJunkie412

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18 is hall effect sensor IIRC. Have you checked your timing with a light?
 

GingerKing13

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18 is hall effect sensor IIRC. Have you checked your timing with a light?
i tested codes with the Engine off using the Memory codes.

using the chart on this page https://therangerstation.com/tech_library/2digitcodes.shtml

Memory code (M) 18 is erratic Tach signal

With engine running, which it was not, code 18 would represent timing.

I set the timing by following the haynes manual procederures at 10* BTDC with the check plug disconnected.

when I plugged the check connector back in at Idle timing was around 20* BTDC

Would this mean the timing advance module on the distributor is bad?
 

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No, it should be about 20-24deg with computer connected(SPOUT connected), depends on engine temp

Tach signal is the PIP(profile ignition pickup) signal the computer gets from the TFI Module, the distributor Hall Effect sensor is where the TFI gets the PIP

So as distributor spins the hall effect sensor sends the PIP to TFI, TFI then grounds and ungrounds the coil's "-" terminal(tach signal), same as points did on older distributors
The TFI also passes the PIP on to the computer so it can time injectors and also have engine RPMs(tach signal)

Since there is no Vacuum Advance on the TFI system there needs to be a way to change spark timing based on engine load and air/fuel mix, thats what SPOUT is for, it changes spark timing based on engine load, throttle position, and temp, same as vacuum advance did, but better.

So 18 can mean the PIP signal from TFI module to computer is erratic, can be wiring issue

TFI wiring seen here: https://therangerstation.com/tech_library/TFI_Diagnostic.shtml
 

GingerKing13

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No, it should be about 20-24deg with computer connected(SPOUT connected), depends on engine temp

Tach signal is the PIP(profile ignition pickup) signal the computer gets from the TFI Module, the distributor Hall Effect sensor is where the TFI gets the PIP

So as distributor spins the hall effect sensor sends the PIP to TFI, TFI then grounds and ungrounds the coil's "-" terminal(tach signal), same as points did on older distributors
The TFI also passes the PIP on to the computer so it can time injectors and also have engine RPMs(tach signal)

Since there is no Vacuum Advance on the TFI system there needs to be a way to change spark timing based on engine load and air/fuel mix, thats what SPOUT is for, it changes spark timing based on engine load, throttle position, and temp, same as vacuum advance did, but better.

So 18 can mean the PIP signal from TFI module to computer is erratic, can be wiring issue

TFI wiring seen here: https://therangerstation.com/tech_library/TFI_Diagnostic.shtml
Okay so If I picked up a new TFI module (module that is bolted on the back of distributor) would fix the issue?

This module has never been replaced since ive had it (4 year) and it sat not running with a blown engine for 2 years. Part of the connectors plastic is actually broken off and am sure it has been to hell and back...
 

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Hard to say, you can throw parts at it and maybe fix it, works for many, testing the wire is free or testing the module
 

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I've had code 18 appear due to a bad connection at the TFI module connector. As a temporary fix, I removed the red plastic strip at the end of the connector, and carefully bent the six contacts to make them tighter. When that helped, I replaced the connector. Otherwise, it's probably the module.

41 is the O2 sensor, so make sure you re-connected the ground wire at the back of the passenger side head when you put your engine back in.

I'm not sure what the difference between 96 and 95 is; they both appear to indicate a lack of voltage on the load side of the fuel pump relay (95 is common when swapping a later non-EGR ECM for an '86 or '87 EGR ECM). There is a wire that runs from the load side of the fuel pump relay to pin 8 of the ECM. You have voltage to your fuel pumps, so I would think it's the wire going to pin 8 of the ECM or the ECM that's causing the code 96. You could check continuity between the load side of the relay and pin 8 of the ECM (orange/light blue). If the continuity is good (and your fuel pumps are getting power from the relay), it's the ECM. But code 96 shouldn't make it run erratic (as long as your fuel pressure is good).
 

GingerKing13

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Ran another timing check on it and engine stopped missing and smoothed out. No codes were throwing after i played with the wires on the tfi module took it for another test run and the lights back with code 41 (checked while running this time) and shows for system lean It also pulled Code 77 (Goose test unable to run) I think is what that one means... Is this okay or?

I found a brown wire attached to the o2 sensor harness that looks to be a ground that was never hooked up. Could this be my issue? I put the ground wire on the block and hopefully that will fix this issue but just wanted to check in. Thank you guys for your help!!!
 
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Paulos

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Yeah, I wouldn't worry about code 77. It's because you didn't floor it when the ECM sent the code to do so during the KOER wide open throttle test (which is supposed to confirm proper operation of the TPS, MAP, and knock sensors).

If the brown wire goes down to the O2 sensor it needs to be grounded for the O2 sensor to operate. It's usually bolted to the back of the passenger side head. Probably the cause of the code 41 if it's the O2 ground.

If it ran better after moving the wires on the TFI module connector, I would try tightening up the contacts in the connector as I mentioned in my last post. Many years ago I found that if I pulled the connector out slightly from the fully inserted position, my instability issues would stop. I have also found that some new modules have slightly thinner blades /spade terminals (the six terminal side), and the old TFI connectors don't make a good solid connection to them. So, either tighten up the contacts in the connector (with a small screwdriver), or replace the connector (soldering with adhesive lined shrink tube works best).

TFI connector retainer.jpg
 
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