Need help please

[heath]

This is my first post here so bare with me. I'm in the process of putting the drivetrain from a 86 broncoII into a 88 body. Everything has gone pretty smooth but I've ran into a problem. I"ll go ahead and say that I've changed plugs,wires, and all sensors except for the TPS. I have the timing set to 12* BTDC with the spout unplugged.
When I first start it up it runs fine for about 30-45 seconds, then when it starts to idle down it spits and sputters and dies. After it does this once or twice it runs pretty good. I've pulled codes and I'm getting 42KOER(too rich) and 89KOEO(EHC system fault). I'm currently on my 2nd brand new bosch O2 sensor, and I spent all day today tracing the wires back and they're good. The fusible link was iffy, so I went ahead and replaced it while I was at it. The only other thing I could think of doing was putting the 86ecm in and trying it. WHen I did that I got 3 codes from having the EGR system removed, one for not detecting knock during the "goose" test, and still had the 42 which is system too rich, and O2 sensor not changing, or something like that. The only thing I can think of on the 89 code is that... I was looking up the codes on google and I found some places that referenced the 89 code to TCC solenoid. Could that be what it is instead of the EHC not working right, since I'm running a manual tranny with a automatic ECM? And I'm at a loss on the running too rich, I guess it could be another bad O2 sensor..

 

[heath]

Also, I'm using the H-pipe from the 86 and the O2 sensor placement is different than what was on the 88. Could the placement of the sensor be causing the rich code?

 

[IMenriched]

the 88 does not have a EGR...the 86' did. So using the 86' ECM will look for a EGR signal. not suprizing that you're getting more codes with that.

as far as running rich, try replacing the collant temp sensor, the one for the ECM, not the dash. if it is faulty then it won't provide the correct info for the ECM...making the engine run rich, it thinks it is colder than it is. could play a part with O2 sensor too.

have you cleaned the AIC (air idle control)??

test your TFI (aka ignition module), they like to have heat issues too

 

[heath]

Which coolant sensor sends the signal to the ECM? Is it the one right beside the t-stat? And yeah, I've replaced the IAC valve, but haven't changed the ignition module. Do you know if on a 88 model ECM will it look for torque converter solenoid lockup?

 

[IMenriched]

As you already realized there are 2 temp sensors...1 for the guages on the dash & 1 for the ECM. should of gave you a heads up. BTW, they function independently of each other, meaning 1 does not provide feedback for the other.

Pretty sure that the temp sensor you're looking for is on the left side of the "T"stat housing area ,(as you are looking from the front of the engine).

Thinking that the ECM does needs to gender specific, shall we say. As far as, whether it is from a Automatic or Manual tranny. So yes... the 88 EMC will look for the TC lockup.
but others here at TRS with vastly more experience with the trannys may better address that...purhaps there is a way to get around it? IDK

 

[heath]

As you already realized there are 2 temp sensors...1 for the guages on the dash & 1 for the ECM. should of gave you a heads up. BTW, they function independently of each other, meaning 1 does not provide feedback for the other.

Pretty sure that the temp sensor you're looking for is on the left side of the "T"stat housing area ,(as you are looking from the front of the engine).

Thinking that the ECM does needs to gender specific, shall we say. As far as, whether it is from a Automatic or Manual tranny. So yes... the 88 EMC will look for the TC lockup.
but others here at TRS with vastly more experience with the trannys may better address that...purhaps there is a way to get around it? IDK

Thanks for the help man. I swapped coolant sensors today, and it's still doing the same thing. So basically the only code I'm even remotely concerned about now is the 42, which is always rich during fuel test. I'm on my 2nd Bosch O2 sensor, and I've traced the wires everywhere and they're good. So I guess the only other thing it could be is another bad sensor?? Since that's the only code I'm getting using both ECM's it kinda rules out a bad ECM. What other options do I have on O2 sensors besides Bosch?

 

[Jspafford]

The sending unit for the gauge is on the side of the block, down towards the motor mount.

The actual sensor the motor reads off of is up near the thermostat on the left side when facing the front.

When the Coolant Sensor goes out the truck will idle at around 1100RPM and never settle down to normal idle.

 

[heath]

Ok, I've pretty much ruled out everything except for another faulty O2 sensor.

 

[hidesertrat]

Just a thought here. I had the same problem when I first put my engine together. However, I noticed after driving the truck around for about 15 - 20 minutes the idle problem went away. I chalked it up to the ecm haveing to update information to find the correct settings to get engine to run better.

Anyone know how long it takes the ecm to "reset" itself? Or does it need to?

 

[heath]

I forced the motor into a lean condition today by creating a vacuum leak. This did away with the 42 rich code. So now I'm thinking it's a faulty fuel pressure regulator. Is there anything else you guys can think of that woud cause a rich condition. the MAP sensor is good.

 

[Psychopete]

I forced the motor into a lean condition today by creating a vacuum leak. This did away with the 42 rich code. So now I'm thinking it's a faulty fuel pressure regulator. Is there anything else you guys can think of that woud cause a rich condition. the MAP sensor is good.

Sounds like it's doing it when the PCM goes into closed loop. While the engine is in a "warm up" stage, not all sensors are used and their values are referenced from a table that's in the PCM.

FPR is definitely going to run rich all of the time. Did you find any raw fuel in the vacuum line or test the actual fuel pressure?

Have you tried just unhooking the o2 sensor? You might consider tapping into the signal wire with a volt meter to see what's it's telling the PCM..

Pete

 

[heath]

Yes, it does the sputtering when it transitions from open loop to closed loop.

"FPR is definitely going to run rich all of the time. Did you find any raw fuel in the vacuum line or test the actual fuel pressure?"

I don't have the right fitting to test my fuel pressure, but I'll be doing that tomorrow. I haven't pulled the vacum line from the regulator eiter. Before I test it though, could this possibly be the problem? I'm not real sure how a vacuum referenced FPR works, but wouldn't if the diaghram ruptured it wouldn't be able to register any vacuum so it would always be referencing the WOT( 0" of vacuum) reading, which would be way too much pressure for idle and or part throttle driving? I"m still trying to figure this older stuff out. I'm used to working on newer model stuff.

 

[IMenriched]

Yes, it does the sputtering when it transitions from open loop to closed loop.

"FPR is definitely going to run rich all of the time. Did you find any raw fuel in the vacuum line or test the actual fuel pressure?"

I don't have the right fitting to test my fuel pressure, but I'll be doing that tomorrow. I haven't pulled the vacum line from the regulator eiter. Before I test it though, could this possibly be the problem? I'm not real sure how a vacuum referenced FPR works, but wouldn't if the diaghram ruptured it wouldn't be able to register any vacuum so it would always be referencing the WOT( 0" of vacuum) reading, which would be way too much pressure for idle and or part throttle driving? I"m still trying to figure this older stuff out. I'm used to working on newer model stuff.

If there is a dribble of fuel out of the little vacuum line as you unhook it then diaphram is bad in the FPR.

have you checked the other vacuum ports for excessive carbon build up??

 

[Mutant Pony]

The fuel pressure regular is very likely the problem. 2.9s are infamous for bad FPRs. The FPR can be bad and not leak fuel into the vacuum line but, if there is fuel in the vacuum line, it is definatly bad.

 

[heath]

I changed the FPR today, and it didn't change anything.LOL

What else could it be? A sticking injector?