Ford code 45?

[ADFD1]

Stumbling through this with the engine cold Key on engine off. We pulled a code 45 this is 1988 F-150 4.9L.

The book says Thermactor Air flow is always upstream (going to exhaust manifold). And????????? I was hoping it would say MAP sensor, I'd change it, and I could go back to sleep.

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[ADFD1]

Additional codes point to MAF sensor. Does an 88 have a MAF sensor?

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[ADFD1]

No MAF sensor in 88's. My buddy went and bought a MAP sensor, I threw it in and cleared the codes. Cold start it stalled twice ran close to a minute died, then ran nice and strong. After the test drive I put the scan tool on it:

Key on Engine off- 11 11 12 11. Code 12 means system can't raise engine speed above normal idle.

With engine running the light would only blink 3 times.

I am going to start looking again for vacuum leaks? Next step is toss in the towel, but I don't like to do that once I'm this involved.

Confused????????

Thanks for all the replies you guys are awesome!

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[mechtech2]

Clear the codes by removing a battery cable, not a tool.
Then test drive it again.
It will relearn a few things, and may idle funny for a little while.
Of course ALL vacuum lines and manifold connections must be perfect, esp the PCV system. Trace each one and check them for leaks and bad connections.

 

[ADFD1]

Thanks for the reply. Codes were cleared via a 20 minute battery disconnect, then I stepped on the brake to be sure there was now stray juice. When I restarted the truck after swapping MAP sensor (buddy insisted). I noticed the same symptoms as before, ran the code scanner again and got results listed above. I am now hunting, again for vacuum leaks.

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[OVERKILL]

If it can't raise the idle, it sounds like the IAC is stuck or FUBAR.

 

[rainman49]

I had to clean the IAC on my '88 F150 with the 5.0L several times during its long life. Not a difficult task at all.

 

[OVERKILL]

Originally Posted By: rainman49
I had to clean the IAC on my '88 F150 with the 5.0L several times during its long life. Not a difficult task at all.


Nope pretty easy. They had replaced the IAC, but I wonder if it is defective.

 

[ADFD1]

I was tempted to pull the IAC to have a look. Was pre-occupied with looking for a vacuum leak. I did see a red plastic vacuum line disconnected, but it was disconnected from both ends, [90* rubber boots] and all the vacuum ports that are not in use are capped. My buddy is the original owner and said that is how it was, nothing is going thru the line. The shop man says red= distributor, this line would have never made it to the distributor and the distributor is not vacuum operated. I'm thinking it was never connected. I seen many plugs etc not in use in cars over the years, but I wasted a good hour looking and came up with nothing. This condition came on all of a sudden it is obvious this red vacuum line was not connected for a very long time, probably never connected as my friend said.

Can I spray power foam into the IAC and into the manifold where it comes off of?

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[Jason2007]

You can remove the IAC and take it apart to clean it. Good shot of carb cleaner will do the trick.

 

[ADFD1]

Just did it. My buddy had the old IAC, we took both apart cleaned them and reinstalled them, to see if there would be any difference. Each time we did it we disconnected the battery so the system could re-learn. No cigar! It starts stalls surges, then if you turn on the A/C it does a dance. It runs exactly the same, with either part. Once warmed up it's fine.

I even put the old TPS back on for S&G. Calling it a day, will take another look in the morning then he will have to take it to a mechanic, I'm just about done!

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[punisher]

Assuming the air pump is still hooked up, remove the belt to deactivate it and see if anything changes.

I did have an old Crown Vic with a 5.0 that had some oddball surge problems. The dump valve would hang and cause surges bacause it continued to pump air to the system when the PCM wasn't expecting it and throwing off the O2 sensors big time. Problem with that theory is it acted up warm, not cold.

You might be at the point where you need to find a shop with a 60 pin breakout box for those EEC-IV systems. You don't have a DCL in the test connector to use with the generic testers most independants use.

 

[ADFD1]

The air pump is hooked up, problem is it is a serpentine belt and there is only one belt so we will lose everything. I guess I can do it for a short time and see what happens. Although I would rather not. The code 45 came with the engine off does that matter?

Now we are getting code 11, 11, 12, 11. Then the light blinks 3 times with the engine on and then doesn't blink anymore. I have a splitting headache.

The new IAC soaking in power foam, it was very clean, but I had it off so! I will put that back in in the morning. No point in using the old one.

Thanks again for all your help! I like a challenge, but this one has me nearly pinned.

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[punisher]

A bit late but don't soak the portion of the IAC with the electrical connector in anything as it can degrade the insulation on the solenoid. It is best to separate the IAC via the two screws and soak the valve portion only.

 

[ADFD1]

Thanks, I sprayed a little power foam into the two holes and let it soak, then turned it so it could drain out. I don't think that will be an issue, I don't think I will fix this thing either.

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[StevieC]

Is it possible someone reversed the wires going to the IAC at some point with a repair? I have seen this affect a GM car. The car wouldn't start properly cold but was fine hot and it turned out to be what I just described.

 

[demarpaint]

I have the same engine, same year, in an E series, and the plugs (TPS, IAC, EGR, etc) are different so reversing wires or plugs would be impossible.

 

[StevieC]

I didn't mean at the connector I meant if there was a repair to the wires feeding the connector. Like someone rejoined the wires or something. Or worse they took what looked like the same IAC off another vehicle and rewired a new connector onto the old wires cutting off the old connector thinking it would work.

 

[ADFD1]

Hello StevieC,

Demarpaint (Frank) has been chatting with you about my nightmare. Thanks to both of you!

The truck is clean, no tampering with any of the under hood wiring. The check engine light was shut down, but everything else looks fine and dandy.

This thing is possessed, I killed a whole day on it and accomplished nothing. I'm going to get up early and check the things you mentioned to Frank. EGR, O2, Timing etc.

Could the computer have gone bad? When we ran the engine with the Scan tool on all it did was blink 3 times, and then stopped blinking. Just a thought? I'd hate to mention it to my friend because he might just run out and try and get one. Before I let him do that I'm going to smack some sense into him and have him take it to a shop. I'm not spending another full day with it tomorrow!

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[StevieC]

Check the timing first as I described to Frank. It could very well be the TFI unit that is the problem and I think that the old computers in Ford timed the fuel based on the signal from the TFI.

I have seen a few TFI's that were bad cause erratic engine behavior instead of just the "stalling out when hot" scenario that the Ford TFI's are common for. It's rare but does happen.

Steve