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350 Wont Idle/Will Idle Too High/ Wont Idle You get The Idea- SOLVED:)

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GalDemSuga

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Folks
Two days ago my 89K5 stopped idling/idled really high until I got code 45 and/or would die if my foot wasnt on the pedal. This happened while in gear or in park. I got around to troubleshooting the issue but after all my efforts I'm back to square one.

I have my receipts folder with me so I swapped all sensors for new ones (TPS, IAC, MAP, EGR Vaccum Selenoid). I pulled the EGR Valve and checked it for functionality and Carbon, it checked out ok. I checked the injectors and they streamed good and didn't leak with engine off. I pulled the TBI unit and replaced the gaskets to the intake manifold.

I started her up and same issue wont idle. I tried to do the minimum air procedure as highlighted by 4X4 HIGH in another thread but she wont keep running with the IAC circuit disconnected. Nothing made sense, so I order another ECM and swapped it in. Still I have the same issue.

Is it possible that the PROM is defective? It's 21 years old now.
 
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Just checked again for vaccum leaks and found none. I've got good vaccum at brake booster, EGR functions good and the TBI ports are all good.

I just had it running and it idled high to low and then high until I got code45 again. She then quit idling again and died.
 
OK, thats it, we got to stop meeting like this........

My Ford is doing the exact same thing. Sometimes goes dead, then idles great, then tries to mate with the car in front in a drive through.

I changed out the MAP, and it helped, but still did it.
I finally ran it down.
Fuel pressure regulator is bad.
Fuel pressure goes from 20 to 80 and all in-between.

Might be the booster pump, but I pulled the vacuum hose on the regulator, and there was fuel in it, so the diaphragm is busted or leaking.

It had to go on the rack for something unrelated, so its in my mechanics shop tonight. It should be ready tomorrow, and I will make sure, but it makes sense.

All the computer can do is control the length of time the injectors are open.
It expects the same amount of fuel to come out for the same length of time.

Of course mine is a Ford, but any engine with an injector has to have constant fuel pressure.
 
It's a new sensor I put on yesterday. The wiring looked good as it hangs from the harness. I will turn my attention to the distributor next. It was replaced a few months ago with one from Autozone. Last week I replaced the plugs and wires as a few wires had rubbed on the exhaust manifold and the truck ran like crap. I pulled the distributor cap and the rotor button and cleaned them up before putting them back on. I wonder now if the wires grounding on the exhaust could have damaged the distributor?


ryoken said:
check your O2 and it's wiring......
Click to expand...
 
You're right man we need to cut out these meeting:) I dont get why it's dumping too much fuel to casue code 45 and then wont ilde. I observed the fuel coming in when she stalls/surges and its less than when she dumps enough to cause code 45.

Fordum said:
OK, thats it, we got to stop meeting like this........

My Ford is doing the exact same thing. Sometimes goes dead, then idles great, then tries to mate with the car in front in a drive through.

I changed out the MAP, and it helped, but still did it.
I finally ran it down.
Fuel pressure regulator is bad.
Fuel pressure goes from 20 to 80 and all in-between.

Might be the booster pump, but I pulled the vacuum hose on the regulator, and there was fuel in it, so the diaphragm is busted or leaking.

It had to go on the rack for something unrelated, so its in my mechanics shop tonight. It should be ready tomorrow, and I will make sure, but it makes sense.

All the computer can do is control the length of time the injectors are open.
It expects the same amount of fuel to come out for the same length of time.

Of course mine is a Ford, but any engine with an injector has to have constant fuel pressure.
Click to expand...
 
Code 45 is for a rich O2 sensor reading. I would highly doubt you have an issue with the 02 sensor itself but the 02 sensor is recognizing a rich condition. What would cause a rich condition that would be bad enough to not allow the engine to idle properly or even die. Well an injector that may intermittently become clogged and drip fuel real bad, a bad fuel pressure regulator, a restriction in the fuel return line causing fuel pressure to rise.

I would start my search now by checking the fuel pressure at idle (try your best to get it to idle long enough to make a reading) then I would drive the truck and check it at cruising speeds (should be somewhere between 9-13 psi and most are right about 12 psi factory).
 
I"m out at work in Gilbert, WV. I'll be here for a few more weeks so I cant do a whole lot. She drives fine with no stalling but will stumble when i come to a stop light etc. She will throw that code everytime. The injectors dont leak and both spay patterns are consistent.

4X4HIGH said:
Code 45 is for a rich O2 sensor reading. I would highly doubt you have an issue with the 02 sensor itself but the 02 sensor is recognizing a rich condition. What would cause a rich condition that would be bad enough to not allow the engine to idle properly or even die. Well an injector that may intermittently become clogged and drip fuel real bad, a bad fuel pressure regulator, a restriction in the fuel return line causing fuel pressure to rise.

I would start my search now by checking the fuel pressure at idle (try your best to get it to idle long enough to make a reading) then I would drive the truck and check it at cruising speeds (should be somewhere between 9-13 psi and most are right about 12 psi factory).
Click to expand...
 
Where do I plug in a fuel pressure guage?

4X4HIGH said:
Code 45 is for a rich O2 sensor reading. I would highly doubt you have an issue with the 02 sensor itself but the 02 sensor is recognizing a rich condition. What would cause a rich condition that would be bad enough to not allow the engine to idle properly or even die. Well an injector that may intermittently become clogged and drip fuel real bad, a bad fuel pressure regulator, a restriction in the fuel return line causing fuel pressure to rise.

I would start my search now by checking the fuel pressure at idle (try your best to get it to idle long enough to make a reading) then I would drive the truck and check it at cruising speeds (should be somewhere between 9-13 psi and most are right about 12 psi factory).
Click to expand...
 
GalDemSuga said:
Where do I plug in a fuel pressure guage?
Click to expand...

For checking at idle there is a fitting that replaces the fuel filter. As for checking while driving that would require you to buy and install the fitting at the TBI unit to accept a gauge there (would be a good idea to have right about now anyways) if you do buy this fitting then you would need a decent length of fuel hose with the gauge attached to the end and run it up through the cowl and under the wiper arm so you can see it as you drive.
 
Mine drives fine too, although I sometimes feel it want to bog and other times want to speed up.
When mine goes dead at idle, I usually see black smoke when I start it back up.

Since mine uses different injectors and more of them then yours, my pressure has to be higher.
But, no matter what pressure it is supposed to be, it has to be controlled.

That computer tells the injector to fire for so many microseconds, and if the pressure is such that it dumps in twice as much fuel as it did 30 seconds ago for the same injector pulse, then that engine is not going to idle.

I think yours has a vacuum hose on it also, someone will jump in and say so I hope.

If so, if you can reach it, pull it off and see if its wet with fuel after it has run for a while. There should not be any fuel getting to it.
Its a one way test. If its dry, it does not mean its good, but if its wet, it does mean its bad.
 
TBI does not use a vacuum referenced pressure regulator from the factory.
 
4X4HIGH said:
TBI does not use a vacuum referenced pressure regulator from the factory.
Click to expand...
Oh well, I was hoping it did. Its a quick check. Thanks for jumping in. Saves him hunting it.
One nice thing about my Ford, it has a schrader (tire) valve right on the fuel rail
Easy to hook to.
 
When I pulled the TBI unit off yesterday, while there was no leaking at the injectors, behind the diaphram seemed a little dirty. You know that brownish color that fuels leaks leave over time, well it looked that way.

4X4HIGH said:
TBI does not use a vacuum referenced pressure regulator from the factory.
Click to expand...
 
I just did a test on those injectors. I cleared the code so the truck started and idled. I unplugged the injector on the passenger side and the truck died. I reconnected it and unpluged the one on the drivers side and the truck ran. It will idle with the passenger side injector only but not the the one on the driver's side.
 
I revisited the diaphram and it checks out, looks like it was fuel spilled from one time or the next that dried up there. I'm having my wife over night my back up TBI Unit, once here I'll rebuild it and swap it in. I will change the distributor controll module too.

GalDemSuga said:
When I pulled the TBI unit off yesterday, while there was no leaking at the injectors, behind the diaphram seemed a little dirty. You know that brownish color that fuels leaks leave over time, well it looked that way.
Click to expand...
 
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GalDemSuga said:
I just did a test on those injectors. I cleared the code so the truck started and idled. I unplugged the injector on the passenger side and the truck died. I reconnected it and unpluged the one on the drivers side and the truck ran. It will idle with the passenger side injector only but not the the one on the driver's side.
Click to expand...

Think you got yourself a little confused there. :D

At any rate, it should still idle with either injector disconnected. You definately have something going on with the injectors I think.
 
:D You're right, I'm confused. I meant that it will ilde with only the passenger side connected and will not idle if only the driver side is connected. I wish I had a back up PROM too.

4X4HIGH said:
Think you got yourself a little confused there. :D

At any rate, it should still idle with either injector disconnected. You definately have something going on with the injectors I think.
Click to expand...
 
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