Rev at Cold Startup

[Tiggie]

Worked on the car again today. It did it's little rev thing when I started it up as usual, no change.

Drove car for twenty minutes to get it nice and hot. Came back and pulled codes:
KOEO: Code 34
KOER: Code 94, 44, 34

Always got a code 98 before on the KOER test, so I was surprised it actually ran the test this time. The 34 is still the EGR, which I don't think is contributing to the problem. I have a spare EGR valve and sensor at the house I may try to see if the code disappears. The 44 and 94 are the same codes according to my service manual, dealing with the pollution controls (which are gone). I'm not really worried about them, but if anyone knows how to make them disappear without the smog equipment in place, that'd be nice.

Both the ECT and intake air temperature sensor were right on the money as far as testing correctly. Maybe the connector wasn't quite on the ECT or something when I got that code in the past. Or maybe the wiggling of the wires helped it out. Who knows, but the code is gone now.

The S&P connectors looked remarkably good.

Will an IAC off an '88 5.0 Turdbird work on my car? I have one of those at home now that I think about it. If it will work, I'll try it and eliminate the IAC as the cause of the revving.

Car ran like a champ today. Almost got a ticket for 80 in a 45!

[86VickyLX]

Worked on the car again today. It did it's little rev thing when I started it up as usual, no change.

Drove car for twenty minutes to get it nice and hot. Came back and pulled codes:
KOEO: Code 34
KOER: Code 94, 44, 34

Always got a code 98 before on the KOER test, so I was surprised it actually ran the test this time. The 34 is still the EGR, which I don't think is contributing to the problem. I have a spare EGR valve and sensor at the house I may try to see if the code disappears. The 44 and 94 are the same codes according to my service manual, dealing with the pollution controls (which are gone). I'm not really worried about them, but if anyone knows how to make them disappear without the smog equipment in place, that'd be nice.

Both the ECT and intake air temperature sensor were right on the money as far as testing correctly. Maybe the connector wasn't quite on the ECT or something when I got that code in the past. Or maybe the wiggling of the wires helped it out. Who knows, but the code is gone now.

The S&P connectors looked remarkably good.

Will an IAC off an '88 5.0 Turdbird work on my car? I have one of those at home now that I think about it. If it will work, I'll try it and eliminate the IAC as the cause of the revving.

Car ran like a champ today. Almost got a ticket for 80 in a 45!

The turd IAC will work. If it's got a 90* neck, you will need to plug in the harness before you install it. My IAC would stick at a high RPM, it would idle normally then all of a sudden, it would jump up (from the ACT being crapped up), and then the IAC would stick making it idle like that until I stepped on the gas.

[gadget73]

You can't make 44 and 94 go away if the smog stuff is gone. Ignore them, they don't affect anything. 34 could be a cracked egr vacuum line, or something wrong in the egr vacuum circuit. It won't affect much, but it will cut into your fuel economy a bit.

[Tiggie]

Little update here.

I took the Air Temp Sensor out. It was completely nasty. I cleaned it with a little thottle body cleaner and a soft brush and reinstalled it. No change.

I also installed a new Motorcraft EGR Valve and sensor. I got it from a friend who bought it for his '88 Cougar but never installed it. In other words, I didn't pay much for it. Still got old code 34. Anyone got a diagram of the EGR valve vacuum circuit? Everything appears fine according to the emissions sticker diagram, but it's not exactly detailed.

The revving problem has to be temperature related. The colder it gets, the worse the problem becomes. Even if the engine is stone cold, and the air temp outside is 60+ F, the problem disappears. I still want to say the air temp sensor. I may try replacing it if no one has any other suggestions.

[86VickyLX]

I thin you would benefit from a new Air Temperature Sensor. To completely rule out that part. Code 34 is voltage related, is the voltage within specifications mang? http://fordfuelinjection.com/index.php?p=46

[gadget73]

EGR vacuum is supplied from the red plastic hose that connects to the upper intake. It runs over to the passenger side through that 4 line connector. Once past that, it splits off to supply the small canister and both of the lower solenoids as well as the upper one. The upper one is the egr vacuum regulator. The ECM applies a pulse-modulated signal to open that upper solenoid varying amounts. Vacuum is supplied to the green hose, through the connector, and over to the egr valve. Thats really about it.

34 means its intermittantly not fully shut. A clogged EVR filter can do that, and so can a sticky EVR. The EVR is that upper solenoid on the passenger fender, the one with the green hose. Pop the cap off and clean the little foam filter in there in soap and water. I'd also spray some wd40 or something down the little tube that sticks up into the filter.



I have sort of the opposite temperature problem. The car starts and runs great when its cold. When its above about 80, it usually stalls when I first start it. I've replaced both of the temperature sensors just to rule it out. I also swapped the ecm and every other sensor on the motor while troubleshooting another problem. None of it fixed it. I quit paying attention to it, apparently its just some gremlin that I can't find.

[Tiggie]

The Air Charge Temp Sensor before and after:



Is everyone else's intake this nasty inside? I'll clean the EVR filter and lube it up the best I can and see if it helps. Haven't popped it open yet, but I expect it's crusty inside. The Air temp sensor is on the list of eventual replacement.

[gadget73]

Every time I've pulled one out, it hasn't looked much different. I think a combination of oil from the pcv and exhaust from the egr getting sucked through there just makes it nasty.

[cld783]

mine looked just like that.. i'm sure they all do