Washed Engine/ Surging

[Roy]

I washed my engine at the car wash to replace the valve cover gaskets. It ran fine untill it warmed up. It runs great cold. As soon as it warms up it boggs and surges bad at cruise speed. If I tromp it to the bottom it runs like a scallded dog untill I go back to running steady. I changed out the TIF modual with one off an old distributor. Base timing is at 10 degrees and advance is working. The throttle position sensor, KOEO, has 5.1 volts on the orange wire. 1.05 volts varying smoothly to 4.53 at WOT on the green wire. Reading the codes, I only had a 23 in continuous memory and a 74 engine running. Any suggestions are appricated.
Roy

 

[IMenriched]

I washed my engine at the car wash to replace the valve cover gaskets. It ran fine untill it warmed up. It runs great cold. As soon as it warms up it boggs and surges bad at cruise speed. If I tromp it to the bottom it runs like a scallded dog untill I go back to running steady. I changed out the TIF modual with one off an old distributor. Base timing is at 10 degrees and advance is working. The throttle position sensor, KOEO, has 5.1 volts on the orange wire. 1.05 volts varying smoothly to 4.53 at WOT on the green wire. Reading the codes, I only had a 23 in continuous memory and a 74 engine running. Any suggestions are appricated.
Roy

I would get the TFI's tested at your local parts store...most do it for free.

remove your distributor cap and dry...check for cracks... you might cracked it when washing

you may want to clean your AIC, remove and spray with carb cleaner repeat as needed.

Also check to see if you knocked off a vacuum line when power washing.

 

[Roy]

The distributor cap was dry but I did find a crack and replaced it with no change. I will try cleaning the AIC. I see the Tec Library has instructions on checking the TIF Module. Will this do the same test as the parts house or do they have a special tester that will tell more? Thanks for your reply.
Roy

 

[IMenriched]

The distributor cap was dry but I did find a crack and replaced it with no change. I will try cleaning the AIC. I see the Tec Library has instructions on checking the TIF Module. Will this do the same test as the parts house or do they have a special tester that will tell more? Thanks for your reply.
Roy

If your going to do the testing for the TFI off the Tech Library...or even at the local parts store....be sure to run test several times.(3-4)

From the Tech library testing, write down the reading that you get... and run test again (3-4 times). The idea is to verify the readings are conssistant through out the testing... and are within the speicified range, IF they very much at all...the get a new one.

double check to see if the wire from the O2 sensor didn't get knock off to.. from the power washing..or maybe even broken

 

[Roy]

The AIC looked good but I cleaned it with contact cleaner and it will hold contact cleaner between the two ports so it is not leaking. It opens when power is applied to it. The TIF did not pass the test on the Tec Library. It will be Wednesday before I can get to town to get a new TIF. Thanks for the info. I 'll let you know how I come out.
Roy

 

[Roy]

The TFI's checked good at the auto parts store three times in a row. I was on the wrong terminals when I thought it failed the test. The O2 senser is hooked up and wires look good. Tomorrow I will run all the test in the Tec Library and pull the wires out of plastic conduit to check them. This is getting more intresting.
Roy

 

[IRKillroy]

I washed my engine at the car wash to replace the valve cover gaskets. It ran fine untill it warmed up. It runs great cold. As soon as it warms up it boggs and surges bad at cruise speed. If I tromp it to the bottom it runs like a scallded dog untill I go back to running steady. I changed out the TIF modual with one off an old distributor. Base timing is at 10 degrees and advance is working. The throttle position sensor, KOEO, has 5.1 volts on the orange wire. 1.05 volts varying smoothly to 4.53 at WOT on the green wire. Reading the codes, I only had a 23 in continuous memory and a 74 engine running. Any suggestions are appricated.
Roy

you might have water in a sensor somewhere.... shorting something out.

it runs fine cold because it's in open loop... it's not taking any readings from the sensors....

so you might want to disconnect everything take some electrical connector cleaners and spray everything out then put some di-electric grease in those connectors... connect them back up and see if you fixed the problem.

it's a lot cheaper than replacing all your sensors that were working before you sprayed it... if that doesn't work then go ahead and take it to the mechanic to throw it on the Machine.

 

[yellowoctupus]

Map sensor?

CHeck your map sensor. They don't do a whole lot at idle and WOT, but they make all the difference in the world mid range.

 

[Roy]

Today I checked everything listed on the TEC Library except the Hall Effects which required a TFI tester. The Spark Advance Test #8 said I should have battery voltage when running. The SPOUT only had 5 volts coming from the TIF and 5.5 volts coming from the computer. I checked all the wiring and connectors and everything looked good. I pulled all the connectors at the sensors and sprayed contact cleaner in both ends. I pulled the Codes again and only get a 74, Brake on/off circuit that shouldn't affect running. I am not ready to give up yet.

 

[tedrisch]

try picking up a ignition voltage guage (adjustable) like this one from autozone:

It will accurately show you how your ignition system is operating and will save time with diagnostics

 

[IRKillroy]

again, when you are WOT the computer forgets sensor input....

does it idel fine? is it possible one of your injectors aren't plugged in properly????

get an injector test light and plug it in into each connector while it's running (it'll be fine if only one).... you can also see if it is just one cylinder by disconnecting spark plugs one at a time to see if it affects the idle or mid-range RPM... if it doesn't affect it, then you found your bad cylinder.... if none of that works then you have a sensor problem.

 

[Roy]

The engine idles fine and runs good until it warms up and goes into closed loop, about 5 miles. I didn't know how to check the MAP sensor. It has three wires like the TPS. With KOEO, one is ground, one has 5 volts and one is open. With KOER there is a ground and two with 5 volts. Connecting a vacuum pump and a gradual increase in vacuum didn't change the voltages while running. Maybe the parts house has can test the MAP sensor Wednesday when I go back into town.

I cleared the codes but the 74 came back which is Brake on/off failure. This circuit is connected to the computer. After driving it some more I now have a Code 42, HEGO sensor circuit indicates rich which I was supprised hadn't shown before.

 

[IRKillroy]

well it seems the surging is from it running rich... the O2 sensor is making it hunt most likely....

I'm not a master mechanic but I think it's supposed to change when the pressure is changed... a maf is flow while map is pressure... it's good for altitude changes... but if you go from low to high, you need to shut the engine off for it to reset....

MAPs only work on start-up if I remember correctly.... it sets the fuel map for the elevation.... if it's showing the full 5 volts then I think it's saying you're below sea level and adding more fuel .... and the engine is trying to adjust with the O2 sensor reads rich when it goes closed loop.

I would try buying a resistor and just jumping those wires to see what will happen.... get something that will put it mid-range... about 3 volts. if that corrects the problem then you know your MAP is bad.

a resistor is cheaper than a MAP sensor.

 

[yellowoctupus]

With KOEO, one is ground, one has 5 volts and one is open. With KOER there is a ground and two with 5 volts. Connecting a vacuum pump and a gradual increase in vacuum didn't change the voltages while running.

Ford map sensors don't use a changing voltage as their signal, they use frequency. I used my dvom to check mine, the numbers were pretty close to the ones published at this link.
http://www.fordfuelinjection.com/?p=27

THIS IS NOT A CHEVY. DO NOT JUST JUMP A RESISTOR IN PLACE.

 

[Psychopete]

Connecting a vacuum pump and a gradual increase in vacuum didn't change the voltages while running. Maybe the parts house has can test the MAP sensor Wednesday when I go back into town.

FWIW, the sensor outputs a frequency as oppose to a voltage that you're looking for. I believe they might be able to check, wouldn't hurt to call and verify...

http://www.fordfuelinjection.com/?p=27

Pete

Edit:
Woops, yellowoctupus beat me to it .