1988 e150 with 302 and EFI

My van has been running rich since I bought it and i am just now getting around to that problem.. It had sat for probably 15 years or so and the PO said that he changed the plugs only, no cap, rotor, or wires..

So I will be doing a complete tune up next week. There is also a slight hesitation sometimes when starting off.. Sometimes at just above idle, pulling up a slight hill, it feels like it is surging a little..

I will also be replacing the TPS, oxygen sensor, and fuel pressure regulator. I don't know if any of them are bad or not but since they are 28 years old, and have 100k on them, seems like it would be good age related maintenance.

That may clear up the running rich problem. While I'm in there changing out parts, are there any other parts that might be cause the engine to run rich?
Any other parts that might fail due to age that require removing the dog house?
Maybe EGR since it has a rubber diaphragm in it?

thanks
Anna

 

Many times a rich condition in an EFI motor is due to a temperature sensor going bad and "telling" the computer the engine is cold. Another favorite is the wrong thermostat. Too cool and it will run like it's cold.

 

These 4 sensors determine fuel flow commanded by the computer.

Manifold Absolute Pressure Sensor (MAP)
Engine Coolant Temperature Sensor (ECT)
Air Charge Temperature (ACT)
Oxygen Sensor (HEGO)

Of the 4, the O2 sensor is the most important as it causes the computer to maintain the ideal fuel/air ratio once the system goes closed loop.

A good read on general Ford EFI is here:
Ford Fuel Injection

These guys are mainly about 302 Mustangs but the EFI is basically the same. jim

 

Thanks Jim! Since you rebuilt your dads van i am sure you understand changing out parts!! What do you think about the EGR valve? Don't they have a rubber diaphragm that goes bad sometimes?
I found a new motorcraft EGR valve for $70, that's less then 1/2 price and about the price of aftermarket valves.. I just need to verify the part number fits my van..
PArt #CX1119

Amazon says it fits my van
https://www.amazon.com/gp/product/co...25&vehicleId=1

But the vendor i found it at, their compatibility list skips from 87 to 89 leaving out 1988..

My tail pipe is black inside and when the wind is right you can smell the fumes.. I am not actually sure on MPG yet as since i have the AC working i haven't been cutting it off much when out working.. But the last 3 fill ups it was averaging 11mpg I think it can do much better

 

Have you pulled codes? This should always be the first step when troubleshooting a problem , if there are codes then you have something to target but even if there aren't that still tells you something, it tells you to forget about sensors and look at things outside computer control like fuel pressure or the ignition system.

 

Ill try to pull check ans see if there are any codes this afternoon..
The CEL light comes on when you turn the key on but I havent seen it come on once the engine is started.. perhaps something in the memory...

 

Can't help much with EGR, the first chance I had it became this. Older than 25 years in Texas, they don't do emissions testing. I pulled off all the parasitic smog stuff. jim



NoEGRValve

 

I have thought about deleting mine but for now it is running ok and I am not sure what this state is going to do.. Right now it is 25 years and you don't need emissions. I think as time goes by they will try to get more older cars off the road..

BUT thanks for the pic! /for some reason I was thinking that the EGR was on the back of the manifold like my 85 but now I remember my 90 TC was on the front...
Can I change the EGR without removing the doghouse?
Also without looking, TPS can be changed from the front?

If so then that means I only need to remove the dog house for the plugs, wires, and FPS and i will have all those by Saturday..

 

Yeah, the EGR is gettable from the front once all the usual stuff is removed. I pulled the TB when I replaced the TPS and once it is out, the EGR is easier. The exhaust tube is maybe a hassle.

 

You must have kept a picture diary of everything you did to that van! Thats great, you should print and sell a repair manual for the 88 e150's

I want to take the TB off and clean it but not right now... I need to make a trip the weekend after the 4th and don't have the extra day to do it right and clean everything..

When you replaced the TP sensor, did you calibrate it with a meter? I ordered a new Motorcraft TPS and if I remember correctly, some of then do not have a slot for adjusting them..


So i will be replacing the EGR, TPS, Oxygen sensor, FPR, Plugs, cap, rotor, all Motorcraft,, and NAPA Belden wires.
I think I will Change the plugs, wires, cap and rotor first then test drive it. Then do a test drive between each of the other part change-outs. That way if there is a problem with it running worse then before, I wont have to dig so far to find the problem..
I guess it would be a god time to do a compression check with all the plugs out...

When doing a compression check, is there a good reason use a little oil in each cylinder if they check out good and even dry?
When I checked my 85 i didn't use oil and they were all right at 165... A couple of the cylinders are a bit hard to get to as you know...

 

I wrote training manuals for maintaining jet aircraft for a living. Retired now but picture taking is still a habit. The van was a hobby so photos help me remember where I was.

I replaced original parts as I got to them, 27 years is a lot of service. I dumped the memory in the computer with each sensor change, then just drove it to let it relearn the fuel trims.

 

Thanks again Jim..
Well I went out there and looked at the TPS this morning. I see why you took off the TB. Now my next question is how in the world would you get in there to adjust it once it is back together? It is on the bottom of the TB, not the top like my Lincoln.

If I remember correctly you can use a feeler gauge to set the idle stop for the throttle plates and then you adjust the TPS.. I can see plugging in the TPS with the TB not yet attached perhaps and then turning the ignition on and adjusting it... I believe it is supposed to be at .98 or .96 Volts.. I will have to get my manual back from my moms house and check that... I think there is also supposed to be a way to set the TPS with the throttle plates wide opened but I don't remember that..

Thanks for the advice on dumping the computer each time...

I think one of my next ventures will be will be remote locating the TFI module as I keep seeing yours and know that would be a much better location.. IF you needed to run the van with the air box off, you just unscrew the TFI module and set it to the side, so long as it doesn't fall off into the fan?


One more question for you Jim.. I have my AC working now and everything is new. It only has a front AC unit and i can't seem to get the vent temps below 50F. It is 50F wither it is 70F or 90F outside.. My question is did your van have a valve on the heater lines to close off the flow? Mine doesn't have a valve and the hoses are original or at least motorcraft stamped on them.. There is also a two wire female connector laying loose in that area with a light blue/green stripe wire and red wire.. I was thinking the duct work probably has a damper that closes off the heat and thought it might be partially opened but then again with the selector switch in the vent position and the fan on, it doesn't blow hot air, so I assume it is working properly.. I know the fresh air intake is working when the AC is on MAX..

Thanks
Anna

 

I don't know of any way to adjust it after it is back together. That's another reason for dumping the computer. It "relogs" the sensors into memory. There is an adjustment on the manual throttle stop screw with the IAC unplugged, ~500 RPM or something similar. There is also a spacer plate between the IAC and throttle body with bleed air screws, put there by Ford to try and maintain idle when the IAC carbons up (at least to get past the service warranty period). Blast those passages out when the IAC is off (that you can do with the TB in place). There is a tech bulletin on adjusting the air bleeds, I'll have to find it.

Running with the air box off is easy, undo the dual hoses from the lid and lay it over by the master cylinder. Then pull the bracket that holds the lower part and take it out. I didn't unhook the TFI module and the SPOUT connector is on top when doing base timing checks. Of course, if you must adjust the timing, then the air box has to come out. jim

 

At the risk of overwhelming you:
https://www.alldatadiy.com/TSB/20/88201101.html

 

Could not find the idle air bypass plate document. It is in here, somewhere?
https://www.google.com/#q=ford+idle+air+bypass+plate
jim

Always check the offline hard drives first!
http://beta.askatech.com/AskATechLiv...Track/F069.pdf