Sorry for the Long first post but I wanted to give you all the info.

We have a 94 E350 15Pass Club Wagon with the 460 that has developed a problem this spring.


First off the van only has 28K miles on it so it does do a lot of sitting. When we started driving it this spring it would start bucking and what seems to be missing when cruising along. Under a hard acceleration it would run perfectly and have all the power you could ever need.

When idling in park, neutral, and drive it also has a distinct miss.


Here is what I have done so far:

1) A fuel drier was added thinking there is water in the fuel
2) Fuel injector cleaner was added
3) Fuel filter changed (on the frame rail under the driver’s seat)
4) Plugs and wires. I also cleaned the rotor and the contacts on the cap.

In messing around with things I have also looked at the MAP sensor:

1) Disconnected the vac. line to it with the engine running and it stalls

2) Disconnected the Electrical connection and the truck idles smooth (but rich) also it does not buck when driving but shifts very harsh.

After looking online I have seen talk of the MLP sensor but would that cause a miss at idle in PARK? or could I have 2 things going on?

I know the MLP sensor has never been changed and is not the updated one.
<!-- / message --><!-- sig -->

 

Did you ever figure out what the problem is?

I have a 1994 Class C with a 460 in it with 55k miles and have replaced almost everything I can.
Map sensor
Fuel Pump and filter
New Dist, cap and rotor
Plug wires, Plugs
MLPS
TPS
IAC
Vacume hoses
Had the ICM tested at 2 different places
Unplugged all electrical connections and cleaned thoroughly.
Ran 200 gallons of fuel through it with Lucas fuel injector cleaner, and other cleaners.
I have used 10 cans of carb cleaner trying to find a vacume leak to no avail.

Same thing, when on the gas it runs good, but when cruising it bucks and misses, and at idle it will sometimes die unless in neutral. It's very anoying and I am not sure what else to go after.

I have seen a lot of problems like this and have done tons of research on this site and others but have never have seen a fix.

Anyone??

 

These ECUs can have logged codes without setting a check engine light, so it's always worth reading the codes. The codes can clear themselves if the problem goes away, so code checking while the problem is happening may be more useful.

 

I agree u can pick up a code reader for your truck with a book of codes for bout 30 bucks online.. Obd-1 i believe. anyway i had a problem kinda like yours ... and i check my codes and replaced all my senors just bout , the main one was the senor in the cat was giving me the problem .. but i figured i would replace them all !! lol anyway
truck runs great ....
well good luck to u ,, hope you post your findings

jayson

 

Thanks guys, but I have the codes read by 3 different current Ford Mechanics and nothing. As they are checking the codes the truck is missing like crazy and still nothing, no codes.

You said there is a sensor in the CAT, is that the catalitic converter? I cant find a sensor anywhere around there, the closest one is the o2 sensor which I have already changed.

What other sensors should I change?

Thanks in advance.

 

Fuel pump maybe?

PK

 

Not a fuel pump, changed that and the pressure is between 35 and 40 at idle.

Still messing with things.

Any more suggestions? At this point I will change anything and everything, I am almost there.

 

I hear ya, had a '89 E-250 460 w/ EFI and had to go with "let's try this module" approach. Finally got it after many trips to the shop though for awhile, I thought it was possessed!

Good luck, PK

 

Your timing is good for asking what our out come was.

I finally gave up and brought it in to the dealer where it was bough new. They had it for 2 days because like yours ours was not throwing codes. so it was trial and error for them too, and all of the parts for this thing were not stocked anymore.

1) they claimed that it needed a new MAP senor so they changed that. They were getting a hard code but I still doubt that. When I was messing around with the truck I ran it with the MAP unplugged so that was prob the code they were finding. We also had put a used aftermarket sensor in it to try and I didn't put ours back, so we didn't fight that. They also said that didn't fix the problem, but again they didn't take it out because of the code they found.


2) They then replaced the ignition control module. It now runs 99% better. I say only 99% because once and while the RPMs will drop real low almost as if it is going to stall. It will then re-catch and be fine.


FYI the MAP was 100 bucks more then ignition control module.

 

I have taken the ICM and had it tested at two different places, both showed it to be in good shape. I have a new MAP also and nothing.

I read a past post about a possible PCM, with a possible burnt sensor. I am going to investigate that today.

Thanks for the suggestion. I might just buy a new one anywayse, couldn't hurt.

 

So just out of curiosity, what module or change ended up fixing the problem?

 

The dealer couldn't/didn't bench test it they just put a new one in. They sent a shop guy almost 2 hours away (one way) to go to the Ford Boston Parts Center just to try it. Plus it was 100bucks cheaper then the MAP.

 

You know the ECM will test its own factory fuel supply settings from time to time by starving the engine a little or going a little rich to see how the engine responds. It does this to assess the natural aging process in our vehicles' systems. That could very well be why your 460 goes to a low idle from time to time. Your new ICM might actually be a 100% fix. I have a similar issue to investigate so I'll check that. Thanks for posting all of this.

 

So I think I found a vacuum leak today. But not sure.

I hope someone can tell me what this tube is for.

The tube is 1/2 inch in diamater and comes from the exhaust manifold up to the EGR valve, and just before the EGR, it bolts on to the side of the intake manifold then screws on to the EGR. As it goes up it curves around the valve cover with a coragated (water heater gas hose looking bend) Well there is a leak in it and I am wondering if it is exhaust or vacume. I could hear it through the heat shield white fiberglass looking thing. Peeled that back and then could feel it and hear it pretty good.

Could this be a vacuum leak? or is it exhaust.

 

Should have listened to pete982 sooner.


I found my problem. The missing while idling and light acceleration.

As I said before, I took my ICM in to 2 different places to have it tested, both places said it was good. Everyone said if it was bad, it wouldn't start. Everyone was very WRONG. $60.00 for the cheap one and it is fixed. Now to Ford for the good one, ICM that is.

At least I have a new fuel <nobr style="color: darkblue; font-weight: bold; font-family: verdana,geneva,lucida,'lucida grande',arial,helvetica,sans-serif;" id="itxt_nobr_13_0">pump</nobr>, filter, distributor, Map sensor, Egr valve and Egr sylonoid, Idle air Mixture valve, Plugs, Wires, cap and rotor, fuel filler cap and some other misc vacuum lines and O2 sensor. haha

Note to self: Replace the cheapest parts first..
<!-- / message --> <!-- controls -->