All,
I have a 1991 Ford Econoline E-250 with a 5.0L engine with original 76K on the engine.

It has what feels to me as a lack of power/performance issue. I have had my fair share of vans and trucks (9) and this thing seems lacking. It will get up to highway speeds but it feels lethargic/struggling and at full pedal seems to bog down and almost stall but as soon as I let up on gas everything seems as it was before.

I considered maybe bad plug or something along those line but there is no bad plug feel. (Meaning it does not have power and then the power goes away intermediately)

I have even considered possibly a exhaust issue as the muffler was severely corroded (broken apart) and I replaced with the large OEM muffler. Maybe something is clogged???

The vehicle prior to my purchase had sat for over 6 years resulting in the dual tank fuel system being replaced. Everything from the tanks up to and including the fuel regulator was replaced (3 pumps and rails, tanks, filters, etc). All do to the Gummed up mess and rust that had gotten into everything fuel wise from the tanks etc. The front filter did its job and had contained the mess to that point.The latest part being the dual tank reservoir which prior to its replacement and fuel filter (again) the vehicle behaved similarly as it does now but would die out of the blue just to start up later fine. Like I said though the reservoir tank and a couple weeks driving has shown that part was problematic. I replaced the fuel filter again as the old reservoir showed signs of rust and corrosion throughout the top and I wanted to make sure everything was clean.

I have given a tune up (plugs, wires, cap) and checked timing at idle. I have also replaced the coil. All fluids in the vehicle have been replaced as well as a large section of the cooling system (Corrosion and plugged radiator). I initially gave the engine a compression check (almost 2 years ago) and had nothing that seemed out of the place.

The engine, even in winter colds (below 20 degrees) always starts right up.

It almost feels to me like a problem I had with a old Chevy were the advance on the timing was not quite right. I am not familiar with the ignition system in this Van other then replacement of cap and rotor.

I have and I also had the computer scanned and nothing comes up. No engine lights.

I am uncertain at this point what to look at next.

Any help or suggestions are appreciated!

Thanks
Chris

 

You said you checked timing. What was it?

I believe that year engine has what's referred to as a "SPOUT" connector. To check timing, the engine needs to be pre-warmmed to normal Op temp, & the SPOUT connector removed to see your actual Base time. If you check timing w/o removing the SPOUT connector, you will be seeing base time w/ the additional degree's of timing added by the ECU.

Additionally, any adjustment to base time must be done w/ the SPOUT connector out, then replace SPOUT connector.

It's possible the SPOUT connector was removed during a prior tune & not replaced. W/ SPOUT out some timing increase will be added as RPM increases, but likely no more than 7-9 degrees.

W/ SPOUT in, there is a 19-21 degree increase at the top of the timing curve (timeng all in) from base time, as there should be.

Toss a can of Seafaom in your tank also.

 

From memory, as I did this last summer with the tune up, was like 10-12 degrees BTDC. I let the engine warm and I had to mess with a wire similar to other engines I have done.

It checked out so I did not loosen the distributor at all. No reason to...so I did not mess with it.

I have retimed more than a few engines Ford and otherwise. One of the thoughts I have is something is frozen up in the distributor.

I can recheck towards this weekend its supposed to be in the 60s...It was 20 this morning.

Thanks
Chris

 

SPOUT plug will look like this. It will be found off the ignition control module (ICM/ aka TFI module):
W/ SPOUT out, you should see 10BTDC at warm curb idle. W/ SPUOT back in it's connection you should be seeing approximately 17BTDC at warm curb idle.

 

Does it have the catalytic converters still? If so, were they checked for being clogged or melted inside?

Just a thought...

 

All,
I will look into the timing again.

I remember the spout connector but probably would not hurt to pull out the light and do a once over again as its been almost a year (last summer).

I thought about the Catalytic Convertor. It has the original factory one tucked just below passenger seat area. Similar to my 1990 F150 Truck I had, (that truck is still in the family - mother-in-law)

Did not see anything unusual about the CAT but it could be plugged....I had a old Chrysler that did that to me and could not get above 25mph when it clogged up on the expressway one cold night.....later found out the cat was a 2.2 L and not a 2.6 L model. That was a Midas replacement which they corrected. Drove me nuts at first to figure out till I just decided to cut it off and see what would happened. Low and behold engine was just fine.

Is there any way to tell a plug CAT...I mean even in a professional shop could it be diagnosed?...we took that Chrysler to 2 different local shops and they put up there arms. What would cause a plug CAT...I know it happens....just want to make sure I get to the source of the problem.

Anything else that may cause the issue I am experiencing I would like to try....I may even pull the plugs again this weekend and do a walk through compression wise and plug check again.

I have a set of Struts and Shocks to do on the Wife's car early Saturday.

Thanks
Chris

 

All,
Sorry about the delay but Unfortunately I did not get a chance to look at the van over the weekend.

I tore into the wife's car and found about a full weekend worth of work which I have completed.

I may get some time tonight but the weather is somewhat crappy in Ohio, at least compared to the weekend, plus I am putting a thermostat in a friends car tonight.....

I will let you know hopefully by weeks end.

Thanks all.
Chris

 

Completely remove the O2 sensor from exhaust. As in, just remove it and let the exhaust blow out that hole. Only way to completely tell without gutting it, cutting it out or having a shop put a gauge on the exhaust to measure back pressure.

Maybe another member can chime in with another wise idea. I know a member had same problem in the 4.9 300 section and that's what the mechanic did at the shop.

 

Thanks for the tip...I never thought of that.... I was dreading either cutting or heating up the exhaust bolts to remove.

Thanks again,
Chris