I have a 1992 F150 with a 351W installed and it does not make much power and hesitates on acceleration, especially at slower engine speeds. (like when it is in high gear at 35 mph or so it surges on acceleration)

I got stranded 60 miles from home with it once and it would not run until the engine had cooled. Even then I could only drive it home with the overdrive off and engine speed in excess of 3000 rpm. When I turned the OD back on it began bucking and surging and would not maintain speed. Now I fear driving it any further that I am willing to tow it.

While checking the engine timing I found that the engine idles fine but when the spout is removed it will run extremely slow and rough and then die. With the spout in it idles fine but my timing light reveals a constant change in timing from 20 - 40 BTDC.

Cam timing is correct, plugs are new, ignition module is new.

Any ideas will be seriously considered. Thanks.

 

make sure your timing meets the ford specifications. if it still runs bad, make sure your intake manifold gasket is good, and the manifold is properly torqued

 

Are you positive your hold down bolt is secure? reset the base timing with the pill out then recheck timing with it in. Also how are your plug wires?

 

Thanks for the replies. I have replaced the intake manifold gasket and all looks good there. My plug wires are good and I do not hear or see any sparks from these wires in the dark. They look to be in good condition. One problem is that I cannot set the base timing with the spout out because the engine will not run for me to do so. I have tried various settings of the distributor and still cannot get it to run with the spout out.

Is the advance on the ignition totally via the ECU? There is no form of advance mechanism on the distributor itself. Is it possible that the ECU is the culprit?

Thanks

 

Say is this carbed or EFI?

 

It is EFI.

 

Then no the only form of advance is the computer, there is no vacuum advance... Well taking the pill out basically that puts the timing on whatever the distibutor is based at, and almost completely taking the ECU out of the equation. What I would do is get number one piston on the compression stroke then move the crankshaft till its at the base time. Then check to see where the rotor is in relation to the number one terminal on the cap, you may need to mark on the outside of the dist where the terminal is so you can see with the cap off... Good luck.

 

When I removed the distributor it did line up quite close with the #1 tower, but I will be sure to double check that when I reinstall it. Right now I have the timing chain cover off since I was checking my cam chain timing. I had to destroy the cover to get it off since one bolt had rusted and swollen due to a water pump gasket leak and sheared off upon removal. I had to cut the housing to free it from the bolt that was basically welded to it.

So before I can go any further I need a timing chain cover for a 5.8 W EFI engine, casting number E7TE. Anybody have an extra laying around?

I will post once I get it back together and running (in it's own peculiar way) again.

 

Well you can always go junkyard hopping for it.

 

There are 4 things you can count on in life; birth, death, taxes, and that at least one of the long water pump/timing cover bolts on your small block Ford will break when either removing it or reinstalling it. Make sure you replace all of the timing cover bolts with new ones, or you're very likely to break another one off when you try and put it all back together.

Your distributor has no advance mechanism, either vacuum or mechanical. It is completely controled by the ECM. Pulling the spout connector disables the ECM's ability to advance the timing at all. Having the timing jump around while checking it with the spout connector plugged in is normal.

mdstud is correct; you need to double check your marks. It's possible that your balancer is bad, and the marks may have drifted. While the front is apart, clean the pointer and the balancer, and with some liquid paper, make a mark the pointer where it says 10 degrees BEFORE top dead center, and on the TDC mark on the balancer. This will make reading it with a timing light much easier.

After you have it back together, pull the #1 spark plug, and stuff a wadded up paper napkin in the spark plug hole. Don't force it into the cylinder, just plug the hole with it. Then use a remote starter switch to bump the engine in small bursts until the napkin pops out. This will put you very close to TDC. Check the balancer, and crank the engine by hand the remaining few degrees until the mark lines up with the mark you made at 10 degrees advanced on the pointer. At this point, the rotor tip should be pointing exactly at the terminal on the distributor cap for the #1 cylinder. Move the distributor until it is. Then try starting it, and checking the timing with the spout removed. Adjust it until the marks line up perfect with the timing light, and reinstall the spout connector.

That will solve your timing issue, but won't have much affect on your initial problem. It sounds to me like your torque convertor is locking up, causing the engine to stumble. You will need to pull your codes and see what they say.

Post your results.

 

Thanks PKRWUD for some good advice. I am in the process of rounding up the parts to get the engine back together so it may be a bit. Is there any way to toubleshoot the torque converter? I have not gotten any engine codes relating to the converter at all.

 

I got my engine back together today and performance is the same. I know that the cam and ignition timing are correct. I set the ignition timing static since it still will not run well enough with the spout out to set the timing. Spout in I have it set to 25 degrees BTDC. It idles fine but hesitates and stumbles on acceleration.

Where to go from here?

 

Although you say its right it still sounds like the cam timing could be off, have you removed it before the problems started? or changed the timing chain maybe?

 

Do me a big favor. Get a helper, and start the engine. Have your helper hold one foot on the brake, and manually shift the transmission into first gear (L1). While the truck is in gear, and idling, try removing the spout connector, and see what happens. I have a hunch that the idle will be okay, rather than stall. If it stalls, put the spout back in, put it in park, and start it up again. This time, try driving it, but only with the transmission manually in first gear. See if the problem is gone. Let me know what happens, and we'll go from there.

 

I checked the engine as suggested by removing the spout with the transmission in low, neutral etc one by one and there was no change. Driving the truck with the transmission in low, or any other gear manually selected makes no change either.

I noticed the other day that when I remove the spout and the engine begins to run very rough (and slow as a result) that I lose my timing light signal so I could not check the timing in that state anyway.

Does this vehicle have a default mode it goes to when an input sensor is inop? It feels like this is what it is doing.