Hello folks... Long post... I have two issues to describe (to be sure that they are not related), but I am primarily concerned with the starting issue.

I have a 1990 Ford F-150 XLT Lariat with the 351 Windsor (5.8L) and an E4OD transmission (with 4 wheel drive). It is approaching 100,000 miles.

First, the good news... The pickup is not my daily driver, so I am not hot to trot to get this figured out. I can take a methodical approach and a couple of weeks to straighten it out.

One interesting fact, once the truck is running and has been so doing for a couple minutes, it has not shown any difficulty in running. It continues to run fine following a successful start and a handful of seconds of continued operation, regardless of the fuel tank in operation.

She has always been a very consistent starter (sometimes going multiple weeks between starts and still firing up within a few cranks). Now, I am having intermittent problems getting her to fire up. Starter is fine, solenoid is fine, battery is fine. She cranks without issue. The trouble is either a lack of fuel or spark to get it going.

The internal fuel pumps have both been replaced in the last 6 years (both tanks) as was the instrument panel rocker switch.

When I have attempted to start my pickup within the last week (3 different days of attempts in that period), I can expect a 50% failure to start within the first handful of attempts when cold and set to the rear tank. When warm, it is more likely to start and run, though it does occasionally act as though it's running out of fuel, sputters and dies immediately following a start. Yesterday, after 30 seconds total of crank attempts in a handful of separate key turns, I gave up on the rear tank and switched to the front tank. Within 3 seconds the truck fired right up. Then, I immediately switched to the rear tank again, trying to determine if the internal pump in the rear tank was bad and I proceeded to drive home, over 60 miles, on the rear tank and without any trouble, no running troubles at all, plenty of downshift acceleration and hill climbing power for a mile or two at a time. Once again, all on the rear tank after starting using the front tank switch position following the failure to start on the rear tank switch position. Previously, I had never tried switching to the front tank to start and just keep trying until it started and ran.

I was thinking that it might be some type of MAF issue, but I don't believe my pickup has an MAF (if it does, it is not betwixt the air cleaner housing and throttle body), which might be normal for this model.

As a secondary concern, I have some increase in cooling system reported temperature (via the gauge). It is not leaving the normal range but does seem to be getting warmer than it had been. I mention this to make sure there is not some silly cooling system temperature sensor or something similar that might have failed and is trying to tell the engine not to start. I just don't trust all of those crazy sensors.

Any suggestions? I appreciate hearing your input and guidance.

Have a great day, thanks for sticking with the long post and regards...

Jason

 

Should be the speed density so it does not have a MAF sensor. I would try to verify the fuel pressure before start up to see if that is the issue. If you don't have a fuel pressure gauge, a simple way is to use a screw driver and quickly push the Schrader valve on the fuel rail. if it sprays you at least know there's pressure. a fuel pressure regulator can bleed down after sitting and cause a hard start. you can also test it with a vacuum gauge or just see if it the vehicle idles differently when the vacuum line is removed from the regulator (if it stays the same, the diaphragm is probably compromised)...

 

Thanks for the suggestion... I went out there, tried to crank her over for a few seconds, did not start on the rear tank, switched to the front rekeyed and cranked again, started on first try.

Once running, I tried to test the regulator as you suggested. A bit of pulling was required to get the vacuum line off, which I guessed was a good sign. Once removed, I detected no difference in idle for at least 20-30 seconds. The vacuum line was squealing like a banshee so I put it back on the regulator, still no change. How long will it take to reflect a change?

Thanks for your continued assistance.

 

Here's my experience with my 95 F250 5.8L M/T. When it was warm and dry out it would usually fire within 5 to 8 seconds of cranking, if it cool outside, it would take longer maybe 15 seconds. after it was started it would never fail to start the rest of the day as soon as I hit the key. I noticed over time if it was wet or raining out it would take even longer to start until finally it refused to start at all. I simply replaced the dist cap and rotor and now it fires up within 2 or 3 seconds every time. Not saying this is your problem but it's easy to check for corrosion on the towers and see if the rotor has rough edges, Just seems to me if the truck will run off the rear tanks for extended periods of time and you have plenty of power, I don't think it's fuel related.

 

It should be instant. If not, that diaphragm is bypassing. you can test it with engine off with a vacuum tester. it should hold 20 Hg I think without bleeding down.

 

Well, two updates...

First, thanks for the further guidance on the idling vacuum test. I will check it again in a little while.

I just got in from the pickup and had the cap and rotor open. It was a slightly rusty mess in there both on the cap and the rotor. I went ahead and cleaned it all up with some 420 grit sandpaper and a cloth bathed in QD Electronic cleaner. Stepped in, rear tank selected and bumped the starter, she fired right up, like all days prior to the last couple of weeks.

Now, I am not excited yet, as there might have still been some pressure in the fuel system. I don't have a gauge and live in a pretty remote area where the local auto parts place wants $99 for their kit. I might see if I can get the mail order unit from Harbor Freight or might wait until I go to one in the first couple weeks of July.

On the other hand, I might just get a fuel pressure regulator and filter from the parts house and replace them anyhow. Might not hurt to just do it.

Thanks again for all the suggestions and input everyone...

Regards...

 

Good deal. It's amazing how even the smallest (looking) spots of corrosion can make a difference. I would say if the idle doesn't change that diaphragm is bad. It doesn't mean you necessarily have to replace it but I would. I think the vacuum kit is great to have around. I use it a lot. I got mine from Harbor Freight. Works great for bleeding motorcycle brakes as well
Mityvac Vacuum Pump - Save on Mityvac Pumps at Harbor Freight!

 

Excellent, glad to hear a thumbs up from a happy customer. It'll make my purchase easier in the end.

I'll keep on trying the pickup for the next few days and let you know what happens, I assure you.

 

I guess that some people might be interested in seeing my pickup, to know what we are dealing with here.

Keep in mind that this was taken a few minutes ago, after several successful first time starts on the rear tank. Looking good so far!

This photo stars 2 of our 3 Ford's here... The third is with the wife at work (Ford Focus).



Our 1950 Ford 8N and 1990 Ford F-150 XLT 4x4.




I'll keep everyone up to date on the situation, thanks again everybody.

 

Have started the pickup with 100% success at least 20-30 times since cleaning out the distributor cap and rotor assembly. She is back to normal as regards the starting cycle. I will update again in a week or so, sooner if there is trouble.

Thank you all again, your help was invaluable!

Jason
Bandon, Oregon

 

Worry not, the fuel pressure regulator and fuel filter are both going to be done in the next couple or few weeks. Thank you again for your suggestions, looking forward to a better running pickup.

Have a great rest of your week...

Jason
Bandon, Oregon