I have a 1989 E-150 with a efi 302 and AOD. The motor has 147,000+ miles. Oil pressure is 25 PSI hot, vacuum is 17-20 inches, haven't checked compression. Fuel pressure is 33-35 PSI with key on engine off and with engine idling.

First cold startup of the morning the van is hard to start. It turns over fine but barely catches, and when it does catch it runs very rough for about ten seconds as the RPMS slowly pick up and eventually it smooths out and idles at 1000-1250 RPM until warm.

It idles nice and smooth at 600-750 RPM, but when hot, it pings wildly on any kind of acceleration, but more often it just bogs down when the throttle is first depressed and then surges. Sometimes it will actually stall, such as when maneuvering into a parking spot or taking off uphill from a stop.

New cap, rotor, plugs, IAC valve, thermostat, air filter, oil and oil filter. Pinging gets less if I fill it with 89 octane mid-grade gas instead of 87 octane regular (duh), but shouldn't I be able to use regular?

No trouble codes, I haev run the diagnostic tests with my OTC 2000 diagnostic tool using 1993 Pathfinder II software and found no problems.

I am at my wits end and contemplating a swap from the 302 to a 300. Does anyone have any suggestions as to what my be causing the poor performance, stumbling, stalling, and hard starting?

Thanks.

 

Too much timing? Did you see where that was?

Try adding Marvel Mystery oil to the gas with your next fill up and see what that does for you.

Also check your plugs. I don't know a lot about efi, but I would guess that you have got a problem with the air fuel mixture, and would see about the TPS and mass air if that thing has got them.

 

Yeah i would check the timing. Also it might be a fuel issue and the injectors could have a problem. My '89 5.0 once had horrible issues with running rough and stumbling while cutting off on me at stop lights and it turned out to be the fuel pressure regulator which checked out fine at first but would randomly jump up in fuel pressure and then regulate sometimes. It showed itself surprisingly by hooking the fuel pressure gauge up and tapping on the fpr somehow this caused the pressure to jump . You will have speed density and if you got another ford sitting around or someone you know thats got one around the same year then you can try a known good MAP sensor off a running car and see if that works cause they are expensive just to be guessing. If i remember correctly it doesn't really matter about the map sensor coming from a different engine size because i think i used one off of a 460 efi motor. Either way im not real good with efi but hope this helps. Early efi can be frustrating to figure out but they are usually reliable so dont let it get you down and good luck.

 

Okay. Timing is on my list check, as is timing chain slack. I checked fuel pressure and it appeared okay with the engine off, the engine on, and revving the engine. I haven't replaced the O2 sensor yet either.

I hate EFI. I can't wait to get my carbed 84 Ford back on the road...

 

Try marvel mystery oil in the gas see what that gets you.

 

Reed, I have a 1991 F150 302 2wd. Thanks for posting, mine is doing the same thing. Except it will usually start fine, but the frequency of it running smoothly opposed to not, is puzzling.

I am leaning more towards how warm the engine is/outside temp. If I have to run it cold, it will go for about a mile or two, then it will start to sputter and like you said when you push on the accelerator it will "bog down and then surge"(Well put). Then again, this will not aways happen when I have to run it cold, sometimes it will run fine.

I replaced my fuel pump, two temp sensors which I think were on the manifold, and my plugs and wires.

This has been extremely irritating becuase it will mess with me on the backroads (which I know to take now) and after about a 1/2 hour of hoping the engine running will smooth out, it will work and give me the confidence to drive it again.

It sometimes stalls when I am backing into parking spots, or taking off on a hill.

Reed, I would love to hear what you tried, or what worked. If anyone else has any more suggestions, I would appreciate your input.

Jeffrey Patterson

 

Gas line dryer triple dose that puppy. You can clean the o2 sensor before you run out and spend money on a new one. Pull it out run the tip in a torch for 15 seconds or
so and wipe it off, try another 10 seconds if it still has build up on it. You can test it
with a multimeter and the torch and see if it is generating it's signal(search) But just
cleaning it and reinstalling (antisieze!!) will probably do the trick.

 

I've also heard of spraying the o2 sensors with brake cleaner and wiping them off real good but i defenitely wouldn't buy one without knowing it was bad or not.

 

Ok, I have never heard of Gas Line Dryer, but i will probably get some tomorrow when the parts store opens along with brake cleaner

Just wondering why the O2 sensor would mess with me on hills and when I am parking?

 

Well im not really certain why the o2 would affect you in the ways you're talking about but sounds like you are losing power so usually if the computer reads no codes you just start from the top. Check the fuel system and if you changed the fuel pump you should be certain its pressurized but still good to get a reading on a pressure gauge. Also check is electrical system like timing and its good you probably changed plugs but when you did, did they look alright? If still puzzled check the mechanical side of things like compression tests are sometimes usefull but i don't really know that much and ur truck sounds like its being frustrating maybe someone will chime in with past experience with this issue.

 

have you pulled cp codes, could help a lot. pull codes and post, ck timing, ck for vacume leaks,

 

Vacuum is 17-20 at idle (higher when cold), no trouble codes. Haven't checked the timing yet.

Clee- sounds like you have my van's twin.

 

yea sounds like it, 400,000 miles on it, newer 302 put in about 50,000 miles on it. its been a pain [p.i.t.a.] keeping motor running smooth. having sursing at low idle,low rpm driving comes and gos, traced it down to egr system, just havent been able to work on it( been sick 4 while) hang in there , somebody will help,as to what to ck. more than likly,simple fix, finding problem lots of fun, uuugh. take care...........srry for spelling..........

 

Don't use brake or carb cleaner on the O2 sensor!!! Use the flame from a propane
torch to heat and cook the build up off, then wipe off the carboned build up,repeat
until it is metal not a coating, The only thing you should use is denatured alcohol
if you feel it needs to be shiny(it doesn't) The reason why the O2 sensor is suspect
is if it has a build up on the sensor it will not read correctly and could cause the Fuel
mixture to be off (air-fuel) The sensor works by making voltage in relation to heat
and a hot exhaust = a lean burn a cooler exhaust stream = a too rich burn (too much
fuel) If you are not burning 14 pounds of air to 1 pound of fuel you are not running the
motor t the optimum ratio. You are physically burning pounds of air and pounds of fuel
not ounces of fuel and cfm of air those are just a measurement value. 1 Pound of air
equals about 13 cubic feet. Yes air has weight and that is why at sea level the air
pressure is higher (14.7psi) then at say 6000 ft. Basically think of a column of air
going straight up above your head all that volume of air is pushing down on you or is
getting pushed into your motor, Yes air is pushed not sucked into your motor!!
Do the gas line dryer first I would go with 2 of heet and 2 of iso heet, the heet is just
methanol and it sinks and gathers up the water at the bottom and the iso heet is just
Isopropanyl alcohol and it mixes with the fuel and grabs the water so it can be burnt.
Changing your fuel filter and filling the filter up with iso heet will grab all the water off
the fuel rail on that first start up.

 

So water can stay inside your lines and at the bottom of your tank through multiple fill-ups? Just curious, I ran 2 bottles through the truck a week or two ago. It didn't really do much, I think the condition is worse because sometimes it wont even fire up. I would try running pressure tests, but I don't have the right equipment, which sucks because in my book they tell you to run those tests to find out a lot of problems. I replaced the fuel pump relay but so far it has not helped. when some tax $ comes back I was planning on taking it to the mechanic. Which I am a little hesitant to do again because only code that came up was a sensor that I replaced and the truck seems to only fu@# up when I need to get somewhere on time :0!!

appreciate the input

Jeff