I had a similar post in here and it looks like it disappared so here we go... Purchased a 98 F150 4wd with 238,000 on an origional engine but I have some questions...

1. When the truck is at idle, if I punch the gas it hesitates for a minute. Last response was that it could be a vacuum leak but I don't see anything wrong with my lines anywhere. Would engine restore help?

2. I have a gash in the cat on the passenger side. Is it possible that the O2 sensor is messing with the computer at idle?

3. Was out driving it yesterday and it almost died like there was either something blocking something in the gas tank or engine. Checked all my fluid levels and their all good. Would seafoam help with this?

4. Anyone happen to have diagrams for the air intake, spark plug wire order(it might be backwards), and steering column w/cc(it's just sitting on the shaft wobbly and not sure how to secure it)? My chilton for this year truck lacks them.

5. How can I tell wither or not the truck's running too lean? I don't think it's running rich as the engine's clean and there's no soot on the exhaust.

This truck's thrown me for a loop. It took all my knowledge of ford trucks and shot it out the window so my questioning will apear noobish. Most of everything on this truck operates - it turns over quickly, AC blows cold and heat blows hot. I did a tune up when I got it but was unable to get the back 2 spark plugs. Also the plugs that I was able to get to were black from oil and the caps were burnt. Brakes are strong too but every now and then if I lightly tap the pedal it'll stop short. Thanks to everyone who helps this EFI noob.

-Matt

 

Well let me bring you up to speed quickly!
First it is a computer controlled engine for which you throw out old carb motor ideas you might have had.
The program is loaded with self diagnostics for which there are over 1000 codes to set when any fail test limits. For this you need a Ford code list and able to interpret them.
For this you need a Scanner to look at and interpret live and stored data.
Otherwise it's all trying to second guess a computer system you found difficult to do.
Some areas are not monitored by the computer directly but can result in drivability issues and code, on a secondary basis..
That being said, is there any codes set?
Have you checked fuel pressure?
Going further, a compression test 'might' be in order to check general engine health.
What is the health of the cats? Are they restricted?
.
What do you mean the engine hesitates a minute when called to accelerate? A minute is a long time in this case.
What say you?
Good luck.

 

O.O to EFI. I knew there was a reason why I loved my early Fords.

Secondly, this truck has two inline cats that come right off the headers with two o2 sensors on each(never seen that before), and the passenger side has a fairly large gash in it because I can see the honeycomb inside. It's not loose it's just there and not sure how to test the drivers side as again, their inline. Fuel preassure's good but now that I think about it, ever since I pulled the plugs and put fresh oil in, oil preassure is kinda on the high side and high humidity seems to make the truck attempt to stall, but doesn't. I notice it more as the truck reaches 65/70 mph.

To clarify, when I first start the truck up and let it idle for a bit to let the engine heat up, whenever I punch the gas quickly it cuts out then comes back. Yes you're right a minute is a long time for anything so it's more like a couple of seconds, it's quick. However, if I tap the gas, it's fine. At first I thought it was either the engine not getting enough oil or the radiator being low but all fluids are at their correct levels and the oils clean. I also thought it might have had something to do with the bit of slack in the accelerator cable but when I pushed on the potometer, it cut out the same so it's something else.

When it almost stalled out on me yesterday I thought it was something in the transmission but that's all good also. Now that I think about it, I did notice when I was at Pep Boys that at idle the tach would fluxuate(not alot, maybe one or two lines) indicating a possible vacuum leake but I have no idea where as all lines are in working order. I also thought it has something to do with the MAF sensor as I found it was disconnected when I got home but hooking it back up didn't change anything. Is it possible the screen in the tank is clogged? I'd check but don't have any way to. If so, I'll get me a can of seafoam and see if that fixes that.

I don't know anything about any codes or compression tests as I don't have gauges or a reader and don't currently have the funds to pay for them as their quite costly, nor do I know where the computer reader port is as I heard I could stick some wire into the port to flash a code though the dash or something like that.

Also something that's sort of related but at what point should this engine be rebuilt? It's about 30,000 miles away from turning 300,000 miles(yes my odometer reads all six and no tenths).

Appreciate the responses,
Matt

 

A physical tear in the cat case renders the CAT useless and likely a code 4xx is set depending on which side.
Min aftermarket cost of a 'replacement assembly' on one side is about $300 plus labor.
At this point in the trucks condition, all the service items likely to be needed and your position on it; the 16 year old truck is ready to be retired.
I'm trying to be honest based on your replies.
Unless you go about it correctly there is no cheap way or short cuts to bring the performance back to even near normal legal emission and drivability without expertise and investment.
Good luck.

 

I appreciate the honesty and yes, it needs alot of work. I just need to get the thing to tow a 5x10 trailor to TN where I'll be able to replace whatever it needs on it. For now I have a temp patch to put over the hole till I can get it to TN. Would this tear in the cat be a possible cause to the engine cutting out?

EDIT: Ok had the truck out today and it seems all problems except for the cut out at idle have fixed itself when I plugged the MAF sensor in. If I can figure out why it's cutting out, I'll be set.

 

Amazing how things work when plugged up. Computer needs the sensor to work with.
The cats normally run at temps over 600 degrees so the patch needs to withstand those temperatures if it works at all.
The hesitation might be a faulty TPS on the throttle body but it's just a guess without investigation.
Get it checked for codes so you have some idea what's going on.
We will get you there yet.
Good luck.

 

Indeed ^.^ I haven't been able to secure a diagnostic tool to read codes but I was reading on another forum that the issue with the engine cutting out when I push the gas might be my o2 sensors being eithe clogged or not working which makes sense I guess since the passenger side cat has a gash in it. Besides running the cats through, are there any effects in disconnecting them? My truck has 2 of em, and I'll be towing a 5x10 uhaul down to TN. Any incite on that would be appreciated.

-Matt

 

The Ox sensors are there for a reason.
They control fuel injection for each cylinder every cycle.
Without them operational, the computer substitutes a 'richer' 'fixed' fuel table to keep the motor running.
This means poor fuel mileage without the benefit of sensor feed back adjusting the fuel ratio to normal levels as the motor runs.
You need to use a Scanner to look at their live operation.
If you replace them without some kind of check, it's just a guess that may not solve anything but spend money.
I can't stress enough, you have a computer system and needs to be looked at this way for live data and codes to tell you what you should be investigating.
Good luck.

 

That makese a heck of alot more sense now actually now that someone has explained their use and should hopefully correct itself once I get that patch on the passenger side(first is around the corner). Thanks bluegrass, once again full of information ^.^

 

Ok I know this is reviving/updating this post but have more to report. Got a patch from autozone to patch the catelytic converter and all that did was reduce the sound in the cab so I know it's working. While I was at autozone I had the tech plug the reader into the onboard computer and it seems the previous owner cleared out whatever codes were in there so I have no idea what was there and the tech couldn't give a length of time it would take for codes to appear in the computer again.

Since patching the cat the truck doesn't seem to lack power anymore which is good but I'm thinking the drivers side cat is clogged but then again i'm not sure because when i got under ther yesterday after driving around doing arronds I held both pipes while wearing gloves and both pipes feel cool to the touch yet I can smell the warmness coming off the engine(almost like the engine's burning oil but it isn't. I've checked all fluids and everything's full and clean).

Truck still hesitates when I first give it gas but if I give it a few before pushing the gas pedal, it'll be fine. Not sure what else to do to correct the hesitation. Also, does anyone have a diagram of the steering wheel? It wobbles up and down and not sure where to secure it. I'm also at a loss where the fuel filter's located as that'll be the next thing I'm replacing.

I know to alot of readers I've got myself a lemon and should be put out of its misury but for now the thing needs to get me, the wife, and a uhaul to TN where I can replace what needs to be replaced correctly.

-Matt

 

if your cats are cool enough to touch them wearing gloves then chances are that they are not plugged up. plugged cats will glow red hot after a couple of miles of driving. hesitation could be a number of things, but like bluegrass mentioned without a proper code reader/scanner it is difficult to tell. an auto zone scanner will only dump hard codes that are set. there are time when a hard code is not set, yet it can still cause driveability issues. pay the money for a dealership to do a through scan where they record the data for a short period of time, a good tech can quickly point out the parameters that are out of range or fluctuating in and out of range that are causing your issues, you can then trouble shoot your way through it.

good luck

ken

 

Yeah... I don't trust any shop with anything(dealers here don't know what their doing, and after a trip to Pep Boys for tires, I won't be going back there again). By reading what seems to be an increasing number of threads with similar hesitation problems then mine, I've come to the conclusion that one or boh of the coils are bad, but I have no way to test or replace them since Pep Boys wants $70/ea. The guy at autozone was clueless when I asked about em.

Reguarding the cats, that makes sense as I remember watching a home video of a friends truck that was stuck in the snow with plugged cats and they glowed red before melting and catching fire. Does it mean then that everything's running correctly exhaust wise? I was under the impression that the pipes would be hot or warm since engine exhause is warm.

-Matt

 

Matt,

below might not apply I am not that familiar with the trucks yet, jsut got mine a year ago and am learning all its quirks, if your truck has the COP system then it should apply, if not , disregard.

If you are tight on cash, try this, get a new set of plugs, get a new set of the springs/boots for the cops, and get two new cops. my truck had the hesitation no power issues but did not throw any hard codes. I took a chance and swapped all of the coils, plugs, and boots. I found that in my case the plugs were probably fine, but the boots were shot, and the coil springs that reside in the boots had corroded causing poor contact between the coil, the spring, and the plug itself causing random misfires that got steadily worse.

if you change all of the plugs, boots w/springs and then starting with the usual suspects coil wise swap them and take it for a test drive. chances are this will fix it up.

also though they are expensive, I highly reccomend the motorcraft coils, I read through too many threads where the poster had just swapped the stock coil with 100,000+ miles with el cheapo brand EBAY, AZ, or Oreily's etc. even respected hipo brands like malory, splitfire etc. to have to swap them again 10, or 15k miles later seems in this case ford got it right (in comparison to the anon OEM makers)

cheers

and good luck

Kenn

 

Hello Kenn, you're not the only one - I've had this one about a month. New to the shift to allowing a computer to handle all aspects of a vehicle(previous truck was an 84 explorer). I've replaced all plugs with the exception of two in the far back as I couldn't reach em and the ones I did pull out were black, oily, and the electrodes were burnt. I'll have to check the wires as I was sure I had replaced all of them also but the coils the wires plug into in the front are what I'm told are either on their way out or are bad. Those I've priced out at $70 a piece and if I had it I'd replace em both but when you're trying to move on a budget, certin things take priority. I was lucky enough to get the tires free over a dispute with a Pep Boys manager(guy in the shop didn't mount the tire correctly and it almost came off the rim). It'll be one of those things I'll end up getting replaced when I get set up in TN.

-Matt