Hey Fellahs, I just bought a 93 xlt with the efi 5.0, when I got it the CATS were clogged so bad the engine wouldnt even idle. I have fixed the exhaust etc. but I am having a weird problem. The truck seems to run ok, has good power, good compression, hitting on all 8, but... it is like there is no choke on the cold start. I have to keep it idle up with my foot until warm. On initial start or when warmed up it starts as soon as I touch the key, If it quits before its warm I have to turn it over (quite a while) until it starts popping then push the pedal and it takes right off. When its warm it runs like a bear and doesnt quit, pop, stutter etc. The only thing it seems to do thats odd is if I am cruising at say 55 and let my foot slowly off the gas it sorta surges like its out of gear and revs itself up and down (by about 500-800 rpm rrrRRRrrrRRRrr) as soon as I touch the gas is goes right on about its business. I am assuming the o2 sensor is bad since the cats were basically black gumballs inside. The old air filter was black with oil from the recirc while it was backed up, is thier a sensor anywhere in the intake tract that could be bad? Or, any other sensors that could cause this, or that I should replace after being drivin so long w/backed up cats? This was a well maintained single owner vehicle driven by an older gentleman (dont think it ever saw > 2500 rpm before I got it) with just minimal rust above the rear wells, I really want to fix it up right but I am a poor boy workin 12 on 12 off. I have replaced all stndard tune up part (a/f, o/f, oil, plugs, pcv, etc etc.) I've read over the whole ford fuelinjection site and understand some of it and cant really find anything through searchs to match my problem, any help much appreciated. I havent found a place to pull codes for me and wont have time to do the manual blinky test till this weekend but I dont want to ruin this engine driving 170miles day back and forth to work.
ugh sensors, which should I change
- Thread starter ANFO
- Start date
Disclaimer: Links on this page pointing to Amazon, eBay and other sites may include affiliate code. If you click them and make a purchase, we may earn a small commission.
BLADE262US
Active member
It could be the IAT intake air temp sensor that is mounted in the intake near the front drivers side if I remember right there about $35 bucks but could be the problem if you had that kinda build up . 
/emoticons/[email protected] 2x" width="20" height="20" />
/emoticons/[email protected] 2x" width="20" height="20" />
Seabronc
New member
Ditto on Blade's comment: Here is a excerpt from a writeup on EFI engine operation at ford foolinjection. You can go there to read more: http://fordfuelinjection.com/?p=64 Caution if you are tempted to buy any of his products. They are great, but you will usually find his total lack of ability in the customer relations area to be a real aggravating experience. He definitely will not respond to emails and often takes months to ship an order while he sets on your money. The bottom line is that you can get anything he has other places without the aggravation, that is sad but true. I had to file a dispute thru PayPal to get him to return my money on an order. OK, off my soapbox, other than that he has some real great information on the EEC system.
Cold Start & Warm Up
The engine has just started and we have to get adjusted. Well EEC does anyway, this strategy is kind of like you waking up with a hangover next to a stranger. Where
Cold Start & Warm Up
The engine has just started and we have to get adjusted. Well EEC does anyway, this strategy is kind of like you waking up with a hangover next to a stranger. Where
firelt90bronco
Ask me about my job
Or the egr is clogged.
thanks fellahs, I will replace the IAT and egr as well as o2. Is the EGR hard to change? I've read that fuelinjection site and downloaded a bunch of the docs but after a while it just makes you brain hurt (esp. that FoMoCo PDF on the strategies lol, I keep seeing that guuy saying "Bueller... Bueller.." as writing that one) . I just had to get gas yesterday for the first time after initial fill up, I'm only getting 8.3 MPG so I definately have some issues. I've looked everywhere for vacuum leaks tried spraying carb cleaner down the lines but it never stumbled. I also ran 2 bottles of chevron techron through in the first tank. Do you think bad sensors would cause the uber bad gas mileage (all 65-70mph highway driving)? Or do I maybe have bigger problems
Is thier a particular brand thats better to get for the sensors? I've gotten a lot of cheap parts from P.A. but I dont want to get crappy sensors
One other thing I've noticed, the temp on this bronc never goes more than the needles width (maybe 1/16th to 1/8th inch) into the normal range. I've read on that site injection site that people use lower temp t-stats to trick the ecc which it said was bad, this engine doesnt look like a wrench has ever been turned on it so Im wondering if the t-stat is just stuck open but we all know how accurate these in dash gauges are.
Is thier a particular brand thats better to get for the sensors? I've gotten a lot of cheap parts from P.A. but I dont want to get crappy sensors
One other thing I've noticed, the temp on this bronc never goes more than the needles width (maybe 1/16th to 1/8th inch) into the normal range. I've read on that site injection site that people use lower temp t-stats to trick the ecc which it said was bad, this engine doesnt look like a wrench has ever been turned on it so Im wondering if the t-stat is just stuck open but we all know how accurate these in dash gauges are.
well, I wont have to replace those sensor after all, driving home down the interstate last night I started hearing a tick/clunky sound (collapsed lifter??) and then I watched the oil pressure gauge instantly go to 0, like it was waiting for me to look at it. Got to the side in rush hour traffic as soon as I could but I dont hold much hope for that engine, I cant believe I just dumped all this money into to it, living on raman noodles since my last pay check and it goes and does this to me, typical woman.
I ran the codes etc. and wound up replace TPS, O2, EGR sensors, no more check engine light and it runs great. I practically dissasembled the engine over the long weekend to clean it all up but man it is running great now, with oil pressure to boot.
