98 explorer with many problems, please help

ok, so i just inhereted a 98 explorer with a 4.0 sohc from my brother. the motor was replaced with one from a 97, but made the mistake of not hearing it run before put in the truck. so here is my problem, it runs crappy, not just at idle, but now it will not rev past 3500 rpms or go past 35 mph. also dumping fuel pretty badly into the exhaust, runs like timing is off and the fuel pump recently went bad. it has never run properly since we replaced the motor, and i have yet to do a compression check, but plan on it in the near future. we took it to a shop to have the transmission replaced and asked them to look at why it doesnt run properly and they said it was the egr, however they didnt replace it because they were jerking us around on the transmission (said it would be done by the weekend, and later that week said it was in the truck when it wasnt even in the shop, took a month to get it done) just wondering if there is anything worth lookin at, im sure its not just an egr at this point, but just my opinion. thanks for any info ahead of time

Who did the engine swap? Sounds like it either has a horrible vacuum leak, leaking fuel injector or injectors, spark plugs/wires/coil issues, or you have some sensors that are not connected or working properly. Since you can smell the unburned fuel in the exhaust I'd check first the general tune up items - plugs, wires, spark, air filter, and intake air tubing.

-Rod

well, me and my brother did the engine swap ourselves, although i wasnt there when he finished up putting it in, however its been like this for about 2 years and he just hasnt worried about fixing it, and its just gone downhill from there, spark plugs have been changed a couple times and so has the coil and plug wires. filter is a little dirty so it could prolly use changed but ive never seen a motor run this bad from a dirty filter, and its the stock intake piping as well. i agree that it could be a vaccum leak, but we have been all over the motor trying to figure out if and where a vaccum leak could be, ill be lookin into that better this weekend. the exhaust is kinda chopped and hacked together, and i believe when you read the codes it says one of the o2 sensors is bad, so i believe those need replaced too. intake gaskets have been replaced so the intake isnt leakin, and i believe the injectors have been swapped with the ones in the old motor at one point, the old ones worked fine, the old motor was a victim of a broken timing guide. ima go over it good this weekend, im just wondering if theres anything i havent thought of that could cause it to run poorly. also the maf isnt that old either, its been replaced in the past couple years as well. i do appreciate the input so far, but its just stuff ive been through so far, though those items will be gone over this weekend as well, but all ideas are welcome and appreciated.

You will also want to check the DPFE and make sure the hoses to it were not connected backward. It's been known to happen, although it usually causes a diagnostic code.

If you have access to a scan tool with the datastream mode though you might be able to get a bit better direction if you understand what the parameters mean and should be.

-Rod

well, im not sure what a dpfe is, but i can ask my bro, he knows alot more about the truck than i do, but i dont really understand anything about reading parameters for vehicles, i know more about the mechanics side of working on cars, not too much about the computers or parameters. but ill check into the dpfe, ima work on it some today, and ill post whatever i find if i can find anything. thanks for the ideas though

*update* i asked my bro about the dpfe, but he said he has had the lines both ways with no difference in running, lately it wont start, but when i put the key in and turn the ignition on or try to start it, the security light flashes pretty quickly, my mountaineer doesnt do that, and this is the first time ive seen the explorer do it, but it wont start, if i hit it with starting fluid, it will try, but not actually start. im stumped.

The no start with the flashing security light suggests that the key being used is not recognized by the PATS system as a valid key. Do you have a second key for the Explorer that had previously been programmed?

-Rod

no, thats the only key that we have for the explorer, is there a way to reprogram it or do i have to take it in to a dealership? is it possible to remove the gem module so i dont have to worry about a chipped key? im on kind of a tight budget for this one, but id like to get it running before winter as my other car is a camaro lol. and just another thought, when you would spray some starting fluid into the intake, it would sputter like it was tryin to start, but wouldnt run, im just curious if the unrecognized key cuts fuel and not spark or just cuts both? thanks for the info, so far it has been informative.

If you had two programmed keys you could program another key, but with only a single key, reprogramming will require a trip to the dealer or a well-equipped locksmith.

The PATS module is linked via the SCM bus to the PCM and the PCM will not allow the engine to start if a properly programmed PATS module is not connected to the bus. There is not an effective way to eliminate that security feature. I think the PATS just disables the fuel injectors and not spark, but I'm not positive on that. Not surprisingly the factory service manual is a bit vague on the operation of the system.

-Rod

ok, guess i gotta call a couple dealers this weekend about getting the key programed, i was hoping to avoid that, but it doesnt look like thats gonna happen lol. now before it stopped running it was running pretty rich all the time, is it possible to have anything to do with the chip in the key, or would that just be a different deal all together? just takin a shot in the dark. thanks for the info though, ima call a couple dealerships now.

Running rich would be completely unrelated.

-Rod

i noticed something tonight, if you leave the key in the on position long enough, the security light stops flashing so fast, it then seems to flash a code like when you check a code on the old chevys with the check engine light. anyhow, the security light seems to flash a 16. flashes once, pause, flashes 6 times the pause again, then repeat. so i dont know of any way to check what the code means, ive tried google searching it with no luck, maybe someone would have some info on it or a website i can try. thanks

Wow, this forum has some awesome information! I would be stumped on what is causing all the trouble as well. If I had to guess, I'd say it has something to do with the timing or compression since it is not burning off the fuel that gets into the engine.

I'm not sure how I missed your post with the potential Lamp Fault Code (LFC) for the PATS system.

Unfortunately the Factory Service Manual does not have a table describing the lamp fault codes. It indicates the light may flash out a code but only says to connect a diagnostic tool to pull down the codes which are different from LFCs.

-Rod