Explorer Low Power Smell Gas

[osteologation]

I picked up a clean 1994 Exploder the other day. I got it supercheap so I wasn't worried about any issues. Well it runs but doesn't have a ton of power, even for an explorer, and it smells of gas but doesn't seem to be leaking and there are no obvious signs of wetness underneath. Also when low on gas prev owner said it would sputter on left turns. I've read that a split in the soft line can cause issues like this. If anybody has had this problem I'd liek it hear about it thanks.

 

[osteologation]

I'm also reading that a bad cannister solenoid could be causing problems because the tank would not be venting. Can loosening gas cap relieve that?

 

[MrShorty]

Loosening gas cap probably won't help the CANP solenoid do its job. The CANP solenoid opens to allow gasoline vapors in the charcoal canister to be drawn into the intake and burned. If the something is preventing the CANP from opening (or otherwise blocking flow from the cannister to the intake), the best thing to do would be to fix it so it can vent to the intake.

Be sure to check carefully for leaks. I've seen cases mentioned where the leak was on top of the gas tank or the engine so that the gasoline was evaporating before it was visible.

 

[osteologation]

i meant as a troubleshooting method to see if it would help. and it didn't.

 

[osteologation]

i probably have 2 separate issues here. first the leak and secondly it msut need a tune up badly.

 

[JDraper]

You might want to check the fuel pressure regulator. When they go bad the diaphragm breaks and it sucks fuel into the motor through the vacuum line causing lousy performance and horrible fuel mileage. It's easy to check. Pull the vacuum line of the fpr and check it for presence of fuel. If it's got fuel in the vacuum line, the fpr is bad.

 

[osteologation]

well i changed the plugs and wires and its even worse it seems. i will check fpr tomorrw along with changing fuel filter and checking fuel pressure.

 

[osteologation]

fpr is not sucking gas. one of the plugs i put in was cracked, explains worse running. didnt check fuel pressure yet. checked codes and i got a lot of them. but i had pulled several sensor plugs while running to troubleshoot. so i reset computer to reset codes. whats interresting is if you pull the tps and force the system into open-loop operation it still misses and runs exactly the same, except no o/d or torque converter lockup. im going to do a compression test as i am pretty sure cyl 1 is the culprit. it has spark. since it doesnt smoke at all i think the injector has failed or is plugged. how do you test injector? i need to know how to test injector and to see if there is power to injector. thanks.

 

[osteologation]

i cleared the codes and after driving it around i get a 186 CM? (the second set of numbers) i got a 539 for koeo but i had left the air on. the cel only comes on when cruising down road. if it sits at a stop light it will go out. i took the maf off and cleaned it with some lens cleaner (all i had). didnt help. i will get some contact cleaner and do it right, it was filthy. i still got to get fuel pressure tested.

 

[osteologation]

checked fuel pressure. got about 19lbs at idle and less than thirty under wot. also removing vac line to fpr gives less than 30lbs. is it possibly a bad fpr or am i looking for a new fuel pump?

 

[osteologation]

bump

 

[MrShorty]

Do you trust the pressure gauge? If you trust the gauge, then those pressures are too low. The next step in diagnosis is to determine if the low pressure is a bad FPR or something upstream of the FPR. To do this, we check to see if the FPR is opening during the low pressure condition. When mine did that, I removed the return line from the FPR, ran the pump briefly to see if any gas came out of the FPR.

Alternatively, find a rubber section of the return line and carefully clamp it off. If the pressure goes up, that indicates the FPR is opening too soon. If the pressure stays the same, then the problem is upstream of the FPR.

 

[osteologation]

well the fpr gushes fuel out at idle and if i pinch the line it gets upto 50lbs real quick, and the miss smooths out

 

[osteologation]

i swapped out another fpr from a parts motor i got. and i got 32 at idle and 40 at wot.
idle vacuum is around 20 lbs? but shows in the "good" section on guage. i checked no 1 cyl that i felt was missing for comp. 140lbs. i checked 2 more cyl and they both were over 120.
i have a light to test for signal to injectors. i checked no 1 (what a pain) and its getting a signal to the injector. im not 100% that its missing. it idles smooth but when you drop in gear and take off it sounds like it is missing. i checked for spark and it had good spark.

doesnt have a but load of power either. it has 3.27 so i know it wont be a rocket, but i had a 91 sport with 3.55 gears that seemed a lot quicker. it takes quite a awhile to get to 75mph. it will spin the tires on dirt now, whereas it wouldn't before. and when you take off, it just slightly stumbles. it seems like it launches hard then just falls abit and the picks up just a little.

cats maybe? has great vacuum and doesnt throw CEL now. i know it wont be fast but i feel it should be better than it is. thanks for all your help.

 

[MrShorty]

Those fuel pressures look a lot better, so I guess the FPR was bad.

If I thought my engine was missing, I'd probably run a cylinder balance test. Your '94 PCM can run a cylinder balance test for you. See the stickies in the EEC-IV forum which should describe how to get the PCM to enter cylinder balance test mode. That will tell you if the computer can see the miss and which cylinder is missing.

 

[osteologation]

Those fuel pressures look a lot better, so I guess the FPR was bad.

If I thought my engine was missing, I'd probably run a cylinder balance test. Your '94 PCM can run a cylinder balance test for you. See the stickies in the EEC-IV forum which should describe how to get the PCM to enter cylinder balance test mode. That will tell you if the computer can see the miss and which cylinder is missing.

i will try that tomorrow. have to get that injector plugged in. its getting late and i gave up.

on a side note. my parts motor is supposedly a 92 4.0 from a ranger. the intake looks exactly like my 94 except it has no egr provisions. just curious if you knew what that was about.

 

[MrShorty]

Ford didn't put an EGR system on the '92's, but decided to put them on for the '94's.

 

[osteologation]

alright i did the KEOR test
111 for CM
172 and 536 for KOER
i was almost hoping for 536 as the cruise doesn't work.
and 172 is O2 not switching, is/was lean.

now i imagine with my low pressure it was running lean.

also i did the pulse test and it gave me the "1" code. so i would venture bad/plugged injector. visually verified spark, has 140lbs comp, and the injector is getting a signal (with goofy tester that plugs into injector harness). i felt it stumble 5 times. 1 time was jsut barely the other 4 were very noticeable. so maybe another one gonna go? im running injector cleaner with every tank right now.

thanks for your help.

 

[MrShorty]

KOER 536 might point to a problem with the BOO switch. Most commonly it would indicate that you neglected to press the brake after engine id.

now i imagine with my low pressure it was running lean.

I thought we had your fuel pressures back up to normal? Did you preheat the O2 sensors before the test by running the engine? A "cold" O2 sensor can give you a false KOER 172.

Didn't cylinder #1 have a higher compression than the others? I don't remember what it's supposed to be, but it seems that all 6 six cylinders are supposed to be within a certain percentage of each other.

 

[osteologation]

number 1 as i remember was around 140 and the other 2 i checked (no 2 and no 5) were over 120 but i didnt get exact i just was happy to seem em over 120.

engine was warmed up when i did the test. i do have another o2 and a set of injectors form a running motor.

the BOO switch, i believe from an aftermarket remote start that was tied into it. i removed the remote start and it didnt throw that code. cruise is still non functional, but thats another problem for another day.

now i had thrown a bosch platinum set of plugs into it that were all carboned up. all but number 1 are now tan. im going to swap injector for numebr 1 and swap that o2 and see what happens. thanks.