Discussion in '2.3L (N/A & Turbo) Tech' started by amorgan93, Oct 26, 2010.

  1. Bought a 1988 mustang lx 2.3 2 days ago. after looking under the hood, trying to figure out why it runs like crap, i noticed the o2 sensor wasnt even plugged up in the car. The previous owner replaced the exhaust on this car (halfway). but the manifold is cracked and plugging up the o2 sensor didnt help anything. The car runs rough as hell, and has about the power of a 5hp briggs and straton lawn mower motor. The car somehow out of a miracle spun the tires in my yard (which was wet and muddy) and spun pos, didnt dogleg. But it has the rear end for the 2.3 in it because the axles only have the 4 lug as opposed to the 5 lugs on the 5.0 cars. The car also doesnt move at all when shifted into (D) from P, but will work in regular D. If i have it in D, and push it forwards into (D) it will click in place, but has tension on it, pulling back. It also wont stay in 1, it just shifts up to 2 when i let go, which leads me to think the shifter linkage needs adjustment. And the car is burning rich. The fuel guage shows either F or E, nothing in between. The coolant temp guage doesnt work. And when turning the ignition to the "on" position, no ligts come on that indicate that the computer is even working. No check engine light, nothing. The previous owner said he had to remove the guage cluster cover thing because a bulb for the speedo burned out, and there is evidence that he did because he didnt put the screws back in it to hold it in place. Is it possible he disconnected the lights for the computer (check engine, etc.). Could the computer be **** shot and just in "limp mode" or whatever you call it? Also i know my vacuum modulator valve is bad because the engine is sucking up transmission fluid into the throttle body.

    where do i even start? please help me because ive had this car for 2 days and already want to stick 20 pounds of ammonium nitrate on it.

    and if it helps identifying the car in any way, it has cruise control on it. doesnt work because the cable connected to the throttle body is broken.

    and there is evidence, im almost 100% sure the motor in it now is not the original. the odometer shows 311,000 miles, but im not sure it wasnt pulled from a car in the junk yard, considering the car has mis matched seats and mis matched rims.
  2. The O2 sensor does provide feedback to the computer for fuel management - even if it looks good - it could be bad and not giving the signal the computer is looking for. If the computer sees no voltage or no fluctuation from below .5 volt to above it and back, it'll assume the O2 is either bad or something else is wrong and throw the CEL. I have an A/F guage in my car and I can always see what my O2 sensor is telling the computer - at idle or constant cruising it rocks back and forth several times a second. This may be part of the problem, a failed or slow O2 sensor. However, the O2 may be reporting accurately and the problem may lie in other areas - the MAP sensor measures intake vacuum and reports that to the computer - if it is bad / broken / not connected it'll throw the computer too. Also, the throttle position sensor, if not connected or adjusted properly will wreak havoac too. Another thing that can throw the computer would be the IAC (Idle Air control valve). It could be plugged up and not allowing the run to run right. it's on the back side of the throttle body and has a 2 wire connection to it. Held on by 2 8 mm bolts. You can usually unplug it, pull it off, and there is two ports on it and a motor that opens and closes a valve between. if this is gummed up and not able to seal, this might be part of the problem you can clean it with carb or brake clean and use a screwdriver (carfully) to ensure that it moves smoothly.

    All Mustangs from 87 to 93 left the factory (with possible exception of "special production" cars like the 93 Cobra or a Saleen car) with 4 lugs on all 4 corners. 5.0 or 2.3. Many do swap out the 94/95 Mustang 5 lugs onto the Fox body - it's a common swap.

    Not familiar with the Mustang auto trans, but I suspect that is the right assumption there

    There are 2 wiring harness connections from the dash to the guages. you are obviously getting power to the right side - via the fuel guage moving. Does the oil pressure move? does the volt guage move? If not, it is possible that the left side connctions are not hooked up. However, Lots of times the water temp guage isn't working because it's disconnected from the engine. It isn't very accurate and lots of people use an aftermarked guage. the sending unit is on the drivers side - back of the block - below the cylinder head, in the block. the oil pressure sending unit is near it too. I suspect that if the engine was swapped the wire to the temp is not connected and should be hanging around in that area. probably right below the steering column. check that and see if you see it connected or not.

    As for dash lights - i really suspect the bulbs are burned out or MIA. Easiest way to rid the CEL is to remove it. He might have used the bulb from the CEL to get speedo light back - and solve his CEL staying on problem.....It is possible that the computer is malfunctioning, it does happen, but i suspect it isn't the problem - most likely sensors it's relying upon are either bad or not connected.

    As for the posi rear - it is possible that the car may have an 8.8 from a 5.0 car (I installed one in mine). Highly unlikely, but possible. I know tht sometimes if the conditions are right - you can get posi symptoms on an open rear just because the friction to both tires is the same.

    below is a link that shows the difference between an 8.8 or 7.5

    Mustang 7.5 & 8.8 Rear Axle info - LRS Blog - Read Here Shop Here
  3. thanks for all the info. ill be checking those connectors whenever i get home. The oil pressure does work though but i never even payed attention if the voltage meter works. Ill also look to see if i have the 7.5 or the 8.8 but its probably the 7.5 and like you said, just spun because friction was the same on both sides. There is quite a bit of plugs on the harness that are not plugged in. So ill take some pictures of these plugs and maybe someone on here will know what they go to.
  4. Pulled the part of the dash that covers the speedometer and other guages. The reason why I'm getting no lights for check engine and stuff is because there is no lighting asseMbly for those lights and there are no plug ins for it. Very confused now. And yes the oil pressure and volt meter work. The lights from the ecu are not built into the speedommeter part but are nonexistant. Wow I'm confused
  5. All the warning lamps are infused on the back of the cluster. some are dash lights, others are various warning lamps - example would be top center of the cluster is the high beam. best way to find out which is which is by taking a flashlight, taking off one of the bulbs at a time - putting the beam in the whole and look at it from the front (a dark room helps) - if you see a warning lamp then that is what it's for. The check engine, low oil, and a few others (on 90 to 93 clusters) are found almost directly below the tach. The high beam, and battery charge light is in the middle between speedo and tach.
  6. To get the cluster out from where you are now - there are 4 screws that hold the cluster in place one on each corner of the cluster. once you undo that you can pull it forward enough to get your hands behind there - there are 3 things tht need to be undo and the cluster comes out. on each side is a bulk electical connector - they unsnap by pushing the tabs at the ends. The other is the speedometer cable. Sometimes its easy, other times it can be a ****. Feel around the back of the cluster to where the cable connects, somewhere at the bas and on the cable, there is a small tab - you have to press that in with a finger or two and kinda pull the cluster toward you or push the cable back - once it releases it's a done deal.
  7. based on what you are telling me - i suspect your problem with the temp guage is that it is not hooked up at the sending unit on the engine. the sending unit is mid way up on the drivers side of the block between the oil filter and the back of the block. look around for a small wire hanging around in that area. you mentioned you think the motor was replaced - chances are they forgot to plug that one in. there is another water temp sensor - it is for the electric fan and it's found near the front - mounted on the intake near the alternator - this is not the one that goes to the guage.

    your fuel guage problem is most likely the anti-slosh module is malfunctioning. the anti-slosh module is located on the back of the instument guage panel - on the upper side behind the fuel guage - it looks like a miniture chip that snaps in sometimes it goes bad or the electrical connection is bad. whenyou have the cluster out - remove the anti-slosh and clean the contacts and snap it back in. the 87 to 89 version has a similiar one but it is held in by one screw, while the 90 to 93s click in with a plastic connector.
  8. The only lights that come on in the entire car are the amp light, the e brake light, the high beam, and the seat belt. There are no other lights whatsoever. No speedo light, no check engine, no check oil, no tach light. And ther is a check engine and check oil light beneath the tach on my cluster and the amp and e brake and high beam run in the middle of the tach and speedo. However there is also a cluster of lights directly to the right of the steering column and is completly seperate from the guage cluster. These lights are not hooked up and have no connectors, no place for bulbs. Nothing. Just 4 orange screens that say check oil, low coolant, low fuel, and washer fluid. Also the switches on this cover thing are only the light switch and hazard light switch but my car has the connectors for the other switches, whatever is underneath the light switch and the hazard switch
  9. Haven't been online all weekend - watched the 1st video - can't turn sound on until boss leaves - but just looking at it, the 4 lens to the bottom right that you are referring to is a common thing. I have the same and pretty 99% sure ALL 87 to 89 Mustangs have the same cover - 2.3 or 5.0.

    The difference is that the extra warning lamps was/is a special GT and police package upgrade - and is part of a special instrument cluster - but they made and used the same cover for everyone. I too noticed it at first and wondered why it didn't light up. I managed to acquire one out of a junkyard - was looking have the 140 Speedometer, and they just put an 1989 GT in the yard - I snagged it because it had the 140 Speedo - but notice the extra panel. The link below is an example of it found on E-bay.


    Most clusters do not have the 4 light package. I managed to snag one and merely plugging in the cluster on my 88 - i've only managed to see the check oil light on the 4 light deal. the low fuel hasn't come on and i've ran it pretty low. probably need a sending unit from a 5.0 to get that to work.

    All the basic warning lamps are still on the back of the cluster - and only can be seen when lit up.
    As for your headlight switch - looks like the big harness got a little toasty - seen that a few times - you might have a bad connection in the wiring or the switch is bad or both. you might need to rob the pigtail harness out of a junkyard car. the dummy switch below the headlight one is just that - unless you have a GT - that switch becomes a foglight switch - and the small harness controls that. Discount / Autozone sells new headlight switches and ironically the GT or 5.0 switch is usually stocked and is cheaper than the non-stocked 2.3 / LX light switch - the difference is tht you get the acutal movable switch for the foglights. I was in a bind when mine was out - and being the cheap person i am, got the GT switch - the headlight part functions fine and the FOG lamp moves but obviously doesn't do anything.

    The Hazzard switch is just that and the dummy switch below that is a spot for 1 of two things (if equipped). My 88 is a 'vert and that is the location for the power top up and down switch. The other thing that would be there would be a rear window defrost - again another option.

    to get the dash lights to work - you must have the headlight switch installed and working. I know that one of the small wires pulled out of the back of mine on an install and it controlled the dash lights - i simply plugged it back in and lights worked - but you need to have the two wire harnesses plugged in to the back side of the cluster.

    more to follow
  10. also, here is an 85 MPH GT cluster with the extra warning lamps.


    my opinion - not worth the money unless you find it at a yard for less than 20 to 30 bucks - unless you find a 140 speedo. keep in mind that there are 2 cluster types - one for the 87 to 89, and the other for 90 to 93. They do not interchange even though they look the same from the drivers seat. the 87-89 are flat accross the bottom and the 90 to 93 have an arc cut out to clear the airbag.
    If you score a 140 speedo cluster it'll bolt in the 2.3 w/o problems but you will have to rob the 4 cylinder tach and swap it out. the 4 banger tach only goes to 6000 while the 5.0 goes to 7000. the tach pops out fairly easy.
  11. As for the miss. COuld be a few things. I'd check 1st for a bad plug - bad plug wire - bad distrib cap.

    unplug one wire at a time - fire the motor and see if it gets worse. if you unplug one wire and start it and it runs worse, stop the motor - plug it in, then unplug the next one, and so on till you find the one that the cylinder that doesn't change when you unplug it. That is where the problem lies, check the wire and plug to see if it is fouled or burnt / problem. also pull the distrib cap and see if one of the contacts on the inside is corroded.

    If that doesn't yield a result - it could be a bad injector or the injector plug is off or corroded. the front to injector wires are fairly easy to get to, and the back ones are a pain - to get to them you either need really skinny hands / fingers or you have to remove the upper intake - if that is the case, then this is the best time to disable the EGR tube - as you have to disconnect it for the upper intake to come off.

    but i'd look at the easy to get to and check stuff - like the plugs / wires / cap.