88 lx 5.0 needs help!
 

I have an 88 lx 5.0 hatchback, 5 speed tranny. Stock except for bbk shortie headers, bbk cold air intake, accell ignition and wires.
Two days ago the stock fuel pressure regulator blew, started pumping gas through the vacuum port, straight into the plenum. Motor flooded out and died instantly, since then I replaced the bad reg with oem part, turns out it was a new BAD part, put another one on today, it works fine, but now I have a dead miss, sounds like at least two cylinders are dead, no knocking, no rattling. Doesn't sound like a bent pushrod, changed plugs before I put the first replacement reg on, haven't pulled the plugs back out after the second new reg was put on though. Any thoughts would be great.
If you need more info about the car just ask, I will tell all I can, only had it about a month, not sure about much history with it, but I will share all i can.

Re: 88 lx 5.0 needs help!
 

change all the plugs out again

Re: 88 lx 5.0 needs help!
 

Yeah change the plugs again. If that doesnt work check the temp of the header tubes to find a potentially dead cylinder.

Re: 88 lx 5.0 needs help!
 

Thanks for the direction guys. I work tonight so I'll try swapping out the plugs first thing in the morning.
By the way, do you think it's possible fuel would have gotten into the sensors through the vacuum lines and ruined them? like the MAP sensor and the rest that have vacuum lines attached?

Thanks again, I'll let you know what I come up with.

Re: 88 lx 5.0 needs help!
 

I hydrolocked my 300zx last summer and it kept fouling the plugs cause water was pooled in the intake manifold. I removed all the spark plugs and jacked the car up on one side high as it would go to make all the pooled water run out of the intake and into the cylinders, then I turned it over in 20 second burst a few times and that seemed to work pretty well. All the water shotout the spark plug holes.

Re: 88 lx 5.0 needs help!
 

This one was hydrolocked also, after the original regulator blew, before I changed plugs, when I took the old (original) plugs out, I turned it over in several short bursts and blew the fuel out of the cylinders, it was fuel. Yours was water?

Re: 88 lx 5.0 needs help!
 

Yeah I drove through some deep water and well you know the rest.:eek:

Re: 88 lx 5.0 needs help!
 

Well, I changed plugs out again, to no avail. EGR was bad, replaced it, as well as TPS, still not fixed. Noticed there were two vacuum solenoids on the right front inner fender on the the rear of the engine compartment that were damp with some gas, presumably from where the reg went bad and flooded the plenum and vacuum lines, I took them apart and cleaned them, that seemed to do the trick with getting the car running right and taking out the majority of the miss. But now I have severe idle surge, almost dropping to the point of killing itself, also running super rich. I've tried almost everything I can think of to narrow the problem down, but am having a heck of a time with it. Any ideas?
Keep in mind, I have just bought this car and don't have much idea about what mods previous owners have done to tune the car.

Re: 88 lx 5.0 needs help!
 

did you replace the tps and set it? surging idle is a problem as old as the 5.0. if you go through a search for surging idle you probably will find quite a few threads. also before i had any mods, i had a surging idle and chased all the gremlins. i got rid of mine with a 1/8th in drill bit through the throttle blade. good luck.

Re: 88 lx 5.0 needs help!
 

thanks for the reply baily_57, tomorrow is my day off so I plan to work on the car all day, hopefully I can chase my demon down, plan on setting the tps voltage, checking fuel pressure, checking compression, and possibly trying the codes, not throwing a check engine light tho, could mean the previous owner installed a chip or removed the bulb tho. Hopefully something will turn up tomorrow though, I am about at wit's end on this problem. Getting super frustrated. I'll post what I find. Thanks again.

Re: 88 lx 5.0 needs help!
 

Might be a good idea to throw in some new o2 sensors.

Re: 88 lx 5.0 needs help!
 

Haven't checked the TPS voltage yet, but bought a code reader today, turns out I had a few codes, IAC valve, coolant sensor, which was my fault because I unplugged them whileengine was running, but also the fuel pump relay circuit was bad, pump is running all the time, which to my thinking would explain the rich condition and also the idle surge, if the motor is loading up with fuel at idle it would pretty much be flooding itself out. Correct? Also, the fuel pressure regulator is bad once again, I guess the pump running all the time is just building up too much pressure in the line and the diaphram in the reg is blowing out.

Re: 88 lx 5.0 needs help!
 

It's supposed to run all the time when the engine is running.. What makes you say the FPR is bad again? You need to set the TPS, before we try to point fingers at anything else....

Re: 88 lx 5.0 needs help!
 

ECM says relay is bad. Trouble code 87. Also, even with the relay removed, fuel pump still runs when ignition is turned on, TPS voltage is now set at .96. Car runs, but still surging after about 3 minutes, also, fuel injecters are getting wet with fuel, on the outside. Not a leak on the fuel rail, it is a mist/smoke coming from around the injectors at about five minutes idle time, after the motor starts loading up with fuel.

Any idea why the fuel pump would run all the time (without the relay)?

Re: 88 lx 5.0 needs help!
 

two things......The pump should NOT run with the relay out. Your referring to the relay under the seat right? That is the fuel relay.

Second, if you see fuel mist from the injectors, something is def wrong. I would pull the injectors and get them tested or serviced, where on the injector is the fuel mist coming from, can you see it exactly?

Re: 88 lx 5.0 needs help!
 

Yes, the fuel relay under the drivers' seat, the mist/vapor is coming from not from the injector, but from the intake around the injector seat, but only after the motor has started loading up with fuel, running rich.
If the fuel pump were running correctly, would it pulse on and off, or would it run all the time?
I know that GM fuel pumps pulse on and off based on back pressure in the line.

Re: 88 lx 5.0 needs help!
 

Your injectors control the pulse of fuel on the stangs, not the pumps. Swap the regulator out and check the injectors O-rings, make sure you don't have any dry rotting and need replacement...

Re: 88 lx 5.0 needs help!
 

Ok, thanks. I will try that, I've gotta work the next coupla evenings. It will probably be saturday before I can do much more work to it. I'll post what I find. Thanks.

Re: 88 lx 5.0 needs help!
 

Ok, more info. Took the Ignition module to be tested today, turns out it was bad, replaced it with a new one. No change to my current problem. (just a refresher, pump relay out and pump still runs, two hots, one constant, one switch one power) Turns out the switch on power is the supply to the fuel pump, pink and black, started checking the harness, past owner had byassed inertia switch, hacking into the pump harness with direct switch on power, also bypassing the relay. I fixed all the hacking, put new relay in, but now have no power to the pump.

Trying to track down problem, this is what I have so far:
1. at the relay, there are five wires, one is constant, two pink and black (one runs in harness towards front of car, unsure of where it goes, i would like to find out if anyone knows, the second pink and black goes to fuel pump), one wire comes into relay from the inertia switch, and one goes from relay to the ecm.
2. Constant power is constant, obiously. Switch on sends power through the inertia switch back to the relay, then this power goes to the ecm.
3. How does the ecm open the gate to the pump?
4. If I probe the wire going to the ecm with a test light, the relay clicks open and the pump runs, still doesn't prime and shut off like I think it should when the car isn't running though.

Anyone have a GOOD wiring diagram of the fuel relay circuit? Good being the operative word there.

By the way, code 87 is now the only code being pulled.

Re: 88 lx 5.0 needs help!
 

Ok, I replaced the EEC relay, still nothing from the pump. I shorted the test terminal out on the test plug and the pump fired up and worked fine, this leads me to believe the EEC is either not grounding good, or is fried. Anyone have anyidea where the EEC grounds at, other than the little black wire behind the kickpanel on the passenger side? I still don't want to believe the EEC is bad because everything else works on the car except the fuel pump and the cruise control, it just seems the EEC is not sending the signal to open the gate in the relay and send power to the pump, I have to believe that it is a failty ground. Any suggestions?

Re: 88 lx 5.0 needs help!
 

Ok, I finally made it to the junk yard today to get another EEC, the guy there told me not to replace the computer, he says he thinks there is what he calls a "multifunction module" on the car that controls fuel pump, a/c compressor, cc, and cooling fans. He told me that he believes starting in 86 they put these on all ford module excluding pickups, says it sounds like it is bad, also says he thinks it is on the left front of the engine compartment. I have looked and can find nothing so far, but it was getting dark out and I have no garage. Anyone have any idea what this "multifunction module" is, or where/if this car has one? It sounds to me like this should be on a newer model to me and not the 88 eec-iv speed density.

Any help is really appreciated. Thanks.

Re: 88 lx 5.0 needs help!
 

Well I have never heard of a multifunction module...

Re: 88 lx 5.0 needs help!
 

Thanks Dark_5.0, I haven't heard of on either, other than OBD II.

Re: 88 lx 5.0 needs help!
 

Alright, I replaced the EEC today, got the fuel pump running, like it should be. Finally! Now it is just time for a tune up and voltage check of tps again and another stang will return to the road! Idles a little rough, but plugs need changed again do to fouled condition, possibly replace IAC and MAP sensor. Maybe tweak the timing a little and install an adjustable fuel pressure reg. and I'll be one happy man. Next is a little body work. I hope to get it painted this coming spring. I'll post some pics when I can, maybe try to do the before, during, and after thing most of us always wish we would have done. I'll try to keep updating as I go. Thanks for all the comments.

Re: 88 lx 5.0 needs help!
 

Did you check all your gaskets for leaks around the fuel system?

Re: 88 lx 5.0 needs help!
 

Chap, thanks for the reply. I just replaced all the fuel injector o-rings and pintle caps, also while I had the plenum off, I went ahead and pulled the intake and replaced the intake gasket, turns out it was leaking in several places also. I would say this will fix all of my problems, when I put the car back together, I had one injector that is leaking, so I need to fix that before I can drive the car. Bad thing is, I had to start back to work on Sunday, my next day off is Friday before I have time to work on it again. But yes, I think it will be an easy fix. Thanks again.

Re: 88 lx 5.0 needs help!
 

Alright, I know it has been awhile since I last posted. I have the car running great. I fixed the fuel problem, and since I have moved on to even greater things. The clutch was givving me fits, harder than hell to depress the pedal, I pulled the motor, turns out the car was originally an automatic, they did a great job converting it to a five speed, but they used an 83 t5, no big deal right? wrong! it wouldn't have been a big deal if they had used all the proper parts when they converted it, but they used an 83 flywheel and an 88 clutch kit. Why is this a big deal? well, it turns out the earlier model used a ten inch clutch, whereas the later model used a 10.5 inch clutch. big difference. The center of the clutch disk was always grinding on the flywheel and therefore the clutch was never fully engaging. I went with the ten inch clutch kit, turned down the flywheel to get rid of the wear and burn marks, and wow did it ever liven the car up!
As of now, the car is in the body shop, complete paint job! A buddy who has his own garage owed me a favor or two, so he is re-doing the whole car for 1200 bucks, can't beat a deal like that! I hope to post a few pics after the rejuvination is complete.

By the way, does any one know where I can get a good deal on some new upholstery, I have some new seats to put in but the upholstery is so damn expensive.